Department of Food Science and Technology, University of Karachi, 75270 Karachi, Pakistan.
Department of Food Science and Technology, University of Karachi, 75270 Karachi, Pakistan.
Int J Biol Macromol. 2021 Mar 31;174:22-31. doi: 10.1016/j.ijbiomac.2021.01.096. Epub 2021 Jan 18.
This study describes the effects of hydroxypropylation (HP) on sorghum and corn cold water soluble (CWS) starches prepared via alcoholic alkaline treatment (AAT). Propylene oxide (5% and 12% on starch weight basis) was used to modify both sorghum and corn starches. SEM analysis revealed that HP modification prior to AAT altered the granular morphology of native CWS starches. The characteristic peaks at 2980.28 cm and 2979.87 cm indicated the presence of hydroxypropyl groups and the complete loss of the granular order for HS12-CWS (hydroxypropylated sorghum CWS starch treated with 12% propylene oxide based on dry starch weight) and HC12-CWS (hydroxypropylated corn CWS starch treated with 12% propylene oxide based on dry starch weight) starches. Increase in swelling power and water binding capacity of HP modified CWS starches was observed. However, Percent transmittance was significantly reduced due to fragmented water-soluble granules. HP-modified CWS starch gels exhibited a more rigid gel network. Broader linear viscoelastic range suggesting greater stability and well dispersed behavior of HP-CWS starches. High G' values of HP-CWS starches were due to the ordered and elastic gel network that resisted deformation. Furthermore, all HP-CWS starches exhibited higher shear and thermal resistance compared to unmodified CWS starches.
本研究描述了羟丙基化（HP）对通过醇碱处理（AAT）制备的高粱和玉米冷水可溶性（CWS）淀粉的影响。使用环氧丙烷（基于淀粉重量的 5%和 12%）对高粱和玉米淀粉进行改性。SEM 分析表明，AAT 前的 HP 改性改变了天然 CWS 淀粉的颗粒形态。特征峰在 2980.28 cm 和 2979.87 cm 处表明存在羟丙基基团，并且 HS12-CWS（用 12%的环氧丙烷处理的羟丙基化高粱 CWS 淀粉，基于干淀粉重量）和 HC12-CWS（用 12%的环氧丙烷处理的羟丙基化玉米 CWS 淀粉，基于干淀粉重量）淀粉完全失去了颗粒有序性。观察到 HP 改性 CWS 淀粉的溶胀能力和水结合能力增加。然而，由于水溶性颗粒的碎片化，百分透光率显著降低。HP 改性 CWS 淀粉凝胶表现出更刚性的凝胶网络。更宽的线性粘弹范围表明 HP-CWS 淀粉具有更大的稳定性和良好的分散性。HP-CWS 淀粉的高 G'值是由于有序且弹性的凝胶网络抵抗变形。此外，与未改性的 CWS 淀粉相比，所有 HP-CWS 淀粉都表现出更高的剪切和耐热性。
