A materials scientist with a yeast allergy set out to make a yeast-free pizza dough that still rises like a classic Neapolitan pie.

Now, in a new paper published March 22 in the journal Physics of Fluids, he and his colleagues report that they've succeeded in their quest — although so far, the team has only baked disks of dough that measure about 0.4 inches (10 millimeters) in diameter and lack any sauce, cheese or other toppings. 

These tiny, naked pizzas allegedly taste "exactly like the yeast pizza," Ernesto Di Maio, a materials scientist at the University of Naples Federico II (UNINA) and senior author of the study, told NPR. "We tried it, and it was nice and crusty and soft," he told Science.

But Francisco Migoya, head chef at Modernist Cuisine, told NPR that he'd need to taste the yeast-free dough for himself to see if that assessment is accurate. "Yeast does so many things to dough, besides fermentation, like the flavors that you find, the complexity of aromas," Migoya said. Alessio Cappelli, a food technologist at the University of Florence, told Science that he also has doubts about the dough's taste and about whether this unique new leavening method will ever be widely used.

Related: Italian physicists wrote a 'perfect pizza' equation, because not all heroes wear capes 

A classic Neapolitan pizza dough contains flour; salt, for seasoning; water; yeast; and sugar, for the yeast to snack on. As the yeast gobbles up the sugar in the mix, the live microbes release carbon dioxide that gets trapped in the sticky dough, causing it to swell up with gas. When the pizza dough gets baked, the yeast dies off in the extreme heat of the oven but these bubbles of gas remain trapped in the crust, giving it a light, airy texture.

"The aim was to try to make the same texture that we love so much in pizza without a chemical agent," Rossana Pasquino, study co-author and UNINA chemical engineer, told Science.

To achieve this, the team made pizza dough using the classic recipe, minus the yeast and sugar. They then placed a small sphere of the dough into a toaster oven-size autoclave, which is a kind of a pressurized oven often used for sterilization to kill bacteria, viruses and fungal spores, according to NPR. 

The researchers then pumped gas into the autoclave, to fill the dough with bubbles, and raised the pressure as high as 10 atmospheres before carefully releasing that pressure, at exactly the right moment. "If you are too late — you reduce the pressure after the dough is solid — then it cracks," Di Maio told Science. "If the pressure release is too early … it collapses." Di Maio uses a similar technique in his lab to inject bubbles into polyurethane, a synthetic polymer, NPR reported.

To ensure the temperature of their dough matched that of a typical wood-fired pizza, study co-author Paolo Iaccarino, a UNINA graduate student and part-time pizzaiolo, or pizza maker, measured the internal temperature of baking dough at the pizzeria where he works. 

Following their initial success with teeny-tiny pies, the team has now procured a larger autoclave, capable of making normal-size pizzas, Science reported. Their dough-making method isn't really accessible to autoclave-less home bakers, but in theory, it would save people time waiting for their dough to rise, Pasquino told NPR. Plus, it could someday be used to make tasty pizza for those with yeast allergies, Iaccarino said.

If you're interested in making yeast-free pizza dough but don't own an autoclave, fear not! You can also make yeast-free dough using other raising agents, namely, baking powder and baking soda. In a dough mix, these ingredients also generate bubbles of carbon dioxide, as yeast would, but they won't achieve the exact same texture or taste as a yeasted dough. An acid, such as buttermilk or lemon juice, is often added to such recipes in addition to the raising agent, NPR reported.

Read more about the yeast-free pizza dough at NPR and Science. 

Originally published on Live Science. 

From science experiments to home economic assignments to baking cookies with grandma, you need a reliable set of measuring spoons that will ensure precise measurements of all the ingredients. Here are some of the best measuring spoons including sets designed especially for the classroom. The best is the Spring Chef heavy-duty measuring spoons. These are made from stainless steel to keep from corroding over time and have more narrow spoon bowls to make it easier to reach inside small or narrow jars and containers. 

The Spring Chef heavy-duty measuring spoons are the best because the bowls are oblong instead of round to make it easier to get into all sizes of jars and containers without a problem. They aren’t too deep, either, so narrow openings in spice boxes are easy to get into, also. On the handle of each of the six spoons is engraved the US Standard measurement and the Metric measurement. Because they are engraved rather than stamped on the measurements won’t wear away as fast. The spoons are grouped together on a handy ring that is easy to open. The only negative feedback users give this set of measuring spoons is that they are made in China. 

This set of six stainless steel measuring spoons have both the Metric and US Standard measurements etched into each spoon. Measurements range from 1/8 teaspoon (0.63ml) to 1 tablespoon (15ml). The spoons come threaded through a steel D ring to keep them all together and make it easier to single out the spoon you need as you work. But the ring is easy to open if you want to remove a spoon entirely from the set before using it. The bowls of each spoon are rounded and quite deep. It may be difficult for these spoons to fit inside some spice jars and smaller containers. Because these measuring spoons are made from stainless steel they won’t rust. They also come with a two-year warranty. 

This five-set measuring spoons set from KitchenAid come in eight different colors. Made from durable plastic, they are easy to clean and have both Metric and US Standard measurements printed on them. The bowls aren’t too deep, so they will slip through more narrow container openings a bit easier than deeper bowl spoons. The measurements range from 1/4 teaspoons (1.25ml) to 1 tablespoon (15ml). There isn’t a 1/8 teaspoon included with this set. Each spoon sits on to a matching colored ring to keep them all together, but they can be easily removed when you need to use one. These plastic spoons won’t hold up as long as stainless steel ones, and you can count on the measurements to rub away after some time. 

This set of measuring spoons by LaMotte is designed specifically to measure out soil and for research projects. Made from plastic these measuring spoons can be used in any field or school laboratory, though they aren’t the best for measuring hot substances. The long handles allow you to reach materials in deep jars without having to strain, and it helps keep your hands free from contaminating your samples as they are collected. There are five spoons in this set with measurements on the handles for grams rather than teaspoons, tablespoons, or milliliters. This set of measuring spoons is not recommended for everyday use in cooking or baking. 

This set includes more than just measuring spoons. It has a set of measuring cups, liquid measurers and five measuring jars with lids included. This set is ready to help your class have a whole lot of learning fun. Designed specifically for liquid, the spoons and other equipment are all clearly marked with the measurement amount each holds. Each of the 19 pieces has both the Metric and US Standard measurements on them. Everything is made from durable plastic that can handle multiple uses. But because the measurements are stamped on they will eventually wear off. 

This stackable measuring spoon set has a different, bright color assigned to each spoon to help you quickly figure out which one you need. Each spoon nests inside the one bigger than it and all can be stored together on the included ring. Most of this spoon set is made from stainless steel, so it will last a long time without rusting. Plus, they are dishwasher safe. Both the US Standard and Metric measuring systems are imprinted on each spoon. This set only has five spoons that range from 1/4  teaspoon (1.25ml) to 1 tablespoon (15ml). It doesn’t come with a 1/8 teaspoon. 

A quick dollop of info 

Spring Chef heavy-duty measuring spoons can be used for any number of tasks. You can use them in the classroom to teach measurements or to get precise measurements of substances for a science experiment. These spoons are also handy in the kitchen for baking pies or cooking a casserole. This set comes with six spoons including a 1/8 teaspoon that is often omitted in other sets. The bowls of these spoons are long rather than round, so they fit in more jars and containers than other measuring spoon sets. The spoons come strung on a stainless steel ring but are easily removed if you need to use only one. You can wash them in the dishwasher and, because they are made from steel, they will last a long time without rusting. 

Few people cook a massive feast complete with a roast turkey more than once or twice a year — and that fact means that Thanksgiving's warmth and camaraderie can just as soon turn into a tale of undercooked bird and food-borne illness.

But there are a few tips and tricks that can help ensure that the turkey and stuffing are not only delicious, but safe for consumption, according to Ben Chapman, a professor of food science at North Carolina's State University. Follow these tips and enjoy your Turkey Day meal with peace of mind.

Defrost with care

There's no perfectly safe way to defrost a frozen turkey, Chapman told LiveScience. But if frozen is what you've got, the key is to keep the outside of the bird below 41 degrees Fahrenheit (5 degrees Celsius). Most dangerous pathogens (such as Salmonella or Campylobacter) don't grow below that temperature, Chapman said.

To maintain that external temperature while still thawing, you can put the bird in cool water, the fridge or even set it on thaw in the microwave, Chapman said. All of these ideas come with downsides: Microwaves are rarely large enough to hold a big turkey, while leaking juices from a bird thawed in water can contaminate the sink, and the temperature of the water is tough to maintain.

Likewise, thawing a turkey in the fridge takes time. According to the U.S. Department of Agriculture, it takes up to six days to thaw a 20- to 24-pound turkey in the refrigerator. If you do choose that route, Chapman said, keep a pan under the turkey to catch any drippings. The biggest danger of fridge-thawing, he said, is that contaminated turkey juices might end up on ready-to-eat foods like raw apples or lettuce.

It is possible to cook a turkey, unstuffed, from its frozen state, Chapman added, though it usually takes about 50% more time than cooking a thawed bird. Or you could bypass the frozen turkey section altogether.

"The safest method is to buy a fresh turkey," Chapman said.

Avoid Exploding Poultry

Defrosting is all the more important if you plan to deep-fry your turkey instead of baking it. Adding a cold bird to hot oil can be an explosive combination — literally — as suddenly-thawed cold water hits the hot oil.

