The chemistry of making tofu

Its chemical principle can be simply summarized as two processes: physical coagulation and chemical acid-base reaction. Tofu, also known as soybean flower and curd, is a traditional food made from soybeans as the main ingredient.

First of all, soybeans are rich in proteins and vegetable fats. When heated in soy milk, protein molecules are denatured due to the high temperature and form a reticulated structure, and under acidic or alkaline conditions, these denatured proteins intersect with each other and come together, thus forming a solid block of tofu.

At the same time, when coagulants are added, the acids and alkalis they represent react chemically with the protein molecules in the soymilk, causing the proteins to ionize, deconvolute, or coagulate, prompting the formation of blocks. Currently commonly used coagulants are mainly gypsum, brine, vinegar and so on.

In addition, different kinds of tofu will also add different auxiliary ingredients, such as sea salt, fresh milk, sugar, etc., to increase the texture and adjust the flavor. However, these auxiliary ingredients do not affect the main chemistry of tofu production.

In short, tofu making is a very old and interesting process whose chemistry involves physical deformations and chemical reactions that profoundly reflect the nutrients and special properties that soybeans possess.