Reduction of chilling injury in stored 'Hass' avocado fruit by 38 degrees C water treatments

'Hass' avocado (Persea americana Mill.) fruit were heat treated in water at 38 degrees C for 0 to 120 minutes, and stored at 0.5 degrees C for up to 28 days. After storage, fruit were ripened at 20 degrees C and their quality evaluated. External chilling injury (CI) developed during storage in nonheated fruit. Skin (exocarp) sectioning showed that browning developed from the base of the exocarp, and with longer storage, this browning moved outwards toward the epidermis. Longer durations of hot water treatment (HWT) progressively reduced CI; 60 minutes was the optimal duration that eliminated external CI, while best maintaining fruit quality. Concomitantly, electrolyte leakage of heated skin tissue increased approximate to 70% during storage, whereas electrolyte leakage of nonheated skin tissue increased approximate to 480% over the same period. Thus, significant protection was conferred by HWTs against low temperature damage to avocados and these effects are reflected in the morphology and physiology of the skin tissue.