Are We Hard-Wired to Want Starch?
Tempted by pasta, potatoes, bread and other starches? Even the great chef Julia Child loved French fries, and she waxed poetic bout the joys of fresh bread. Tastes and our reactions to them are more complex than we realized, and a newly discovered sixth sense of taste may help explain some common cravings.
Scientists have long known that our tongues register salty, sweet, sour and bitter tastes. More than a century ago chefs and chemists recognized what the Japanese call umami, a meaty or savory taste that is generally recognized as pleasant and delicious. In 1985 umami was recognized as the scientific term to describe the taste of glutamates and nucleotides, which have been common in cooking since Roman times. In 2009 umami was recognized as the fifth taste sense.
A NewScientist story by Jessica Hamzelou describes research by Juyun Lim, an assistant professor of food science and technology at Oregon State University, who was curious about how taste works. “Every culture has a major source of complex carbohydrate,” she told Hamzelou. “The idea that we can’t taste what we’re eating doesn’t make sense.”
Complex carbohydrate such as starch are made of sugar molecules, Lim explained, and because enzymes in saliva break them down into shorter chains and simple sugars, many food scientists have assumed we detect starch by tasting these sweet molecules. Lim and colleagues gave volunteers a variety of carbohydrate solutions and discovered they were able to detect a starchy taste apart from sweetness. Asians would call it rice-like, and Caucasians would call it bread or pasta-like, she said.
Some scientists think there may be many specific tastes that receptors on the tongue can register. Michael Tordoff at Monell Chemical Senses Center in Philadelphia is investigating whether people can specifically taste calcium. Other taste possibilities are also being studied, and researchers believe new understandings will have many health implications. However, food scientists say there are strict criteria for what can be called a new taste sense.
One criterion, Lim said, is that the flavor has to be useful to us. Starch is a valuable source of slow-release energy so it qualifies as useful. “I believe that’s why people prefer complex carbs,” she said, adding that a little chocolate is nice but bread and rice are more useful as daily staples.