Formulation of a Liquid Synbiotic Candidate Based on Musa paradisiaca L. Peels with Lactobacillus acidophilus and Lactobacillus casei

Background: Musa paradisiaca L. peels are largely considered agro-industrial waste, although they contain carbohydrates and fiber that have the potential to be utilized as a fermentation substrate for the development of a synbiotic candidate. Objective: This study aimed to formulate a liquid synbiotic based on Musa paradisiaca L. peels using Lactobacillus acidophilus and Lactobacillus casei and to evaluate its physical, chemical, and microbiological characteristics. Methods: The initial stage was conducted using L. acidophilus with lactose concentrations of 1–3% (w/v). Since no colonies were detected in the total lactic acid bacteria test for the three lactose concentrations, the main study was continued using L. casei with 1% lactose and starter concentrations of 4%, 5%, and 6% (v/v). Fermentation was conducted at 37°C for 72 hours. The evaluated parameters included total lactic acid bacteria, pH, lactic acid content, color, aroma, and viability after seven days of refrigerated storage. Results: The formula containing a 5% starter concentration (F2) shows the most consistent results, with the pH decreasing from 3.88 to 3.37 and total lactic acid bacteria decreasing from 7.42 to 7.05 log CFU/mL after storage. Conclusion: F2 is selected as the optimal formula based on the balance of its microbiological, chemical, and physical characteristics.