Of all the major food molecules, proteins are the most challenging and mercurial The others, water and fats and carbohydrates, are pretty stable and staid But expose proteins to a little heat, or acid, or salt, or air, and their behavior changes drastically This changeability reflects their biological mission Carbohydrates and fats are mainly passive forms of stored energy, or structural materials But proteins are the active machinery of life They assemble all the molecules that make a cell, themselves included, and tear them down as well; they move molecules from one place in the cell to another; in the form of muscle fibers, they move whole animals They’re at the heart of all organic activity, growth, and movement So it’s the nature of proteins to be active and sensitive When we cook foods that contain them, we take advantage of their dynamic nature to make new structures and consistencies Amino Acids and Peptides Like starch and cellulose, proteins are large polymers of smaller molecular units The smaller units are called amino acids They consist of between 10 and 40 atoms, mainly carbon, hydrogen, and oxygen, with at least one nitrogen atom in an amine group — NH>2— that gives the amino acids their family name A couple of amino acids include sulfur atoms There are about 20 different kinds of amino acids that occur in significant quantities in food Particular protein molecules are dozens to hundreds of amino acids long, and often contain many of the 20 different kinds Short chains of amino acids are called peptides Amino Acids and Peptides Contribute Flavor Three aspects of amino acids are especially important to the cook First, amino acids participate in the browning reactions ...Amino Acids and Peptides Like starch and cellulose, proteins are large polymers of smaller molecular units The smaller units are called amino acids They consist of between 10 and 40 atoms, mainly carbon, hydrogen, and oxygen, with at least... There are about 20 different kinds of amino acids that occur in significant quantities in food Particular protein molecules are dozens to hundreds of amino acids long, and often contain many of the 20 different kinds... carbon, hydrogen, and oxygen, with at least one nitrogen atom in an amine group — NH>2— that gives the amino acids their family name A couple of amino acids include sulfur atoms There are about 20 different