A probiotic biocatalyst was prepared through Lactobacillus plantarum ATCC 14917 immobilization on a prebiotic carrier (delignified wheat bran) and was used for fermentations of pomegranate juice. Initially, pomegranate juice was fermented for 24 h and then was stored for 28 days at 4 °C. The obtained results regarding sugar and organic acid analysis revealed that the probiotic biocatalyst was effective. Ethanol was produced in small amounts (0.4-1% v/v). Total phenolic content and antioxidant activity was greater in the fermented pomegranate juice than in unfermented juice after 24 h of fermentation and over the time span of 28 days. Viability of probiotic cells was well maintained (above 8.65 log cfu/mL) after 24 h of fermentation and during 4 weeks of storage at 4 °C, and it is noteworthy that no pathogens were observed. The strength of viability of probiotic cells can be attributed to the immobilization carrier (delignified wheat bran) that exhibits prebiotic properties providing a protective effect to the cells. Finally, the proposed bioprocess of employing the proposed synbiotic biocatalyst for pomegranate juice fermentation shows great potential for commercialization while sensory evaluation highlights the degree of quality of the produced functional pomegranate beverages.
Keywords: Antioxidant activity; Immobilization; Lactobacillus plantarum ATCC 14917; Pomegranate juice; Total phenolic content; Wheat bran.