Tibetan Kefir Yogurt And Sour Milk Powder Production Technology Optimization

In this study, Tibetan kefir grains were with the same strains of kefir grains as the object.Studying the conventional nutrients of Tibetan kefir grains and its fermented milk compare tothe common yoghourts, optimizing the extraction process of polysaccharide of unique Tibetankefir and production process of Tibetan kefir grains fermented milk in the mean time. Theproduction technology of Tibetan kefir yogurt powder that is the subsequent products ofTibetan kefir grains fermented milk was optimized. The main results are as follows:(1)The national standard method were used for determining ash, solids content, proteincontent, fat content, crude polysaccharide content and acidity of the conventional nutrients ofTibetan kefir grains and its fermented milk. The content of each nutrient in the yogurt sold inTibetan kefir fermented milk were compared to the city’s. The results showed that the contents ofnutrition of Tibetan kefir grains body and fermented milk were higher than that of yoghurt,protein and fat content is particularly prominent, relatively low acidity of yoghurt.(2) In order to enhance the extraction rates of Tibetan kefiran, using a single factorexperimental and orthogonal test to optimize the extraction process of Tibetan kefiran. The resultshowed that extraction temperature and ratio of solid to liquid had significant effects on theextraction rates of Tibetan kefiran (p<0.05).The optimum extraction process as follows:extraction time of4h, extraction temperature of85℃, solid to liquid ratio of1:60, extractedtimes of4times, and the extraction rate of Tibetan kefiran was20.96%under this condition. Theanalysis of Infrared Spectra showed that the organic substance which extracted from TibetanMushroom possessed Sugar characteristic peak, and the sample of heteropolysaccharidecontained D-mannopyranose.(3) In this experiment, conditions of production process of four factors and three levelsorthogonal design of Tibetan kefir fermented milk were optimized. The optimal results wereobtained: Inoculum11%, fermentation temperature22℃, fermentation time9h, sucrose5%.Through the verification test, sensory evaluation of Tibetan kefir fermented milk under the optimal conditions, the value can reach96.52. Influence of Tibetan kefir fermented milk sensoryevaluation of inoculation and fermentation temperature significantly (p<0.01), and Influence ofTibetan kefir fermented milk sensory evaluation the fermentation time was significant (p<0.05).Sucrose sensory evaluation of Tibetan kefir fermented milk is not significant.(4) By sensory evaluation, effects of sucrose, Tibetan kefir addition, vector addition on thefreeze drying yoghurt powder quality influence. Optimizing the process conditions of Tibetankefir yogurt powder by orthogonal design. The optimum process conditions are as follows:Sucrose6%, adding7%mushroom body, vector addition10%. The production of Tibetan kefiryogurt powder under the optimum process conditions and determine the quality index. Theresults show that: Tibetan kefir yogurt powder as the uniform color, milky white or light yellowpowder, porous, no agglomeration has typical yogurt flavor, wet sinking fast, brewed with nolumps, bottom of the cup with a little precipitation. By the detection of the living bacterianumber was212×10~6CFU/g, water content is4.3%, recovery of yogurt titratable acidity was70.5, pH was4.63.