Along with the actual flavour and aroma of food, the texture matters a great deal:
As eaters, we tend to downplay texture’s importance. A 2002 study in the Journal of Sensory Studies found that texture lagged behind taste and smell — and only occasionally beat out temperature — in terms of the perceived impact on flavor. But you only have to look at pasta to see how strongly texture impacts our perception of taste. We’ll eat macaroni and cheese in the form of spirals, shells, and noodles shaped like Spongebob Squarepants, but spaghetti mixed with florescent “cheese” powder seems anathema — it’s the texture that makes the difference.
For the longest time, food scientists downplayed texture’s importance as well. “When I was a student pursuing a degree in food science, I was taught that flavor was a combination of mainly taste and smell,” recalls Jeannine Delwiche, one of the authors of the 2002 study.
But how a food feels affects our enjoyment of the thing. There is, of course, the actual texture of the food, which scientists call rheology. Rheology focuses on consistency and flow. For example, it’s fairly evident that cotton candy has a different texture than plain sugar, even though sugar is its only ingredient. But the perception of a food’s rheology — what scientists call psychorheology — is another thing entirely. If you’ve ever wondered why sour candy always seems to come coated in rough sugar, the reason is simple: We perceive rougher foods as being more sour. Psychorheology is why we like gummy bears in solid but not liquid form, why we enjoy carbonated soda but balk at its flavor when it goes flat. It’s why we perceive gelato as creamier than ice cream — even though the latter has more fat.
Texture is an important indicator of a food’s fat content. If we can figure out how to trick our tongues into sensing more fat than is actually present in a food, we can increase satiation while decreasing a food’s calorie count. That’s why some researchers are finally turning their attention to these taste-making sensations.