Integrated processes for adding value to soymilk and okara

Abstract

Due to behavior change of consumers, who has been looking for healthier foods, consumption of soybean and its derivatives has been growing continuously since they have high quality protein, fiber and bioactive compounds such as isoflavones. Soymilk could be considered as one of the most important soybean products, because it is a product ready for consumption and easy to obtain. However, significant amount of proteins and isoflavones are not extracted during soymilk processing, being retained in the insoluble byproduct called okara or soy pulp. Usually, okara is underutilized as animal feed or discard, constituting a waste of nutrients which could have been used in human food. Thus, the present project aims to investigate the different processes in order to add value to these soybean products. In a first stage, the application of enzymes carbohydrase and protease during soymilk processing will be studied, aiming to enhance the yield of protein extraction and isoflavones and to produce bioactive peptides. Drying of soymilk by spray dryer and powder stability will be also evaluated. With respect to okara, since this byproduct is perishable, it is interesting to dry it. Because this product possesses high cohesiveness, different dryers will be studied: spouted bed using inert material and rotating-pulsed fluidized bed with and without microwaves application. The effect of type of dryer and process conditions on isoflavone content, antioxidant activity and technofunctional properties of proteins will be evaluated in dried products. (AU)