Pigeon pea protein isolates (PPI) are an option to obtain a high yield of good quality proteins and represent a great potential for the food industry. In this work, physicochemical and structural properties of albumin (ALB), globulin (GLB), and PPI obtained at different pHs (8, 9, 10, and 11) were studied to deepen the knowledge of these proteins for future application. GLB presented protein aggregates and polypeptides characteristics of 7S vicilin subunits while ALB presented polypeptides with low molecular masses. GLB showed a more compact and less flexible structure than ALB fraction due to the distinct conformational characteristics found in DSC, fluorescence spectroscopy, Ho. These structural characteristics conferred GLB greater conformational stability (∆G H2O ) than ALB fraction. The latter presented a higher proportion of β -strand in aggregated structures. PPI11 showed the highest protein recovery, but the least So with more presence of protein aggregates with the least proportion of β -strands in aggregated structures. A higher percentage of protein unfolding and exposure of hydrophobic residues to solvent was observed as the extraction pH of the isolates increased. Enthalpy change of transition decreased, and the maximum emission wavelength shifted to red in fluorescence spectroscopy. However, PPI11 showed only a slight increase in Ho (10%) with respect to PPI8. The variation in pH for protein extraction constitutes a simple, rapid, and low-cost method to obtain PPI with physicochemical and structural properties that will determine its functional properties and their use as food ingredients.

中文翻译：

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木豆 (Cajanus cajan L.) 分离蛋白及其主要蛋白组分的结构和理化性质的比较研究


木豆分离蛋白 (PPI) 是获得高产量优质蛋白质的一种选择，代表着食品工业的巨大潜力。在这项工作中，研究了在不同 pH（8、9、10 和 11）下获得的白蛋白 (ALB)、球蛋白 (GLB) 和 PPI 的理化和结构特性，以加深对这些蛋白质的了解，以供未来应用。 GLB呈现7S豌豆球蛋白亚基的蛋白质聚集体和多肽特征，而ALB呈现低分子量的多肽。由于 DSC、荧光光谱、Ho 中发现的独特构象特征，GLB 表现出比 ALB 组分更紧凑且灵活性较差的结构。这些结构特征赋予 GLB 比 ALB 更高的构象稳定性 (ΔG H2O )。后者在聚集结构中呈现出更高比例的β-链。 PPI11 显示出最高的蛋白质回收率，但蛋白质回收率最低，蛋白质聚集体较多，聚集结构中 β 链比例最少。随着分离物提取 pH 值的增加，观察到蛋白质解折叠和疏水残基暴露于溶剂的百分比更高。跃迁焓变减小，荧光光谱中最大发射波长向红色移动。然而，与 PPI8 相比，PPI11 的 Ho 仅略有增加（10%）。蛋白质提取过程中 pH 值的变化是一种简单、快速且低成本的方法来获得 PPI，其理化和结构特性将决定其功能特性及其作为食品成分的用途。