Stability of probiotics encapsulated with Thai herbal extracts in fruit juices and yoghurt during refrigerated storage

This study intended to investigate the impact of alginate encapsulation with Thai herbal extracts including cashew flower, pennywort and yanang on viability of probiotic bacteria suspended in fruit juices (i.e. mulberry, maoberry, longan and melon juices) and stirred yoghurt during storage at 4 °C. The strains of probiotics used in this work were Lactobacillus casei 01, Lactobacillus acidophilus LA5 and Bifidobacterium lactis Bb-12. The results displayed that the surviving population of L. casei 01 cells entrapped with 0.05% (w/v) cashew flower extract were significantly higher than those encapsulated with pennywort and yanang extracts, after storage for 30 days. Accordingly, this level of cashew flower extract was selected to immobilize the cultures before inoculation into fruit juices and yoghurt, in order to comparison with green tea extract (a standard plant extract). Upon storage, cashew flower and green tea extracts noticeably improved the stability of probiotic beads in all the products, as compared to the controls. Encapsulated L. casei 01 and B. lactis Bb-12 showed better survival than encapsulated L. acidophilus LA5. The diminution of pH values in each product was also observed.