Enhancement of storability and quality maintenance of carambola (Averrhoa carambola L.) fruit by using composite edible coating

Introduction. Our investigation aimed to examine the influence of eco-friendly edible coatings composed of sodium alginate, olive oil and green tea extract (GTE) on improving the shelf life and nutritional quality of carambola (A. carambola L.). Materials and methods. The combinations and concentrations of composite coatings tested were (2% sodium alginate + 0.1% olive oil) (T1), (2% sodium alginate + 0.2% olive oil) (T2) and (2% sodium alginate + 0.1% olive oil + 0.25% GTE) (T3), while the untreated fruit served as control (T4) and were stored at (25 ± 5) °C and (65 ± 5)% RH. All the stored fruit were subjected to physico-chemical and biochemical analysis at regular intervals of 4 days up to 16 days of their storage period. Results and discussion. Weight loss and decay occurrence were least in the fruit treated with T1 and T2 as compared with those of T3 and uncoated fruit (T4). The contents of total soluble solids, total sugars and changes in pigments were found to be least in fruit treated with T1 followed by those treated with T2 and T3. The addition of GTE (T3) to treated fruit during the storage helped enhance the antioxidants such as total phenols and ascorbic acid. Conclusion. The composite edible coatings tested in our study enhanced the shelf life of coated carambola fruit, i.e., thirteen days for T1, sixteen days for T2, fourteen days for T3 and twelve days for control or untreated fruit (T4); the nutritional quality of carambola was enhanced with the treatment of edible coating containing GTE.