An important cause of the deterioration in flavor, texture, and vitamin content of frozen fruits and vegetables during storage is the action of hydrolytic enzymes released from the vacuoles of the cells. blanching (a quick dip in boiling water) prior freezing improves the keeping qualities of produce. how do you suppose blanching works?

Blanching works by denaturing the enzymes, rendering them inactive. Enzymes are proteins produced by the cells to perform various biological functions. Their effectiveness is critically dependent upon their shape. They act as catalysis to speed up chemical reactions. When you heat a protein, you cause the hydrogen bonds created when the protein is folded to break, changing the shape of the protein. And since enzymes are proteins, their shape and therefore their effectiveness also changes. So by blanching, you destroy the effectiveness of the enzymes that would cause the food to deteriorate.