Calcium impregnation during isochoric cold storage to improve postharvest preservation of fresh blueberries

Abstract

Isochoric cold storage can be used to extend the shelf-life of fresh produce by delaying senescence through storage at subfreezing temperatures as well as hinder microbial growth with pressure. The effect of isochoric impregnation with CaCl2 on qualitative parameters of blueberries during isochoric cold storage at −2.5 °C and refrigerated storage at 5 °C for four weeks was investigated in this study. The results showed the synergistic effect of calcium impregnation and isochoric cold storage on the quality of blueberries. Isochoric impregnated blueberries better retained their weight, had better mechanical properties and had higher nutrient contents (anthocyanins, total phenolics and antioxidant capacity) than non-impregnated blueberries refrigerated at 5 °C. The benefits of isochoric impregnation with CaCl2 were greater for samples stored under isochoric conditions than under refrigerated conditions. However, the impregnated refrigerated samples still had better quality properties than non-impregnated refrigerated samples. Furthermore, panelists found no significant differences in preference for any of the sensory attributes between fresh blueberries and impregnated blueberries. Also, isochoric cold storage inhibited the growth of mesophilic aerobic bacteria, yeasts and molds under isochoric and refrigerated storage conditions. In conclusion, this study showed the possibility of using isochoric cold storage with calcium impregnation to develop ready-to-eat fresh blueberries with higher nutrient content and extended shelf-life.