Taste Perception of Sugars in Wine
The Role of Sugar in the Taste Perception of Wine
Taste buds can register four types of sensation; sweet, sour, bitter and salt. The process by which molecules cause these sensations is extremely complicated and is not as important as understanding how these taste sensations relate to each other.
Generally, the sweetness of sugar balances out the bitterness of phenols. Although the relationship is not that simple, your overall perception of a wine is based on these properties. Different factors influence sweetness; for instance, alcohol enhances your perception of sweetness.
Perceptible sweetness is the threshold level of sweetness that your brain registers. Each individual has a different threshold value; the most acute will be around 0.2% sugar by volume. However, most people begin to perceive sweetness at around 1%.
Winemakers must take individual differences in threshold into account for the final product. In addition, winemakers must pay careful attention to the types of sugars in the wine. Different sugars illicit different responses, and these are based on molecular structure.
Taste Perception of Sugars on a Molecular Level
The phenomenon of sugar sweetness is a perceived on a macro level, buts its fundamentals are built on molecular level. Sugar molecules have the basic formula of (CH2O)n. The most common and important sugar, glucose, has the formula C6H12O6. The chemistry of sugar is of the utmost importance in the perception of sweetness.
Sugars tend to bond together to form long chains. This is beneficial to organisms for a multitude of reasons; with storage and maintaining osmolarity being the most important.
The perception of sweetness is dependent on the size of the sugar molecules. In taste perception, you perceive fructose as the sweetest sugar, then glucose. This is because they are single sugar molecules. As the sugar molecules join together, their perceived sweetness decreases. This is why carbohydrates (long chains of sugars) do not taste sweet.
The mechanism behind this abstract, but simple in principle; on the molecular level, your taste buds have sensors that fit specific molecules. Once a molecule binds to these sensors, a signal is sent to your brain, and you consciously perceive “sweetness.” This is relevant because larger glucose polymers (long chains of sugars) do not fit into these receptors.
It makes sense then, that the smallest sugars are the sweetest. And long chain carbohydrate, like those in potatoes, are not.
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