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

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.