Modeling the retention kinetics of conjugated linoleic acid during high-pressure sterilization of milk

Abstract

The retention kinetics of conjugated linoleic acid (CLA) in enriched milk treated by high-pressure sterilization conditions was studied at pressures of 100–600MPa and temperatures of 90–120°C. The experimental data were well described by the Weibull model. Pressure and temperature influenced the scale parameter, according to the Eyring and Arrhenius models. The remaining CLA content decreased with an increase of temperature and more CLA was retained with an increase of pressure. At 120°C and 600MPa, the ratio of oxygen consumed per CLA converted suggested that isomerization of CLA was the predominant reaction mechanism instead of oxidation. The retention of CLA in high-pressure sterilized milk was graphically illustrated through pressure–temperature diagrams. The processing conditions at which commercial sterilization can be achieved (120°C and 600MPa with 3min of holding time) retained more than 80% of CLA.