Study considering the microwave pasteurization of the raw milk used for yogurt production

摘要

The aim of this research was to assess how the variation of the microwave power and of the exposure time during different pasteurization regimes of raw milk affects the obtained yogurt. The novelty of the study was the use of microwaved milk in the production of probiotic yogurt. The obtained products were analyzed considering their organoleptic, physical and chemical characteristics. The most appreciated yogurt was yogurt B, obtained by heating the raw milk in the microwave oven set on the 80 % (640 W) power, for 240 s (4 minutes), which received the highest overall average of the organoleptic assessment, of 4.768. Also, yogurt B had the lowest value for acidity, 85°T which can be justified by the fact that the fat content decreased least of all, of only 9.77 %. This percentage of fat reduction can be explained by a reduced lipolysis, because this yogurt had the lowest acidity value in spite of the highest decrease suffered by lactose of 30.8 %, generating the highest quantity of lactic acid during the thermostatation process. Also, the fact that the lipases were most affected by this regime of pasteurization can explain the smallest average grade obtained by this yogurt for smell.