INFLUENCE OF CELL-FREE SUPERNATANT OF LACTIC ACID BACTERIA AS ADDITIVE IN PRESERVATION OF PINEAPPLE JUICE

Abstract

This research explored the use of cell-free supernatant from Lactic Acid Bacteria (LAB) as a preservative in pineapple juice. LAB strains, Levilactobacillus brevis and Lactiplantibacillus spp., were sourced from healthy pineapple and soursop fruits, identified through standard biochemical analyses, and incorporated into the juice as freeze-dried supernatant. The sensory attributes of the juice (mouthfeel, taste, flavor, aroma, color, and overall acceptability) scored between 6.00 and 8.40. Interestingly, while juices with LAB extracts turned brown, the control retained its yellow hue, yet all samples were acceptable to assessors, with preferences ranked as follows: Control > Juice with Lactiplantibacillus spp. extract > Juice with Levilactobacillus brevis extract. The study also observed a slight pH increase in juices containing LAB extracts during the first three days, contrasting with the control’s pH decrease within two days. Moreover, LAB-supplemented juice significantly inhibited pathogenic Escherichia coli survival at varying concentrations (2%–10%), comparable to sodium benzoate. This microbial reduction is attributed to compounds like lactic acid, hydrogen peroxide, diacetyl, and bacteriocin produced by LAB, with lactic acid playing a central role. Consequently, freeze-dried supernatant of these LAB strains shows potential as a natural preservative against Escherichia coli-induced diarrhea in pineapple juice.