School of Food Technology, Institute of Agricultural Technology, Suranaree University of Technology, Nakhon Ratchasima, 30000, Thailand.
UR1268 Biopolymères Interactions Assemblages, INRA, F-44300 Nantes, France; UMR0408 Sécurité et Qualité des Produits d'Origine Végétale, INRA, Université Avignon, F-84000 Avignon, France.
Carbohydr Polym. 2019 Feb 1;205:143-150. doi: 10.1016/j.carbpol.2018.10.042. Epub 2018 Oct 15.
This work investigates the macromolecular structure of native and amylomaltase (AM) treated cassava starch at various reaction times. AM-treated starches showed lower amylose content compared to their parental starch. Long chain proportions (DP 25-80) increased with reaction time up to 4 h and then slightly decreased at 24 h. Macromolecular and fine structure of AM-treated starches for 5 min (AM5min) and 4 h (AM4 h) were characterized more deeply by using HPSEC-MALLS and H NMR combined with β-amylolysis and MALDI-TOF-MS. Molar mass and dispersity of both AM-treated starches were lowered. Nevertheless, AM5min had longer external chains whereas AM4 h exhibited a larger and denser macromolecular core. A cyclo-structure with DP 8 was found in both AM-treated starches; however, AM4 h contained cyclo-structures with various sizes (DP 8-32). Finally, by controlling reaction time and substrate constituents, which are important factors affecting the AM action modes, AM-treated starch with various structural features can be obtained.
本研究考察了不同反应时间下天然木薯淀粉和糖化酶（AM）处理木薯淀粉的高分子结构。与原淀粉相比，AM 处理的淀粉直链淀粉含量较低。长链比例（DP25-80）随反应时间的增加而增加，4 小时后略有下降，24 小时后略有下降。通过使用 HPSEC-MALLS 和 1H NMR 结合β-淀粉酶解和 MALDI-TOF-MS，更深入地研究了 AM 处理 5 分钟（AM5min）和 4 小时（AM4h）的淀粉的大分子和精细结构。两种 AM 处理的淀粉的摩尔质量和分散度都降低了。然而，AM5min 具有更长的外部链，而 AM4h 则具有更大和更密集的大分子核心。在两种 AM 处理的淀粉中都发现了 DP8 的环结构；然而，AM4h 含有各种大小的环结构（DP8-32）。最后，通过控制反应时间和底物成分（影响 AM 作用模式的重要因素），可以获得具有不同结构特征的 AM 处理淀粉。
