大豆可溶性多糖与Fe2+对O/W乳状液物理稳定性及流变特性的影响

研究大豆可溶性多糖(soybean soluble polysaccharides,SSPS)及不同浓度的Fe2+对大豆分离蛋白(soy isolated protein,SPI)稳定的O/W乳状液的物理稳定性和流变特性的影响。通过测定14 d内添加SSPS和不同浓度的Fe2+的乳状液的稳定动力学指数(turbiscan stability index,TSI)、稳态流变、粒径大小及分布和Zeta-电位,确定其物理稳定性。结果表明,与SPI乳状液相比,添加SSPS后,SSPS-SPI乳状液的TSI显著降低(p<0.05),液滴的表面积平均直径(d_3,2)和体积平均直径(d_4,3)增加,粘度系数增加,Zeta-电位绝对值降低,表明SSPS增加了SPI乳状液的粘度,提高了乳状液的物理稳定性;添加0.1 mmol/L Fe2+后,乳状液的TSI最低,液滴的d_3,2和d_4,3分别为0.686、2.136 μm,为最小粒径,粘度增加,稳定性较好;随着Fe2+浓度的增加,乳状液的TSI显著增加(p<0.05),粒径增大,分布范围变宽,表明0.2~0.5 mmol/L的Fe2+降低了乳状液的物理稳定性。总之,SSPS和0.1 mmol/L Fe2+的添加,提高了SPI稳定的O/W乳状液的物理稳定性。

Effect of Soybean Soluble Polysaccharides and Fe2+ on Physical Stability and Rheological Properties of O/W Emulsion

The effects of soybean soluble polysaccharides (SSPS) and different concentrations of Fe2+ on the physical stability and rheological properties of soy isolated protein (SPI) stabilized oil-in-water emulsions were investigated. The turbiscan stability index (TSI), steady rheology, particle size and distribution and Zeta-potential of the emulsions containing SSPS and different concentrations of Fe2+ within 14 days were determined. The results showed that the TSI of the SSPS-SPI emulsion was significantly lower than that of the SPI emulsion, and the surface area average diameter (d_{3, 2}) and volume average diameter (d_{4, 3}) of the droplets increased, the viscosity coefficient increased and the absolute value of Zeta-potential decreased, indicating that SSPS increased the viscosity of the SPI emulsion and improved the physical stability of the emulsion. After addition of 0.1 mmol/L Fe2+, the TSI was the lowest, and the particle size was the smallest with the d_{3, 2}and d_{4, 3} of 0.686, 2.136 μm, respectively, the viscosity of emulsion increased, its physical stability was better. With increasing of Fe2+ concentration, the TSI increased significantly (p<0.05), the particle size became larger and the distribution range became wider, indicating that 0.2~0.5 mmol/L Fe2+ decreased the physical stability of the emulsions. In a word, the addition of SSPS and 0.1 mmol/L Fe2+ improved the physical stability of the SPI-stabilized O/W emulsion.