Effects of milk fat substitution by canola oil on the properties of high-fat high-protein yoghurt

Abstract

High-fat high-protein yoghurts [9% fat, 8.2% protein (w/w)] with substitution of milk fat by canola oil were produced. The effects of milk fat substitution (0–100%) and milk homogenisation pressure (10 or 35 MPa) on the texture, syneresis, and rheological properties were evaluated. The aroma profile after 0, 14, and 28 days of storage (5 °C) was also determined. Increasing the proportion of canola oil reduced the firmness and increased the syneresis of yoghurt, but had no effect on the elastic and viscous modulus at 1 Hz. Increasing milk homogenisation pressure increased yoghurt firmness, elastic and viscous modulus, and apparent viscosity because smaller droplets were better embedded into the yoghurt structure. The substitution of milk fat by canola oil and storage time affected the yoghurt aroma profile. Some impacts of milk fat replacement by canola oil could be overcome using a higher homogenisation pressure.