influence of simulated gastrointestinal conditions on survivability of microencapsulated probiotic lactobacillus casei in symbiotic frozen yogurt

in this study, symbiotic yog-ice (rozen yogurt) was produced that was inoculated with different levels of inulin(0,2.5 amd 5%)as prebiotic compound and lactobacillus casei as probiotic bacteria in two types; free and encapsulated with sodium algint-whey protein concentration for low fat yog-ice cream.the survivability of this probiotic bacteria was evaluated under simulated gastro-intestinal conditions ,during 30 days storage at -18oc. in the samples with free state of probiotic bacteria, the number of viable cells ,after 1h exposuring simulated gastric juice(ph=2,pepcine) decreased from 9.78-9.81 log cfu/ml to 6.97-7.26 log cfu/ml,at the end of 30 days storage at -18oc,while, the viable number of encapsulated state of probiotic bacteria, after 1h exposuring simulated gastric juice, decreased from 8.15-8.66 log cfu/ml to 6.80-7.09 log cfu/ml at the end of 30 days storage at -18oc.after exposuring simulated gastric juice, samples was ezposured 2.5h under simulated intestinal juice(ph=7.4,panceratin), and the results that was gained showed that, the samples containing free probiotic bacteria after 2.5h exposuring simulated intestinal juice decreased from 8.808-9.355 log cfu/ml to 5.159-5.9 log cfu/ml at the end of 30 days storage at -18oc.while, in the samples containing sodium alginate-whey protein concentration capsules, the viable number of cells decreased from 7.38-8.201 log cfu/ml to 6.151-6.672 log cfu/ml, at the end of 30 days storage at -18oc. the results indicate that there are significant differences (p<0.05) between samples containing free and encapsulated bacteria.and, encapsulation improved protection of probiotic bacteria under simulated gastro-intestinal conditions during 30 days storage at -18oc. in samples with encapsulated forms of probiotic bacteria, after exposuring simulated gastro-intestinal digestion, the viable numbers of cells was in the recommended range by international dairy federation (106-107 cfu/g).