Optimization of Wheat Embryo Globulin Fermenting Process and Variation in Properties during Fermentation

Abstract

In this study, an efficient preparation technology of fermented wheat embryo globulin (FWEG) was developed, and the changes of nutritional characteristics and structure of FWEG were studied during the fermentation process. Protein concentration was selected as the evaluation index, and Box-Behnken experiment design was employed for optimizing the preparation conditions of FWEG. The nutritional characteristics of FWEG during fermentation were dissected through SDSPAGE and free amino acid assay. The structural changes of FWEG during fermentation were analyzed through circular dichroism, sulfhydryl detection, and electron microscope scanning. The optimum fermentation conditions were determined. The protein concentration of FWEG reached 2.09 ± 0.15 mg mL-1 under the optimal conditions. Acidity, contents of protein and protease increased while the content of FWEG decreased in the fermentation. The concentration of small molecule protein and free amino acids went up along with the fermentation. Due to changes in the secondary structure of FWEG and massive released of sulfhydryl groups, the surface of FWEG became uneven during the fermentation. The optimal fermentation process was noticed after Baker's yeast fermentation, lasting for 3.2 h; Lactobacillus plantarum was inoculated, and the fermentation continuous for 14.8 h, in which the ratio of baker's yeast to L. plantarum (V:V) was 1:2. The nutritional quality of wheat embryo globulin was improved, and its structure was changed during fermentation, which increased the absorption of FWEG and enhanced its suitability as a food ingredient. © 2019 Friends Science Publishers