Impacts of various postharvest treatments on storage and fruit quality of 'lane late' oranges

In this study, the effects of various packing house treatments on postharvest physiology of the fruit, storage time, disease and disorders of 'Lane Late' oranges were investigated. For this purpose, chemical and non-chemical treatments were made to oranges. The oranges were harvested at commercial harvest maturity and 1000 ppm fludioxonil, 1000 ppm fludioxonil+wax, 1000 ppm imazalil, 1000 ppm imazalil+wax, hot water dip (53 °C, 1 min) and potassium sorbate (KS) (1%, 53 °C, 1 min) were applied in the packing house. After various postharvest treatments, fruits were stored at 0 °C temperature with 90-95% relative humidity. Fruit samples were taken at one month intervals from the storage room and various physical and chemical changes on the fruit were determined during the storage. Physical and chemical analyses such as weight loss, soluble solids content, titratable acidity, skin colour (L*, C*, h°), L-ascorbic acid content, total phenolics content, total flavonoid content, phenolic composition, changes in fruit taste and appearance, percentage of disease and disorders were carried out on the samples taken from storage rooms and shelf life periods. According to the results obtained; it has been observed that different post-harvest treatments have important effects on the quality characteristics of 'Lane Late' oranges during both cold storage and shelf life. In first year of experiment; at the end of cold storage the lowest weight loss, the highest taste and appearance values were recorded in fruit treated with fludioxonil+wax, the maximum L-ascorbic acid, total phenolics and total flavonoid values were noted in oranges treated with fludioxonil; the highest total soluble solids (TSS), titratable acidity (TA) and amount of juice, C* value of fruit and the lowest amount of fruit decay were determined in imazalil group of fruit.The maximum L* value of fruit skin were found in oranges treated with imazalil+wax. In first year of experiment during shelf life, maximum L* value of fruit skin, L-ascorbic acid, taste, appearance value and minimum amount of fruit decay were determined in fludioxonil+wax treatment. The highest C* and h° values of fruit skin and total phenolics values were found in imazalil+wax treatment. The lowest weight loss, the highest TSS and amount of juice were determined in oranges treated with imazalil+wax. The maximum amount of TA were obtained in fruit treated with hot water dip. In second year of experiment, at the end of cold storage; minimum weight loss, maximum amount of TSS, TA, amount of juice, L-ascorbic acid, fruit skin C* value, taste and appearance values were determined in fruit treated with fludioxonil+wax. The highest total flavonoid content in fludioxonil, the lowest amount of fruit decay in imazalil and maximum amount of total phenolics were determined in oranges treated with KS. In second year of experiment, during shelf life, maximum TA, amount of juice, L-ascorbic acid content and fruit skin L*, C*, taste, appearance values and minimum amount of fruit decay were determined in oranges treated with fludioxonil+wax. The lowest weight loss and the highest h° value of fruit skin was noted in fludioxonil group of fruit whereas maximum amount of juice was determined in oranges treated with imazalil. The highest total phenol and total flavonoid contents were recorded in fruit treated with imazalil+wax. As a conclusion, 'Lane Late' oranges can be stored commercially up to 5 months at 5 °C temperature and 90-95% RH. It was concluded that fludioxonil+wax treatment was more suitable than other applications to maintain postharvest quality.