Bactericidal effect of ultrasound on glutinous rice during soaking and its influence on physicochemical properties of starch and quality characteristics of sweet dumplings

• Published in: Ultrasonics sonochemistry 2024-11, Vol.110, p.107034, Article 107034
• Main Authors: Wang, Shuli, Wang, Xiaojie, Liu, Yu, Dong, Wenjing, Fan, Huiping, Fan, Shijia, Ai, Zhilu, Yang, Yong, Suo, Biao
• Format: Article
• Language: English
• Subjects: Anti-Bacterial Agents - chemistry; Anti-Bacterial Agents - pharmacology; Chemical Phenomena; Food Handling - methods; Food Quality; Glutinous rice; Microbial inactivation; Original; Oryza - chemistry; Oryza - microbiology; Sonication; Starch - chemistry; Starch physiochemical properties; Sweet dumplings; Ultrasonic treatment; Ultrasonic Waves
• ISSN: 1350-4177; 1873-2828; 1873-2828
• DOI: 10.1016/j.ultsonch.2024.107034

[Display omitted] •Ultrasound effectively reduced viable cell number in glutinous rice after 4 h of soaking.•Ultrasound destroyed the granule morphology of starch, leading to cracks on the surface.•Ultrasonic treatment improved the physicochemical properties of glutinous rice starch.•The quality of sweet dumplings made of ultrasound treated glutinous rice is improved.•The effects of ultrasound on the physicochemical properties improved with increasing power. The soaking process of glutinous rice allows the growth and reproduction of microorganisms, which can easily cause food safety problems. In this work, the effects of different ultrasonic powers (150 W, 300 W, 450 W, and 600 W) on the bactericidal effect of glutinous rice, the physicochemical properties of starch and the quality characteristics of sweet dumplings were studied. Compared with soaking for 0 and 2 h, sonication of glutinous rice after soaking for 4 h was more effective at reducing the number of microorganisms in soaked glutinous rice, and the bactericidal effect increased with increasing ultrasound intensity. After 30 min, the total number of bacteria decreased by 2.04 log CFU/g. Moreover, ultrasonic treatment destroys the grain structure of glutinous rice starch, resulting in the formation of dents and cracks on the starch surface, increasing the amylose content, improving its expansion, reducing its short-range order and relative crystallinity, and altering its gelatinization characteristics. In addition, ultrasonic treatment increased the soup transparency of sweet dumplings from 51.8 % to 63.95 %, reducing their hardness, chewiness and adhesiveness. In summary, ultrasonic treatment can not only effectively kill microorganisms in soaked glutinous rice but also improve the quality of glutinous rice dumplings by changing the physicochemical properties of glutinous rice starch. The results of this study provide theoretical support for the application of ultrasonic technology in glutinous rice food production.