A comparative analysis of passionfruit (passiflora edulis f. flavicarpa deg.) wine fermentation using saccharomyces cerevisiae versus indigenous passionfruit microflora

Abstract

Passionfruit (Passiflora edulis f. flavicarpa Deg.) is valued for nutritional and bioactive properties, suitable for winemaking. This study evaluated fermentation with commercial Saccharomyces cerevisiae (yeast) and indigenous passionfruit microflora to assess physicochemical and bioactive effects on the wine. Wines used both inocula, six replicates per treatment. Fermentation was monitored weekly for four weeks by determining pH, temperature, residual sugar (°Brix) content, and alcohol content, although the first 7 – 10 days may capture critical changes. Microbial diversity was assessed on Sabouraud Dextrose Agar and Plate Count Agar, confirming S. cerevisiae in both fermentations. Antioxidant activity and antimicrobial activity were determined using DPPH free-radical scavenging assay and agar well diffusion, respectively, against Staphylococcus aureus, Enterococcus faecalis (Gram-positive), Escherichia coli, Pseudomonas aeruginosa (Gram negative), and Candida albicans. Data was analysed using two-way ANOVA by Past4.03. Yeast-fermented wine (YW) showed a significantly higher (p < 0.05) pH (3.8±0.06), higher alcohol content (10.60±0.43)%, lower residual sugar content (9.20±0.36) °Brix and rapid increment in temperature compared to indigenous wine (IW) with pH (2.40±0.12), alcohol content (3.10±0.91)%, and sugar content (9.92±0.34) °Brix. Microbial colony diversity decreased over time in both wines. Compared to YW, IW produced significantly greater antioxidant activity (IC50 of 2.14±0.14 mg mL–1) for yeast wine (p < 0.05). Compared to IW, YW exhibited smaller inhibition zones: S. aureus (14.08±3.00 vs. 0 mm), E. faecalis (19.22±1.60 vs. 10.92±2.00 mm), E. coli (14.33±1.00 mm vs. 5.31±1.47 mm), P. aeruginosa (8.00±0.84 vs. 0 mm), and no inhibition against C. albicans. Indigenous microflora enhances antioxidant and antimicrobial properties of passionfruit wine, supporting potential functional benefits. Yet, further validation (toxicity, sensory, in vivo studies) is needed. The lower alcohol content in indigenous wine may limit its classification as a wine, suggesting the need for optimisation.