Development Of Honey Yogurt And Edetermined Of The Main Ingredients

Honey yogurt was a new type of high nutritional value dairy products fermented by lactobacillus under the aseptic conditions, which used fresh milk as the main source of nitrogen, and honey as the main source of carbon. In order to improve the quality of the honey yogurt, the optimal processing parameters was studied by using the response surface method. Furthermore, the impact of stabilizer combination on water holding capacity, the nutritional value, and the storage period of honey yogurt were studied. The main experimental results were as follows:1. The fermentation technology of honey yogurt:Then main indexes of honey yogurt quality were studied, which included the curd time, acidity, pH, conversion ratio of reducing sugar, and sensory score. The results showed that the conversion ratio of reducing sugar could directly reflect the quality of honey yogurt. Based on the single factor experiments of sterilization conditions, the proportion of honey and milk, inoculation amounts, inoculation ratio and fermentation temperature, three factors for three levels of the response surface method were designed to analyze and optimize honey yogurt fermentation technical parameters. The proportion of honey and milk (Xi), inoculation amounts (X2) and fermentation temperature (X3) were defined as independent variables, and the reducing sugar conversion ratio(Y) was defined as dependent variable. The regression equation of the reducing sugar conversion ratio was received by the Design Expert8.0software Y=9.51+0.19X1+0.36X2+0.056X3+0.062X1X2-0.033X1X3-0.10X2X3-0.77X,2-0.60X22-0.067X32The maximum of reducing sugar conversion ratio was9.58%, which was obtained by the analysis of regression equation. The best technical parameters of honey yogurt fermentation were:the proportion of honey and milk was8:72, inoculation amount was2.3%, and fermentation temperature was42℃.2. The composite stabilizers of honey yogurt:The impact of a single stabilizer on the water holding capacity, viscosity and senses of honey yogurt were studied. The results showed that the sucrose esters, locust bean gum and gellan gum were the best stabilizers. Each two of three were mixed to test the value of the water holding capacity, viscosity and senses of honey yogurt. Results showed that the better ratio of sucrose esters and locust bean gum was1.5:0.5. At the basis of the best ratio of sucrose esters and locust bean gum which was1.5:0.5, gellan gum was added. The best ratio of sucrose esters, locust bean gum and gellan gum was1.5:0.5:0.5.3. The nutrition value and the storage period of honey yogurt were determined:(1) Compared with common yogurt, the water content, protein content, fat content and viscosity of honey yogurt were not changed greatly, but the reducing sugar contents and the total lactic acid bacteria of the honey yogurt were significantly higher than common yogurt.(2) During the fermentation process, the pH value and the reducing sugar contents of honey yogurt declined, but acidity had a rising trend.(3) The best storage temperature of honey yogurt was4℃, the storage period was7d. In this period, the change of pH value and acidity of honey yogurt were not obvious, but the number of lactic acid bacteria reached to the maximum, and the best texture and organization form were obtained.