Selection of novel starter lactic acid bacteria with probiotic potential native to chilto (Solanum betaceum) fruits

Abstract

Solanum betaceum (chilto) fruits are valued for their health-promoting properties, but like many fruits, they have a short shelf-life. Lactic fermentation of chilto juice represents an effective strategy to preserve the fruit while enhancing its nutritional and functional qualities. This study aimed to isolate and select potentially probiotic native lactic acid bacteria (LAB) strains from chilto fruits for use in fermented juice production. A comprehensive screening protocol was employed to evaluate tolerance to gastrointestinal conditions, cell surface properties, exopolysaccharide production, safety traits, and the capacity to ferment chilto juice. Forty-three autochthonous LAB strains (Gram-positive, catalase-negative, and non-motile) were isolated from chilto fruits native to Tucumán, Argentina. Based on their probiotic potential and fermentation performance, eleven strains were selected and identified as Leuconostoc citreum IBFV-6 and IBFV-16, Leuconostoc pseudomesenteroides IBFV-7, Enterococcus pallens IBFV-8, Levilactobacillus brevis IBFV-11, Lactococcus lactis IBFV-13 and IBFV-15, Weissella confusa IBFV-12, Weissella cibaria IBFV-14, and Lactiplantibacillus paraplantarum IBFV-9 and IBVF-10. Among them, L. paraplantarum IBVF-10 was identified as the most suitable starter culture for chilto juice fermentation. Juice fermented with IBVF-10 exhibited increased phenolic content and enhanced ABTS•+ radical scavenging and α-amylase inhibitory activities compared to unfermented juice. These findings highlight the potential of the native strain L. paraplantarum IBVF-10 as a starter culture for the development of a functional chilto-based beverage, contributing to the valorization of this underutilized fruit.