Zhang Genyi, Ao Zihua, Hamaker Bruce R
School of Food Science and Technology, Southern Yangtze University, 170 HuiHe Road, Wuxi, Jiangsu Province 214036, People's Republic of China.
Biomacromolecules. 2006 Nov;7(11):3252-8. doi: 10.1021/bm060342i.
The slow digestion property of native cereal starches, represented by normal maize starch, was investigated. The in vitro Englyst test showed that 53.0% of the maize starch is slowly digestible starch (SDS), and scanning electron microscopy (SEM) revealed that SDS starts from an increase of pore size until almost complete fragmentation of starch granules. However, similar amounts of SDS ( approximately 50%) were shown for partially digested fragmented starch residuals, which would normally be considered resistant to digestion based on the Englyst assay. Molecularly, both amylopectin (AP) and amylose (AM) contributed to the amount of SDS as evidenced by a similar ratio of AP to AM at different digestion times. Consistently, similar degrees of crystallinity, comparable gelatinization behavior, and similar debranched profiles of starch residuals following different digestion times indicated that the crystalline and amorphous regions of starch granules were evenly digested through a mechanism of side-by-side digestion of concentric layers of semicrystalline shells of native starch granules.
以普通玉米淀粉为代表的天然谷物淀粉的缓慢消化特性进行了研究。体外Englyst试验表明，53.0%的玉米淀粉是慢消化淀粉（SDS），扫描电子显微镜（SEM）显示，SDS始于孔径增加，直至淀粉颗粒几乎完全破碎。然而，部分消化的破碎淀粉残渣也显示出相似量的SDS（约50%），基于Englyst分析，这些残渣通常被认为对消化具有抗性。从分子角度来看，支链淀粉（AP）和直链淀粉（AM）都对SDS的量有贡献，不同消化时间下AP与AM的比例相似证明了这一点。同样，不同消化时间后淀粉残渣的结晶度、糊化行为和脱支谱相似，表明天然淀粉颗粒半结晶壳的同心层通过并排消化机制使淀粉颗粒的结晶区和无定形区被均匀消化。
