Effect of TGase Crosslinking on the Structure, Emulsification, and Gelling Properties of Soy Isolate Proteins

Soy isolate protein (SPI), as a high-quality plant protein source, is often processed into various soy products. In this study, the physicochemical properties of SPI treated with transglutaminase (TGase) were investigated in correlation with emulsification characteristics and rheological behavior. T...

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Main Authors: Ziqi Peng, Kunlun Liu, Ning Liao
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Foods
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Online Access:https://www.mdpi.com/2304-8158/14/12/2130
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author Ziqi Peng
Kunlun Liu
Ning Liao
author_facet Ziqi Peng
Kunlun Liu
Ning Liao
author_sort Ziqi Peng
collection DOAJ
description Soy isolate protein (SPI), as a high-quality plant protein source, is often processed into various soy products. In this study, the physicochemical properties of SPI treated with transglutaminase (TGase) were investigated in correlation with emulsification characteristics and rheological behavior. The polyacrylamide gel electrophoresis with sodium dodecyl sulfate (SDS-PAGE) and Fourier-transform infrared spectroscopy (FTIR) and endogenous fluorescence spectrum analysis results showed that TGase was able to promote the covalent binding of lysine and glutamine residues in SPI. The moderate pre-crosslinking treatment of TGase (5–7.5 U/g TGase pre-crosslinked for 2 h or 5 U/g TGase pre-crosslinked for 2–3 h) improved the emulsification and gel properties to varying degrees: the nanoparticle and emulsification performance increased by 24.35% and the storage modulus of the gel increased by 288%. Furthermore, the surface charge of SPI increased due to the crosslinking impact of TGase, indicating a considerable rise in the surface electrostatic potential. Simultaneously, the protein surface exhibited a substantial increase in hydrophobicity, while the level of free sulfhydryl groups reduced. These changes indicate that TGase enzymatic crosslinking could significantly improve the structural stability of nanoparticles by enhancing the generation efficiency of covalent bonds between protein molecules.
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spelling doaj-art-cf65d26613974b8e8d199d4d674a78ba2025-08-20T03:27:29ZengMDPI AGFoods2304-81582025-06-011412213010.3390/foods14122130Effect of TGase Crosslinking on the Structure, Emulsification, and Gelling Properties of Soy Isolate ProteinsZiqi Peng0Kunlun Liu1Ning Liao2College of Food Science and Engineering, Henan University of Technology, Zhengzhou 450001, ChinaCollege of Food Science and Engineering, Henan University of Technology, Zhengzhou 450001, ChinaCollege of Food Science and Engineering, Henan University of Technology, Zhengzhou 450001, ChinaSoy isolate protein (SPI), as a high-quality plant protein source, is often processed into various soy products. In this study, the physicochemical properties of SPI treated with transglutaminase (TGase) were investigated in correlation with emulsification characteristics and rheological behavior. The polyacrylamide gel electrophoresis with sodium dodecyl sulfate (SDS-PAGE) and Fourier-transform infrared spectroscopy (FTIR) and endogenous fluorescence spectrum analysis results showed that TGase was able to promote the covalent binding of lysine and glutamine residues in SPI. The moderate pre-crosslinking treatment of TGase (5–7.5 U/g TGase pre-crosslinked for 2 h or 5 U/g TGase pre-crosslinked for 2–3 h) improved the emulsification and gel properties to varying degrees: the nanoparticle and emulsification performance increased by 24.35% and the storage modulus of the gel increased by 288%. Furthermore, the surface charge of SPI increased due to the crosslinking impact of TGase, indicating a considerable rise in the surface electrostatic potential. Simultaneously, the protein surface exhibited a substantial increase in hydrophobicity, while the level of free sulfhydryl groups reduced. These changes indicate that TGase enzymatic crosslinking could significantly improve the structural stability of nanoparticles by enhancing the generation efficiency of covalent bonds between protein molecules.https://www.mdpi.com/2304-8158/14/12/2130protein nanoparticlestransglutaminasecrosslinkingconformational changesproperties
spellingShingle Ziqi Peng
Kunlun Liu
Ning Liao
Effect of TGase Crosslinking on the Structure, Emulsification, and Gelling Properties of Soy Isolate Proteins
Foods
protein nanoparticles
transglutaminase
crosslinking
conformational changes
properties
title Effect of TGase Crosslinking on the Structure, Emulsification, and Gelling Properties of Soy Isolate Proteins
title_full Effect of TGase Crosslinking on the Structure, Emulsification, and Gelling Properties of Soy Isolate Proteins
title_fullStr Effect of TGase Crosslinking on the Structure, Emulsification, and Gelling Properties of Soy Isolate Proteins
title_full_unstemmed Effect of TGase Crosslinking on the Structure, Emulsification, and Gelling Properties of Soy Isolate Proteins
title_short Effect of TGase Crosslinking on the Structure, Emulsification, and Gelling Properties of Soy Isolate Proteins
title_sort effect of tgase crosslinking on the structure emulsification and gelling properties of soy isolate proteins
topic protein nanoparticles
transglutaminase
crosslinking
conformational changes
properties
url https://www.mdpi.com/2304-8158/14/12/2130
work_keys_str_mv AT ziqipeng effectoftgasecrosslinkingonthestructureemulsificationandgellingpropertiesofsoyisolateproteins
AT kunlunliu effectoftgasecrosslinkingonthestructureemulsificationandgellingpropertiesofsoyisolateproteins
AT ningliao effectoftgasecrosslinkingonthestructureemulsificationandgellingpropertiesofsoyisolateproteins