Effect of edible coatings on quality and shelf life of carambola (Averrhoa carambola L.) fruit during storage

Carambola fruit have limited marketability due to high degree of perishability and higher moisture content which lead to the extensive postharvest losses. The aim of this study was to determine the efficacy of chitosan (CH), gum arabic (GA) and alginate (AL) coatings on the shelf life and overall quality of carambola fruit. Carambola fruit were dipped for 2 min into the solution of CH (0.3 and 0.5 %), GA (1 and 3 %) and AL (1.5 and 2 %) were stored at 26 ± 1 °C, 65–70 % RH, while the uncoated fruit served as control. Carambola fruit coated with edible coatings showed significant delay in the change of weight loss, decay percentage, titratable acidity (TA), pH, total soluble solids (TSS), sugar accumulation, pigment degradation and ascorbic acid content as compared to uncoated control fruit. In addition, the edible coatings showed a positive effect on maintaining higher concentration of total phenolics, which decreased in control fruit due to their over-ripening and senescence processes. Compared to control, all the coatings had positive effects on the inhibition of cell wall degrading enzyme activities and among them CH 0.3 % and GA 1 % had shown superiority in inhibiting the enzyme activity. After 12 days of storage, the sensory evaluation indicated that carambola fruit coated with CH 0.3 % and GA 1 % had maintained better visual quality than the other coated as well as control samples. These findings suggested that the use of CH 0.3 % and GA 1 % coatings will maintain the carambola fruit quality and lead to better acceptance by consumers.