"Water in the turkey, or whatever, boils very fast causing the surface to explode with bubbles, some of which could spray oil on the burner," John Coupland, associate professor of food science at Penn State, wrote in an e-mail to LiveScience in November 2010. Oil plus burner equals instant fire, so take care to treat that turkey right. According to the USDA, only turkeys that weight less than 12 pounds (5.4 kilograms) should be deep-fat fried. 

Don't wash that bird

One mistake many people make in the kitchen is to wash their turkey, Chapman said. Running a raw turkey under the faucet does nothing to reduce pathogens, he said, and worse, it can spread them.

"You can spread Campylobacter and Salmonella up to three feet away from your sink," he said. "When you have fast, running water that hits the fairly uneven surface of your turkey, it can aerosolize those pathogens a little bit and spread them around."

Fortunately, there's an easy solution if your turkey is sporting feather fragments or blood, Chapman said. Wipe the turkey with a damp cloth or paper towel, and then stick the cloth right in the washing machine or the paper towel directly in the garbage.

Keep it clean in the kitchen

Making Thanksgiving dinner is a big production, and it's easy to lose track of cutting boards and knives. Such lapses raise the risk of cross-contamination, a big food-safety risk.

"You've got this complex system going on, especially when you've got folks who might not be used to handling raw meat all the time not thinking about that cross-contamination potential," Chapman said.

Cutting boards and utensils that have touched raw meat should be washed with soap and water and then sanitized, Chapman said. A dishwasher will do both, but a bit of bleach will also work if you're washing by hand. Just be sure to clean first and sanitize separately, Chapman said, as sanitizing solutions won't work on dirty utensils.

"You can't just clean stuff," he said. "There are going to be pathogens that stick really well to the cutting board." 

Look for the magic number in the oven

Perhaps one of the most intimidating tasks for a Thanksgiving chef is figuring out when the turkey is done. Luckily, you just have to remember one number: 165 degrees Fahrenheit (that's 74 degrees Celsius).

Salmonella and Campylobacter are killed off when the temperature hits 165 F, Chapman said. The trick is to be sure that the whole bird has reached that temperature, not just the outside or the drumstick.

"The leg portion has more surface area, so it's going to cook a lot quicker than internal parts," Chapman said. "Your leg may show 180 degrees while the breast hasn't hit 165."

Use a digital, tip-sensitive thermometer and test multiple portions of the bird, especially in thick muscles away from the turkey body cavity or bone.

Don't forget the sides

Cooking is the key to knocking out nasty bugs like Salmonella, so take care if you're serving any raw side dishes this Thanksgiving. Make sure they haven't come in contact with raw turkey drippings, and keep them away from turkey-contaminated utensils.

Washing raw fruits and vegetables can get rid of grit and pesticides, but it won't do much to reduce pathogens, Chapman said. Soap and other solutions are no better than cold, running water, he added.

To keep raw foods safe, store them below 41 F (5 C), Chapman said.

Take care of leftovers

All the cooking is done and you can relax, right? Almost — but you've still got to put away the leftovers. The key to safe leftovers is cooling them quickly to that magic 41 F, Chapman said. Because Thanksgiving foods tend to come in bulk, and throwing a bunch of warm foods into a giant storage container isn't the best option.

"If you have this big vat of gravy or whatever, you want to make sure you're breaking it down into smaller sizes so you get the most chilling action in the shortest amount of time," Chapman said.

To cool turkey quickly, cut the meat off the bones and divide it among plastic zip-top bags laid flat on a rack in the fridge, Chapman said. That method allows lots of cool air to circulate, cooling the turkey and leaving it ready for post-Thanksgiving midnight snacks — and days of turkey-sandwich lunches.

• 10 Terrific Facts About Turkeys
• Thanksgivings Past: Check Out These Old Holiday Menus
• Thanksgiving Science: Why Gratitude Is Good for You

Originally published on LiveScience in 2013 and updated in 2019.

Often called a "miracle food" and a "nutritional powerhouse," an apple a day really may keep the doctor away as they're one of the healthiest foods a person can eat. These round and juicy fruits are high in fiber and vitamin C, and they are also low in calories, have only a trace of sodium, and no fat or cholesterol.

"Apples are high in polyphenols, which function as antioxidants,” said Laura Flores, a nutritionist based in San Diego. “These polyphenols are found in both the skin of the apples as well as in the meat, so to get the greatest amount of benefits, eat the skin of the apple."

All of these benefits mean that apples may mitigate the effects of asthma and Alzheimer's disease, while assisting with weight management, bone health, pulmonary function and gastrointestinal protection.

Here are the nutritional facts from the U.S. Food and Drug Administration, which regulates food labeling through the National Labeling and Education Act:

Health benefits

Apples are loaded with vitamin C, especially in the skins, which are also full of fiber, Flores said. Apples contain insoluble fiber, which is the type of fiber that doesn't absorb water. It provides bulk in the intestinal tract and helps food move quickly through the digestive system, according to Medline Plus.

In addition to digestion-aiding insoluble fiber, apples have soluble fiber, such as pectin. This nutrient helps prevent cholesterol from building up in the lining of blood vessels, which, in turn, helps prevent atherosclerosis and heart disease. In a 2011 study, women who ate about 75 grams (2.6 ounces, or about one-third of a cup) of dried apples every day for six months had a 23 percent decrease in bad LDL cholesterol, said study researcher Bahram H. Arjmandi, a professor and chair of the department of nutrition at Florida State University. Additionally, the women's levels of good HDL cholesterol increased by about 4 percent, according to the study.

When it comes to polyphenols and antioxidants, Flores explained that they "work in the cell lining to decrease oxidation resulting in lowering risk of cardiovascular disease." A 2017 article published in Trends in Food Science & Technology adds that blood pressure may also be reduced in those with or at risk of hypertension, which also lowers the risk of cardiovascular disease. A decreased risk of Type 2 diabetes, which can also lead to cardiovascular disease, was found in a study of more than 38,000 women and was also attributed to certain polyphenols and the high-fiber content of apples.

There may be respiratory benefits to eating apples, as well. "Apples' antioxidant benefits can help lower the risk of asthma,” Flores told Live Science. A 2017 study published in the journal Nutrients indicates that the antioxidants in a variety of fruits and vegetables, including apples, potentially decrease the risk of asthma by helping control the release of free radicals from inflamed cells in the airways and in the oxygen-rich blood coming from the heart.

Health risks

"Eating apples in excess will not cause many side effects," Flores said. "But as with anything eaten in excess, apples may contribute to weight gain."

Furthermore, apples are acidic, and the juice may damage tooth enamel. A study published in 2011 in the Journal of Dentistry found that eating apples could be up to four times more damaging to teeth than carbonated drinks.

However, according to the lead researcher, David Bartlett, head of prosthodontics at the Dental Institute at King's College in London, "It is not only about what we eat, but how we eat it." Many people eat apples slowly, which increases the likelihood that acids will damage tooth enamel.

"Snacking on acidic foods throughout the day is the most damaging, while eating them at meal times is much safer," Bartlett said in a statement from King's College. "An apple a day is good, but taking all day to eat the apple can damage teeth."

Dentists recommend cutting up apples and chewing them with the back teeth. They also recommend rinsing the mouth with water to help wash away the acid and sugars.

Apples and pesticides

"Most apples will have pesticides on them, unless they are certified organic," Flores said. In 2018, the Environmental Working Group, a nonprofit environment and human health organization, concluded that 98 percent of conventional apples had pesticide residue on their peels. However, the group also said that "the health benefits of a diet rich in fruits and vegetables outweigh the risks of pesticide exposure." [Infographic: Guide to Pesticides in Produce]

Washing apples well helps remove pesticides, according to the Colorado State University Extension Service. "Washing apples and making sure you rub the skin in some way will do the trick," Flores said. "You can do this with your hands or a fruit scrubber." However, using chemical rinses and other treatments for washing fresh produce is not recommended because the Food and Drug Administration has not evaluated those products for safety or effectiveness.

Some researchers say not to worry about pesticides. Dr. Dianne Hyson, a research dietitian at the University of California, Davis, writes that laboratory tests have shown very low levels of pesticide residue on apple skins.

Are apple seeds poisonous?

Apple seeds, also called pips, contain a chemical compound called amygdalin, which can release cyanide, a powerful poison, when it comes into contact with digestive enzymes. Whole seeds pass through your digestive system relatively untouched, but if you chew the seeds you may be exposed to the toxins. One or two will not be harmful, as the body can handle small doses of cyanide, but if you or a child chews and swallows a lot of seeds, you should seek medical attention immediately.

How many seeds are harmful? According to John Fry, a consultant in food science, about 1 milligram of cyanide per kilogram of body weight will kill an adult person. Apple seeds contain about 700 mg (0.02 ounces) of cyanide per kilogram; so about 100 grams (3.5 ounces) of apple seeds would be enough to kill a 70-kilogram (154 lbs.) adult. However, an apple seed weighs 0.7 grams (0.02 ounces), so you would have to munch on 143 seeds to get that amount of cyanide. Apples typically have about eight pips, so you'd have to eat the seeds of 18 apples in one sitting to get a fatal dose.

Apple history and facts

Apples originated in the mountainous region of present-day Kazakhstan. The trees grew 60 feet tall and produced fruit in all sizes between a marble and a softball in shades of red, green, yellow, and purple, according to Cornell University. According to the University of Illinois Extension service, apples were consumed at least as far back as 6500 B.C.

Various trade routes passed through these trees, and apples were likely picked by hungry traders, who then discarded the seeds along their paths and probably carried the seeds with them to plant in other destinations. The seeds naturally hybridized with other local species, producing thousands of different types of apple trees across Europe and Asia. The seeds eventually made it to other continents and countries, including North America and New Zealand.

