In an article – What's Cooking America; How To Cook With Wine – I found that wine has three main uses in the kitchen – as a marinade ingredient, as a cooking liquid, and as a flavoring in a finished dish. The alcohol in the wine evaporates while the food is cooking, and only the flavor remains. Boiling down wine concentrates the flavor, including acidity and sweetness.
The function of wine in cooking is to intensify, enhance, and accent the flavor and aroma of food – not to mask the flavor of what you are cooking but rather to fortify it.
My question is how does wine in cooking intensify, enhance, and accent the flavor and aroma of food? What is the chemistry behind?
Best Answer
The other answers make good points, but OP in comments keeps asking whether alcohol helps ingredients "release their flavor" more. And yes, it does.
As to how it does so, one reason is simply because alcohol is a good solvent. Many things dissolve more easily in alcohol than in plain water. (Note that alcohols are often used in other household applications requiring solvents, stain removal, removal of other "gunk" when cleaning, etc. Household cleaning fluid can make use of various alcohols -- not just ethanol, as found in wine -- but the chemistry of how most alcohols work in creating better solubility is similar.)
Another comparison to think of is the use of alcohol in creating things like extracts. You'll get more flavor out of a vanilla bean by soaking it in high-proof alcohol compared to plain water. That's the same rationale behind the concept of a "vodka sauce" too.
Obviously wine doesn't have as high of an alcohol content, but the alcohol that is present can help "release flavors" through better solubility, part of the reason why wine is often used for deglazing pans too during cooking. (As mentioned in other answers, the specific flavor components found in wine are also tasty in and of themselves.)