Production of probiotic pineapple juice with encapsulation of Lactobacillus plantarum by chitosan and tragacanth gums

Encapsulation with polysaccharides is one of the new methods for increasing the stability of bioactive compounds and improving the viability of probiotics during food processing and storage. In this study, due to the high benefits of probiotic products on human health, the effect of Lactobacillus plantarum encapsulated by chitosan, tragacanth gums and their combination in a concentration of 1% (w/w) on the physicochemical and overall acceptance of pineapple juice were evaluated during 30 days storage in the refrigerator. The results showed a decrease in pH and an increase in the acidity of all samples (P<0.05). In addition, the viability of Lactobacillus plantarum was increased in the treatment encapsulated by the combination of chitosan and tragacanth gums so that, the number of viable bacterial cells was higher than 6 log cfu/ml on the 30th day of storage. The formalin index increased between the 20th and 30th days of storage in all samples (P<0.05). Also, the highest overall acceptance was belonged to the sample containing the Lactobacillus plantarum encapsulated by chitosan (P<0.05). The results showed that pineapple juice is a suitable substrate for the growth of Lactobacillus plantarum and it can be considered as a carrier for the transmission of probiotic strains to the human body. Moreover, those with special nutritional needs can take advantage of probiotic pineapple juice, including lactose and cholesterol deficiency as well as richness in mineral substances.