The first apples grown in North America were planted by European settlers in the Massachusetts Bay Colony. Newton Pippin apples were the first type of apple to be exported from the colonies, when they were sent to Benjamin Franklin in London. Today, nearly 25 percent of apples grown in the U.S. are exported around the world.

More fun facts about apples from the University of Illinois Extension service:

• There are 7,500 varieties, or cultivars, of apples grown throughout the world and 2,500 varieties in the U.S.
• The world's top apple producers are China, the United States, Turkey, Poland and Italy.
• Apples are grown in all 50 states.As of 2010, the U.S. Department of Agriculture reported that 60 percent of the apples produced in the U.S. were grown in Washington state, 13 percent in New York, 6 percent in Michigan, 5 percent in Pennsylvania, 3 percent in California and 2 percent in Virginia.
• In 1730, the first apple nursery was opened in Flushing, New York.
• The science of apple growing is called pomology.
• Apples are members of the rose family, Rosaceae

Further reading:

• Check out even more fun facts about apples from the University of Illinois.
• Review more apple crop yield statistics from the USDA National Agricultural Statistics Service.
• Find information on fruit and vegetable safety from the CDC.

This article was updated on Dec. 12, 2018 by Live Science Contributor Rachel Ross.

There's nothing like a fresh, tangy glass of orange juice to go with your morning oatmeal. But if you've just brushed your teeth, you may find that the beverage tastes … less than delicious. 

So, why does toothpaste affect the taste of orange juice and other sweet breakfast (or midnight) snacks? It all boils down to what's happening with the taste receptors on our taste buds, Guy Crosby, a nutrition professor at the Harvard T.H. Chan School of Public Health, told Live Science.

In a nutshell, a compound in toothpaste called sodium lauryl sulfate (SLS) alters the way we process certain tastes, at least temporarily. [Why Do Some People Hate the Taste of Beer?]

But let's start with how we detect different tastes. If you touch your tongue, you'll notice that it's covered with bumps and mini-ridges. Each of these bumps is made up of taste buds, which in turn are made up of taste receptors. Our mouthshave between 2,000 and 4,000 taste buds in total, and each taste bud has between 10 and 50 receptors. In other words, humans are well-equipped to savor different foods.

All of our taste buds help us to perceive five types of flavors: sweet, salty, sour, bitter and umami. (That last term describes savory foods, like cured meats, mushrooms and fermented cheeses.)

The act of tasting is a bit like a chemical puzzle. When we chomp into something, that food releases molecules that have certain shapes, and these shapes float around in our mouths. Each flavor of food has a unique shape, which matches up to a type of taste receptor with a corresponding shape. For instance, when the bitter molecules from our lunchtime arugula salad bind to a bitter receptor, that sends a series of neural signals to our brain announcing that we've tasted something bitter. 

However, a compound present in most toothpastes wreaks havoc on this tango between flavor molecules and taste receptors. 

During a vigorous toothbrushing, toothpaste bubbles and froths in your mouth. This happens because the paste includes that aforementioned compound, SLS, which acts as a detergent on your teeth. SLS is found in products that bubble or foam, including personal care products such as shaving cream and household cleaners like dish soap. But research has shown that SLS affects the ability of our taste receptors; it makes them more susceptible to bitter tastes and dials back how much we can taste sweet flavors.

Oranges are slightly bitter, thanks to citric acid, but that taste is typically obscured in juice by the extra sugar that companies mix into the drink. According to the American Chemical Society, SLS not only suppresses our sweetness receptors, but also wipes out our phospholipids — compounds that hinder our bitterness receptors. In effect, our taste buds suddenly taste a lot more of OJ's bitter taste than its sugary-sweet goodness.

All research on the topic of SLS and its impact on taste traces back to a 1980 study in the journal Chemical Senses, Crosby said. According to Crosby, the paper's authors state that SLS reduces the sweetness of sucrose (essentially sugar), the saltiness of sodium chloride (salt) and the bitterness of quinine (the flavoring used in tonic water) but increases the bitterness of citric acid (typically found in fruits like limes and oranges). [Do Mouthwashes Work?]

However, there is no specific mention in the paper of toothpaste's effect on the taste of orange juice, Crosby said. Even so, "I believe it is best to describe the effect of toothpaste on the taste of orange juice as a theory, but one that makes good sense based on the research reported,"Crosby said. 

But juice lovers, don't despair. These taste effects dissipate "on the order of minutes," according to the 1980 paper.

Crosby said that waiting just a few minutes is all that's needed, as the physical interaction between SLS and taste cells is a temporary change. The SLS dissolves away with additional saliva, and once we eat other foods, normal taste sense is restored, he said. 

Simply put, next time you want OJ for breakfast, you might consider brushing your teeth, showering and then dashing off to the refrigerator for your morning juice. Or, you can just brush your teeth after you gulp down your juice. 

Original article on Live Science.

Should you buy organic? Or avoid foods made with genetically modified ingredients? Americans are divided in their thinking on whether such choices are beneficial for their health, a new survey finds.

Just over half of all Americans, or 55 percent, consider organic produce to be healthier than conventionally grown produce, and 39 percent of Americans think that foods with GM ingredients are less healthy than those without such ingredients, according to the survey.

On the other hand, 41 percent of Americans think that organic produce is neither better nor worse for one's health than conventionally grown produce, and 48 percent of Americans think the same about GM foods, according to the nationally representative survey, published today (Dec. 1) by the Pew Research Center. [10 New Ways to Eat Well]

"The data suggest that people's divisions are linked to their interest in food issues and how they think food consumption ties to their well-being," Cary Funk, the associate director of research at Pew Research Center and the lead author of the report on the survey, said in a statement.

Based on the survey respondents' answers to other questions, the researchers also concluded that people's views on food "are not driven by their political attitudes, their level of education, their household income or where they live," Funk said.

For example, roughly equal shares of Republicans and Democrats think that GM foods are worse for a person's health than foods that don't have GM ingredients, according to the survey. And 50 percent of Republicans and 60 percent of Democrats think that organic foods have health benefits beyond those of conventionally grown foods.

Age, however, did appear to play a role in people's views: Adults under 50 were more likely than older adults to say that organic produce is healthier than conventionally grown produce, the researchers found. And 48 percent of adults ages 18 to 29 thought that GM foods are worse for health than non-GM foods, compared with 29 percent of adults over 65 who think this, according to the survey.

Is there anything Americans agree on?

Americans aren't completely divided, the researchers found. Indeed, 72 percent of Americans said that healthy eating habits are very important for a long and healthy life, and 71 percent said that getting enough exercise is very important for a long and healthy life, according to the survey.

But the majority of Americans feel like they aren't meeting their healthy-eating goals: 58 percent said that on most days, they feel like they should eat healthier, the researchers found. [6 Easy Ways to Eat More Fruits and Vegetables]

In addition, depending on a person's level of science knowledge, it may be difficult to know how to eat healthy, the researchers found. For example, among those with low science knowledge, half said "the core ideas of eating healthy are pretty well understood," while 47 percent said that conflicting information from news reports made it difficult to know how to eat healthy.

Among those with high science knowledge, however, 92 percent said that the core ideas of healthy eating were well understood, the researchers found.

Can food scientists help?

The researchers also looked into how Americans view food scientists.

They found "that Americans have limited trust in scientists connected with GM food," Funk said. Only 19 percent of Americans think that scientists understand the health effects of GM foods "very well," the survey found. Another 44 percent said they think that scientists understand these health effects "fairly well," and 35 percent think that scientists either do not understand these effects at all or "not too well."  

However, although only 35 percent of Americans said that they trust scientists to give the public complete and accurate information about the health effects of GM foods, 60 percent say they think scientists should play a major role in food-policy issues, the survey found.

The findings were based on surveys completed by 1,480 adults in all 50 states and the District of Columbia between May 10 and June 6, 2016. Surveys were either mailed or emailed to the participants.

Originally published on Live Science.

Grainy, flavorless, rigid, yet soggy — is there anything worse than an old, cold french fry?

But how does a warm, golden, crispy and all-around perfect french fry go from a delicious food that you can't stop eating to a food that you can't get away from fast enough?

One of the main reasons that french fries lose their appeal when cold is that their texture changes, said Matt Hartings, an assistant professor of chemistry at American University in Washington, D.C. 

Related: Does salt make water boil faster?

That change in texture can be explained by the chemistry of potatoes, Hartings told Live Science. Potatoes are filled with starch, Hartings said. Starches taste good when they are "hydrated," he said.

Think of the starches in potatoes as tiny crystal spheres, Hartings said. At really high temperatures (like in fryers), water will go into those spheres and fill them up like balloons, he said. Instead of a small, hard sphere, you end up with something more "poofy," he said.

And this "poofy" texture is something people really like, Hartings said.

But as fries cool down, the water starts to move out of the crystals, and you lose the fluffy texture, Hartings said. The spheres become more crystalline and gritty, he said.

And where does the water go when it leaves the starchy spheres? Right into the crust of the fry, Hartings said. That turns the crispy crust that came out of the fryer into a soggy mess.

Temperature also partially explains why the taste of fries changes as they cool down, Hartings said. Simply put, heat can heighten the flavors in foods, he said. Consider how different your morning coffee tastes when it gets cold, he added.

Finally, smell plays a big role in how a food tastes, Hartings said. Fresh french fries have a great aroma, but when they're cold, the smell is largely gone, he said. Without that smell, a lot of the flavor disappears, he said. 

