Carbohydrates like pizza, pasta, and polenta are a favorite of many. For those looking to lose weight, they are incredibly hard to resist, and are often seen as a food-enemy. Now, a new study suggests that there may be a scientific reason for our love of carbs – because they are our 6th taste.
Previously, scientists have stated that we have 5 primary tastes which live on our tongues, salty, sweet, sour, bitter, and savory. But the new study suggests that carbohydrates may actually be the sixth taste. And it would make sense, considering almost every culture has carbohydrate-laden staple foods that they enjoy on a regular basis. 
Coordinating author Juyun Lim of Oregon State University echoed this sentiment, stating:
“Every culture has a major source of complex carbohydrate. The idea that we can’t taste what we’re eating doesn’t make sense.”
Carbs, particularly starch, are made of chains of sugar molecules and are actually very important for our diet. Previously, it was thought that we were unable to taste these starches specifically, and instead were responding to the sweet molecules in our saliva.
The team tested various volunteers by giving them different carbohydrate solutions. Most people, says Lim, identified them as “starchy.” Most often, those of Asian descent described the taste as being similar to rice, while Caucasian participants identified it tasting similar to bread or pasta.
Volunteers were also given an enzyme to block the receptors of sweetness on the tongue to see if what they were tasting was actually the sugar. It was discovered that they could still taste the starch in short-chain carbohydrates, but not in long-chain carbs. This suggests that the starch taste people detect is typically only from short-chain carbs.
Lim says that this is the first in a long line of research that will delve into taste. She says that scientists are moving away from the 5-taste model, delving into the idea of us having many more. One scientist is also working to see whether humans can taste calcium specifically.
Lim also notes that people likely prefer complex carbs not just because of their taste, but because of they are a slow-release energy source.
 IFL Science
 New Scientist