Effect of microwave assisted extraction on yield and protein characteristics of soymilk

Microwave assisted extraction (MAE) has been investigated for its potential to aid in extraction of soymilk from soybeans. A batch type grinding cum microwave heating unit was specifically designed and developed for this purpose. MAE of soymilk has resulted in significant increase (p < 0.05) in extraction yield (24%) and protein content (44.4%) as compared to conventional soymilk. Protein characteristics such as protein solubility and protein digestibility of extracted soymilk also showed significant increase (p < 0.05) with respect to conventional milk. The influence of microwave process parameters including microwave power level (540-810W), target temperature (70-90 degrees C) and stirring speed (140-180 RPM) on protein characteristic of soymilk were analysed. Microwave power level and target temperature were significant (p < 0.05) parameters for the extraction process. The optimal MAE conditions were power level of 675W, target temperature of 80 degrees C and stirring speed of 160 RPM.