Originally published on Live Science.

Dried whiskey at the bottom of a glass produces stunning images that closely resemble fine art paintings, shows new research that also helps explain how the patterns form.

The effect results from both the chemical composition of whiskey as well as fluid dynamics. The presentation “Painting Pictures with Whiskey,” explaining the phenomenon, took place today during the American Physical Society’s Division of Fluid Dynamics Meeting, held in San Francisco.

7 Ultimate Destinations for Booze Aficianados

Phoenix-based professional photographer and artist Ernie Button has been creating photos of the patterns formed after letting a drop or two of whiskey coat and dry in the bottom of a glass.

“It’s infinitely fascinating to me that a seemingly clear liquid leaves a pattern with such clarity and rhythm after the liquid is gone,” Button said in a press release.

Curiosity compelled him to reach out to Howard Stone and his Complex Fluids Group at Princeton University’s Department of Mechanical and Aerospace Engineering for insight.

“My group focused on gaining a better understanding of the composition of whiskey, identifying the possible ‘suspended material,’ and doing controlled model experiments to understand possible shapes and forms of deposits during evaporation,” Stone explained.

To study the flow patterns and concentration in the solution, as well as the final dried deposits from suspended particles, a postdoctoral researcher in Stone’s lab, Hyoungsoo Kim Kim, and colleagues used video microscopy of drying droplets of actual whiskey and compared it to video microscopy of an alcohol-water solution representative of whiskey. Typical whiskies are 40 percent by volume ethanol (alcohol) and 60 percent by volume water.

Optical Illusions: Your Brain Is Way Ahead of You

They found that initially, the droplet of alcohol-water solution creates a complex mixing flow. Ethanol evaporates first, due to the lower vapor pressure compared to water. Once the ethanol vanishes, a radial pattern can be observed.

As the initial ethanol concentration increases, the mobility of the receding contact line is increased as well. At high ethanol concentrations, the contact line recedes and draws groups of particles along with it that are then deposited in ring-shaped patterns.

All demonstrate what is known as the Marangoni Effect, which is the mass transfer along an interface between two fluids (in this case, alcohol and water) due to surface tension.

“The alcohol-water solution shows circulation flow patterns (triggered by the Marangoni Effect), which occur during drying and influences patterns formed in evaporating whiskey solutions,” Kim noted. “Deposits in the actual whiskey come from a small amount of inherent raw materials present from the preparation process.”

Barrel aged whiskey, for example, might leave behind trace particles of oak or other woods.

Is Climate Change Ruining Wine Corks?

Stone even wondered if younger versus more aged versions of the same whiskey would create different patterns, but he and his colleagues could find no such differences. Perhaps that’s because the basic components are all still the same, even if the two whiskies develop different flavor properties.

The work by Stone’s group may have wider implications, because the ability to control the deposition of a thin film of particles is highly desirable for many industrial applications. The science behind all of this also helps to explain patterns left behind by other beverages, such as wine, tea (think reading tea leaves) and coffee.

To see more of Button’s photography, including what single malt Scotch looks like when dried and up close, visit his website.

Originally published on Discovery News.

NEW YORK — Leading scientists, artists and thinkers from around the world will convene here this week for the World Science Festival, but even if you can't make it to the Big Apple for the five-day event, you can still catch all the action live online.

The festival will feature panel discussions on everything from the future of brain-machine interfaces to the physics of chocolate. You can watch the World Science Festival webcast on Live Science.

Since it began in 2008, the annual World Science Festival has drawn more than a million people to more than 300 programs throughout New York City, festival representatives said. [The 10 Biggest Mysteries of the Mind]

"This year's programming, with an emphasis not only on main stage events but also on more intimate gatherings involving great scientists and general audiences of all ages, brings cutting-edge science directly to the public," Tracy Day, the festival's CEO and co-founder, said in a statement.

The festival kicks off tonight with a theatrical exploration of Albert Einstein's life. Actors Paul Rudd and Cynthia Nixon will perform in Alan Alda's "Dear Albert," a reading of the letters by the world's most famous scientist to his wives and other women. After the performance, Alda and Brian Greene, a physicist at Columbia University and co-founder of the World Science Festival, will lead an onstage discussion about Einstein.

Tomorrow morning (May 29), the biennial $1 million Kavli Prizes, awarded for major advances in the fields of astrophysics, nanoscience and neuroscience, will be announced via a live webcast from the Norwegian Academy of Science and Letters in Oslo, Norway.

You can also view planet Earth projected and animated on a giant, suspended globe in Gould Plaza. Watch wild weather and see movies about space, tsunamis and waterfalls on the massive orb, as part of the National Oceanic and Atmospheric Administration's "Science on a Sphere." The event is free and open to the public.

In the evening, experts in neuroscience, engineering and biology will explore breakthroughs in the field of brain-machine interfaces, and ask whether scientists are any closer to realizing the sci-fi dream of being able to upload information from a computer to the brain, like in the film "The Matrix." [Super-Intelligent Machines: 7 Robotic Futures]

Also tomorrow evening, the Intrepid Sea, Air & Space Museum will host a science, space and astronomy night, with free entry to special NASA exhibits, stargazing with astronomers and more. A ticketed screening of the film "Gravity" will take place under the space shuttle Enterprise at the Intrepid, followed by a discussion with astronauts Sandra Magnus and John Grunsfeld.

On Friday (May 30), a panel of researchers will debate the recent findings of gravitational ripples from the Big Bang, one of the year's biggest scientific developments, if it's confirmed. But some scientists suggest the champagne may have been popped prematurely. Prominent theorists and members of the research team will take part in the conversation.

During the day, a scale replica of comet Churyumov-Gerasimenko, which will be visited by the European Space Agency's Rosetta spacecraft this summer, will be on display at Brooklyn Bridge Park.

In the evening, a biophysicist and pastry chef will meet to explore the physics of pie, at the Momofuku Milk Bar bakery in Williamsburg, Brooklyn. Experts will explain the secrets of good pie, from gluten-protein networks to polymorphic phase behavior. Naturally, tasting is involved.

Mary-Claire King of the University of Washington, the geneticist who discovered the breast cancer gene BRCA1, will speak on Saturday (May 31).

Saturday evening, astrophiles can bring their telescopes for an evening of urban stargazing (weather permitting) and live music under the Brooklyn Bridge.

On Sunday (June 1), hundreds of thousands of people will convene in Washington Square Park for the Ultimate Science Street Fair, featuring robots, brain games and stage performances.

You can watch the World Science Festival webcast on Live Science.

Follow Tanya Lewis on Twitter and Google+. Follow us @livescience, Facebook & Google+. Original article on Live Science.

A perfect steak is a tasty centerpiece to an impressive meal. Fortunately, science can help make this dinner delicious.

The ideal steak is a matter of taste, but proper cooking involves balancing a high external temperature with a lower internal temperature. Getting the balance right ensures that the steak is tender and juicy on the inside, and browned and flavorful on the outside.

"It really is a game of temperatures," said Jeff Potter, author of "Cooking for Geeks: Real Science, Great Hacks and Good Food" (O'Reilly Media, 2010).

Safe steak

"Steak" describes a cut of meat cut perpendicular to the muscle fibers, and typically refers to beef. Steaks can come from different areas of the cow: Chuck steak, for example, comes from the shoulder, sirloin from the cow's back, near the rear. T-bone and porterhouse are cut from the short loin, along the animal's side.

Steaks can be safely eaten with less cooking than ground meat, in most cases, said Ben Chapman, a professor of food safety at North Carolina State University. Ground beef or hamburger mixes surface meat — where nasties such as E. coli can thrive — with internal meat. The U.S. Department of Agriculture recommends cooking all ground beef to an internal temperature of at least 160 degrees Fahrenheit (71 degrees Celsius). [Top 7 Germs in Food that Make You Sick]

Pathogens can't penetrate the internal muscle tissue of a steak, so cooking it rare is low-risk, Chapman told Live Science. That's true unless the steak has been needle- or blade-tenderized, methods that involve puncturing the steak to break up toughness. In those cases, pathogens from the outside of the steak can end up inside. Meat plants are required to label needle- and blade-tenderized meat if they're federally inspected, but not if they're state-inspected or if the tenderizing is done at a grocery store. For that reason, the U.S. Department of agriculture recommends cooking steak to an internal temperature of 145 F (63 C).

If, like Chapman, you prefer rare or medium-rare steak that is cooked less thoroughly, you can always query your butcher.

"I ask specifically, 'Has this been needle-tenderized or blade-tenderized?'" Chapman said. "If I hear that is has been, I don't buy it."

Cooked to perfection

But back to that game of temperatures. The reason meat changes texture, color and taste when it cooks is that proteins in the muscle tissue denature, or change shape. There are different proteins that make up muscle tissue, including myosin, which plays an important role in muscle contraction, and actin, which is also involved in muscle contraction as well as cell division and other functions.

Myosin starts to denature around 120 to 130 F (49 to 55 C), Potter told Live Science. Actin denatures around 150 F (66 C).

For taste, "it seems we prefer when myosin is denatured and actin is in its native state," Potter said.

