Effects of trehalose and hyaluronic acid on the survival of probiotic loaded by calcium alginate during freeze-drying and storage
YUAN Yongkai1, YIN Ming1, CHEN Ling1, LIU Fei1, CHEN Maoshen1, ZHONG Fang1,2*
(1 State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, Jiangsu, China;2 International Joint Laboratory on Food Safety, Jiangnan University, Wuxi 214122, Jiangsu, China)
Abstract:
The commercial application of probiotic loaded by calcium alginate (CA)hydrogel is limited due to its low freeze-drying survival rate. The possibility and related mechanisms of introducing trehalose (T) and/or hyaluronic acid (HA) in the gel system to improve the survival rate of freeze-drying Lactobacillus rhamnosus GG (LGG) were explored. The results indicated that the addition of T and HA could increase the freeze-drying survival rates of LGG from 66.24% to 75%~90% when the pre-freezing temperature was -18 ℃, or from 79.62% to 90%~95% when the pre-freezing temperature was -80 ℃. The bacterial biochemical analysis showed that the increase of the freeze-drying survival rate of LGG was related to the effective reduction of cell membrane permeability and the loss alleviation of intracellular metabolic activity caused by T and HA. Two months of storage at room temperature indicated that environmental water activity (Aw) higher than 0.313 could cause the survival decrease of naked bacteria from 9.16 log CFU/g to 4.44 log CFU/g or even all deaths, while CA/T and CA/T/HA could retain 6.0~6.9 log CFU/g of viable bacteria when the environmental Aw was 0.812. At low environmental Aw,the storage stability of LGG was dominated by the initial physiological state of the bacteria. CA/T with low moisture absorption was more suitable for the application scenarios of Aw>0.3. This study guides the commercial application of probiotics loaded by CA.
KeyWords:
probiotic；freeze-drying survival；room temperature storage survival；calcium alginate；hyaluronic acid；trehalose
