Optimization of technical and technological indicators of kefir added with defatted sesame flour and rice bran

Abstract

Defatted sesame cake and rice bran are all by-products of agricultural processing. The aim of the study was to optimize the recipes of kefir added with defatted sesame flour and rice bran. The previous study has yielded some results including dietary fiber content, pH values and sensory evaluation values of kefir samples added with 0, 2 %, 4 %, 6 %, 8 % DSC and 0, 0.1 %, 0.3 %, 0.5 %, 0.7 % RB, but made no optimization of kefir products. Based on these data, formulation optimization was done using a mathematical model. Two central composite designs for the two-factor analysis (x1x2 and x1x3, respectively) and one three-factor design (x1x2x3) were drawn up to predict the optimal formulation and reduce the number of future experiments. After studying the results of mathematical modeling, the optimal prescription composition corresponds to the 2 % DSC or 0.1 % rice bran content or 2 % DSC and 0.4 % RB content in the recipe. Through mathematical optimization, products with high dietary fiber content, suitable acidity and excellent sensory quality can be obtained. The products meet the current social demand for healthy food and have very good research value. In practical use, three kinds of kefir can be developed: 1. DSC should be ground separately before used, 2 % DSC was introduced into cow milk (m/v), fermented at 28°C for 22 h until pH reached 4.7, then stored at 4 °C; 2. RB should be ground before used, 0.4 % RB was introduced into cow milk (m/v), fermented at 28°C for 22 h until pH reached 4.7, then stored at 4°C; 3. DSC and RB should be ground before used, 2 % DSC and 0.4 % RB were introduced into cow milk (m/v), fermented at 28 °C for 22 h until pH reached 4.7, then stored at 4 °C