RATE OF FREEZING AND INTEGRITY OF VEGETABLE TISSUES: IV: Observations on Summer Squash (Cucurbita pepo L.).

This paper reports histological observations on blanched and unblanched summer squash tunnel frozen at different rates. The detected textural damage consisted of detached cell layers, cell tearings, cavities, and various changes in the cytoplasm, nucleous, and starch granules. The number and extent of these damages increased as the freezing rate decreased. Blanching made the tissue more sensitive to freezing damage. With 5 mm thick slices, the critical freezing time is less than 15 min at - 35°C.