Combined Effect of Ozone Treatment and Modified Atmosphere Packaging on Antioxidant Defense System of Fresh-Cut Green Peppers

Abstract

The changes in respiration rates, malondialdehyde (MDA) content and antioxidant enzyme activities of fresh-cut green peppers treated with ozone (6.42 mg/cm3, 15 min), modified atmosphere packaging (MAP; 3% O2, 4% CO2 and 93% N2) and ozone + MAP during storage at 5C for 21 days were investigated in a laboratory environment. The three treatments all reduced respiration rates and MDA content compared to the control group. The enzyme activities in fresh-cut green peppers including peroxidase (POD), superoxidase dismutase (SOD) and L-phenylalanin ammonia-lyase (PAL) were induced by ozone and MAP treatments while polyphenol oxidase (PPO) activities were inhibited. And a much better effect was observed when the ozone and MAP treatment were combined which indicated ozone and MAP had a synergistic effect on inhibiting the respiration rates and the predication of MAD by enhancing the effectiveness of the antioxidant defense system through enhancing the activity of POD, SOD, PAL and inhibiting the activity of PPO. Practical Applications Because of the nutritional qualities and convenience, fresh-cut fruits and vegetables have gained popularity in recent years. However, fresh-cut fruits and vegetables shelf ife are limited due to the natural inherent barriers of fruits and vegetables are damaged during processing. The antioxidant defense system which consists of a series of antioxidase such as superoxidase dismutase, peroxidase, catalase, is an important enzyme system which can inhibit oxidation reactions in tissues. It is beneficial for extending shelf life of fresh-cut fruits and vegetables. This study has given an experimental evidence that ozone and modified atmosphere packaging (MAP) both can enhance the effectiveness of the antioxidant defense system. And the combination of ozone and MAP treatment can enhance the induction. Thus, ozone and MAP treatment have the advantages of prolonging shelf life of fresh-cut fruits and vegetables.