Abstract: In order to clarify the metabolic response mechanism of fruits and vegetables to moderate intensity pulsed electric field (MIPEF) and to determine the optimal treatment conditions for increased contents of bioactive compounds in baby cabbage, the effects of different electric field intensities (0.4–2.0 kV/cm) and duty ratios (0%–49.2%) on the contents of bioactive compounds, the activity of antioxidant enzymes and antioxidant capacity in baby cabbage were investigated. The results showed that MIPEF increased the contents of bioactive compounds including phenols, ascorbic acid, glutathione, total glucosinolates and isothiocyanates by 2.76%–818.03% compared with the control group, and enhanced the activity of antioxidant enzymes including catalase (CAT), peroxidase (POD), superoxide dismutase (SOD), ascorbate peroxidase (APX) and glutathione reductase (GR) by 2.22%–42.00%, and the scavenging activity toward 1,1-dipenyl-2-pierylhydrazyl (DPPH), hydroxyl and superoxide anion radical as well as total reducing power by 1.81%–202.11%, thus delaying the senescence process. The results of model prediction and validation experiments showed that the optimized treatment conditions were found to be 1.1 kV/cm and 46.4% for electric field intensity and duty ratio, respectively, under which the predicted levels of bioactive compounds in MIPEF treated baby cabbage were 88.91%–103.40%. In conclusion, MIPEF treatment can significantly increase the contents of bioactive compounds and antioxidant capacity in baby cabbage, thus being a promising candidate for non-thermal processing of fruits and vegetables.

Key words: moderate intensity pulsed electric field (MIPEF); baby cabbage; bioactive compounds; antioxidant enzymes; antioxidant capacity