CHINESE CABBAGE MIDRIBS AND LEAVES PHYSICAL CHANGES AS RELATED TO FREEZE-PROCESSING

摘要

Differences were investigated in texture, drip and pectic composition of raw or blanched Chinese cabbage midribs and leaves after conventional (F) or program freezing (PF). Softening of tissues and amount of drip were least to greatest: PF-5 degrees C/min < PF-2 degrees/min < F-35 degrees C < F-20 degrees C, respectively. Freezing-thawing accelerated release of pectin but the freezing rate did not affect pectin release much. Total pectin in raw midribs was less than in raw leaves. The leaves contained more low methoxyl pectin than midribs, but the: high methoxyl pectin was almost the same. Cell damage in frozen-thawed midribs and leaves by light- and electron-microscopy appeared extensive.