Extraction of walnut protein using deep eutectic solvent aqueous two-phase system: Investigation of structural and functional properties

Walnut protein (WP) exhibits high nutritional value and excellent techno-functional properties, making it a promising candidate for broad applications in the food industry. It is commonly extracted from the meal after oil processing of walnut through alkali extraction with isoelectric precipitation...

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Main Authors: Yun-Kun Zhu, Mei-Hui Li, Min Yang, Jiang-Xia Xu, Meng-Yao Ren, Zhong-Kai Zhao, Liang Wang, Jie Yang, Jun Liu, Min-Wei Zhang
Format: Article
Language:English
Published: Elsevier 2025-05-01
Series:Food Chemistry: X
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Online Access:http://www.sciencedirect.com/science/article/pii/S2590157525003931
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author Yun-Kun Zhu
Mei-Hui Li
Min Yang
Jiang-Xia Xu
Meng-Yao Ren
Zhong-Kai Zhao
Liang Wang
Jie Yang
Jun Liu
Min-Wei Zhang
author_facet Yun-Kun Zhu
Mei-Hui Li
Min Yang
Jiang-Xia Xu
Meng-Yao Ren
Zhong-Kai Zhao
Liang Wang
Jie Yang
Jun Liu
Min-Wei Zhang
author_sort Yun-Kun Zhu
collection DOAJ
description Walnut protein (WP) exhibits high nutritional value and excellent techno-functional properties, making it a promising candidate for broad applications in the food industry. It is commonly extracted from the meal after oil processing of walnut through alkali extraction with isoelectric precipitation (AE-IP). In this study, an aqueous two-phase system (DES-ATPS) consisting of betaine-urea/K2HPO4 was used for the extraction of WP from walnut kernels and cold-pressed walnut meal. Comparison with AE-IP, WP extracted through DES-ATPS exhibited enhanced color characteristics and there was no significant difference in protein subunit composition. The WP extracted by DES-ATPS displayed lower Surface hydrophobicity (H0) and intrinsic fluorescence intensities. Conversely, the exposure of internal groups in WP extracted by AE-IP resulted in a higher Zeta potential and a decrease in protein particle size. The comparative analysis revealed fundamentally distinct structural impacts between the two extraction methodologies. Notably, DES-ATPS-isolated WP demonstrated superior solubility under acidic conditions (pH 2).
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institution OA Journals
issn 2590-1575
language English
publishDate 2025-05-01
publisher Elsevier
record_format Article
series Food Chemistry: X
spelling doaj-art-5a4e57b5cb1241009c7351f8e1c571e32025-08-20T02:31:54ZengElsevierFood Chemistry: X2590-15752025-05-012810254610.1016/j.fochx.2025.102546Extraction of walnut protein using deep eutectic solvent aqueous two-phase system: Investigation of structural and functional propertiesYun-Kun Zhu0Mei-Hui Li1Min Yang2Jiang-Xia Xu3Meng-Yao Ren4Zhong-Kai Zhao5Liang Wang6Jie Yang7Jun Liu8Min-Wei Zhang9Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi 830017, ChinaXinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi 830017, ChinaXinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi 830017, ChinaXinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi 830017, ChinaXinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi 830017, ChinaXinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi 830017, ChinaXinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi 830017, ChinaXinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi 830017, ChinaCollege of Food Science and Nutritional Engineering, China Agricultural University, No.17 Qinghua Donglu, Haidian District, Beijing 100083, China; Corresponding authors.Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi 830017, China; Corresponding authors.Walnut protein (WP) exhibits high nutritional value and excellent techno-functional properties, making it a promising candidate for broad applications in the food industry. It is commonly extracted from the meal after oil processing of walnut through alkali extraction with isoelectric precipitation (AE-IP). In this study, an aqueous two-phase system (DES-ATPS) consisting of betaine-urea/K2HPO4 was used for the extraction of WP from walnut kernels and cold-pressed walnut meal. Comparison with AE-IP, WP extracted through DES-ATPS exhibited enhanced color characteristics and there was no significant difference in protein subunit composition. The WP extracted by DES-ATPS displayed lower Surface hydrophobicity (H0) and intrinsic fluorescence intensities. Conversely, the exposure of internal groups in WP extracted by AE-IP resulted in a higher Zeta potential and a decrease in protein particle size. The comparative analysis revealed fundamentally distinct structural impacts between the two extraction methodologies. Notably, DES-ATPS-isolated WP demonstrated superior solubility under acidic conditions (pH 2).http://www.sciencedirect.com/science/article/pii/S2590157525003931Walnut proteinDeep eutectic solventsProtein extractionStructural propertiesFunctional properties
spellingShingle Yun-Kun Zhu
Mei-Hui Li
Min Yang
Jiang-Xia Xu
Meng-Yao Ren
Zhong-Kai Zhao
Liang Wang
Jie Yang
Jun Liu
Min-Wei Zhang
Extraction of walnut protein using deep eutectic solvent aqueous two-phase system: Investigation of structural and functional properties
Food Chemistry: X
Walnut protein
Deep eutectic solvents
Protein extraction
Structural properties
Functional properties
title Extraction of walnut protein using deep eutectic solvent aqueous two-phase system: Investigation of structural and functional properties
title_full Extraction of walnut protein using deep eutectic solvent aqueous two-phase system: Investigation of structural and functional properties
title_fullStr Extraction of walnut protein using deep eutectic solvent aqueous two-phase system: Investigation of structural and functional properties
title_full_unstemmed Extraction of walnut protein using deep eutectic solvent aqueous two-phase system: Investigation of structural and functional properties
title_short Extraction of walnut protein using deep eutectic solvent aqueous two-phase system: Investigation of structural and functional properties
title_sort extraction of walnut protein using deep eutectic solvent aqueous two phase system investigation of structural and functional properties
topic Walnut protein
Deep eutectic solvents
Protein extraction
Structural properties
Functional properties
url http://www.sciencedirect.com/science/article/pii/S2590157525003931
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