Protein Extraction from Defatted Soybean Flour with Viscozyme L Pretreatment

Abstract

Defatted soy flour (DSF) was pretreated with Viscozyme L to hydrolyze cell wall polysaccharides with the objective of enhancing protein extraction. Response surface methodology (RSM) was used to study the effects of treatment variables, Viscozyme L concentration (15–45 fungal beta-glucanase units [FBG]/10 g solids) and temperature (45–65C), on protein extraction and reducing sugars released from DSF. The regression model represented the relationship between the independent variables and the responses. Protein extraction from DSF was mainly affected by temperature, whereas the content of reducing sugars was affected by the enzyme concentration. From the RSM-generated model the optimum conditions for maximum hydrolysis of carbohydrates occurred at temperature of 45C with Viscozyme L concentration of 45 FBG/10 g of DSF, but the most carbohydrate hydrolysis did not result in higher protein extraction which was affected mostly by the temperature of pretreatment, with higher extraction at the higher temperatures (55 and 65C). Practical Applications The enzyme treatment to legume or cereal flours have been recognized in the food industry and the main objective is to improve the utilization of nutrients in raw materials. The multicomponent nature of Viscozyme L, which contained a wide range of carbohydrases including arabanase, cellulase, hemicellulase and xylanase seemed to be advantageous in cleaving the linkages within the polysaccharide matrix, and hence liberating more intercellular constituents like nitrogen. However, preprocessing of soy flour with Viscozyme L for the extraction of protein has not been previously reported. This study provides very important information about the optimum Viscozyme concentration and temperature that is useful for increased protein extraction and to produce the best quality products.