What Color Tastes Like

Start reading the ingredients list on pre-packaged foods, and you may be in for a surprise. I’m not talking about the “high fructose corn syrup” that always appears to be the second main ingredient, or the various preservatives only a chemist or National Spelling Bee contestant has any hopes of pronouncing; although those often make me reconsider my own menu, I’ve come to expect them. What still often surprises me are the artificial colors: Red #40, Yellow #5, and a whole host of other dyes. Given how many artificial dyes have been banned as health hazards, I had to wonder why food manufacturers still bothered. Could the color of a food really matter that much?

Turns out, yes. The color of our food can overwhelm and overrule our taste buds. A new classic science fair experiment for kids seems to be seeing how adding color of carbonated water will lead people to perceive different flavors, probably based on associations like red strawberries and purple grapes.

In brief, people were asked to compare small cups of orange juice and rate how different the tastes were, from “exactly the same” (numerically, a 1) to “very different” (numerically, a 7). What these people didn’t know was that researchers had gone in and adulterated that orange juice, by adding some combination of aspartame sweetener (brand name Equal) and yellow food dye (brand name McCormick). Just a few drops of yellow food dye were enough to alter perceptions, because the eyes overruled the tongue. People would say that two cups of orange juice that had the same color but different amounts of aspartame were relatively similar (about a 3), while two cups of orange juice that had the same amount of aspartame but different colors were more different (almost a 5). In other words, people weren’t tasting the orange juice with their tongue, or not with their tongue alone; they tasted with their eyes, and a color difference could prompt the mind to taste something that wasn’t really there.

Given two identical orange juices of a slightly different color, people will taste a difference that isn't there.

Given two identical orange juices of a slightly different color, people will taste a difference that isn’t there.

This overruling of the tongue is specific to color: being told that orange juices were different brands didn’t lead to a false perception of differences, nor did being told they were different prices. But is this enough to justify all those artificial dyes?

The problem is that we don’t know where this expectation of color=taste comes from, and it might come from our previous experiences with artificial dyes. Since using dyes to make food attractive (not necessarily tasting different, just looking more appealing) has been around for my entire life, I have probably drunk enough artificially colored orange juice for my mind to have formed associations between what I was seeing and what I was tasting. Those previous experiences might color (pun intended) my perceptions of orange juice from here on out. But if food manufacturers hadn’t bothered coloring food for the past decades, would my eyes find it so easy to invent taste differences?

This may be one of those unanswerable questions – not because it’s a bad question, but because the people we need to ask it have gone the way of the unicorn. After all, who grows up without eating artificially colored food these days? The dyes may be on the decrease, but my mid-day fruit snack featured “vegetable juice (carrot, cabbage) for color”. Unless I eat with my eyes closed, my taste buds will never get the chance to decide for themselves.

ResearchBlogging.org
Hoegg, J, & Alba, J. W. (2007). Taste perception: More than meets the tongue Journal of Consumer Reports, 33, 490-498 DOI: 10.1086/510222

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