Effects of combined enzymatic and ultrasonic treatments on the structure and gel properties of soybean protein isolate. (15th March 2022)

• Record Type: Journal Article
• Authors: Ma, Zhaolei; Li, Lijia; Wu, Changling; Huang, Yuyang; Teng, Fei; Li, Yang
• Is Part Of: Lebensmittel-Wissenschaft + Technologie =. Volume 158(2022)
• Publication Date: 2022-03-15
• Subjects: Soybean protein isolate -- Papain -- Ultrasound -- Structure -- Gel properties; Food industry and trade -- Periodicals; Food -- Composition -- Periodicals; Microbiology -- Periodicals; Nutrition -- Periodicals; 664.005
• DOI: 10.1016/j.lwt.2022.113123
• Languages: English
• ISSNs: 0023-6438

Abstract

Abstract: This study aimed to investigate the effects of combined treatment of enzyme and ultrasound on the structure of soybean protein isolate (SPI) and the properties of SPI gel cross-linked with glutamine transaminase (TG). The papain-hydrolyzed SPI with hydrolysis degrees of about 0%, 0.1%, 0.5%, and 1.0% was treated with ultrasound (300 W, 20 min) to obtain different modified proteins. The sodium dodecyl sulfate–polyacrylamide gel electrophoresis of SPI after combined treatment showed lower molecular weight, indicating dissociation of some subunits into smaller units. In addition, the protein structure extended, promoting the exposure of free sulfhydryl and hydrophobic groups. Compared with untreated SPI, the SPI gel prepared by the combined treatment formed a uniform and dense gel network, and its gel strength and water-holding capacity (WHC) significantly improved. The gel strength and WHC were higher in the SPI gel treated with a combination of ultrasound and enzyme than that treated with ultrasound or enzyme alone, exhibiting the synergistic effect of enzymatic and ultrasonic treatment. In conclusion, the combined treatment of enzyme and ultrasound might be an effective way of improving the structure and gel properties of SPI. Highlights: Transglutaminase-induced SPI gel were formed at low temperature. The combined treatment changed secondary and tertiary conformations of SPI. The combined treatment significantly improved gel strength and WHC of SPI. The combined treated SPI gel formed a uniform and dense microstructure. The combined treatment had synergistic effect on the modification of SPI.