Kou Tingting, Gao Qunyu
College of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510640, China; Guangdong Province Key Laboratory of Green Processing of National Products and Product Safety, Guangzhou 510640, China.
College of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510640, China; Guangdong Province Key Laboratory of Green Processing of National Products and Product Safety, Guangzhou 510640, China.
Carbohydr Res. 2018 Mar 22;458-459:13-18. doi: 10.1016/j.carres.2018.01.009. Epub 2018 Feb 1.
The crosslinked starch has been studied for many years, but it is difficult to characterize degree of substitution on crosslinking of the very high and low crosslinked starches. The available approaches (including viscosity, settling volume, and P content) all have their limitations, i.e., not applicable in a large scope, pollution problem, and can not reflect the internal structure change. Here in this paper starch-iodine (St-I) method was proposed as a new approach to characterize the crosslinking degree. In this investigation, three starches of A, B, and C crystalline pattern with different amount (from very low to very high, 0.01, 0.05, 0.1, 0.5, 1, 5, 10%) of crosslinking reagent added were studied. This method is based on the mechanism that crosslinking reaction take place between amylose/amylopectin, amylopectin/amylopectin, whereas the amylose dose not crosslink one another. After crosslinked to amylopectin, the result amylose-amylopectin complex can be considered as a new amylopectin. Results showed that the St-I method can characterize all the crosslinked starches of the three starches, at low reagent level (0.01-0.1%), the amylose was found to decrease rapidly, this can also replace the viscosity method, whereas at high reagent level (1-10%), although the significant differences can still be observed, the effect was not so obvious as it for the lower crosslinked starches, here we firstly applied dose efficiency to characterize this phenomenon, which was informative and helpful in determining this modification process.
交联淀粉已被研究多年，但对于高度交联和低度交联淀粉的交联取代度进行表征却很困难。现有的方法（包括粘度、沉降体积和磷含量）都有其局限性，即适用范围不广、存在污染问题，且无法反映内部结构变化。本文提出用淀粉 - 碘（St - I）法作为表征交联度的新方法。在本研究中，对添加不同量（从极低到极高，0.01%、0.05%、0.1%、0.5%、1%、5%、10%）交联剂的A、B、C三种晶型淀粉进行了研究。该方法基于直链淀粉/支链淀粉、支链淀粉/支链淀粉之间发生交联反应，而直链淀粉之间不发生交联的机制。与支链淀粉交联后，生成的直链淀粉 - 支链淀粉复合物可被视为一种新的支链淀粉。结果表明，St - I法能够表征这三种淀粉的所有交联淀粉，在低试剂水平（0.01 - 0.1%）时，直链淀粉迅速减少，这也可替代粘度法，而在高试剂水平（1 - 10%）时，虽然仍能观察到显著差异，但效果不如低度交联淀粉明显，在此我们首次应用剂量效率来表征这一现象，这对于确定该改性过程具有参考价值且很有帮助。
