The effect of different blanching methods on physical-chemical characteristics, bioactive compounds, and inactivation of peroxidase enzyme in green bell pepper
Subject Areas : Food Science and Technology
I. Fathollahy
1
,
Azita Khaghani
2
1 - Assistant Professor, Department of Food Science and Technology, Mamaghan Branch, Islamic Azad University, Mamaghan, Iran
2 -
Keywords: Blanching, Bell pepper, Microwave, Vitamin C, Peroxidase,
Abstract :
Blanching is a crucial step in the processing of fruits and vegetables, as it inactivates enzymes and helps preserve nutritional quality, bioactive compounds, texture, and color. This study investigated the effects of hot water, steam, and microwave blanching (applied for 60, 90, and 120 seconds) on sweet bell peppers, focusing on weight loss, color, antioxidant activity, ascorbic acid and phenolic content, and peroxidase enzyme inactivation. Weight loss varied significantly across blanching methods, with the lowest loss (2.36%) observed in microwave blanching at 60 seconds, and the highest (12.10%) in hot water blanching at 120 seconds. Peroxidase enzyme inactivation was incomplete after 60 seconds for all methods. The most substantial reduction in peroxidase activity was achieved with microwave blanching at 120 seconds, whereas hot water blanching at 60 seconds resulted in the least reduction (p < 0.05).
Total phenolic content increased with all blanching methods, ranging from 7.4–65.31% for hot water, 11.56–44.8% for steam, and 11.12–67.16% for microwave treatments. Ascorbic acid loss was minimal with microwave and steam blanching at 60 seconds but peaked with hot water blanching at 120 seconds, with longer blanching durations generally leading to greater losses. Antioxidant activity showed the least increase following hot water blanching at 60 seconds and the most with microwave blanching at 90 seconds. Blanching also significantly influenced color parameters (p < 0.05), with extended treatment durations resulting in increased L*, a*, and b* values. These findings underscore the importance of selecting appropriate blanching methods and durations to optimize the quality and nutritional retention of sweet bell peppers.
