Effects of pretreated ozone and modified atmosphere packaging on the quality of fresh-cut green asparagus.

摘要

The changes in lignifying, antioxidant enzyme activities and cell wall composition of fresh-cut green asparagus (Asparagus officinalis L.), pretreated in 1 mg l-1 aqueous ozone and subsequently packaged in modified atmosphere (MAP), were investigated during storage at 3 degrees C for 25 days. The enzyme activities in fresh-cut asparagus including phenylalanine ammonia lyase (PAL), superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione reductase (GR) were inhibited by aqueous ozone treatment and subsequent modified atmosphere packaging. Changes in lignin, cellulose and hemicellulose contents were also monitored during storage. Similarly, the increase of the cell wall composition elements under the aqueous ozone treatment and/or MAP were significantly reduced (P<0.05). The possible mechanisms in which changes in enzymatic activities and cell wall composition occurred were discussed. Compared to the control group, enzyme activities in MAP and/or group remained high, which means that asparagus in the two latter groups remained a high-ability scavenger of free radicals. It was found that as a result of treatment in O3 and/or MAP, PAL activity presented a peak at day 10 of storage, but its activities were significantly lower than in the control group. The increase in lignin levels during storage is attributed to the toughening which occurs in asparagus a few days after harvest..