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Effect of moderate inlet temperatures in ultra-high-pressure homogenization treatments on physicochemical and sensory characteristics of milk

Amador-Espejo, G.G., Suàrez-Berencia, A., Juan, B., Bárcenas, M.E., Trujillo, A.J.
Journal of dairy science 2014 v.97 no.2 pp. 659-671
UHT milk, UHT treatment, buffering capacity, color, detection limit, ethanol, flavor, homogenization, hydrolysis, microstructure, particle size, proteolysis, sensory evaluation, temperature, viscosity, whole milk
The effect of ultra-high-pressure homogenization (UHPH) on raw whole milk (3.5% fat) was evaluated to obtain processing conditions for the sterilization of milk. Ultra-high-pressure homogenization treatments of 200 and 300MPa at inlet temperatures (Ti) of 55, 65, 75, and 85°C were compared with a UHT treatment (138°C for 4s) in terms of microbial inactivation, particle size and microstructure, viscosity, color, buffering capacity, ethanol stability, propensity to proteolysis, and sensory evaluation. The UHPH-treated milks presented a high level of microbial reduction, under the detection limit, for treatments at 300MPa with Ti of 55, 65, 75, and 85°C, and at 200MPa with Ti=85°C, and few survivors in milks treated at 200MPa with Ti of 55, 65, and 75°C. Furthermore, UHPH treatments performed at 300MPa with Ti=75 and 85°C produced sterile milk after sample incubation (30 and 45°C), obtaining similar or better characteristics than UHT milk in color, particle size, viscosity, buffer capacity, ethanol stability, propensity to protein hydrolysis, and lower scores in sensory evaluation for cooked flavor.