英语时差：偏爱妈妈“口味”（上）

Why do most people like “Mom’s cooking”? Although family attachments can account for part of our appreciation, the fact that Mom’s (or Dad’s) cooking tastes good to us also has some basis in genetics. As we chew our food, we produce saliva, which contains a group of enzymes that start to digest the food even before we swallow it. One of these enzymes, amylase, is primarily responsible for breaking down starches, such as pasta or potatoes, into sugars, which stimulate our “sweet tooth.” All starches eventually are broken down into sugars in your system, but you can only enjoy the sweet taste if the changes happen before you swallow. As it happens, though, there are many different varieties of amylase, and the various types of this enzyme work in different ways to break down different starches.