以“温185”纸皮核桃为原料,探讨在不同温度(40、70、100、130、160 ℃)下榨油对核桃蛋白结构、非共价作用力及功能特性的影响。结果表明,随着温度升高,核桃蛋白的微结构由圆球状颗粒转变为堆叠紧密的片状结构。红外光谱最大吸收峰红移1.68 nm,表明蛋白二级结构发生变化。具体来看,α-螺旋和β-折叠含量分别下降了0.75%和0.03%,而无规则卷曲的比例上升了1.73%,其中100 ℃被确定为二级结构变化较大的关键温度。温度升高还导致氢键和离子键减少,疏水基团暴露,从而降低了蛋白亲水性,进而导致溶解度和乳化性下降。该研究为深入理解核桃蛋白功能特性变化的机制及开发核桃饼粕类产品提供了理论依据。
‘Wen 185’ walnuts were used as the raw material, and this study investigated the effects of oil extraction at different temperatures (40, 70, 100, 130, and 160 ℃) on the structure, non-covalent interactions, and functional properties of walnut protein.Results indicated that as the temperature increases, the microstructure of walnut protein transitions from spherical particles to tightly stacked sheet-like structures.Infrared spectroscopy showed a red shift of 1.68 nm in the maximum absorption peak, suggesting changes in the secondary structure of the protein.Specifically, the contents of α-helices and β-sheets decreased by 0.75% and 0.03%, respectively, while the proportion of random coils increased by 1.73%.Notably, 100 ℃ was identified as a critical temperature for changes in internal interactions.Additionally, the increase in temperature led to a reduction in hydrogen bonds and ionic bonds, exposing hydrophobic groups and consequently decreasing the protein hydrophilicity, which in turn reduced its solubility and emulsifying properties.This study provides a theoretical basis for a deeper understanding of the mechanisms behind changes in the functional properties of walnut protein and for the development of walnut meal products.
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