The Production Of Microencapsulated Lactobacillus Plantarum LIP-1 With Aqueous Phase Separation

Microcapsule embedding improves the survival of probiotics in adverse environments.The use of milk protein as a wall material to prepare microcapsules by emulsification is a commonly used method for entrapping probiotics,but there are still disadvantages of high cost and low embedding rate.This study selected Lactobacillus plantarum LIP-1 as a research object.Skim milk was used as the wall material,and milk protein was degraded by chymosin and then induced by calcium ion.The microcapsules were prepared by aqueous phase separation..On this basis,the microcapsules prepared by the emulsification method were used as controls to study the embedding rate,the size of the microcapsules,the appearance of the microcapsules,the tolerance of simulated gastric juices,the release of simulated intestinal fluids,and their properties.Antifreeze drying and storage stability under different temperature conditions were determined.The main test results are as follows:(1)The optimum conditions for the preparation of microcapsules by aqueous phase separation method are as follows: Add 2% growth-promoting factor to 35% skim milk,and ferment till titration acidity 95°T.Use this fermentation broth as wall material raw material in ice.In the bath(0-4°C),chymosin was added to degrade for 1 hour.Then 0.15% calcium chloride crosslinker was added.After stirring in ice bath for 10 minutes,the temperature was raised to 40°C.After stirring for 5 minutes,the mixture was solidified for 10 minutes,then after centrifugation the supernatant was removed and the recipitated microcapsules slurry was collected.(2)The detection of microcapsule properties showed that the encapsulation rate of microcapsule prepared by water phase separation method was 86.59%,the particle size was 80-110?m,the particle size was smaller and the particle size distribution was more concentrated,the surface structure was dense,the microencapsulation rate of microcapsules was 59.2%,the particle diameter was 100-140 ?m,the particle size was larger and the distribution was not very much.The two surface encapsulation of Lactobacillus plantarum LIP-1 microcapsules can release completely in 120 min of intestinal juice.However,after digesting artificial gastric juice with p H 2.0 for 120 minutes,the survival rate of the microcapsules encapsulated by aqueous phase separation was 83.24%,and the survival rate of the microcapsules obtained by emulsification was 56.39%.Compared with the emulsification method,there was a significant difference in the survival rate of the microcapsules prepared by the two methods(P<0.05).(3)After the freeze-drying of the probiotic microcapsules,the survival rate of the microcapsules prepared by the aqueous phase separation method after stored at 4°C for 28 days is 91.9%,and the survival rate of the microcapsules prepared by the emulsification method is 81.6%.Significant difference(P<0.05).The survival rate of the microcapsules prepared by the aqueous phase separation method was higher than that of the emulsification method at different temperatures,and there was a significant difference between the two(P<0.05).(4)Through scanning electron microscopy observation of the ultrastructure of microcapsules and gel electrophoresis analysis of wall protein composition,microcapsules prepared by aqueous phase separation method have richer protein fragments,resulting in more compact surface structure of microcapsules,higher embedding rate and better protection to thalli.The results showed that the microcapsules prepared by the water phase separation method were feasible,and compared with the microcapsules prepared by the emulsification method,the microcapsules prepared by the water phase separation method could significantly improve the resistance to the adverse environment of the probiotic Lactobacillus plantarum LIP-1.