Effect of pectin edible coating enriched with essential oils of citrus on strawberry quality during refrigerated storage and shelf life

Postharvest life of strawberry fruit is very short due to humidity and high metabolic activity. In order to extend the shelf life and quality of strawberry (cv. parous), effects of pectin coating enriched with different concentrations of lemon and orange peel essential oil were assessed at 20˚C for 6 days or 5˚C to 12 days. The experiment conducted based on a complete randomized design (CDR) in 3 replications with 6 treatments including control (distilled water), pectin (1%), pectin enriched with orange peel essential oil (0.5 and 1%) and pectin containing lemon peel essential oil (0.5 and 1%). Fruit quality was evaluated by marketing, weight loss, anthocyanin content, ascorbic acid content, total protein and chlorophyll of calyx every 3 days. Based on results coating fruits with citrus essential oil carried by pectin delayed the change in weight loss, total protein, anthocyanin content, maintained ascorbic acid content of fruits and also reduced chlorophyll destruction of calyx. The results showed that pectin coating containing lemon essential oil had a significant effect on the maintaining the visual quality of the fruit during the storage, delayed the weight loss and showed better results compared to the other coatings and to the control fruit. In addition, the maximum content of ascorbic acid and anthocyanin were obtained for strawberries coated with pectin containing lemon essential oil 1% after 12 days storage of fruits at 5˚C. All coatings significantly reduced weight loss of fresh strawberries during storage at 5˚C and 20˚C compared to the uncoated fruits. Results indicated that adding high concentrations (1%) of orange peel essential oil into pectin coatings did not improve quality of fruits. In addition, it was found that adding orange peel essential oil to pectin coating accelerate decay of fruits. Based on results, pectin coating containing 1% lemon essential oil considered an appropriate treatment to improve shelf life and storage quality of strawberry (cv. parous). However, further studies are necessary in order to minimize the sensory impact of citrus essential oils on fruits.