Abstract

Jackfruit (Artocarpus heterophyllus Lam.) is a nutrient-rich tropical fruit that provides a favorable environment for lactic acid bacteria (LAB). However, the investigation of LAB, particularly Lactiplantibacillus plantarum, from tropical fruits in Indonesia is limited, especially for jackfruit, which has not yet been investigated. Therefore, this study aimed to isolate, identify, and characterize L. plantarum from ripe jackfruit collected in Semarang, Indonesia, and to evaluate its functional properties for potential applications in food fermentation. Four LAB isolates were obtained and subjected to morphological, biochemical, and physiological characterization using de Man-Rogosa-Sharpe (MRS) agar supplemented with CaCO3. The results showed that all isolates were Gram-positive, catalase-negative, non-motile, and capable of fermenting different types of carbohydrates without gas formation. Optimum growth occurred at a temperature between 25–45°C, pH range between 5–6, and 6.5% NaCl. Molecular identification based on 16S rRNA sequence confirmed all the isolates to be L. plantarum with a similarity of over 99%. Functionally, the four isolates showed proteolytic and lipolytic activity, production of exopolysaccharide (EPS), and antioxidant capacity in the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, although amylolytic activity was not detected. The fact that L. plantarum was found to be present in jackfruit in a functionally active form suggests the potential as a natural source of beneficial LAB. By characterizing four native L. plantarum strains, this work provided a preliminary investigation of LAB in jackfruit and supports the potential future use of these isolates as starter cultures for developing functional fermented foods tailored to local conditions.