Plum is a perishable fruit with a very short shelf life of 3-4 days. Several studies have suggested the possible use of edible coatings on maintaining quality and prolonging storage life of fresh horticultural produce. Hence, different edible coatings, namely, lac-based (2:3), Semperfresh™ (1:3) and Niprofresh® (1:5) were selected to observe their efficacy on quality retention of 'Santa Rosa' plums. The effects of these coatings on the physical, physiological and biochemical attributes were studied under cold storage conditions (2 ± 1 °C and 85-90% relative humidity). Our results revealed that all the coatings, especially the lac-based significantly reduced the weight loss and maintained higher firmness throughout the storage period. These surface coatings modified the respiration and ethylene rates of the plums and slowed down their metabolism as shown by the retention of texture of the tissue and delayed colour development. At the end of 35 days of cold storage, lac-based coating helped to retain nearly 55% higher fruit firmness and 21% higher antioxidant activity in fruits as compared to uncoated ones. However, the changes in total anthocyanin content were found to be suppressed by 13% in lac-based coated fruits. Overall, the results suggested that lac-based coating of plum fruits was most effective to extend the storage life of 'Santa Rosa' plums over other coatings and uncoated fruits under low temperature storage conditions.
Keywords: Anthocyanin; Antioxidant activity; Edible coating; Plum; Quality.