Harmful compounds of soy milk: characterization and reduction strategies

Soymilk is a plant based product which is a rich source of nutrients. However, various harmful compounds including allergens, anti-nutritional factors, and biogenic amines (BAs) exist in soybeans that may be transferred into soymilk. These compounds cause difficulties for consumers from mild to severe symptoms. Soymilk production is considered as a critical step in quantity of harmful compounds in final product. Common steps in soy milk manufacturing include soaking, grinding, and heating process. Allergens contents could be decreased by heating alone or in combination with structural modifiers and fermentation. BAs could be reduced by optimizing fermentation process and using suitable strains, especially BAs degradable types. Soaking, grinding and heating of soybeans in water are considered as effective methods for inactivation of antinutritional factors. Isoflavones are soy phytochemicals, which potentially leads to breast cancer in some women, can be converted to less bioavailable forms during processing. Other treatments such as high hydrostatic pressure and irradiation are also effective in harmful compounds reduction. Combination of the processes is more effective in harmful compounds removal. Considering the increasing trends in soymilk consumption, this review is focused on introduction of harmful compounds in soymilk and investigating the effects of processing condition on their concentration.