Hot-Water Dipping and Storage Temperature Interact to Reduce Dehydration and Modulate Peel Oxidative Markers in ‘Owari’ Satsuma Mandarin (Citrus unshiu Marc.)

Satsuma mandarin is a non-climacteric fruit with limited storage potential, as dehydration and physiological stress can accelerate postharvest quality loss. This study evaluated the combined effects of hot-water dips (HWD; 48 °C or 52 °C for 3 min) and cold storage temperatures (1 °C or 3 °C for 8 weeks, followed by 7 days at 18–20 °C) on ‘Owari’ (Citrus unshiu Marc.) fruit quality and peel oxidative status. HWD reduced weight loss compared with untreated fruit at both temperatures, and total weight loss at 1 °C was 17.85% (HWD 48) and 18.27% (HWD 52), compared with 22.26% in the control. Storage at 1 °C reduced fruit weight loss compared with 3 °C, while fruit stored at 3 °C retained higher juiciness. Peel hydrogen peroxide level was lower at 1 °C, with the lowest value in HWD 48 fruit (5.56 nmol g−1 FW). Lipid peroxidation increased after storage across treatments but was lowest in HWD 48 at 1 °C (thiobarbituric acid reactive substances 11.82 nmol g−1 FW). HWD 48 at 1 °C also maintained the highest α-tocopherol level (411.18 µg g−1 FW) and showed the highest catalase activity. Overall, HWD 48, combined with storage at 1 °C, provided the most favourable peel oxidative stability. However, the risk of chilling injury at low temperatures must be assessed using a defined scoring protocol before commercial recommendation.