Enhancing carotenoid contents, antioxidant properties and cytotoxicity against human colon adenocarcinoma (HT-29) of gac aril juice (Momordica cochinchinensis Spreng) through kefir grain fermentation and hydrolytic enzyme treatment

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 valueadded product development in the food and beverage sector.