Edible Composite Coating of Chitosan and Curdlan Maintains Fruit Quality of Postharvest Cherry Tomatoes

Abstract

Postharvest cherry tomatoes are prone to senescence, decay and nutrient loss during the storage period owing to microbial invasion and their own metabolism. In this work, postharvest cherry tomatoes were treated with a composite coating of 1% chitosan and 1% curdlan, and the characteristics of postharvest cherry tomatoes during storage were investigated. Compared to control samples, after 21 d of storage under ambient conditions, the cherry tomatoes treated with the chitosan and curdlan coatings showed less rottenness, less weight loss, a lower respiration rate, reduced ethylene production, lower malonaldehyde (MDA) content and reduced membrane permeability. After the samples were treated with the composite coating, the activities of free radical scavenging enzymes such as superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) were maintained at higher levels; the activities of related disease-resistant enzymes such as chitinase (CHI) and glucanase (GLU) were also maintained at higher levels. The soluble solids, titratable acidity, firmness, vitamin C content, lycopene content and antioxidant activities of postharvest cherry tomatoes treated with the composite coating exhibited higher levels as well. The composite coating of chitosan and curdlan might be a potentially promising method for preserving postharvest cherry tomatoes and other fruits.