Chicken noodle soup, macaroni and cheese and mashed potatoes. Why do these comfort foods taste so good?
The answer isn't just that mom makes them. Many comfort foods contain the precursors to compounds that help store genetic information, said Robert Lindsay, a UW-Madison food science professor.
\They just make food taste good, make your mouth water and are satisfying to go down,"" Lindsay said. ""Comfort foods go beyond the social 'Yes, I'm comfortable' setting.""
The flavor-enhancing compounds are often released during cooking.
Eating raw potatoes, for example, isn't as satisfying as eating cooked potatoes. Heat releases an enzyme in the potatoes to help make the two types of compounds available, Lindsay said.
The freshest fish isn't usually the tastiest for the same reason, he said. It takes a dead fish three to five days to start releasing the enzymes that make flavor-enhancing compounds available, but after two weeks the enzyme cascade decreases and the fish stops tasting good. The bland-tasting frozen fish at the grocery store may not be spoiled, Lindsay said, but these compounds are gone.
Freshness is one part of taste, but why foods taste good goes beyond sweet, sour, salty and bitter. Instead, taste relies on a mix of psychology, sight , sound, texture and a flavorful chemical symphony.
Imagine how food would taste if one of these variables were off.
""When you order a plate of fajitas, you better hear them sizzling when they come to your table,"" said Scott Rankin, UW-Madison food science associate professor.
Marketing campaigns often appeal to the non-taste aspects of flavor perception, Rankin said, like a shiny apple or extra crunchy potato chips. What people think tastes good is subjective, Rankin said, and does not necessarily represent food quality.
Smell is linked to fl avor perception too. People who have had nose surgery sometimes lose their sense of smell and lose weight, Rankin said, because food isn't as appealing.
But the actual food flavor tastes the way it does largely from scent molecules.
""Most of the flavors we look at, there's a molecular basis for,"" Rankin said. Rankin researches flavor chemistry and often uses people to judge flavors. Some flavors, like sweetness, are easy to rate. Others, like rich butter flavor, require super-sensitive taste buds.
""I compare that ability to athletic ability,"" Rankin said.
Typically, smokers are poor tasters because the smoke aroma lingers on them. Young people are more sensitive tasters, but older people have more experience concentrating on and describing a taste, he said.
Natural flavors are more complex than artificial flavors. Vanillin, artificial vanilla, is just one chemical. Real vanilla flavor contains dozens of molecules contributing to the overall flavor. Experiencing a flavor comes from processing all the chemicals at once.
""If you listen to a symphony and you don't know much about music, you might ask 'Which
are the instruments that really make the music?' It's similar in flavors. You can perceive many, many compounds at once. The real challenge is to find the one molecule [that makes the flavor],"" Rankin said.
Professor Lindsay has dedicated his career to food chemistry. Sitting in his office with Flavor Chemistry scientific journals and Betty Crocker cookbooks lining his bookshelves, he said one of the most exciting parts of flavor chemistry is altering flavors to make foods more appetizing.
Foods that are most desirable are usually high in fats and carbohydrates, he said. Originally, scientists thought people could only smell-and thus taste-volatile, airborne chemicals, which are not in fats and carbohydrates, Lindsay said.
Scientists now recognize a fifth flavor, umami, which is essentially MSG. It is a taste just like salty or bitter.
""MSG is the poster child of these magic flavor compounds that convey deliciousness,"" Lindsay said.
""Now, we are learning unknown mechanisms. We can smell nonvolatile compounds,"" he said. ""This bridges the gap on why fatter foods taste so good.""
Lindsay said scientists could someday replace, say, broccoli's bitterness with the delicious umami taste.
""We could put some good taste into nutritional food,"" he said.
