热处理对大豆油脂体乳液特性的影响

Effects of Heat Treatment on Properties of Soybean Oil Body Emulsion

以大豆油脂体乳液为研究对象,利用动态表面张力测量、动态激光散射、圆二色光谱、共聚焦等技术研究大豆油脂体在不同温度(30、50、70、90℃)条件下乳液的物理稳定性、氧化稳定性及油脂体表面蛋白二级结构的变化,考察了温度对乳液界面张力、界面特性的影响。结果表明:热处理降低了大豆油脂体乳液表面电荷和界面张力,改变了界面强度;油脂体表面蛋白的二级结构α-螺旋含量从(17.71±0.01)%下降到(15.3±0.03)%,无规卷曲含量从(29.96±0.01)%下降到(27.3±0.06)%,β-转角含量从(22.34±0.05)%下降到(21.2±0.03)%,β-折叠含量从(29.89±0.06)%增加到(36.1±0.02)%,热处理改变了维持油脂体表面蛋白二级结构的作用力,影响二级结构含量变化,表现出不同的界面特性;4个温度热处理没有明显促进油体的絮凝;30℃和50℃热处理的乳液,油脂氧化的氢过氧化物相对较少,表明热处理改变了大豆油脂体乳液的界面特性,进而影响油脂体乳液的物理稳定性和氧化稳定性。

In this study, soybean oil body emulsion was subjected to heat treatment at different temperatures. The changes inphysical stability, oxidative stability, the secondary structures of oleosins, interfacial tension, and interfacial characteristics inthe oil body emulsion were examined using dynamic surface tension measurement, dynamic laser light scattering, confocallaser technology and circular dichroism to evaluate the effectiveness of heat treatment. The results showed that heat treatmentreduced surface charges and interfacial tension, and changed the interfacial strength of oil bodies. In addition, heat treatmentcaused a decrease in α-helix structure from （17.71 ± 0.01）% to （15.3 ± 0.03）%, unordered structure from （29.96 ± 0.01）% to（27.3 ± 0.06）% and β-turn from （22.34 ± 0.05）% to （21.2 ± 0.03）%, and it could increase β-sheet structure from （29.89 ± 0.06）%to （36.1 ± 0.02）%. Heat treatment changed the forces maintaining the secondary structure of oleosins, which in turn could affectthe secondary structure contents and resulted in different interfacial properties. Furthermore, heat treatment could not significantlypromote the flocculation of oil bodies; heat treatment at 30 ℃ and 50 ℃ had relatively small amount of hydrogen peroxide. Thisresult suggested that heat treatment changed the interfacial properties of soybean oil body emulsion and consequently had animportant impact on its physical properties and oxidative stability.