Effet de l'application combinée de1-MCP et d'une faible teneur en oxugène sur la réduction des dégâts dus au frois et la stabilité de l'oxydation des lipides chez l'avocat (Persea americana Mill.) stocké à basse température

Résumé

Introduction. The avocado (Persea americana Mill.) fruit is sensitive to chilling injury (CI) when exposed to low temperatures. High lipid content in avocado pulp makes it prone to oxidation, resulting in rancidity and subsequent production of undesirable flavours and quality loss during storage. Materials and methods. Avocado fruit (cv. Becon) were treated with 1 ?L·L-1 1-MCP for 24 h at 20 °C, and thereafter stored at 4 °C for 21 d under low oxygen atmosphere (3.5% O2), followed by transferring to 20 °C for 14 d to simulate the shelf life. The CI index, firmness, peel colour, relative electrical conductivity (EC), respiration, ethylene evolution, malondialdehyde (MDA) content, peroxidase (POD) activity, peroxide value and iodine value were measured throughout the storage period. Results and discussion. The CI incidence and severity of fruit treated with a combination of 1-MCP and low oxygen were significantly lower and delayed compared with the other treatments. The combined application of 1-MCP and low oxygen treatment was effective and delayed the onset of climacteric peaks of respiration and ethylene production. The delay was associated with reductions in fruit softening and cell membrane permeability as expressed by EC. The results of MDA content and POD activity of fruit treated with a combination of 1-MCP and low oxygen were significantly reduced. Moreover, significantly lower peroxide values and higher iodine values suggested that a combination of 1-MCP and low oxygen treatment effectively controlled the lipid oxidation in avocado fruit pulp. Conclusion. Overall, the results support the hypothesis that combined treatment (as compared with either 1-MCP or low oxygen treatment) was the most effective for alleviation of CI, lipid oxidation stability and extending the shelf life of avocado fruit under low temperature storage