Department of Food Science and Technology, College of Agriculture, Isfahan University of Technology, Isfahan 84156-83111, Iran.
Department of Food Chemistry and Biocatalysis, Wrocław University of Environmental and Life Sciences, 50-375 Wroclaw, Poland.
Molecules. 2024 Nov 16;29(22):5415. doi: 10.3390/molecules29225415.
This study aimed to investigate the impact of physical treatments, namely heat (70 °C for 48 h), atmospheric cold plasma (10 kW for 20 min), and ultrasonic frequency (40 kHz for 15 min), on the physicochemical and interfacial properties of soy protein isolate (SPI) and whey protein isolate (WPI) in the context of oleogel production by foam template (cryogel) method. The physical modification of both SPI and WPI was monitored using SDS-PAGE, Fourier transform infrared spectroscopy (FTIR) spectroscopy, and differential scanning calorimetry (DSC), measuring interfacial tension, color, solubility, foam volume, foam stability, and, finally, the density and oil absorption of the produced cryogel. The findings revealed that the application of ultrasonic waves resulted in a significant reduction in the content of alpha-helical of SPI and WPI while the other treatments increased the content of random coil proteins. FTIR analysis further showed that ultrasonic and heat treatment led to a decrease in C-N tensile vibration within the range of 1200-1650 cm in SPI. Meanwhile, in cold plasma treatment, an increase was observed which was confirmed by the elevation of enthalpy from 100 to 128 kJ/kg. Physical treatments significantly altered the surface properties of both SPI and WPI, where this value was reduced in SPI and increased in WPI. The cold plasma method demonstrated superior performance in enhancing the solubility of SPI from 10 to 58.2%, while the solubility of WPI decreased from 96.4 to 90.4%. By modifying the proteins, the foam volume and oil adsorption ability of the related cryogel improved, as shown by the maximum oil absorption obtained after ultrasonic treatment for SPI (11.6 g/g) and cold plasma (9.17 g/g) for WPI. These results could be useful in applying physical treatments to modify proteins and create the cryogel as an oleogel template for structuring liquid oil and producing innovative health value-added foods.
本研究旨在探讨物理处理（70°C 加热 48 小时、10kW 大气压冷等离子体处理 20 分钟和 40kHz 超声处理 15 分钟）对大豆分离蛋白（SPI）和乳清分离蛋白（WPI）的理化和界面性质的影响，这些蛋白是通过泡沫模板（冰晶）法制备油凝胶的。通过 SDS-PAGE、傅里叶变换红外光谱（FTIR）和差示扫描量热法（DSC）监测物理改性后 SPI 和 WPI 的变化，测量界面张力、颜色、溶解度、泡沫体积、泡沫稳定性，最终测量所制备冰晶的密度和吸油率。研究结果表明，超声处理会显著降低 SPI 和 WPI 的α-螺旋含量，而其他处理方法会增加无规卷曲蛋白的含量。FTIR 分析进一步表明，超声和热处理导致 SPI 中 1200-1650cm 范围内的 C-N 拉伸振动减少。与此同时，在冷等离子体处理中，观察到 C-N 拉伸振动增加，这一变化通过焓值从 100kJ/kg 增加到 128kJ/kg 得到了证实。物理处理显著改变了 SPI 和 WPI 的表面性质，使 SPI 的表面疏水性降低，而 WPI 的表面疏水性增加。冷等离子体处理方法在提高 SPI 的溶解度方面表现出色，SPI 的溶解度从 10%提高到 58.2%，而 WPI 的溶解度从 96.4%降低到 90.4%。通过改性蛋白质，相关冰晶的泡沫体积和油吸附能力得到提高，SPI 经超声处理后最大吸油率为 11.6g/g，WPI 经冷等离子体处理后最大吸油率为 9.17g/g。这些结果有助于应用物理处理方法来改性蛋白质，以冰晶作为油凝胶模板来构建液体油，并生产具有创新性健康附加值的食品。
