Influence of high pressure homogenization with and without lecithin on particle size and physicochemical properties of whey protein-based emulsions

This study evaluated the quality attributes of high pressure homogenized whey protein emulsions with and without lecithin. Samples were prepared by mixing whey protein concentrate (10%), soybean oil (0 or 5%) and soy lecithin (0 or 5%). The premixtures were processed by a laboratory scale high pressure homogenizer at various pressures (25, 50, 75, and 100 MPa) at an initial temperature of 21 °C. The samples were evaluated for particle size, electrical conductivity, color, °Brix, and pH. Increasing homogenization pressures significantly decreased particle sizes of all samples. After 25 MPa treatment, emulsions with lecithin had smaller particle sizes than those made without lecithin. However, lecithin did not further reduce particle size for emulsion samples treated at ≥50 MPa. Electrical conductivity of samples increased with increasing homogenization pressures. Homogenization increased the lightness (L*) while reduced redness (a*) and yellowness (b*) of emulsions. The °Brix of emulsions increased after homogenization, but no change in pH was observed. Practical applications: Consumer interest in clean label products prompted the food industry to investigate various processing methods such as high pressure homogenization to reduce additive use. The results of this study demonstrated the potential of applying high pressure homogenization in preparing whey protein-based food products, with less use of lecithin.