Konjac glucomannan/low-acyl gellan gum edible coating containing thymol microcapsule regulates cell wall polysaccharides disassembly and delays postharvest softening of blueberries

Softening is one of the crucial factors causing the deterioration of postharvest fruit quality. In this study, the effects of konjac glucomannan/low-acyl gellan gum/microcapsule of thymol (TKL) coating on the storage characteristics, the ultrastructure of cell wall and transcription expression of pectin-related metabolism of blueberries fruits during low-temperature storage were investigated. TKL coating suppressed the expression of pectin-related enzymes disassembly (VaPE2, VaPE3, VaPG3, VaPL2 and Vaβ-Gal2), reduced the activity of cell wall polysaccharide degrading enzymes (PG, PE, PL, β-Gal, α-Man, α-Af, Xth, β-Xyl, Cx, β-Glu), maintained the normal morphological structure and stability of cell wall, and prolonged the shelf life of blueberries fruits. Overall, TKL is a promising coating that can effectively maintain the firmness, inhibit the postharvest softening and prolong the shelf life of the blueberries during storage period.