Chemical, nutritive and sensory characteristics of tomatoes before and after conventional and microwave blanching and during frozen storage

The objective of this study was to evaluate the effects of microwave blanching on chemical, physical and sensory characteristics of tomatoes prior to and after frozen storage. Tomatoes were blanched (4 min) using four treatments. conventional boiling water (BW), steam (ST), microwaved in a glass container (MW), and microwaved in boilable bags (MWB). The lowest moisture content occurred in MW-blanched tomatoes before (92%) and after (86%) frozen storage. These tomatoes had the highest reduced ascorbic acid (RAA) content and the highest RAA retention (>23 mg/100 g, >91%) after blanching and after frozen storage. After blanching, MWB-blanched tomatoes were the lightest while after frozen storage, ST-blanched tomatoes were the lightest. BW-blanched tomatoes had generally higher flavor texture and appearance scores. This study demonstrated that though visual color and sensory attributes were highest for BW-blanched tomatoes, MW-blanched tomatoes retained more nutritive value in the finished product.