Effect of Preharvest Ca-chitosan Application on Postharvest Quality of 'Garmrok' Kiwifruit during Cold Storage

Abstract

We evaluated the influence of preharvest calcium chitosan (Ca-chitosan) on the physicochemical properties of 'Garmrok' kiwifruit (Actinidia deliciosa) during postharvest cold storage at 0 degrees C. Preharvest treatment of kiwifruit with Ca-chitosan increased the fruit weight but had no significant effects on fruit size at harvest. The Ca-chitosan-treated kiwifruit at harvest displayed a significantly lower (p < 0.05) respiration rate (11.9 mg.kg(-1).h(-1)), possibly due to the selective permeability of Ca-chitosan for respiratory gases. In addition, preharvest treatment of Ca-chitosan delayed the loss of firmness in kiwifruit during cold storage. Furthermore, preharvest Ca-chitosan-treated kiwifruit had the significantly lowest (p < 0.05) soluble solids content (SSC) and the significantly highest (p < 0.05) titratable acidity (TA) at harvest, indicating that Ca-chitosan as a biostimulant can be used as a maturity-delaying agent to prolong the postharvest life of kiwifruit. In this study, we demonstrate that preharvest treatment of Ca-chitosan has a positive effect on the overall quality of kiwifruit during cold storage, suggesting a new way to extend the postharvest life of kiwifruit.