Effect of harvest date and ripening degree on quality and shelf life of Hass avocado in Mexico

Introduction. Canada is an important avocado importer from Mexico. For most of the harvest season, fruit reach adequate pulp dry matter content, ripen properly and, consequently, quality and shelf life are excellent. However, after January, fruit dry matter content increases and blackened skin occurs. Shipments to Canada containing blackened fruit are rejected because this characteristic is wrongly associated with low pulp firmness and short shelf life. The objective of our research was to determine the effect of harvest time and ripening degree on initial quality and shelf life of Hass avocado. Materials and methods. Fruit were harvested from October 2007 to April 2008, and grouped into five ripening categories according to the degree of blackened skin. Fruit were then refrigerated for 7 d to simulate shipment to Canada. Thereafter, fruit were stored under simulated market conditions until they reached the edible ripening stage. Dry matter content was calculated only at the beginning of the storage period while quantification of weight loss, fruit with blackened skin, pulp firmness, and pulp color was done at the beginning of the storage period, at the end of the refrigeration period, and every three days during market conditions. Results and discussion. Dry matter content, skin color and pulp hue angle significantly increased with harvest date and ripening degree. Weight loss decreased with harvest date but increased with ripening degree, while firmness was affected by harvest date but was not associated with ripening degree. Conclusion. There is no reason to reject or downgrade blackened fruit, since quality and shelf life are not affected.