Optimization of Carrot-fermented Blueberry Milk Tablet by Response Surface Methodology

The carrot-fermented blueberry milk tablets were prepared from skim milk powder,carrot powder and fermented blueberry lyophilized powder,and the related process was optimized. The optimal conditions for fermenting blueberries were determined by orthogonal test with the total antioxidant capacity for identification. The blueberry fermentation broth was made into lyophilized powder by vacuum freeze-drying method. The milk tablets process was optimized by single factor experiment and response surface method with the sensory score of milk tablets as the response value. The results showed that the optimal conditions for fermenting blueberries were fermentation temperature 35℃,5% strain addition,fermentation time 25 h. Under this condition,the total antioxidant capacity of blueberry fermentation broth was 230.158 U/mL,which was 33.18% higher than that before blueberry juice fermentation. The best preparation formula for milk tablets was milk powder:Fruit and vegetable powder=2:1,7.5% maltitol,0.3% citric acid,0.5% magnesium stearate,the sensory score under this condition was 95 points. This product retains the nutritional value of blueberries and has a good market application prospect.