Agboola SO, Singh H, Munro PA, Dalgleish DG, Singh AM
Department of Food Technology, Massey University, Palmerston North, New Zealand, Department of Food Science, University of Guelph, Ontario, Canada, and New Zealand Dairy Research Institute, Palmerston North, New Zealand.
J Agric Food Chem. 1998 Jan 19;46(1):84-90. doi: 10.1021/jf970365b.
Oil-in-water emulsions (4 wt % soy oil) were prepared with 0.5-5 wt % whey protein hydrolysate (WPH) (27% degree of hydrolysis), in a two-stage homogenizer using various first-stage pressures of 10.3, 20.6, and 34.3 MPa and a constant second-stage pressure of 3.4 MPa. Destabilization studies on the emulsions were carried out for up to 24 h, using both laser light scattering and confocal laser microscopy. It was found that emulsions formed with <2% WPH showed oiling off and coalescence at all homogenization pressures. Emulsions formed with 2, 3, and 4% WPH showed coalescence and creaming only, while slight flocculation but no creaming occurred in emulsions formed with 5% WPH. Furthermore, the apparent rate of coalescence increased with homogenization pressure but decreased with WPH concentration. In contrast, the surface concentration of WPH increased with the WPH concentration in the emulsions but decreased with homogenization pressure. Analysis of WPH by high-performance liquid chromatography showed an increase in the concentration of high molecular weight peptides at the droplet surface compared to the WPH solution. This was considered very important for the stability of these oil-in-water emulsions.
使用含0.5 - 5 wt%乳清蛋白水解物（WPH）（水解度为27%）制备水包油乳液（4 wt%大豆油），在两阶段均质机中进行，第一阶段采用10.3、20.6和34.3 MPa的不同压力，第二阶段压力恒定为3.4 MPa。使用激光散射和共聚焦激光显微镜对乳液进行长达24小时的失稳研究。结果发现，WPH含量低于2%时形成的乳液在所有均质压力下均出现油析和聚并现象。含2%、3%和4% WPH形成的乳液仅出现聚并和乳析现象，而含5% WPH形成的乳液出现轻微絮凝但无乳析现象。此外，聚并的表观速率随均质压力增加而增大，但随WPH浓度降低。相比之下，乳液中WPH的表面浓度随WPH浓度增加而升高，但随均质压力降低。通过高效液相色谱分析WPH发现，与WPH溶液相比，液滴表面高分子量肽的浓度增加。这被认为对这些水包油乳液的稳定性非常重要。
