Currently, there is an increasing focus on comprehending the solubility of plant-based proteins, driven by the rising demand for animal-free food formulations. The solubility of proteins plays a crucial role in impacting other functional properties of proteins and food processing. Consequently, understanding protein solubility in a deeper sense may allow a better usage of plant proteins. Herein, we discussed the definition of protein solubility from both thermodynamic and colloidal perspectives. A range of factors affecting solubility of plant proteins are generalized, including intrinsic factors (amino acids composition, hydrophobicity), and extrinsic factors (pH, ionic strength, extraction and drying methods). Current methods to enhance solubility are outlined, including microwave, high intensity ultrasound, hydrostatic pressure, glycation, pH-shifting, enzymatic hydrolysis, enzymatic cross-linking, complexation and modulation of amino acids. We base the discussion on diverse modified methods of nitrogen solubility index available to determine and analyze protein solubility followed by addressing how other indigenous components affect the solubility of plant proteins. Some nonproteinaceous constituents in proteins such as carbohydrates and polyphenols may exert positive or negative impact on protein solubility. Appropriate protein extraction and modification methods that meet consumer and manufacturers requirements concerning nutritious and eco-friendly foods with lower cost should be investigated and further explored.

中文翻译：

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植物蛋白溶解度：挑战或难以克服的障碍

目前，由于对无动物食品配方的需求不断增长，人们越来越关注了解植物蛋白的溶解度。蛋白质的溶解度在影响蛋白质的其他功能特性和食品加工方面起着至关重要的作用。因此，更深入地了解蛋白质溶解度可能有助于更好地利用植物蛋白质。在这里，我们从热力学和胶体的角度讨论了蛋白质溶解度的定义。影响植物蛋白溶解度的一系列因素被概括，包括内在因素（氨基酸组成、疏水性）和外在因素（pH、离子强度、提取和干燥方法）。概述了目前提高溶解度的方法，包括微波、高强度超声、静水压、糖化、pH 变换、酶水解、酶交联、络合和氨基酸调节。我们的讨论基于可用于确定和分析蛋白质溶解度的氮溶解度指数的各种修改方法，然后讨论其他固有成分如何影响植物蛋白质的溶解度。蛋白质中的一些非蛋白质成分（例如碳水化合物和多酚）可能对蛋白质溶解度产生积极或消极的影响。应研究和进一步探索适当的蛋白质提取和修饰方法，以满足消费者和制造商对成本较低的营养和环保食品的要求。