Which compound reacts with amino acids in heated milk to create flavor and color?

The correct response involves the Maillard reaction, which is a complex process that occurs when amino acids react with reducing sugars under heat. In heated milk, lactose, which is the primary sugar found in milk, participates in this reaction. When lactose reacts with the amino acids present in milk upon heating, it leads to the development of characteristic flavors and colors that enhance the overall sensory attributes of dairy products, especially during processes such as cheese making or milk pasteurization.

This reaction is particularly significant because it influences the taste and appearance of a variety of cooked milk products, contributing to the creation of new molecules that give rise to browning and intricate flavors that are desirable in many culinary applications.

As for the other compounds mentioned, casein and whey are types of milk proteins that provide structure and nutrition but do not directly contribute to the flavor and color changes in the same way that lactose does when subjected to heat. Milk fat, while important for the mouthfeel and creaminess of the product, also does not engage in the Maillard reaction with amino acids to produce flavor and color as lactose does.