Combined Effect of Mild Heat Treatment by Warm Sodium Hypochlorite Aqueous Solution and Active MAP on Browning of Fresh-Cut Celery

Abstract

The combined effect of mild heat treatment during the decontamination process (HT) and active modified atmosphere packaging (active MAP) during cold storage (MA) on browning of fresh-cut celery was examined in this study. A sodium hypochlorite aqueous solution at 50 ℃ was used for the decontamination treatment and regarded as the medium for the mild heat treatment. The initial gas composition and concentrations of active MAP were 9.0 ％ O 2 , 13.0 ％ CO 2 , and 78 ％ N 2 . The results for 9 days of storage showed that the aerobic plate count (APC, Log 10 CFU/g) during storage for the solo-MA and HT ＋ MA combination was under 6 and comparatively lower than that of the control and solo-HT. This result indicated that solo-HT had a lower role in reducing bacterial growth. In contrast, solo-HT, similar to solo-MA and HT ＋ MA combination, moderated the variation of the hue angle ( H °), which is an index of the degree of browning fresh-cut celery surface during storage. Additionally, the solo-HT and HT ＋ MA combination prevented phenylalanine ammonia-lyase (PAL) activity and the relative increase in apparent polyphenol content, which is associated with the reduction of browning during storage. These results showed that the HT ＋ MA combination could extend the storage stability of fresh-cut celery.