Quality attributes and cell wall properties of strawberries (Fragaria annanassa Duch.) under calcium chloride treatment

Effects of CaCl 2 (0%, 1% and 4%) treatment on quality attributes and cell wall pectins of strawberry fruits stored at 4 °C for 15 d were investigated. Strawberry firmness was not significantly affected by CaCl 2 treatment. Compared to the other groups, the 1% CaCl 2 group had better quality attributes, including decay rate, weight loss and soluble solids content. The treatment with 4% CaCl 2 inhibited weight loss but caused phytotoxicity. During storage, the chain widths and lengths of water-soluble pectin (WSP), chelate-soluble pectin (CSP) and sodium carbonate-soluble pectin (SSP) decreased. Strawberry softening seemed to be due to modifications of CSP and SSP, especially the side chains. CaCl 2 treatment significantly slowed the breakdown of CSP and SSP chains by strengthening the ionic crosslinkages among these pectin molecules. These results illustrate the fundamental CaCl 2 effects and will help improve the application of CaCl 2 to postharvest fruits. Keywords Strawberry Calcium chloride Pectin Nanostructure Atomic force microscopy (AFM)