On the outside, though, the perfect steak is browned. Browning occurs because of the Maillard reaction, a chemical reaction in which sugars and amino acids in the meat react and create new, flavorful compounds. (The same reaction occurs when you toast bread.) To get a Maillard reaction, the surface temperature of the steak needs to be around 350 degrees F (177 degrees C), Potter said. (An infrared thermometer can give the temperature of surfaces, he added.) Some people advocate salting steak and letting it sit to pull moisture off the surface and hasten this Maillard reaction. Most likely, the small amount of liquid pulled out of the steak by the salt won't make a huge difference in cooking time. Letting salt sit for a time on the meat might allow the seasoning to penetrate the outer layers, however, creating a more flavorful experience overall.

Balancing high heat on the outside with low heat on the inside is a skill on the grill. The truly dedicated and precise can try a different technique: sous-vide. Sous-vide is a French method that uses immersion in water to poach food at a low temperature. The cooked meat can then be seared over high heat to finish it off.

Sous-vide works well to cook perfect steak, Potter said. But there's another side of cooking, too.

Most of the time, "I'm probably just going to throw a steak into a hot cast-iron pan or on the grill outside," Potter said. "That's a little more fun."

The perfect steak is a matter of taste, and Potter recommends experimenting to see what your palate prefers. Here are the basic steps for steak perfection:

1. Choose a cut with plenty of fat and thickness. Fat equals moisture, and no one wants a dry steak.

2. If you want to salt your steak, let the salt sit on the meat for a minimum of 40 minutes (you can salt your steak even several days in advance, if you prefer). This allows the salt to dissolve into the meat. Pre-salting steak is controversial in the cooking world, so feel free to experiment. 

3. From here, it's a game of heat. The internal temperature of a rare steak is 130 F (54 C). For medium-rare, aim for 135 F (57 C). To cook to medium, aim for 145 F (63 C). Finally, medium-well takes about 160 F (71 C). Take the steak off the grill 5 F (3 C) below your target, as the surface will heat the interior slightly even after the meat is off the grill.

Don't worry about searing first to "lock in juices." Steam (aka moisture) is perfectly capable of escaping through seared meat as well as partially cooked meat. You do want to finish with a flourish of high heat, though, to create those crusty Maillard reactions.

Another myth about steak is that you shouldn't flip it too often, lest it become tough. No truth there. Flipping a steak multiple times can help it cook more evenly, Potter said.

4. Let the meat rest for a few minutes after you cook it. If the liquids inside the steak cool slightly before you cut the meat open, they will be more viscous, meaning they're less likely to flow all over your plate — or burn your tongue. Win-win.

Follow Stephanie Pappas on Twitter and Google+. Follow us @livescience, Facebook & Google+. Original article on Live Science.

Preparing a Thanksgiving feast can seem like a daunting task, but understanding a bit about the science behind the cooking may cut down some of the stress in the kitchen this holiday season.

In Brookline, Mass., chefs at America's Test Kitchen dissect recipes down to their most basic scientific reactions, and meticulously test each step of the cooking process. It's exacting work, but it helps the chefs figure out the most effective ways to prepare some of the most popular meals. And with only days to go before turkeys hit dinner tables across the country, the Test Kitchen chefs have been busy, said Jack Bishop, chef, TV personality and editorial director of America's Test Kitchen.

"From a cooking perspective, Thanksgiving is the most important week of the year," Bishop told LiveScience. "For most people, the holidays are all about the food. But the line between cooking a good turkey and awful turkey is relatively small. It's not hard to cook a turkey well, but it's pretty easy to cook one poorly." [Thanksgiving Gallery: 8 Fascinating Turkey Facts]

Still, the prospect of cooking a whole turkey should not intimidate chefs, Bishop added. By avoiding some of the most common mistakes, and injecting a bit of science into the process, even a novice can ensure the end result is a meal to be thankful for, he said.

Brining your turkey

If possible, Bishop suggests purchasing a fresh turkey, rather than a frozen one. "If you're willing to make the investment in time and planning, that's the best route," he said.

To prepare a fresh turkey, Test Kitchen chefs recommend brining the bird overnight, which involves soaking the turkey in a container of salty water for at least 12 hours. This brining process helps keep the turkey moist and juicy.

"The salt will change the protein structure within the muscle fibers, so the turkey will hold onto more moisture in the cooking process," Bishop explained. "You'll end up with a better-seasoned and juicier bird."

Still, Bishop cautions that more is not necessarily better, and it's important to avoid making the brining solution too salty. As a general rule, he recommends using a half-cup of table salt for every gallon of water.

After six to 12 hours of brining, the turkey can be patted dry and left on a baking sheet in the refrigerator. Before placing the turkey in the oven, Bishop suggests brushing the raw bird with butter.

Cooks who opt for a frozen turkey do not need to worry about brining it in advance. Most frozen turkeys are already injected with brine, and kosher varieties are processed with salt, Bishop said. The most important tip for using frozen turkeys is to let the birds thaw in the refrigerator before cooking them, he added. [5 Myth-Busting Facts for a Safe Turkey]

Turkey temperature

This year alone, the Test Kitchen chefs experimented with more than 100 turkeys to determine the optimal cooking method and temperature, Bishop said. (In the last 20 years, Bishop estimates the Test Kitchen has cooked thousands of turkeys.) The tests' results indicated that roasting a turkey at 400 degrees Fahrenheit (roughly 200 degrees Celsius) works best.

But, there are some challenging aspects to cooking a turkey, Bishop said. For one, the shape of the bird — complete with a huge cavity in the center — means it heats unevenly in the oven. Plus, the turkey's white meat and dark meat should ideally be cooked to different temperatures.

"You don't want white meat to be overcooked, because it begins to dry out," Bishop said. "Dark meat, on the other hand, shouldn't be undercooked, because it'll be chewy."

The easiest, and most reliable, way to ensure parts of the turkey are not under- or overcooked is to use a meat thermometer. Before taking the turkey out of the oven, the white meat in the breast should be 160 degrees F (71 degrees C), and the dark meat in the thighs and legs should be 165 degrees (74 degrees Celsius).

And there's no need to fuss around with the turkey too much while it's in the oven, Bishop said. The Test Kitchen chefs found that basting the bird does not actually improve the juiciness of the turkey. Instead, to brown and crisp up the skin, Bishop recommends placing the turkey on a rack that sits inside a roasting pan. This will allow air to circulate evenly, and the skin will not get soggy from sitting in the drippings.

"If you're willing to do a bit more work, it's good to start the turkey breast side down, which will shield the breast from the direct heat of the oven, and the juices will run into the breast," Bishop said. "At the one-hour mark, take two wads of paper towel and flip the bird by hand so it's breast-side-up. We've found that really helps get juicier breast meat, and rather than basting the bird, this is one thing worth doing."

Finally, before carving and serving the turkey, Bishop recommends letting the finished product rest for 30 to 40 minutes. This will help ensure the turkey is still juicy and moist when served.

"When a turkey is heated, the muscle fibers tighten up and physically contract," Bishop explained. "If you start cutting when it's hot from the oven, the muscle fibers will expel juices, and all the juices will run onto the carving board. But if you let the meat rest, the muscle fibers will hold onto their internal moisture as you carve."

But there's more to a Thanksgiving meal than just a turkey. Here are other tips from Bishop and the Test Kitchen team:

For perfect pie dough, just add vodka:

The secret to baking a flaky pie crust is to add vodka to the mix, Bishop said.

"Usually, ice water is what brings pie dough together to make it workable, but if you skimp on water, you end up with a dough that's cracked and hard to work with," Bishop said. "So, most cooks add extra water, which makes the dough easier to work with, but the extra water activates the glutens in the flour." (And too much gluten makes the dough tough instead of flaky.)

Test Kitchen chefs discovered that the ethanol in vodka helps moisten the dough, but it does not activate gluten development. As such, Bishop recommends using half-ice water and half-vodka when making pie dough.

And there's no need to worry about boozing up your pie dough. "The alcohol bakes off in the oven, so you can't taste it," Bishop explained. 

Use a ricer for lump-free mashed potatoes:

For fluffy, lump-free mashed potatoes, Test Kitchen chefs found that a potato ricer is the best tool to use.

"It's basically a big garlic press, but you get very fine shreds, so it's easier to work with the cooked potatoes," Bishop said. "It's pretty cheap, but if you can't get one, then a regular masher can make light and fluffy potatoes, too."

And which variety of potato is best for mashing? Russets are ideal, but Yukon Gold potatoes can also be used, Bishop said.

Cook stuffing separately, not inside the turkey:

Cooking stuffing inside the turkey's cavity may be a nice tradition, but it slows down the entire cooking process, Bishop said.

"Stuffing has eggs in it, so it has to heat up to 165 degrees [Fahrenheit] to be at a safe temperature. But in order to get up to that temperature, you end up overcooking the bird," Bishop said. "You don't want to be waiting for the stuffing, and meanwhile the breast meat is drying out."

If you don't want to cook the stuffing separately, however, Bishop recommends warming it up before the stuffing goes inside the bird. 

"Warming stuffing in the microwave so it's not ice cold will at least give it a head start," he said.

Follow Denise Chow on Twitter @denisechow. Follow LiveScience @livescience, Facebook & Google+. Original article on LiveScience.

(ISNS) -- Calories are the most basic nutrition information. They're on every cereal box. But recent scientific evidence implies that those numbers may not tell you all you need to know.

A recent study by scientists at the U.S. Department of Agriculture indicates that the common calorie counts of two tree nuts, pistachios and almonds, are inaccurate, and the scientists involved say that may be true of other foods as well. Another study suggests that the satiating effect of calories could be more mental than chemical.

Calories are not just calories, said Rick Mattes, professor of foods and nutrition at Purdue University, in West Lafayette, Ind. They are more than simple numbers.

