Reduction of cold damage during cold storage of Hass avocado by a combined use of pre-conditioning and waxing

• Hydrocooling with a solution of 0.3% CaCl2 reduce lenticelosis in avocado cv. Hass
• Hydrocooling in 0.3% CaCl2 with wax delay colour breakage in Hass avocado fruit.
• Low Temperature Conditioning with wax delay colour breakage in Hass avocado fruit.
• Wax (17.2% Carnauba, 1.8% Shellac and 24% total solids) reduce cold damage.
• Wax decreases metabolism and ethylene production in Hass avocado stored at 3 °C.

To reduce cold damage (CD) and loss of quality during cold storage of early season Hass avocados (22.9–26.3% dry matter), a pre-conditioning treatment that consisted on pulp hydrocooling to 6 °C in a 0.3% CaCl2 solution was effective in comparison to a control group of fruit pre-conditioned at 6 °C for 3 days in a cold room. Half of the fruit from both pre-conditioning treatments were waxed and stored at 3 ± 1 °C for 1, 23 and 46 days. After each storage time, quality parameters such as: epidermis and pulp damage, fruit firmness, % weight variation, colour, respiration, ethylene production, ethanol and acetaldehyde were assessed. Results demonstrated that the hydrocooling pre-treatment alone does not completely reduce lenticelosis but in combination with waxing resulted in a three fold reduction of internal damage and retarded fruit colour break. The use of waxing, independently of the initial pre-conditioning treatment, retarded fruit colour break, minimized quality loss, reduced metabolism and ethylene production and allowed to extend the commercialization period of the fruit at room temperature after storage at 3 °C for 46 days.