A Comparative Study of the Effects of Postharvest Treatments on Occurrence of Kohansho and Quality of 'Kiyomi' Tangor

Abstract

　The effects of postharvest treatments, namely, perforated film packaging (PFP), hot water dip (HWD), and hot calcium dip (HCD), on the occurrence of "Kohansho (rind disorder)" and the quality attributes of 'Kiyomi' Tangor (Citrus unshiu Marc. ×C. sinensis Osb.) fruit were compared. Samples of the fruit were treated, packed in corrugated fiberboard boxes, and stored at 10℃ for up to 4 weeks. Weight loss was significantly lower and firmness was significantly higher in the fruit treated by PFP than in those treated by other postharvest treatments or in the control fruit. All postharvest treatments reduced the occurrence of Kohansho compared with control, and PFP and HWD treatments were more effective than HCD in reducing the occurrence of Kohansho. None of the postharvest treatments impaired quality attributes tested (total soluble solids [TSS], titratable acidity [TA], TSS/TA ratio, ascorbic acid content, and ethanol content), when compared with the attributes of the control. We conclude that PFP treatment, which can maintain a high relative humidity and a modified atmosphere except in the presence of high CO₂ levels (＞8%) and/or low O₂ levels (＜5%) was the most effective and commercially practical method to control Kohansho and preserve quality.