Blowing up your food

A calorie is a measurement of heat, a concept originating with the 19th century French scientist Nicolas Clément in 1824. The term calorie, when used with food, usually refers to the amount of heat required to raise the temperature of a kilogram of water one degree Celsius. American scientist Wilbur Atwater used calories as a unit to measure the energy in food in the 1890s, according to David Baer of the USDA's Agricultural Research Service.

Calorie measurements then and now are made in a "calorie bomb" or a "bomb calorimeter" developed by the French scientist Antoine Lavoisier in 1790. A small pellet of the food being measured is placed in a device that looks like a pressure cooker. Pure oxygen is pumped into the bomb, and then the food is ignited. Thermometers measure the heat given off and that is the calorie count.

"It's called a bomb because you literally explode the food and capture the heat and measure it," said Susan Roberts, professor at the Friedman School of Nutrition Science and Policy at Tufts University in Boston, Mass. "Calories are heat. All you are doing is measuring how much heat the food converts to when you burn it."

They wouldn'’t blow up an entire pizza, just a small piece of it, and extrapolate the calorie measurement from there.

What goes in versus what comes out

Just because the pizza box says the pizza has 800 calories doesn't mean your body will metabolize 800 calories. 

Not all food is digested. What is not digested is excreted out of the body in feces and urine. Some of the food provides the energy required to eat or drink--chewing for example. This is called metabolized energy.

Estimating the metabolized energy in food gets complicated. It involves mathematical calculations of proteins, carbohydrates, and fats multiplied by algorithms developed by Atwater, so-called Atwater factors. 

But, the calculations may not give the right answer. Baer's lab, for instance, found this when studying the two tree nuts. 

They took 18 volunteers and fed them a base diet for three weeks. After they adapted to the diet -- about 10 days -- the nuts were added to their diets, and samples of feces and urine were taken regularly.

By knowing what food went in and what came out, the researchers were able to measure the metabolic energy of the individual nuts. The numbers used on food packaging is the metabolizing energy using the Atwater factor.

What the USDA experiment did was actually measure the unused calories as opposed to doing the calculation.

Baer found the usual calorie count given for pistachios was probably too high, about 5 percent more than the actual energy in the nuts. Almonds were off by about 20 percent. 

Baer thinks that the discrepancy happens because of the indigestible fiber in the nut cell walls traps the fat.

Caloric minds games

Scientists have known for a while that the form of food makes a difference. People think solid food is more filling than liquids despite the calorie count.

The Purdue researchers wanted to know if that was true

"We think our hunger drops less and your fullness rises less when we think it is going to be a liquid in our bodies rather than a solid," Mattes said. The operative word was "think."

The Purdue scientists told 52 subjects they were going to drink a cherry-flavored liquid, and that it would remain a liquid throughout their bodies. On another day, they then took what looked like the same substance and showed the subjects how adding a chemical instantly turned the liquid into a solid. The scientists said the same phenomenon would happen in their stomach. 

In reality, they all drank the same liquid both times, without any added chemical and it remained liquid inside their bodies. The subjects just thought it would turn into a solid. The researchers called that trick “cognitive manipulation.” 

Yet, the subjects reported that they were less sated in the first case, and more satisfied when they thought it would turn into a solid. The liquid even went through their body faster because the body’s chemistry reacted to the thought that it was a liquid and thus would absorb fewer calories.

They published their work in the American Journal of Clinical Nutrition. Both Baer and Mattes will present papers at the Institute for Food Technologists meeting in Chicago on July 14. 

Tufts' Roberts thinks calories still count.

"The environment is so full of junk food and excess portions that the only way many people can keep their weight healthy is to watch what they eat," she said. "And for that you need numbers, because even if you have a Ph.D in nutrition, it is impossible to accurately tell how many calories are in most of the foods out there."

Inside Science News Service is supported by the American Institute of Physics. Joel Shurkin is a freelance writer based in Baltimore. He is the author of nine books on science and the history of science, and has taught science journalism at Stanford University, UC Santa Cruz and the University of Alaska Fairbanks.

Cuisiniers and gastronomes share an appreciation for the so-called "65-degree egg" — an egg cooked for long periods at or near 65 degrees Celsius (149 Fahrenheit). But recipes for the ideal egg aren't as scientific as they could be, says food scientist and chef César Vega.

Speaking at a meeting of the American Chemical Society on April 7, Vega, a research manager at Mars Inc., who has a doctoral degree in food science and culinary training from Le Cordon Bleu, explained how cooking can be a platform to engage the public in science. He used the 65-degree egg or its 6X-degree counterparts (for instance, 67 degrees C or 69 degrees C) as an example.

This is a style of cooking known as "sous-vide," which involves heating things in a vacuum (or for eggs, in the shell) at relatively low temperatures. "There's this belief that when you cook an egg sous-vide, once water reaches the temperature you are interested in, how long you cook it for doesn’t matter," Vega told LiveScience. "This is not true."

When an egg is cooked, the proteins in the yolk unravel, a process known as denaturation. Proteins can be denatured by strong chemicals such as acids, mechanical action or heat — as in the case of the 6X-degree egg.

There's a false notion, even among scientists, that proteins have definitive, discrete denaturation temperatures, Vega said. "The belief is, 67 degrees C [153 F] is the temperature at which egg yolk proteins start to coagulate," he said, but that isn't true. It all depends on the thermal history of the egg, he explained: "I can heat it at 35 degrees C [95 F], and if I wait long enough, it will denature it." Boiling the egg denatures it too, but it happens so fast that the textural outcome is different, Vega said. [Top 10 Modern Kitchen Innovations]

Some proteins in the egg yolk denature at higher temperatures than others, Vega found, and more proteins denature the longer the egg is cooked. The hotter the temperature and the longer the cook time, the more viscous the yolk becomes.

To help chefs achieve an egg with their desired texture, Vega has created a graph that shows them what temperatures and cooking times to use. Based on these variables chefs can create eggs with the texture of mayonnaise (yolk proteins that are less denatured), honey — even cookie icing (highly denatured yolk proteins), Vega said. His findings are detailed in a paper on the science of the 6X-degree egg, published in March 2011 in the journal Food Biophysics.

And the science of cooking eggs extends to other foods, too, such as meringues, which are made from whipped egg whites and sugar. Cream of tartar or lemon juice is often added to meringues, but why? It has to do with the degree of acidity, Vega said. Egg whites are slightly basic, or alkaline, which makes the proteins clump together when they're whipped, causing the foam to collapse.

Cream of tartar and lemon juice are both acidic, so adding them to egg whites neutralizes them and they don't clump up as much. "You can whip and whip and whip and the egg whites won't aggregate," Vega said. Garlic juice works really well too, he said, though "It's a little stinky."

Vega blends his passions for science and cooking at his lab at Mars Inc. World-class chefs come to him with their problems or ideas, and he helps them.

"Chefs are very curious minds," he said. "This opens up the possibility to team up with them and listen to their ideas and think through if it's possible to make what they are envisioning."

Follow Tanya Lewis on Twitter and Google+. Follow us @livescience, Facebook & Google+. Original article on Live Science.

Interesting background

"I've never eaten a museum exhibit before," said a man sampling hydroponic watercress this week during a preview of the new exhibition on food at New York's American Museum of Natural History.

"Our Global Kitchen: Food, Nature, Culture" opens Nov. 17, taking visitors on an interactive, visual tour of food as sustenance, entertainment, ritual, and more. The show explores the surprising history of many favorite foods, and displays sample meals of people like writer Jane Austen, Olympic athlete Michael Phelps, and Mongolian leader Kublai Khan. Visitors can even sample treats inside a working kitchen, and take a test to tell if they are "supertasters."

Here are the top 10 things we learned touring the exhibition:

Waste

About 30 percent of all food produced is never eaten. The world produces enough food to feed all its human inhabitants, but the problem is distribution — the food doesn't always get to the people who need it. For example, just one U.S. family of four wastes 1,656 pounds (751 kilograms) of food every year.

Egg Hatchers

Wild chickens naturally produce only about 15 eggs a year, but farmers have bred domesticated chickens to lay up to 200 or 300 eggs per annum.

Peppers, Chocolate & Tomatoes

Many of the foods central to cuisines around the world originated in the Americas. For example, until 500 years ago, no one outside of the Americas had ever tasted chili peppers, chocolate or tomatoes. Now those ingredients are essential to the cuisines of Thailand, France, Italy and many other places. [7 Perfect Survival Foods]

Square Melons

People in Japan grow watermelons in glass cubes to force them into forming square-shaped. These cubic melons are easier to store in refrigerators and slide into squares, and sell for significantly more than regular watermelons. The seeds from these melons still produce round watermelons, unless those, too, are grown in cubes.

Spicy Bird Seed

Birds can't taste capsaicin, the chemical that gives chili peppers their kick, enabling birds to eat spicy peppers and spread their seeds far and wide without being bothered by the irritant.

Table Manners

American people didn't start using forks to eat food until the mid 1800s. Before then, they used their hands, knives and spoons to transfer food from plate to mouth.Meanwhile, some people in China say the use of chopsticks over knives for eating there reflects the importance of scholars over warriors in Chinese culture.

Land Use

Humans use about 40 percent of the world's ice-free land to grow crops and livestock for food.

Bring to a Boil, Then Simmer

The technique of simmering food to cook it didn't develop until 10,000 years ago, because boiling food requires using airtight containers, which weren't available until then.

A Taste for Spice

Women who eat very spicy foods while pregnant and breast-feeding can pass along an appreciation for hot dishes to very young children. That's why many small kids in places like India, Mexico and Thailand can stomach foods much spicier than many grown adults elsewhere.

