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

IF 6.5 1区农林科学 Q1 CHEMISTRY, APPLIED

Food Chemistry: X Pub Date : 2025-05-01 DOI:10.1016/j.fochx.2025.102546

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

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引用次数: 0

Abstract

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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深共熔溶剂-水两相体系萃取核桃蛋白：结构和功能性质研究

核桃蛋白具有较高的营养价值和优良的技术功能特性，在食品工业中具有广阔的应用前景。通常从核桃油加工后的粕中采用等电沉淀法（AE-IP）碱法提取。本研究采用甜菜碱-尿素/K2HPO4双水相体系（DES-ATPS）从核桃仁和冷榨核桃粕中提取WP。与AE-IP相比，DES-ATPS提取的WP具有增强的颜色特征，蛋白质亚基组成无显著差异。DES-ATPS提取的WP具有较低的表面疏水性（H0）和本征荧光强度。相反，AE-IP提取的WP内部组暴露导致Zeta电位升高，蛋白质粒径减小。对比分析揭示了两种提取方法之间根本不同的结构影响。值得注意的是，des - atps分离的WP在酸性条件下（pH 2）表现出优越的溶解度。

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来源期刊

Food Chemistry: X CHEMISTRY, APPLIED-

CiteScore

4.90

自引率

6.60%

发文量

315

审稿时长

55 days

期刊介绍： Food Chemistry: X, one of three Open Access companion journals to Food Chemistry, follows the same aims, scope, and peer-review process. It focuses on papers advancing food and biochemistry or analytical methods, prioritizing research novelty. Manuscript evaluation considers novelty, scientific rigor, field advancement, and reader interest. Excluded are studies on food molecular sciences or disease cure/prevention. Topics include food component chemistry, bioactives, processing effects, additives, contaminants, and analytical methods. The journal welcome Analytical Papers addressing food microbiology, sensory aspects, and more, emphasizing new methods with robust validation and applicability to diverse foods or regions.