The purpose of this paper is to investigate the relationship between pectic substances and the separation into strands during cooking of spaghetti squash. Spaghetti squash flesh separated into strands when boiled. Pec...The purpose of this paper is to investigate the relationship between pectic substances and the separation into strands during cooking of spaghetti squash. Spaghetti squash flesh separated into strands when boiled. Pectic substances of raw and cooked flesh were fractionated into three reagents. The galacturonic acid compositions of hydrochloric acid （HC1）-soluble pectin （PA）, sodium acetate buffer-soluble pectin （PB） and sodium hexametaphosphate-soluble pectin （PC） of raw flesh were 69.0%, 28.9% and 2.1%, respectively. Also, the degree of esterification （DE） ofPA, PB and PC was 67.4%, 61.5% and 55.6%, respectively. The DE of pectin was from the greatest to the least： PA 〉 PB 〉 PC, respectively, and the diethylaminoethyl （DEAE）-cellulose column chromatograms of PA and PB showed that they were comparatively in high methoxyl pectin. Therefore, about 50% of pectic substances in flesh were released into a cooking solution during 15-30 min of cooking. Highmethoxylpectin was degraded by β-elimination during boiling. Consequently, the flesh was separated into strands. This suggests that highmethoxylpectin glues strands together in the flesh of spaghetti squash.展开更多
文摘The purpose of this paper is to investigate the relationship between pectic substances and the separation into strands during cooking of spaghetti squash. Spaghetti squash flesh separated into strands when boiled. Pectic substances of raw and cooked flesh were fractionated into three reagents. The galacturonic acid compositions of hydrochloric acid （HC1）-soluble pectin （PA）, sodium acetate buffer-soluble pectin （PB） and sodium hexametaphosphate-soluble pectin （PC） of raw flesh were 69.0%, 28.9% and 2.1%, respectively. Also, the degree of esterification （DE） ofPA, PB and PC was 67.4%, 61.5% and 55.6%, respectively. The DE of pectin was from the greatest to the least： PA 〉 PB 〉 PC, respectively, and the diethylaminoethyl （DEAE）-cellulose column chromatograms of PA and PB showed that they were comparatively in high methoxyl pectin. Therefore, about 50% of pectic substances in flesh were released into a cooking solution during 15-30 min of cooking. Highmethoxylpectin was degraded by β-elimination during boiling. Consequently, the flesh was separated into strands. This suggests that highmethoxylpectin glues strands together in the flesh of spaghetti squash.
