Yu-Chieh Chou, Wei-Lun Ku, Kuan-Chen Cheng, Chen-Che Hsieh, Shella Permatasari Santoso, Yung-Kai Lin, Wei-Lun Hung, Shin-Ping Lin
Male jelly fig (Ficus pumila L. var. awkeotsang) syconia are an underutilized by-product in Taiwan. This study evaluated male fig powder (0–2%, w/v) as a substrate for producing male fig-altered kombucha (FK) using a defined co-culture of Komagataeibacter xylinus and Saccharomyces cerevisiae. Fermentation markedly reshaped FK metabolites. Glucuronic acid increased in a dose-associated manner, reaching 6.63 g/L in 2% FK, whereas vitamin C declined during fermentation but remained highest in 2% FK. Gallic acid increased and peaked at 0.5% FK (320.75 mg/L), while acetic and succinic acids showed formulation-dependent patterns; conversely, caffeine decreased in all male fig-containing groups. FK also exhibited concentration-dependent color divergence from the control at day 9 (ΔE* up to 17.81 at 2% FK). Numerical increases in DPPH and TPC were observed; however, no significant differences were detected among the treatments. Importantly, male fig supplementation substantially enhanced kombucha bacterial cellulose (KBC) yield (0.56 to 7.28 g/L from 0 to 2% FK) without compromising high water content (~96–99%) or swelling (~90–94%). FTIR confirmed retention of the cellulose backbone, SEM showed formulation-dependent fibril diameters, and TGA indicated higher early-stage thermal stability with dose-dependent shifts in main degradation behavior. Collectively, male figs can be valorized to produce FK with altered metabolite profiles and improved KBC productivity. © 2026 by the authors.
Ph.D. Program in Drug Discovery and Development Industry, College of Pharmacy, Taipei Medical University, 250 Wu-Hsing Street, Taipei, 11031, Taiwan; School of Food Safety, Taipei Medical University, 250 Wu-Hsing Street, Taipei, 11031, Taiwan; Institute of Biotechnology, National Taiwan University, Taipei, 10617, Taiwan; Institute of Food Science and Technology, National Taiwan University, Taipei, 10617, Taiwan; Department of Optometry, Asia University, Taichung, 41354, Taiwan; Department of Food Science, Fu Jen Catholic University, New Taipei City, 242062, Taiwan; Department of Medical Research, China Medical University Hospital, China Medical University, Taichung, 40402, Taiwan; Department of Seafood Science, College of Hydrosphere, National Kaohsiung University of Science and Technology, Kaohsiung, 81157, Taiwan; Department of Chemical Engineering, Faculty of Engineering, Widya Mandala Surabaya Catholic University, Surabaya, 60114, Indonesia; Chemical Engineering Master Program, Widya Mandala Surabaya Catholic University, Surabaya, 60114, Indonesia; Collaborative Research Center for Zero Waste and Sustainability, Widya Mandala Surabaya Catholic University, Surabaya, 60114, Indonesia; Institute of Food Safety and Risk Management, National Taiwan Ocean University, Keelung City, 20224, Taiwan; Research Center of Biomedical Device, Taipei Medical University, 250 Wu-Hsing Street, Taipei, 11031, Taiwan