发芽燕麦淀粉的分子结构与体外消化性

Molecular Structure and in vitro Digestibility of Germinated Oat Starch

摘要:

对晋燕八号燕麦避光发芽，并分别提取不同时间段的淀粉，用凝胶渗透色谱，特征黏度法和高效离子交换色谱对提取样品分别进行了分子量分布、特征黏度和链长分布的表征。结果发现，发芽过程中燕麦直链淀粉的含量升高，特征粘度增大，二者存在有显著的正相关关系；聚合度在27~33的链段始终是燕麦淀粉结构中的主体，所占比例超过60%，发芽过程中聚合度小于31的链段比例不断减小，而大于33的链段随发芽进行比例不断升高，这预示着，发芽期间生物自身对淀粉的利用以短链为主。对发芽过程中提取的淀粉与未发芽燕麦淀粉进行了体外消化性比较实验，结果表明，发芽过程降低了燕麦中淀粉的水解指数和血糖指数。燕麦淀粉中间级分对于体外消化指数影响明显，显著正相关系数0.82。

Abstract:

The Jinyan Ⅷ oat was geminated in the dark, and then starches were extracted from different germination periods. The intrinsic viscosity, molecular weight and chain length distribution of samples were characterized by Ubbelohde viscometer, gel permeation chromatography and ion exchange chromatography, respectively. It was found that the amylose content and intrinsic viscosity of germinated oat starches increased compared to raw oat starches, and a significant positive correlation presented between them. The degree of polymerization (DP) in segments 27~33 dominated raw and malted oat starches, occupying more than 60%. The segments with DP≤31 decreased continually, while the segments with DP≥33 increased, indicating that energy conversion during germination depended on utilizing short-chain starch. The in vitro digestibility of raw and germinated oat starches showed that the germination process reduced the hydrolysis index and the glycemic index of oat starch, and intermediate fractions of oat starch played obviously impact on in vitro digestion index, with a significant positive correlation coefficient of 0.82.