Functional properties and structure changes of soybean protein isolate after subcritical water treatment

Abstract

Subcritical water is an emerging method in food industry. In this study, soybean protein isolate (SPI) was treated by subcritical water (SBW) at various temperatures (0, 120, 160, 200°C) for 20 min. The changes in the appearances, physicochemical properties and structural changes were investigated. After SBW treatment, the color of SPI solution modified turned to be yellow. The mean particle size and turbidity of SPI had similar behaviors. The mean particle size was decreased from 263.7 nm to 116.8 nm at 120°C and then reached the maximum at 160°C (1446.1 nm) due to the aggregation of protein. Then it was decreased to 722.9 nm at 200°C caused by the protein degradation. SBW treatment could significantly enhance the solubility, emulsifying and foaming properties of SPI. With increasing temperature, the crystalline structure of protein was gradually collapsed. The degradation of the protein advanced structure occurred, especially at 200°C revealed by ultra-high resolution mass spectrometry. Better functional properties exhibited in hydrolysis products indicating that SBW treatment could be used as a good method to modify the properties of soy proteins isolate for specific purposes under appropriate treatment condition.

Effect of maleylation on physicochemical and functional properties of rapeseed protein isolate

“…Fourier transform infrared (FTIR) spectroscopy was carried out on solid samples by KBr pelleting method using Perkin Elmer Spectrum-100 model (Zhang et al 2015). Secondary structure quantitations were performed by the Gaussian curve-fitting of the spectrum in the Amide I region (Shevkani et al 2015).…”

Structure of the zein protein as treated with subcritical water

“…[18] Remarkable improvement of emulsifying ability and physical stability of emulsion by subcritical water treatment was probably associated with higher surface protein loads. [19] Subcritical water treatment could significantly enhance the emulsifying and foaming properties and solubility of SPI and could modify the structure of SPI, [20] which demonstrated that the subcritical water pretreatment could change the structure and improve the functional properties of SPI.…”

Water‐soluble myofibrillar proteins prepared by high‐pressure homogenisation: a comparison study on the composition and functionality

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“…These results suggested that solubility might not be the only factor determining protein adsorption at the oil‐/water interface. It had been indicated that surface hydrophobicity of a protein was a critical factor in affecting the emulsifying properties (Wang et al ., ; Ghribi et al ., ; Zhang et al ., ). The increased hydrophobic groups exposed on protein surface would promote the interaction between the protein and lipid phase (Fig.…”