Response surface optimization of lyoprotectant from amino acids and salts for Bifidobacterium bifidum during vacuum freeze-drying

Abstract

High quality probiotic powder can lay the foundation for the commercial production of functional dairy products. The freeze-drying method was used for the preservation of microorganisms, having a deleterious effect on the microorganisms viability. In order to reduce the damage to probiotics and to improve the survival rate of probiotics during freeze-drying, the Response Surface Methodology (RSM) was adopted in this research to optimize lyoprotectant composed of amino acids (glycine, arginine) and salts (NaHCO3 and ascorbic acid). Probiotic used was Bifidobacterium bifidum BB01. The regression model (p < 0.05) was obtained by Box- Behnken experiment design, indicating this model can evaluate the freeze-drying survival rate of B. bifidum BB01 under different lyoprotectants. The results indicated these concentrations as optimal (in W/V): glycine 4.5%, arginine 5.5%, NaHCO3 0.8% and ascorbic acid 2.3%, respectively. Under these optimal conditions, the survival rate of lyophilized powder of B. bifidum BB01 was significantly increased by 80.9% compared to the control group (6.9±0.62%), the results were agreement with the model prediction value (88.7%).