Application of Electromagnetic Radiations and Superheated Steam for Enzyme Inactivation in Green Bell Pepper

Abstract

The effect of electromagnetic radiation (microwave and infrared) based dry blanching and superheated steam enzyme inactivation on product quality of green bell pepper was evaluated and the performance was compared with that of water and steam blanching. Processing conditions (time and temperature) were standardized mainly on the basis of degree of inactivation of peroxidase enzyme. Superheated steam and water blanching required lesser duration (110 and 140 s, respectively) when compared to steam (180 s), microwave (230 s) and infrared (580 s) blanching. The retention of ascorbic acid (91.1%) and soluble protein (91.6%) was higher in microwave and superheated steam-blanched slices, respectively. Although texture of infrared blanched slices was firmer compared to unblanched as well as blanched by other methods, it had higher retention of β-carotene (131.2%) and chlorophyll (136.4%) compared to unblanched. PRACTICAL APPLICATIONS Blanching is one of the preprocessing steps before drying, freezing and canning of most of the vegetables. Conventional water and steam blanching has many drawbacks such as loss of water soluble nutrients and effluent generation. The electromagnetic radiation-based dry blanching methods employed in the present study can overcome these drawbacks and result in a continuous process. This study also explored that superheated steam blanching can be effectively used for enzyme inactivation which in turn requires lesser processing time besides minimizing the loss of nutrients. This research area has ample scope for further studies and the techniques have great potential to be used as an alternative to conventional blanching methods.