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 blanch ing on chemical, physical and sensory characteristics of tomatoes prior to and after frozen storage. Tomatoes were blanched (4 min) using four treatme nts. conventional boiling water (BW), steam (ST), microwaved in a glass con tainer (MW), and microwaved in boilable bags (MWB). The lowest moisture con tent occurred in MW-blanched tomatoes before (92%) and after (86%) frozen s torage. These tomatoes had the highest reduced ascorbic acid (RAA) content and the highest RAA retention (>23 mg/100 g, >91%) after blanching and afte r frozen storage. After blanching, MWB-blanched tomatoes were the lightest while after frozen storage, ST-blanched tomatoes were the lightest. BW-blan ched tomatoes had generally higher flavor texture and appearance scores. Th is study demonstrated that though visual color and sensory attributes were highest for BW-blanched tomatoes, MW-blanched tomatoes retained more nutrit ive value in the finished product.