内源多酚对松仁各组分蛋白理化性质、功能特性和结构的影响

以松仁粕（pine kernel meal,PKM）和脱酚松仁粕（dephenolized pine kernel meal,DPKM）为原料，利用碱溶酸沉法和Osborne分级法分别提取分离蛋白（protein isolates,PI）、球蛋白（globulin,Glo）、清蛋白（albumin,Alb）和谷蛋白（gluten,Glu），研究内源多酚对松仁各组分蛋白理化性质、功能特性和结构的影响。结果表明：脱酚处理后多酚含量、灰分以及碳水化合物显著降低，但蛋白质含量显著提高（P<0.05）。DPKM各组分蛋白的总巯基含量、游离巯基含量显著高于PKM(P<0.05)，二硫键含量和表面疏水性均降低。与PKM相比，DPKM各组分蛋白的溶解性、乳化稳定性、起泡性、起泡稳定性显著提高，乳化性降低（P<0.05）。脱多酚改变了松仁蛋白的二级结构，PKM与DPKM均有典型的蛋白吸收峰，并在酰胺I带和酰胺II带的位置发生偏移。DPKM各组分蛋白质β-折叠占总空间结构百分比增加，而α-螺旋、β-转角和无规卷曲结构相对含量降低。荧光光谱显示多酚物质对PI、Alb和Glu都有荧光猝灭作用...

Effects of Endogenous Polyphenols on the Physicochemical and Functional Properties and Structure of Pine Kernel Proteins

Protein isolates (PI) were obtained from pine kernel meal (PKM) and dephenolized pine kernel meal (DPKM) by alkali dissolution followed by acid precipitation, and globulin (Glo), albumin (Alb) and gluten (Glu) were prepared from PKM and DPKM by Osborne fractionation method. The effects of endogenous polyphenols on the physicochemical and functional properties and structure of these proteins were explored. It was shown that after the removal of phenolics, the contents of phenolic compounds, ash and carbohydrates decreased, while the protein content significantly increased (P < 0.05). The contents of total and free sulfhydryl groups in the proteins from DPKM were significantly higher than those in the proteins from PKM (P < 0.05), whilst the opposite was observed for the content of disulfide bonds and the surface hydrophobicity. Higher solubility, emulsion stability, foaming capacity and foam stability were observed in the proteins from DPKM, while the emulsifying capacity decreased after the removal of phenolic compounds (P < 0.05). The secondary structure of pine kernel proteins was changed by the removal of polyphenols. Dephenolization could alter the secondary structure of pine kernel proteins. The proteins from both PKM and DPKM had typical absorption peaks, and the positions of the amide I and amide II bands were shifted. In addition, the proportion of β-sheet increased, while the proportions of α-helix, β-turn and random coil decreased in DPKM proteins compared with PKM proteins. Fluorescence spectra showed that polyphenols had a fluorescence quenching effect on PI, Alb and Glu, but not on Glo. The structure and properties of pine kernel proteins can be significantly affected by dephenolization, and this treatment method can be selected according to the application purpose.