The influence of dietary fiber from rice bran and defatted sesame flour on fermented milk drink

Both rice bran (RB) and defatted sesame flour (DSC) areby-products of agricultural processing, they are rich in dietary fiber. In modern society, dietary fiberis increasingly being paid attention to for its health benefits. This paperis aimed onstudying the properties of kefir added with RB and DSC, including content of dietary fiber, pH, titratable acidity, viscosity, amount of Lactococcus spp., Lactobacillus spp. and yeast. Three different kefirs were investigated(control sample, kefir with 0.1% RB, kefir with 2% DSC) and stored for 28 days at 4±1 °C. The content of dietary fiber in samples of kefir, pH, titratable acidity, viscosity, amount of Lactococcus spp., Lactobacillus spp. and yeast were determined at 1st, 7th, 14th and 28th days of storage. Results showed that the introduction of RB and DSC increased the content of dietary fiber in kefir samples by 300% and 680%, compared to control sample, improved the viscosity by 6 times and 25 times compared to control sample, and acidity — by 9% and 75%, stimulated growth of probiotics including Lactococcus spp. (content increased by 6% and 8% compared to control sample), Lactobacillus spp.(content increased by 16% and 4% compared to control sample) and yeast (content increased by 7% and 1% compared to control sample on the 7th day of storage). The increase of dietary fiber content and probiotics quantity could improve the health properties of kefir, the increase viscosity make kefir more popular with consumers (according to the data from a survey of consumers, they tend to prefer thicker kefir) and the increase of acidity would shorten fermentation time and reduce production cost. To reach better quality of kefir, RB and DSC should be pretreated: crushing, decolorization, deodorization. And adding largeramount lead to bad taste, so the urgent problem which needs to be resolved is to decrease the adverse effect of RB and DSC on properties of kefir.