The Production Of Microencapsulated Lactobacillus Plantarum LIP-1 With Emulsification And The Research On The Improvement In Freezing Resistance

Lactobacillus plantarum LEP-1 was identified as a probiotic with cholesterol-reducing health benefits, which was valuable. But there are many unfavorable factors influence the stability of probiotics, thus affect the effectiveness of L. plantarum LIP-1. Microencapsulation techniques have been used to increase the viability of probiotics in adverse conditions and the probiotics can been released in gut quickly. Milk proteins are generally recognized as safe (GRAS) raw materials with high nutritional value and good sensory properties. They also have the properties required for the delivery of functional ingredients. For example, they have good emulsification properties, are highly soluble and superb gelation properties; they are biocompatible and biodegradable, and have an excellent buffering capacity against the harsh acid environment of the stomach. These properties indicate that dairy proteins are good candidates for encapsulating probiotics, and as such they are attracting more research attention.In our research, we use milk proteins for wall material and discuss the effect of different calcium salts (CaCO3 and CaCl2) on the characteristics of microencapsulated Lactobacillus plantarum LIP-1. Results indicated that microcapsules prepared by CaCO3 showed significantly better qualities than microcapsules prepared by CaCl2. Specifically: microencapsulation efficiency (ME), particle size and size distribution, the surface morphology and the microstructure, resistance to passage through simulated gastric fluid (SGF), release characteristic in simulated intestinal fluid (SIF) and viability during 4 weeks storage at different temperatures (4℃,20℃ and 37℃) were all better in the microcapsules prepared by CaCO3.In order to enhance the storage stability and transportation convenience of microcapsule, freeze drying is commonly used, and in order to decrease the loss in viability of cells due to freeze and dry, cryoprotectants are commonly added to samples before freeze-drying. In this study, we investigate the optimal ratio of cryoprotectants and the effect of cryoprotectants on the properties of L. plantarum LIP-1 microcapsules. Single factor and Orthogonal experimental design were used to research the influence of adding different types of cryoprotectant on microencapsulation efficiency (ME) and survival rate of LIP-1 during freeze-drying process. The results showed that the best cryoprotectant formulations were glycerol of 2%, maltose of 1%, L-cysteine of 2%, lactose of 2%, and based on this formulation, ME was 67.60% and the survival rate was 83.80%; which significantly (P<0.05) improve the properties of L. plantarum LIP-1 microcapsules than the blank (microcapsules without cryoprotectants). The results of research also can provide a theoretical basis and technical guidance for improving the properties of probiotic microcapsules during the commercial production.