热处理对花生蛋白结构与乳化性质的影响

    Effect of heat treatment on the structure and emulsifying properties of peanut protein

    • 摘要: 为了改善花生蛋白的乳化性能,采用不同温度(80、90、100、120℃)对花生蛋白进行热处理,探讨热处理对花生蛋白结构和乳化性质的影响。结果表明:温度≥90℃的热处理促使花生蛋白产生了部分高分子量的聚集体且绝对电位(ζmin=(18.87±0.32) mV)显著降低;小角X射线散射测定结果表明所有温度热处理后花生蛋白天然球状结构均有所缺失,回转半径增加(Rg max=(5.19±0.01) nm)而分形维数降低(Dm min=1.83±0.09);热处理后花生蛋白的荧光发射最大波长发生明显红移(Δλmax=10 nm),表面疏水性、分子柔性均显著提高,这表明了蛋白分子结构已展开;只有在100℃和120℃热处理时花生蛋白的乳化活性才显著增加,而所有温度热处理后花生蛋白的乳液离心稳定性和耐盐稳定性均显著增加。热处理通过改变花生蛋白分子结构提高了其乳化性质,从而拓宽了花生蛋白的应用范围。

       

      Abstract: To improve the emulsifying properties of peanut protein, heat treatment at different temperatures range from 80 to 120 ℃) was applied, and the effects of heat treatment on the structure and emulsifying properties of peanut protein were investigated. The results indicated that heat treatment at temperatures ≥90 ℃ promoted the formation of partial high-molecular-weight aggregates in peanut protein and significantly reduced the absolute Zeta potential (ζmin=(18.87±0.32) mV). Small-angle X-ray scattering measurements revealed that the natural globular structure of peanut protein was partially lost after heat treatment at all temperatures, with an increase in the radius of gyration (Rg max=(5.19±0.01)nm) and a decrease in the fractal dimension (Dm min=1.83±0.09). The maximum wavelength of the fluorescence emission of peanut protein showed a significant red shift (Δλmax=10 nm) after heat treatment, and the surface hydrophobicity and molecular flexibility were significantly improved, indicating the unfolding of protein molecular structure. Notably, the emulsifying activity of peanut protein significantly increased only at 100 ℃ and 120 ℃, whereas the centrifuge stability and salt tolerance of emulsions stabilized by peanut protein significantly improved after heat treatment at all temperatures. Heat treatment enhanced the emulsifying properties of peanut protein by changing its molecular structure, thereby broadening the application range of peanut protein.

       

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