Storage And Incubation Properties Of Wheat Germ And The Development Of Its Nutritional Powder

The changes of major nutrients in fresh wheat germ during storage were investigated and the optimum storage conditions were obtained in this paper. Then the incubation condition for increment of protease activity and peptides accumulation was optimized. In the end, a nutrition powder rich in wheat germ peptides was developed. The major results were below:After stored at 4℃,25℃ and 37℃ for 35 d, the water content of wheat germ decreased, some big molecular such as protein, starch degraded into small molecules and the fatty acids defeated seriously. In addition, no significant decrease was recored in the activity of protease and the accumulation of wheat germ peptides. However, after stored at 4℃ for 10 d, there were no obvious changes in the water content, protein content, fatty acids content, protease activity and peptides accumulation of wheat germ. Hence, the storage condition of wheat germ was set at 4℃ for 10 d.In this paper, the incubation conditions of wheat germ for peptide accumulation were investigated. A significant influence of incubation time, temperaure, initial pH and liquid to solid ratio on peptide concentration of incubation medium was evaluated by single-factor experiments. These factors were further optimized using a Box-Behnken design. A combination of incubation time 6 h, temperature 49℃, initial pH 3.0 and liquid to solid ratio 10 was optimum for maximum peptide concentration (88.46 mg/g). Compared to the control (unincubated wheat germ), a 2.98-fold enhancement of peptide concentration was obtained after optimization in incubation medium.Peptide-enriched nutrition powder made of wheat germ was developed. The optimum ingredients of peptide-enriched nutrient power was:the germinated brown rice powder 72.50 g, incubated wheat germ powder 12.17 g and carrot powder 4.47 g, respectively. The optimum flavor composition was:10% defatted milk,10% sugar and 1% spirulina based on the aforementioned mixture powder. It was detected that the content of peptides in this powder was 93 mg/100g. Fuzzy comprehensive evaluation methodology showed that this powder was likely acceptable to sensory test members.