Effect of microwave pretreatment on the kinetics of ascorbic acid degradation and peroxidase inactivation in different parts of green asparagus (Asparagus officinalis L.) during water blanching

In this study, the effects of two blanching conditions on ascorbic acid (AA) and peroxidase (POD) in different segments of asparagus (bud, upper, middle, and butt) were investigated. The blanching treatments were: blanching in water at 70, 80 and 90 °C (WB); microwave heating (900 W, 30 s) followed by water blanching (MW + WB). AA degradation and POD inactivation in all segments of asparagus for both treatments are well described by first-order models. The degradation rate of AA and POD is gradually increased from butt to bud segment of asparagus. In addition, MW pre-treatment could increase the Ea of AA degradation and decrease the Ea of POD inactivation during water blanching of asparagus. Therefore, it is recommended that the different segments of asparagus should be subjected to different blanching times, and MW pre-treatment could be applied for alleviating AA degradation and accelerating POD inactivation during blanching, cooking and pasteurisation in water.