Kessara Mungkunkoth¹, Vijitra Luang-In¹, Luchai Butkhup¹, Issaraporn Somboonwatthanakul¹, Manatchaya Sungsri-in¹, Anuchita Moongngarm¹, Ekapol Limpongsa², Nyuk Ling Ma³, Sirirat Deeseenthum¹*

¹Natural Antioxidant Innovation Research Unit, Faculty of Technology, Mahasarakham University, Maha Sarakham 44150, Thailand

²College of Pharmacy, Rangsit University, Pathum Thani 12000, Thailand

³BIOSES Research Interest Group, Faculty of Science and Marine Environment, Universiti Malaysia Terengganu, 21030, Malaysia

 

*Corresponding author’s email: sirirat.d@msu.ac.th

Received: 29 July 2025 / Revised: 05 December 2025 / Accepted: 09 December 2025 / Published Online: 08 January 2026

 

Abstract

 

A tropical fruit, Gac (Momordica cochinchinensis Spreng), is valued for its high carotenoid content and antioxidant potential. This study investigated the physicochemical and biofunctional changes in Gac aril juice (GAJ) subjected to fermentation with 2% (w/v) kefir grain and enzymatic treatment using (2% v/v) food-grade pectinase or cellulase for 48 h under control conditions. Parameters assessed included pH, color, total dissolved solid, lycopene, β-carotene content (via HPLC), total flavonoid content, phenolics, antioxidant activity (DPPH, FRAP), volatile organic compounds (GC-MS), and cytotoxicity against HT-29 human colon cancer cells (MTT assay). Results revealed that both treatments significantly improved carotenoid content and antioxidant activity. Pectinase-treated juice showed the highest β-carotene and antioxidant levels, while kefir-fermented juice notably increased phenolic content and exhibited cytotoxic effects with an IC50 of 401.00 ± 1.76 µg/mL. Additionally, the volatile compound profile exhibited treatment-dependent changes in aroma. Morphological changes in HT-29 cells confirmed the cytotoxic effect of the fermented GAJ. This is the first report to demonstrate the cytotoxic potential of kefir-fermented GAJ against HT-29 cells, indicating its promise as a functional ingredient for value-added product development in the food and beverage sector.

 

Keywords: Cellulose, Pectinase, Lycopene, Flavonoids, β-carotene, Probiotic

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