Development Of Functional Dairy Products Rich In CLA

Conjugated linoleic acid (CLA) has a wide range of beneficial effects, such asanticarcinogenic, antiatherogenic, and antidiabetic. That biology isomerization of LA intoCLA with the use of food-grade microorganisms like lactobacillus casein finds a new way forCLA-fortified foods. To increase the function of dairy and decrease the cost, ultraviolet lightwas used to create CLA-hyperbiosynthesis mutant. The conditions of fermentation,immobilization of the mutant and manufacture dairy products fermented withCLA-producting strain were also optimized in this study.One mutant lactobacillus casein-mt was selected. The CLA production was enhancedsignificantly by UV inducement (30w,30cm) for20s，reaching the total CLA yield of104.4μg/mL.The optimal conditions for lactobacillus casein-mt to transform LA to CLA wassummaried as follows: culture temperature of37℃; incipient pH of6.5; LA concentration of0.05%; lactose of2%; inoculum size of4%; culture time of36hours, the concentration ofCLA got the maximum biosynthesis394.1μg/mL.The results from crosscut experiment indicated that the concentration of calcium chloridewas the most important factor for CLA synthesis. The best synthesis condition wassummaried as follows: culture temperature of40℃; sodium polymannuronate of2.5%;calcium chloride of2.5%; ratio of lactobacillus casein-mt to water of1:1; the size of colloidparticle of1.6G, the concentration of CLA got the maximum biosynthesis523.39μg/mL. Theresults from continuous fermentation experiment indicated that the concentration of CLA wasstable during fermentation for many times.Through the sense organ and the acidity experiment, the best synthesis condition asfollows: skimmed milk of12%; inoculum size of3%; sucrose of3%; fermentation time of5h.