Acetyl substitution patterns of amylose and amylopectin populations in cowpea starch modified with acetic anhydride and vinyl acetate

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• 作者：Junrong Huang ; Henk A. Schols ; Rianne Klaver ; Zhengyu Jin ; Alphons G.J. Voragen
• 关键词：Cowpea starch ; Amylose ; Amylopectin ; Acetic anhydride ; Vinyl acetate
• 刊名：Carbohydrate Polymers
• 出版年：2007
• 出版时间：19 February 2007
• 年：2007
• 卷：67
• 期：4
• 页码：542-550
• 全文大小：556 K

文摘

To study the effect of reagent type on the distribution pattern of acetyl groups in acetylated cowpea starch, amylose and amylopectin populations were isolated from the starch granules after modification to a low degree of substitution (DS < 0.1) with acetic anhydride and vinyl acetate, respectively. Slowly reacting reagent vinyl acetate resulted in higher DS values for the amylopectin populations when compared to the rapidly reacting reagent acetic anhydride. The two reagents had similar effects on the acetylation level of amylose, suggesting that the amorphous regions of granules were easily accessible for both reagents. The acetyl substitution patterns were analyzed by enzymatic degradation followed by characterization of the obtained fragments using chromatographic and mass spectrometric techniques. The distributions of acetyl groups along the amylose and amylopectin chains were more clustered for modification with vinyl acetate as compared with modification with acetic anhydride. Between the two acetylation types, pronounced differences in the acetyl substitution patterns were observed for the large fragments obtained after α-amylase digestion; only slight differences were exhibited for the small fragments obtained by exhaustive enzymatic digestion of amylose and amylopectin populations.