Technical Optimization And Nutritional Evaluation Of Wheat Germ Yoghourt

The weight of wheat germ only accounts for 2% to 3% of the whole wheat grains, but it contains almost all kinds of nutrients of wheat grain. Many recent researches have shown that wheat germ is rich in protein, fat, vitamins and minerals and also contains some bioactive substances, such as flavonoids and glutathione. However, in China, for many years, the researches on the comprehensive utilization technology of wheat germ was in food industry were still in the primary stage, most of the wheat germ treated as by-products of flour processing and mixed into the feeds. The utilization of wheat grem resources is very limited.ObjectivesTo improve the nutritional quality of the yogurt and reduce the cost of yogurt producing, around 7.5% of milk powder was replaced by the wheat germ in the product manufacturing.Methods1. Single-factor experiments and response surface analysis were applied in the optimization of the fermentation process of wheat germ yogurt.2. The nutrient content in ordinary yoghurt and the wheat germ yoghurt were compared. The measured nutrients included crude protein, crude fat, crude fiber, minerals, vitamin B1, vitamin B2, vitamin E and flavonoids.Results1. The optimum conditions to produce wheat germ yogurt were as following:the proportions of whole milk powder and wheat germ. The inoculation were 12%,7.2%, and 8.8% respectively and the duration of fermentation was five hours.2. The levels of nutrients in wheat germ yogurt, such as crude protein, crude fat, crude fiber, calcium, magnesium, iron, zinc, copper, vitamin B1, vitamin B2, vitamin E and flavonoids were higher than that of ordinary yogurt and the contents were increasing with the increased proportion of wheat germ. The difference was statistically significant (P<0.05).3. The replacement of wheat germ with one third of the milk powder improved nutritional value of the yogurt product. The contents of crude protein, crude fiber, magnesium, iron, zinc, copper, vitamin B1, vitamin E and flavonoids were higher than that in the ordinary yogurt and the levels were increased with more proportion of wheat germ added, the difference was significant (P<0.05), while the contents of crude fat and copper were decreased, the difference was also significant (P<0.05).ConclusionThe technology of adding wheat germ and wheat germ replacement with milk powder to make yogurt was feasible. The inspections of the yogurt product in physical, chemical and microorganism aspects all fit the requirements of GB2746-1999. Addition of wheat germ not only increased the nutrition value, but also improved the flavor and taste of the yogurt. The process of wheat germ yogurt production was simple and easy to follow. Therefore, it is a novel way on the comprehensive utilization of wheat germ.