Inclusion of prebiotics on the viability of a commercial Lactobacillus casei subsp. rhamnosus culture in a tropical fruit beverage

The viability of probiotics in the development of functional tropical fruit beverages is a technological challenge that may benefit from the addition of prebiotics, due to the synergistic (synbiotic) interaction. This study evaluated the viability of a commercial probiotic (Lactobacillus casei) in a blended red fruit beverage (RFB; 20% strawberry, 10% blackberry and 5% papaya), enriched with three separate prebiotics: inulin (IN), fructooligosaccharides (FOS) and galactooligosaccharides, added at 1 and 5%. The consumer preference for the beverages was also examined. The inoculum was produced in MRS broth supplemented with 10% RFB, which reached the exponential phase (9.96 log CFUmL(-1)) after incubation at 37 degrees C for 24h. In search of the probiotic strain's adaptation and viability in the presence of the different prebiotics (measured by optical density, OD600 nm), the prebiotics were added to MRS broth at 1 and 5%. Since 1% IN (OD=3.99 +/- 0.36) and 1% FOS (OD=3.48 +/- 0.28) were the most significant, these treatments, without inoculation of probiotics, were assessed by the sensory panel. Although neither RFB was significantly preferred the RFB with 1% IN received the greatest number of responses (n=33/60). Its effect on the viability of L. casei inoculated in the RFB was monitored by the growth kinetics at 37 degrees C for 50h. The findings indicated that fortification with 1% IN could have a possible protective effect on the stability of L. casei in RFBs, highlighting the use of tropical fruits as potential carriers of probiotics.