超声波清洗对鲜切紫甘蓝抗氧化系统的影响

Effects of Ultrasonic Washing on Antioxidant Systems of Fresh-Cut Red Cabbages

摘要:

为探究超声波清洗对鲜切紫甘蓝抗氧化系统的影响,将鲜切紫甘蓝进行超声波清洗[超声频率(28±2)kHz、功率密度60W/L、频率周期400ms、处理时间20min]后,于4℃条件下贮藏 8d,研究超声处理对鲜切紫甘蓝中活性氧(reactive oxygen species,ROS)水平、抗氧化酶活性、抗氧化剂含量、抗氧化能力以及氧化损伤等指标的影响。结果表明,与蒸馏水清洗对照组相比,超声波清洗在贮藏初期能诱导鲜切紫甘蓝中超氧阴离子(superoxide anion radical,O·-₂)和H₂O₂的产生,在贮藏后期减少了O·-₂和H₂O₂的积累。超声处理提高了抗氧化酶,即超氧化物歧化酶(superoxide dismutase,SOD)和过氧化氢酶(catalase,CAT)的活性。尤其是在贮藏第2天,超声清洗后鲜切紫甘蓝中的SOD和CAT活性分别增加了31%和26%。此外,超声处理还通过增强抗坏血酸过氧化物酶(ascorbate peroxidase,APX)和谷胱甘肽还原酶(glutathione reductase,GR)的活性提高了鲜切紫甘蓝中内源性抗氧化剂抗坏血酸(ascorbic acid,AsA)和还原型谷胱甘肽(reduced glutathione,GSH)的含量。尤其是在贮藏第4天,超声清洗后鲜切紫甘蓝中的APX活性、GR活性、AsA含量、GSH含量分别增加了20%、17%、9%和9%。超声清洗还提高了鲜切紫甘蓝的抗氧化能力,并有效抑制了贮藏后期丙二醛和相对电导率的增加。由此可见,超声清洗引起的ROS的累积,触发了鲜切紫甘蓝的氧化应激防御机制。抗氧化酶活性的激活以及抗氧化剂含量的增加,提高了鲜切紫甘蓝的抗氧化能力,降低了鲜切紫甘蓝的氧化损伤。

Abstract:

To explore the influences of ultrasonic washing on the antioxidant systems of fresh-cut red cabbages, fresh-cut red cabbages were subjected to ultrasonic washing [frequency (28±2) kHz, power density 60W/L, frequency cycle time 400ms, and ultrasonic time 20min] and stored at 4℃ for 8d. The effects of ultrasonic washing on levels of reactive oxygen species (ROS), antioxidant enzyme activities, antioxidant contents, antioxidant capacities, and oxidative damages in fresh-cut red cabbages were examined. The results revealed that ultrasonic washing initially induced the production of superoxide anion radicals (O·-₂) and H₂O₂ in fresh-cut red cabbage during the initial storage period and subsequently reduced their accumulation during the later storage stages compared with the control group (distilled water washing). Ultrasonic treatment significantly enhanced the activities of antioxidant enzymes such as superoxide dismutase (SOD) and catalase (CAT). The SOD and CAT activities of the ultrasound-treated samples increased by 31% and 26% compared with the control ones on Day 2, respectively. In addition, ultrasonic washing improved the contents of endogenous antioxidants, including ascorbic acid (AsA) and reduced glutathione (GSH), by enhancing the activities of ascorbate peroxidase (APX) and glutathione reductase (GR). In particular, the APX activity, GR activity, AsA content, and GSH content in fresh-cut red cabbages after ultrasonic washing were increased by 20%, 17%, 9%, and 9% on Day 4, respectively. Ultrasonic washing also improved the antioxidant capacities of fresh-cut red cabbages and effectively inhibited the increase of malondialdehyde and relative conductivity during the later storage stages. These findings indicated that the accumulation of ROS caused by ultrasonic washing actively activated the antioxidant defense mechanisms of fresh-cut red cabbages. Ultrasonic washing increased the antioxidant capacities and alleviated oxidative damage of fresh-cut red cabbages by increasing enzyme activities and antioxidant contents.