Designing and Manufacturing of a Non Thermal Milk Pasteurizer Using Electrical Field

Abstract

Using of traditional milk pasteurization methods caused fouling by heat, particularly rapid pasteurization by ohmic heating at 220 volts resulted protein denaturation, when milk holding of 15 sec under ohmic heating at 72°C. So to control these properties a Non-thermal treatment by different electrical fields at 20, 27.5, 55 V/cm (80, 110, 220V, AC) and quickly milk pass between poles in a long narrow tube during less than 0.8 sec. The study focused on applying different electrical fields in milk pasteurization as a non thermal treatment and calculates the electrical conductivity, viscosity of milk, holding time, productivity, performance coefficient and measurement of final output milk temperature at 20, 27.5, 55 V/cm, pH, acidity, chemical composition, microbiological characteristics and storage periods for the pasteurized milk. The obtained results indicated that the final output milk temperature was reached 40°C and electrical conductivity was increased and viscosity was decreased with increasing temperature and productivity and performance coefficient were 1140 L/h, 99.8 respectively. More over pasteurized milk chemical composition and it’s pH were not influenced in electrical field. Resulting of bacteria elimination and alkaline phosphatase was inhibited by the electrical field as well. The results showed that the electrical field 55 V/cm is better than other electrical fields (20, 27.5 V/cm).