The Study On Probiotic Properties And CLA Production Ability Of Lactobacillus Plantarum

The probiotic properties of twelve Lactobacillus plantrum strains which had better tolerance in gastrointestinal transit were studied. The properties of antimicrobial and coaggation were used to analyze their probiotic properties. The conjugated linoleic acid (CLA) converting ability of six strains was studied both in sunflower oil and soymilk. The changes of CLA composition and fatty acids during soymilk fermentation and storage were analyzed by gas chromatography. The main conclusions as followed:The results of aggregation showed that the auto-aggregation rate was growing with the prolongation of culture time. All the tested strains could co-aggregate with pathogens and showed higher co-aggregation rate with Staphylococcus aureus. The L.plantrum with high auto-aggregation rate although had high co-aggregation ability with pathogens. There was positive correlation between these two properties. The antimicrobial test showed that the supernatant could inhibit the growing of pathogens. IMAU70004 showed the highest inhibition ability.All six L.plantrum showed the ability of converting LA to CLA when using sunflower oil as substrate or during soymilk fermentation. The production of CLA was increased with adding high concentration of substrate in sunflower and IMAU60042 produced the highest CLA both in sunflower and soymilk.The production of CLA was decreased during the storage of fermented soymilk. the CLA content was decreased significantly in two weeks, but was not obvious in the first week. The CLA was composited by two isomers: c9,t11-CLA and c12-CLAThe fatty acid in soymilk was not affected by the fermentation of L.plantrum. But the proportion of unsaturated fatty acids decreased during fermentation, so the oxidative stability of soybean milk was improved. The proportion of unsaturated fatty acids was also decreased the during storage.The research on the prebiotic properties and the ability of converting CLA of L.plantrum could be basis for the future research and development of fermented soy milk products.