Development of fresh fruit coating based on banana peel pectin with Pickering emulsion of cellulose nanocrystals/Javanese turmeric essential oil for snake fruit preservation

Snake fruit ( Salacca zalacca var. Pondoh) is susceptible to postharvest deterioration caused by respiration, transpiration, and spoilage fungi. This study developed a banana peel pectin (P)-based coating incorporating a cellulose nanocrystal (CNC)-stabilized Pickering emulsion of Javanese turmeric essential oil (TEO) as an alternative coating for snake fruit preservation. Three coating-forming formulations, namely pectin (P), P/Tween/TEO, and P/CNC/TEO, were evaluated using uncoated fruit as the control, with the fruit tip immersed in the coating solution for 1 min. The selected formulation contained 0.5% P, 0.5% TEO, and 0.05% CNC. Transmission electron microscopy analysis revealed rod-like or needle-like nanoscale morphology of CNC, while gas chromatography–mass spectrometry showed that TEO was dominated by α-curcumene and β-curcumene . Incorporation of 0.05% CNC produced a coating solution with greater electrostatic stability and stronger antifungal activity than the conventional Tween 80-stabilized emulsion. The P/CNC/TEO showed the most negative zeta potential (−83.37 ± 0.55 mV) and the strongest in vitro antifungal activity against Botrytis cinerea and Penicillium digitatum , with inhibition values of 87.37 and 72.53%, respectively. During fruit storage, P/CNC/TEO maintained delayed peel darkening, as indicated by a significantly higher peel L* value on day 7, whereas a* and b* values were not significantly affected. The coating did not significantly affect weight loss, total soluble solids, or pH. These results indicated that CNC-stabilized TEO Pickering emulsions enhanced the in vitro antifungal activity of pectin coatings and helped delay peel darkening of snake fruit.