Abstract
Out of six samples of tropically grown fruits and leaves, ten lactic acid bacteria belonging Leuconostoc, Weissella and Lactobacillus species were isolated and identified by 16S gene sequencing and (GTG)5 fingerprinting. Acidification kinetics determined from BHI broth cultures showed genus-related patterns. In particular, Weissella cibaria appeared to act as a potent acidifier. Tolerance to acid, oxidative or salt stress of isolates was highly variable and strain dependent. Isolate S14 (Leuconostoc pseudomesenteroides) growth was not affected by the presence of 0.05% H2O2 while Lactobacillus spp. isolates (S17 and S29) were the most tolerant to pH 4.5. The growth of four isolates, S5 (Leuconostoc mesenteroides), S14 and S10 (Leuc. pseudomesenteroides) and S27 (W. cibaria) was not affected by 5% NaCl. Nutritional beneficial properties were examined through measurement of antioxidant activities of short-term fermented pineapple juice, such as LDL oxidation and polyphenol content, and through exopolysaccharide formation from sucrose. Two isolates, S14 and S27 increased antioxidant capacity of pineapple juice. The robust capacity of W. cibaria and of Leuc. pseudomesenteroides for vegetable lactic fermentation aimed to ameliorate food nutritional and functional quality was highlighted.