富含岩藻糖苹果皮果胶的提取与理化性质

Extraction and Physico-chemical Properties of Fucose-Rich Pectins from Apple Peel

以超声辅助柠檬酸提取法从苹果皮中提取苹果果胶,并对所提取苹果皮果胶进行理化性质测定和分析。在最佳提取条件下(pH 2.5柠檬酸,450 W超声30 min),苹果皮果胶得率为14.6%。理化性质分析表明:所得苹果皮果胶的酯化度为69.9%、糖醛酸含量为58.5%、总糖含量为92.8%,分子质量大于400 kD。气相色谱法分析表明:该方法提取的苹果皮果胶由鼠李糖、岩藻糖、阿拉伯糖、木糖、葡萄糖、半乳糖、葡萄糖醛酸及半乳糖醛酸8种单糖组成,单糖组成的物质的量比为9.5∶19.2∶4.6∶0.1∶4.6∶3.6∶2.3∶56.3,岩藻糖含量高达19.2%。而超声法、盐酸法提取的苹果皮果胶中未检测到岩藻糖。进一步研究表明:富含岩藻糖的苹果皮果胶的提取与柠檬酸作萃取剂有一定关系。

In this study, apple pectins （APs） were extracted from apple peel by ultrasound-assisted extraction with citric acid, and investigated for physico-chemical properties. Under the optimized conditions of pH 2.5 citric acid solution as the extraction solvent, 450 W ultrasound power and 30 min radiation time, the yield of APs was 14.6%. The extracted APs were characterized by a degree of esterification of 69.9% and a molecular weight larger than 400 kD, and contained 92.8% total sugar, 58.5% aldonic acid. G-C data indicated that the APs consisted of eight monosaccharides including Rha, Fuc, Ara, Xyl, Glc, Gal, GlcA and GalA, with a relative molar ratio of 9.5：19.2：4.7：0.1：4.6：3.6：2.3：56.3 and a significantly high percentage of Fuc, reaching 19.2%. Further results revealed that the extraction of Fuc-rich APs was likely associated with the method using citric acid as the extraction solvent.