Pasteurization is the process of heating food followed by immediate cooling for the purpose of killing harmful microorganisms. The study was conducted to evaluate the effect of heating patterns and efficiency of microwave heating system at different power levels on pasteurization. The study also covered the estimation of microwave power and time combination for milk pasteurization on the basis of energy consumption and quality of pasteurized milk. Time temperature heating curves were obtained for 100w, 200w, 300w, 400w, 500w, and 600w power levels. Heating curves for smaller power values (10w, 20w, 30w, 40w and 50w) were also obtained for ‘holding phase ’of pasteurization. During microwave pasteurization, the rate of temperature rise was higher at higher microwave power level without affecting the efficiency of heating. The holding of milk at 720C can be done at 20W power level without temperature change. Microwave heating time can be found at any microwave power level by power-time relationship i.e. Time = 62638 (power)−0.9699. Microwave pasteurized milk showed higher storage life (4 days) at 50C compared to raw milk without spoilage. pH of pasteurized milk was higher (6.69–6.79) than the raw milk (5.36).
Microwave heating, Milk pasteurization
