Insight into the Processing, Gelation and Functional Components of Tofu: A Review

Abstract

Soybeans are a good source of protein and functional nutrition for humans and are used in the production of many foods, such as soymilk and tofu, which are popular in Asia. Soymilk is a beverage with a milky appearance and is produced by grinding soybeans in water; this raw soymilk is then filtered and heated. Soymilk can be used to produce tofu, a gelatinous food, in a process that generally involves coagulating, forming, and pressing soymilk. Tofu is also a source of functional ingredients, such as isoflavones, that have received much attention for their antioxidant properties. These isoflavones bind to soy protein to form soy protein–isoflavone complexes in tofu. In this review, we examined the processing, gelation and functional components of tofu. First, we introduced novel processing technologies (such as thermal and nonthermal processing) and hydrocolloids that affect the rheological property and texture of tofu. Then, because the coagulation and gelation of soymilk are important steps in the tofu manufacturing process, we also described detailed coagulation and gelation mechanisms of soybean proteins in tofu. Finally, we described the functional compounds and ingredients in tofu. This review provides basic knowledge for the further application of novel processing technology in tofu processing.