Under and Overfed

A person can be both overweight and malnourished, if they eat too many fatty foods high in calories that lack the vitamins and minerals a body needs.

Follow Clara Moskowitz on Twitter @ClaraMoskowitz or LiveScience @livescience. We're also on Facebook & Google+.

Wine goes with cheese. Meat sandwiches go with a pickle. Green tea goes with Asian food. Sushi goes with pickled ginger. Oil goes with vinegar. Soda goes with chips. Many of the world's most beloved food combinations pair an astringent food, which causes the mouth to pucker up, with a fatty food, which makes the mouth feel slippery.

But why? "The kernel of this idea of pairing astringents with fats is found in gastronomies all over the planet, but it's never been clear how or why these pairings work," said Paul Breslin, an experimental psychologist at Rutgers University and Monell Chemical Senses Center who studies taste perception.

In a new paper published online Oct. 8 in the journal Cell, Breslin and colleagues propose a theory of food pairings that explains for the first time how astringent and fatty foods oppose one another to create a balanced "mouthfeel."

Because fat is oily, eating it lubricates the mouth, making it feel slick or even slimy, Breslin said. Meanwhile, astringents, chemical compounds such as the tannins in wine and green tea, make the mouth feel dry and rough. They do this by chemically binding with lubricant proteins present in saliva, causing the proteins to clump together and solidify, and leaving the surface of the tongue and gums without their usual coating of lubrication. [Tip of the Tongue: The 7 (Other) Flavors Humans May Taste]

We don't like slimy, but we don't like puckered up, either. "We want our mouth to be lubricated but not overly lubricated," Breslin told LiveScience. "In our study, we show that astringents reduce the lubricants in the mouth during a fatty meal and return balance."

Although this food-pairing idea had been proposed before, it was a mystery how that balance might actually be struck, because wine, green tea and the other widely consumed astringents are only mildly astringent. No one knew how they managed to cut the fat as well as they do. [Will People Really Be Forced to Stop Eating Meat?]

The researchers discovered that astringents have a stronger effect each time the mouth is exposed to them. Every time study participants took a sip of green tea, for example, they perceived it to be more astringent than during the previous sip, indicating that the astringents were reacting more strongly with the lubricating proteins in their mouths upon each exposure. This growth in astringency is why, even though tea and wine have only a weak effect at first, sipping them throughout a fatty meal eventually enables the astringents to counterbalance the strong lubricating effect of the fat.

A second experiment supported this conclusion. When the study participants alternated their sips of tea with bites of salami, the perceived slipperiness of their mouths (caused by the fatty salami) gradually decreased as they took more sips. When they sipped water, by contrast, the slimy feeling in their mouths continued to build.

The importance of repeated exposure explains why we don't tend to gulp down an entire glass of wine then eat our entire steak. Nor do we polish off our whole pickle before setting into our sandwich. The new research justifies the widespread use of astringent foods as "palate cleansers" that people sample throughout a meal.

This general principle of yin and yang food pairings goes part of the way in explaining gastronomy, but what about the specifics? Why do we pair sushi with pickled ginger rather than with a soda, despite the fact that they're both astringents? And why does cheese seem to taste better with red wine than with green tea?  As Breslin put it, "Is there something to the idea that a particular astringent and a particular fatty food go together?"

The famous pairings could simply be cultural accidents — a matter of which foods were available in which regions. But Breslin said it's also possible that cultures have unknowingly worked out the most balanced pairings based on the chemical properties of the foods.

"Different kinds of astringents give rise to different rates of growth of astringency. As you repeatedly sample them, one will have a steep rise and the other a shallow rise," he said. "It could be that there's a particular mixing of an astringent and a fatty food that determines how strong the astringent is going to be and how quickly it gets there. This is a mystery of gastronomy."

Biting into a lemon has never tasted so sweet. New research reveals the secret ingredient of a little red "miracle fruit," which turns sour into sweet. The results won't just make for sweet lemons, but could lead to more believable non-sugar sweeteners.

The effect of the fruit is so mind-bending it is even used during "flavor-tripping parties," where people pop a berry and eat sour foods. These parties received lots of attention after a New York Times article about the phenomenon in 2008. The effect from one berry, which costs around $2, lasts about an hour.

The researchers found that this little berry contains a special protein, called miraculin, which attaches to sweet-sensing taste buds. It seems to hold on tighter to these receptors when there are acids, which give foods a sour taste, in the mouth as well.

"Miraculin itself is flat in taste," study researcher Keiko Abe, of the University of Tokyo, told LiveScience in an email. "Under acidic conditions, MCL [miraculin] changes its molecular structure so that the binding gets much stronger."

Holding tight

This strong binding turns on the sweet switch in the taste bud cells, sending a "Hey, this is sweet!" signal to the brain. How this protein binds to our buds so sweetly could help in the design of new artificial sweeteners.

The miracle fruit, which goes by the scientific names Richardella dulcifica or Synsepalum dulcificum, was discovered in tropical West Africa in 1725 by a European explorer. He noticed that the locals chewed the berries before meals.

To figure out how the berry works, the researchers studied the interaction between miraculin and cells that were engineered to express either the mouse or human versions of the sweetness receptor. Since mice don't respond to miraculin, the researchers looked for differences between the human and mouse receptors, seeing what parts were important to send the sweetness signals. That way they isolated a small area on the human receptors that miraculin likely binds to and results in the sweetness effect.

"We scientifically solved the miracle riddle of why miraculin changes sourness into sweetness in the mouth," Abe said. Miraculin works differently than other known sweeteners, including calorie-free sweeteners found in diet sodas, which bind to a different area on our taste receptors.

Sweeter than sugar

In the presence of sour foods, miraculin binds to the sweetness receptor a million times stronger than the artificial sweetener aspartame and 100 million times stronger than sugar. The stronger the compound binds, the sweeter the taste.

"At acidic pH in the mouth, it changes the sour taste of any acidic substance into sweetness and can thus be used as a sweetener only for sour foods such as lemon, vinegar, beer and so on, although most common foods are acidic to a greater or lesser extent," Abe told LiveScience. "So, the utility of this protein may be very large."

Researchers are currently working on ways to "grow" miraculin in the lab, by designing other fruits or vegetables that can make the protein, including lettuce or microorganisms like mold.

The study was published today (Sept. 26) in the journal Proceedings of the National Academy of Sciences.

You can follow LiveScience staff writer Jennifer Welsh on Twitter @microbelover. Follow LiveScience for the latest in science news and discoveries on Twitter @livescience and on Facebook.

What's July Fourth without the sizzle of the grill and plates piled high with hot dogs and burgers (and veggie burgers for the non-carnivores among us)? But if you want to avoid shriveled dogs and tough patties, you've got to understand not just the art of grilling, but the science. Don't worry: LiveScience is here to help.

We got on the phone with Dave Joachim, a food writer and author of "Mastering the Grill: The Owner's Manuel for Outdoor Cooking" (Chronicle Books, 2007) and "Fire It Up. 400 Recipes for Grilling Everything" (Chronicle Books, 2011). When Joachim says "everything," he means it: His cookbook contains recipes for everything from bison cheeseburgers to grilled watermelon.

We asked Joachim what's really going on when you cook on charcoal, gas or wood and why a seared steak is so delicious. Read on for what we learned — and for Joachim's recipe for those bison burgers.

What's the difference between grilling and barbecue?

People sometimes use the terms "grilling" and "barbecuing" interchangeably, Joachim said, but they're actually polar opposites.

"Grilling is typically cooking directly over a heat source at relatively high heat, 350 degrees Fahrenheit (176 degrees Celsius) or above for a relatively short amount of time, about 30 minutes," Joachim said. "Barbecue is somewhat the opposite. It's cooking at 250 degrees F or less for a long period of time, usually at least two hours."

What happens to meat as it cooks?

Meat goes through a few stages when you put it over heat. At about 110 degrees F (43 degrees C) internal temperature, muscles fibers begin to coagulate and toughen, Joachim said. At around 115 degrees F (46 C), fats start to melt.

When the internal temperature of the meat hits 130 F (54 C), the proteins in the muscle fibers denature, meaning that long, convoluted strands of protein lose their shape and unravel. Then they coagulate back together. That's when meat starts to take on an opaque look. At 160 F (71 C), the connective tissues that hold together the muscle fibers start to melt and turn into gelatin. That's the jelly-like yellowish-white stuff you see at the bottom of a roasting pan that you've cooked meat in, Joachim said. [7 Foods Your Heart Will Hate]

When you barbecue, Joachim said, the goal is to use those long, not-so-hot cooking times to melt the connective tissues and create barbecue's trademark tender mouthful. Grilled cuts of meat usually contain less connective tissue, so they don't need hours of heat to taste delicious.

Does it matter if I cook on gas, charcoal or a wood grill?

Absolutely, Joachim said.

"The big difference is the temperature and the moisture," he said. "Charcoal and wood burn hotter and drier than gas."

That's because propane contains moisture, Joachim said. For every hour of grilling on gas, you release a half-cup to a cup of water vapor into your grill. That keeps the temperature down and prevents the formation of a seared, browned crust on your meat.

Some gas grills now come with a sear burner, Joachim said, which is a ceramic block that holds heat better than the grill grates. Because the burner can build up more heat, home grillers can use it to brown the outside of a steak or pork chop to get that dark crust.

Okay, but why does a seared crust taste so good?

