Ripeness stage at harvest influences postharvest life of cranberry fruit: physiological and anatomical explanations

Abstract

Abstract We investigated the relationship between postharvest life of cranberry ( Vaccinium macrocarpon Ait. cv. Stevens) fruit and ripeness stage at harvest. Wet harvested, mature fruit were sorted into four ripeness stages and rated for quality after 4 and 7 weeks of cold storage at 3 °C. In addition, CO 2 and ethylene production as well as anthocyanin content were measured. After 7 weeks of storage, the marketable fruit among dark-red, light-red, blush, and white were 82, 74, 63, and 44%, respectively. The ethylene production was nearly the same for all the ripeness stages. However, white, blush, and light-red fruit had significantly higher respiration rates than dark-red fruit. We also found that cuticle thickness was significantly higher for red fruit as compared to other ripeness stages. There were stomata present at the calyx end of the fruit, which became impregnated with wax in red fruit. Furthermore, a compact cell layer in the calyx opening accumulated anthocyanins in red fruit only. Our studies suggest that red fruit have longer postharvest life, possibly because (i) red fruit have lower respiration rates, (ii) thicker cuticle and wax accumulation (especially at the calyx end) on these fruit may retard the entry of microorganisms into the fruit during wet harvest and may mitigate mechanical injury by harvesting equipment.