88E-5 |
Effect of low oxygen atmospheres treatments on the storage life of Hass avocado (Persea americana). |
A. ARGAIZ-JAMET, Laboratorio de Investigación de Alimentos, Universidad de las Américas Puebla, Apdo. Postal 43, Sta. Catarina Martir, Cholula, Puebla, 72820, Mexico and P. Wesche-Ebeling. Postharvest techniques that extend the shelf life of Hass avocado and avoid chilling injury development during storage at low temperatures (injurious temperatures) are very important to the Mexican avocado producers since it is exported overseas. The aim of this work was to evaluate the effect of low oxygen atmosphere pretreatment on the delay of ripening, quality maintenance and prevention of chilling injury development during storage at an injurious temperature. Avocado Hass variety of uniform maturity was divided in three lots. Two of the lots (lots 1 and 2) were exposed for 24 h at 4 °C to a low oxygen atmosphere (97 % N2 and 3 % O2) an the last one was used as a control. After treatment, all lots were stored in air at 4 °C. The low oxygen atmosphere treatment was repeated in lot one after 15 days of storage and returned to the refrigerated storage after the treatment. After 30 days of storage the three lots were transferred to 22 °C to ripen. At the beginning, after the pretreatments and storage the avocado were evaluated for respiration rate, polyphenoloxidase, pectinmethylesterase, polygalacturonase, total phenols, chlorophyll content in peel and pulp as well as texture, chilling injury and ripening. Pretreatments with the low oxygen atmospheres significantly reduced the activity levels of the enzymes and the respiration rate, and increased the chlorophylls and total phenols retention, specially in the lots treated twice with the low oxygen atmospheres. The firmness decreased during the experiment and there was no difference after ripening between treated and the controls fruits. However, during the ripening period the treated fruits remained firmer that the non treated fruits. Pretreatment significantly reduced chilling injury symptoms and lengthened ripening time, being more efficient the repeated low oxygen atmosphere treatment. Repeated exposure of Hass avocado to low oxygen atmospheres during 24 h at 4°C helps to maintain their quality during refrigerated storage at injurious temperatures and extend its storage life.
Session 88E, Fruit & Vegetable Products: Processing
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