Effect of prestorage short-term Anoxia treatment and modified atmosphere packaging on the physical and chemical changes of green asparagus

The effects of prestorage short-term Anoxia treatment combined with modified atmosphere packaging (MAP) on quality changes during the storage of green asparagus (Asparagus officinalis L.) spears were investigated. Two sets of asparagus were used in this study. The first set underwent short-term Anoxia treatment via the administration of gaseous N2 for 8 h at room temperature, while the second set was kept in ambient air at the same temperature. Consequently, treated and untreated spears were stored either freely or packaged in plastic bags with low density polyethylene, in which a passive modification of the atmosphere was allowed to develop. All samples were stored at 4 °C for 8 days, followed by 8 days at 10 °C. Samples treated with neither Anoxia nor MAP were used as a control. Our results show that treating the asparagus samples with Anoxia and MAP (Anoxia + PE) caused lower respiration, slowing the decrease in headspace O2. In the Anoxia + PE treated samples, spears lost <12% fresh weight after 8 days at 10 °C. All treatments showed less increase in shear force while exposed at 4 °C for 8 days, as compared with the significant increase found when transferred to 10 °C. This increase in shear force was accompanied by the accumulation of fiber and lignin content. There was a positive relationship between toughening and fiber (R2 = 0.958) and toughening and lignin (R2 = 0.915). Moreover, the degradation of chlorophyll, sugar and ascorbic acid content under the Anoxia and MAP treatments were significantly reduced. The results of the present work indicate that Anoxia treatment, a non-chemical and simple postharvest technology, feasible for use in developing countries where food storage technologies are lacking.