Slowly digestible waxy maize starch prepared by octenyl succinic anhydride esterification and heat-moisture treatment: Glycemic response and mechanism
Slowly digestible waxy maize starch prepared by octenyl succinic anhydride esterification and heat-moisture treatment: Glycemic response and mechanism
复制标题
辛烯基琥珀酸酐酯化和湿热处理制备的慢消化糯玉米淀粉的血糖反应和机制
DOI：
10.1021/bm700951s
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发表时间：
2008-01-01
影响因子：
6.2
通讯作者：
Zhang, Genyi
中科院分区：
文献类型：
--
作者：
He, Jinhua;Liu, Jie;Zhang, Genyi
研究了辛烯基琥珀酸酐（OSA）酯化和湿热处理制备慢消化糯玉米淀粉的机理和分子结构。体外Englyst测试表明，当蜡质玉米淀粉与3%的OSA（淀粉重量计）酯化时，缓慢消化淀粉（SDS）的比例为28.3%，并且当OSA-淀粉（10%水分）在120 ℃下进一步加热4 h（称为HOSA-淀粉）时，获得最高的SDS含量为42.8%。HOSA-淀粉的体内血糖反应显示出血糖峰值的延迟出现和峰值葡萄糖浓度的显著降低（32.2%），进一步证实了其缓慢消化特性。支链淀粉脱支分析表明HOSA淀粉对异淀粉酶和支链淀粉酶的脱支酶具有最高的抗性，并且当HOSA淀粉被α-淀粉酶或淀粉葡萄糖苷酶消化时，还显示K-m和V-m（酶动力学）同时降低，表明HOSA淀粉的缓慢消化是由于消化过程中酶活性的非竞争性抑制。HOSA-淀粉的尺寸排阻色谱分析显示具有更多非还原性末端的片段化支链淀粉分子，其有利于通过淀粉葡糖苷酶在Englyst测试中的作用将RS转化为SDS。进一步的溶解度分析表明，HOSA-淀粉的水不溶性是由OSA介导的支链淀粉的交联和OSA改性淀粉分子之间的疏水相互作用引起的。HOSA-淀粉的水不溶性会降低其酶可及性，而与OSA分子相连的消化产物也可能直接作为非竞争性抑制剂降低酶活性，导致HOSA-淀粉消化缓慢。
The mechanism and molecular structure of the slowly digestible waxy maize starch prepared by octenyl succinic anhydride (OSA) esterification and heat-moisture treatment were investigated. The in vitro Englyst test showed a proportion of 28.3% slowly digestible starch (SDS) when waxy maize starch was esterified with 3% OSA (starch weight based, and it is named OSA-starch), and a highest SDS content of 42.8% was obtained after OSA-starch (10% moisture) was further heated at 120 degrees C for 4 h (named HOSA-starch). The in vivo glycemic response of HOSA-starch, which showed a delayed appearance of blood glucose peak and a significant reduction (32.2%) of the peak glucose concentration, further confirmed its slow digestion property. Amylopectin debranching analysis revealed HOSA-starch had the highest resistance to debranching enzymes of isoamylase and pullulanase, and a simultaneous decrease of K-m and V-m (enzyme kinetics) was also shown when HOSA-starch was digested by either alpha-amylase or amyloglucosidase, indicating that the slow digestion of HOSA-starch resulted from an uncompetitive inhibition of enzyme activity during digestion. Size exclusion chromatography analysis of HOSA-starch showed fragmented amylopectin molecules with more nonreducing ends that are favorable for RS conversion to SDS by the action of amyloglucosidase in the Englyst test. Further solubility analysis indicates that the water-insolubility of HOSA-starch is caused by OSA-mediated cross-linking of amylopectin and the-hydrophobic interaction between OSA-modified starch molecules. The water-insolubility of HOSA-starch would decrease its enzyme accessibility, and the digestion products with attached OSA molecules might also directly act as the uncompetitive inhibitor to reduce the enzyme activity leading to a slow digestion of HOSA-starch.