Flaxseed oil - Whey protein isolate emulsions: Effect of high pressure homogenization

The effect of high-pressure homogenization (20-100 MPa) and the number of homogenization cycles (1-7) on the stability of flaxseed oil - whey protein isolate emulsions was evaluated. All the emulsions were stable to creaming for at least 9 d of storage. An increase in homogenization pressure from 20 to 80 MPa and number of passes through the homogenizer up to 3, decreased the mean droplet size of the O/W emulsions despite the higher polydispersity. Emulsions homogenized at lower pressures (20 MPa) showed a monomodal distribution of the particles, whereas, an increase in pressure to 80 MPa led to a bimodal distribution, indicating droplets coalescence. High-pressure homogenization (80 MPa) and an increase in the number of homogenization cycles, led to the formation of high molecular weight aggregates (>200 kDa), which favored an increase in viscosity of the emulsions. The increase in homogenization pressure also increased the formation of primary oxidation products, which could be explained by the increase in temperature and in the surface area of the droplets. (C) 2012 Elsevier Ltd. All rights reserved.