Xanthan gum coating delays ripening and softening of jujube fruit by reducing oxidative stress and suppressing cell wall polysaccharides disassembly

Harvested jujube fruit are prone to rapid ripening and softening during postharvest storage. In this work, jujube fruit were coated with xanthan gum (0.3%) and compared with uncoated control during storage at 20 ± 1 ºC for 15 d. Xanthan gum coating suppressed disease incidence (DI) and reduced fruit weight loss (FWL) of coated jujubes. Similarly, coating delayed reddening index development and suppressed relative ion leakage (RIL), malondialdehyde (MDA), superoxide anion (O2–•) and hydrogen peroxide (H2O2) concentrations. The coated jujubes exhibited suppressed respiration and ethylene production rates along with higher antioxidative enzymes activity. On the other side, xanthan gum coating preserved higher firmness and showed lower water-soluble pectin (WSP) along with conserved concentrations of Na2CO3-soluble pectin (SSP), cellulose (CS), hemicellulose (HCS) and chelate-soluble pectin components (CSP) owing to suppressed activities of polygalacturonase (PG), cellulase (CX), pectin methylesterase (PME) and β-galactosidase (β-gal) enzymes. The coated jujubes showed reduced total soluble solids increase and exhibited higher ascorbic acid content. So, xanthan gum coating could be applied as an eco-friendly postharvest treatment for the quality preservation of fresh jujube fruit.