Effects of Microwave, Steam and Water Blanching on Freeze‐Dried Spinach

Abstract

ABSTRACT Microwave energy was demonstrated to be a convenient and effective method of blanching. Compared to steam or water, microwave blanching was superior in retention of ascorbic acid. The texture of rehydrated, microwave blanched spinach was firm, chewy and highly acceptable. Water blanching ruptured the cells and destroyed fine cellular structure as compared to steam blanching which caused less cellular disruption and greater retention of tissue structure. Microwave blanching resulted in coagulated protoplasmic material surrounding the cell walls. Cell and tissue structure remained intact which resulted in h gh rehydration ratios and acceptable textural characteristics. Microwave blanching yielded a superior freezedried product as compared to water and steam blanching.