Water Loss: A Postharvest Quality Marker in Apple Storage

Apple fruit can be stored for long periods of time, especially with the use of controlled atmosphere storage, but like many fruits and vegetables are susceptible to water loss. Water loss can result in compromised appearance such as skin shriveling, as well as loss of firmness, and reduced saleable weight, which in turn affect the income of growers and other industry stakeholders. Preharvest factors that can influence water loss in apples during the postharvest period include climate, cultivar, fruit size, tree age, orchard practices, and harvest maturity. Postharvest factors such as the storage temperature, relative humidity, storage type, and duration can also affect water loss in apple fruit during storage. The mechanisms of cuticle biosynthesis in water permeance, the role of stomata and lenticels, microcracking, crosstalk with mechanical injuries, storage disorders, and decay incidence during the storage of apples are reviewed. Additionally, the review summarizes: preharvest and postharvest factors influencing water loss; recent management strategies including pre-cooling, cold storage, controlled atmospheres, packaging, and anti-senescence chemicals; the use of edible coatings, as well as other non-chemical approaches for modulating water loss and maintaining storage quality. The review also provides direction for the industry to manage this destructive problem in the postharvest supply chain of apple fruit.