Physicochemical and sensory characteristics of a UHT milk-based product enriched with conjugated linoleic acid emulsified by Ultra-High Pressure Homogenization

- Emulsions containing conjugated linoleic acid were homogenized at 15 and 200 MPa.
- Emulsions were added into a skim milk-based product before UHT treatment.
- Emulsions treated by 200 MPa showed greater physicochemical stability.
- Emulsions treated by 200 MPa presented lesser primary lipid oxidation.
- The product with the emulsion treated by 200 MPa exhibited better sensory acceptance.

In the past decade, there has been an increasing interest in the incorporation of conjugated linoleic acid (CLA) into foodstuffs. Physicochemical and sensory characteristics of a UHT milk-based product enriched with CLA (0.6% v/v in final product) in a free fatty acid form and emulsified by Ultra-High Pressure Homogenization (UHPH, 200 MPa) was evaluated and compared with conventional homogenization (CH; 25 MPa). Particle size changes were evaluated until the final milk-based products were produced (CH-P and UHPH-P). Rheological properties, colour, pH, physical stability, proteolysis, primary and secondary lipid oxidation and sensory characteristics were analysed during storage. UHPH-P exhibited similar viscosity (≈ 2 mPa × s) but greater physical stability compared to CH-P due to the smaller particle size (≈ 200 nm). UHPH-P also presented lower content of lipid hydroperoxides and less perception of oxidized attributes.Industrial relevanceAn emulsion containing CLA in a form more prone to lipid oxidation was treated by UHPH or CH. The results in this manuscript address the physicochemical stability and sensory properties improvement of a UHT milk-based product enriched with the CLA-emulsion homogenized by UHPH. Thus, UHPH is suggested as an antioxidant emulsification technique.