Time for a chemistry lesson: When you apply heat to meat, you get something called a Maillard reaction. The amino acids that make up the meat's proteins react with sugars in the meat, creating hundreds of flavor compounds.

Maillard reactions make pretty much everything taste awesome, including roasted coffee, grilled vegetables and even your morning toast.

"Any browned food tastes so good because it's something new added to the food," Joachim said. Browning doesn't just lock in flavors; it creates new ones.

What's the key to the perfect Fourth of July burger?

"The trick with ground meat is once you grind up meat, you're grinding up the muscle fibers, and these are what hold the moisture in," Joachim said. "What I recommend doing is adding moisture back in."

That added moisture can take many different forms, Joachim said. He uses apple butter in turkey burgers and steak sauce in hamburgers. Simplest of all, he said, you can just mix ice water into the ground meat, along with whatever seasonings you want to use to spice up your burger. The ice water adds in moisture while keeping the inside of the burger cool so it doesn't overcook. [Grilled to Perfection: Joachim's Recipe for Bison Cheeseburgers with Horseradish Mustard]

Fat is another important component of a good burger, Joachim said. He recommends a ground beef that's 80 percent protein and 20 percent fat. Contrary to popular belief, though, extra fatdoesn't make a burger juicier. Instead, fat stimulates saliva production, moistening your mouth.

When you add fat to a burger, Joachim said, it's not getting juicier: "You're getting juicier."

I'm a vegetarian, get me out of here.

Wait, come back! Just because you don't eat meat doesn't mean you're doomed to an Independence Day full of limp veggie burgers. The grill is the perfect place to cook plants, Joachim said.

"Grilling plant foods completely changes their character and makes them taste better," Joachim said. "Grilled tofu, for instance, tastes so much better than braised or steamed or sautéed."

The trick to grilling vegetables is remembering that they're edible raw, Joachim said, so you don't need to leave them on the grill until they scream for mercy. Just oil them, sear them over medium-high heat and enjoy. For firmer veggies like corn, you'll need a little more time. For corn, Joachim says simple is best: Throw the ears, husks and all, on the grill over medium-high heat and let them cook for 15 or so minutes, turning occasionally, until the husks are blackened. Inside, the corn will be perfectly done. [Read: How to Have a Healthier Cook Out]

What is the craziest thing I could possibly put on the grill?

You can grill doughnuts, Joachim said. Make them or buy them, coat them with cooking spray and put them on the grill over medium heat. The heat will caramelize the sugar and puff up the dough.

"It's unlike a regular doughnut, and it's just so completely delicious," Joachim said.

If that's not impressive enough for your July Fourth guests, confuse them by grilling watermelon. These fruits are more than 90 percent water, Joachim said, so putting them on the grill concentrates their flavor and gives you an entirely new texture.

You can follow LiveScience senior writer Stephanie Pappas on Twitter @sipappas. Follow LiveScience for the latest in science news and discoveries on Twitter @livescience and on Facebook.

Food writer and author David Joachim has grilled up just about everything, and we mean everything, including watermelon, doughnuts and bison. Here's his recipe for all-American juicy bison burgers, adapted with permission from "Fire it Up: 400 Recipes for Grilling Everything" by Andrew Schloss and David Joachim:

Bison Cheeseburgers with Horseradish Mustard

If you didn’t know they were bison, you’d swear these were all-American cheeseburgers. To ramp up the flavor of the mild meat, we mix a little steak sauce into the meat and spoon some mayonnaise flavored with horseradish and mustard over the burgers. The addition of toppings like ripe slices of beefsteak tomatoes and torn pieces of crisp lettuce are entirely up to you, but resist the urge to cook these past medium doneness. Grilled bison burgers go from juicy to leathery in minutes.

Makes 6 servings

INGREDIENTS:

1/3 cup whole-grain Dijon mustard

2 tablespoons prepared mayonnaise

1 tablespoon prepared horseradish

2 pounds ground bison chuck

1/4 cup bottled steak sauce, such as A1

1 tablespoon olive oil

3 scallions (green and white parts), sliced

3/4 teaspoon coarse salt

1/4 teaspoon freshly ground black pepper

6 slices sharp cheddar cheese

6 hamburger buns, split

DIRECTIONS:

Mix the mustard, mayonnaise, and horseradish in a small bowl.

Heat a grill for direct medium heat, about 375ºF. Using your hands, mix together the bison, steak sauce, oil, scallions, salt, and pepper in a bowl until well blended; avoid overmixing. Using a light touch, form into 6 patties no more than 1 in thick.

Brush the grill grate and coat with oil. Grill the burgers directly over the heat for 6 to 7 minutes for medium-done (about 150ºF on an instant-read thermometer, and slightly pink in the center), flipping once. Put the cheese on the burgers 1 minute before they will be done. To toast the buns, grill them, cut-side down, directly over the heat for 1 to 2 minutes. If serving the burgers directly from the grill, serve on the buns. If the burgers will sit, even for a few minutes, keep the burgers and buns separate until just before serving. 

In what might seem to defy the laws of comfort foods, researchers are setting out to concoct a healthy, yes healthy, ice cream.

If the food scientists are successful, ice cream would become another so-called functional food, alongside whole oat products and foods made with soy protein, which have scientifically established health benefits beyond basic nutrition. (The United States doesn't currently have a formal definition for functional foods.)

In addition to ice-cream's fat- and calorie-filled ingredients, the researchers hope to add dietary fiber, antioxidants and probiotics (gut bacteria that support a healthy digestive system) to your delectable dessert. Antioxidants could protect cells from damage caused by molecules called free radicals and are suspected of helping to prevent a slew of diseases.

The scientists expect to have a prototype, meaning a product ready for tasting but not yet ready for market, within six months and a marketable product in perhaps two years.

If and when it does hit store shelves, the researchers don't advocate replacing your fruits and veggies with the functional ice cream.

"The intent is that instead of feeling guilty because you are eating this ice cream, which has received a bad rap because it is so high-fat, to really say that 'Yeah I treated myself to a full-fat ice cream, but I did contribute to my nutritional needs in regard to my gut health, my antioxidant needs and my dietary fiber,'" said ice-cream researcher Ingolf Gruen, a professor of food chemistry at the University of Missouri-Columbia.

Gruen and his colleagues chose the added ingredients because they have been shown to contribute to a person's health and also because they are familiar to consumers.

Gruen said people buy a food for two reasons: either because they really enjoy the food or because it's good for them. If the researchers were to add foreign, albeit beneficial, ingredients, consumers might pass right by the treat. "We're trying to hit the big three, so to speak, of what consumers know about," Gruen told LiveScience.

The researchers foresee a healthy ice cream that tastes good but likely wouldn't be the ultra-delicious stuff that makes you gain weight just thinking about it.

They also foresee consumers saying, "Oh it's not as good as the full-fat heavy ice cream, but because it is good for me, and it still tastes good, I will purchase it," Gruen said.

Challenges abound, however.

"Our major challenges are texture, flavor and psychological acceptance," Gruen said. "The nutrients we add often have bitter tastes and affect the texture of ice cream that we have to mask."

He added, "Flavors like chocolate are easier to work with because the flavor is so strong that it can overcome other flavors from the nutrients."

For instance, they could just add a dash of dietary fiber to avoid too gritty a texture, but Gruen said that's not the point.

"We want to make sure if you consume it there is a significant contribution to health benefits from these ingredients," Gruen said. He said the final product could contain between 10 and 15 percent of your daily fiber requirements.

To inject the ice cream with antioxidants, the team is trying out different amounts of the açai berry. The berry has an unpleasant flavor, Gruen noted, so the researchers are figuring out how to balance a good antioxidant punch with the least açai flavor.

• Good Foods Gone Bad
• Top 10 Bad Things That Are Good For You
• Why Does Ice Cream Cause Brain Freeze?

{{ video="LS_091110_healthy-ice-cream" title="Making Ice Cream Healthy" caption="University of Missouri researchers describe how they are working to make ice cream good for you by adding fiber and nutrients. Credit: University of Missouri News Bureau." }}

Testing the hotness of a habanero chili pepper just went digital.

A team of chemists has developed a mathematical computer model to measure the "heat" inside a chili pepper, a process that could provide quicker and cheaper information to certain food and drug industries. For instance, some arthritis medications contain chemicals from hot peppers.

Peppers get their hotness from a family of chemicals called capsaicinoids, with two members (capsaicin and dihydrocapsaicin) of the group making up 90 percent of the capsaicinoids.

The spiciness of each pepper depends on the relative amounts of these hot compounds hidden inside the pepper's flesh.

“Capsaicinoids are the active ingredient in pepper spray, tear gas and some arthritis medications, not to mention spices and foods like salsa, so a wide range of industries could find this new approach useful,” said lead scientist Kenneth Busch, a chemist at Baylor University in Texas.

Currently, the standard test of pepper hotness relies on a process called high-performance liquid chromatography. This method is expensive and time consuming (each sample can take 10 minutes to run), because the machine chemically separates all the different compounds before spitting out a reading.

Busch and his colleagues developed a computer model that can calculate the hotness of a pepper based on information gleaned from spectroscopy, which measures how a substance absorbs light. The program is set up so that when a scientist feeds a "spectra" into it, the program disregards components uninvolved in spicy heat and focuses only on the capsaicinoid factors.

The research will be published in an upcoming issue of the Journal of Agricultural and Food Chemistry.

• Why do Chili Peppers Taste Hot?
• Ancient Crumbs Reveal History of Chili Peppers
• Top 10 Good Food Gone Bad