背景:苹果酸淀粉酯(MSE)的制备主要是使用高温方法进行的,但是存在高能耗等问题,准备时间长,和不均匀的加热。微波技术可以用来克服这些限制。淀粉颗粒的半结晶结构阻碍了改性剂进入基质,从而限制了酯化反应。物理技术可以作用于淀粉的内部以产生许多活性位点,从而促进淀粉与酯化试剂的反应。因此,本研究考察了微波预处理淀粉的效果,热-湿气,和超声波技术对取代度(DS)的影响,结构,微波法合成MSE的理化性质。
结果:预处理后MSE的DS升高。不同预处理方法得到的改性淀粉均未出现新的特征峰,而合成的MSE在1735cm-1附近显示出新的吸收峰。通过微波和热湿预处理获得的改性淀粉的颗粒结构和形态进行糊化和聚集,而通过超声预处理获得的改性淀粉的一些淀粉颗粒出现了孔径。MSE的相对结晶度和糊化焓降低,但结晶模式保持为A型。
结论:总体而言,结果表明,各种预处理方法可以通过破坏淀粉的结构来提高MSE的DS。本研究结果为提高酯化淀粉的DS提供了理论支持。©2024化学工业学会。
BACKGROUND: The preparation of malic acid starch ester (MSE) is mostly carried out using a high temperature method, but there are problems such as high energy consumption, long preparation time, and uneven heating. Microwave technology can be used to overcome these limitations. The semi-crystalline structure of starch granules hinders the modifier\'s access to the matrix, thus limiting the esterification reaction. Physical techniques can act on the interior of the starch to create a number of active sites, thereby facilitating the reaction of the starch with esterification reagents. Therefore, this study investigated the effect of starch
pretreatment by microwave, heat-moisture, and ultrasonic techniques on the degree of substitution (DS), structure, and physicochemical properties of MSE synthesized by the microwave method.
RESULTS: The DS of MSE was increased after pretreatments. The modified starch obtained by different
pretreatment methods did not show new characteristic peaks, while the MSE synthesized showed new absorption peaks near 1735 cm-1. The granular structure and morphology of the modified starch obtained by microwave and heat-moisture
pretreatment were gelatinized and aggregated, while some of the starch particles of the modified starch obtained by ultrasonic
pretreatment appeared pore-sized. The relative crystallinity and gelatinization enthalpy of the MSE were reduced, but the crystallization pattern remained as A-type.
CONCLUSIONS: Overall, the results suggest that various
pretreatment methods can enhance the DS of MSE by disrupting the structure of starch. The findings of this study provide theoretical support for improving the DS of esterified starch. © 2024 Society of Chemical Industry.