向日葵盘及其果胶主要组成的研究

研究结果表明，向日葵盘组成复杂，初步测定出１０多种天然化合物，其果胶含量以海绵状肉质部位最高，锯齿形苞片部位最低。用气相色谱法分别测定了向日葵盘及其果胶中各种糖基的相对含量，发现它们都含有木糖、阿拉伯糖、甘露糖、半乳糖和葡萄糖等，向日葵盘中葡萄糖含量最高果胶中含半乳糖最多。向日葵盘用水预洗得到的水溶性果胶，其酯化度大于５０％，属于高酯果胶，其表观分子量为１７３４００，向日葵盘经一分别用稀无机酸及多

THE MAIN COMPONENT OF SUNFLOWER HEAD PECTIN

Investigation was carried out on chemica1 composition and characteristics of mature sunflower head and sunflower pectin from Jilin and Ningxia areas. Results show that the composition of sunflower head is quite complicated. More than ten types of natural chemical compounds were identified. Pectin contents in different parts of sunflower head are different.The highest content of pectin exists in the spongy flesh part and the lowest in the bracts.The sunflower head and sunflower pectin were hydrolysed with sulfuric acid and then ratios of sugar contents of their hydrolyzates were determined by gas chromatographic analysis. It was found that they all contained xylose,arabinose,mannose, galactose and glucose. Among them, glucose was of the highest content in sunflower head,and galactose was of the highest content in sunflower pectin. The water soluble pectin in sunflower head accounted for one half of the total pectin content of the head. The esterification degree of water soluble pectin exceeded 50%. It was classified as high-ester pectin and its apparent molecular weight was 173 400. After washing sunflower head three times with water prior to the process of extraction,the yields of pectin extracted from sunflower head with dilute hydrochloric acid as extractant were different from those extracted with sodium hexametaphosphate. But in both cases the esterification degree were lower than 50%. They belong to low-ester pectins. The apparent molecular weight of the former was 95 200,and the latter 67 300.