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

Abstract

Abstract 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 relevance An 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.