Construção de sistemas automatizados para pasteurização de leite e produção de iogurte natural

Abstract

Milk due to its composition is an excellent culture medium for the development of microorganisms, or for producing a food very susceptible to rapid spoilage. To increase or reduce the shelf life of this product, it is possible to use heat treatments, and one of these treatments is pasteurization, which is a treatment capable of eliminating pathogenic and deteriorating microorganisms. Among the main dairy derivatives is yogurt, which is produced from lactic acid fermentation through a symbiotic mixture of lactic acid bacteria. In pasteurization of milk as well as yogurt production it is necessary to monitor and control variables that are important to the process and ensure a quality standard for the product obtained. The objective of this work is to construct a low cost low cost pasteurization system in pilot scale and in the development of a fermentation system for yogurt production using Arduino technology for process control and monitoring. In the closed system for slow pasteurization, the water used for heating / cooling the milk is the same throughout the process, the monitored variables are temperature, time and water level of the main reservoir, variables properly controlled through sensors and actuators connected the arduino platform. For the development of the monitoring and control system of the yogurt fermentation stage, the monitored variables are temperature, time and pH, with the control applied to temperature. Temperature control for both systems developed was efficient due to the rapid response of the systems through the temperature sensors and the fast actuation of the relays to turn the heating means on / off. The pH monitoring presented a good performance due to the fast reading, which allowed to clearly detect the differences between the fermentation curves of the samples used and the large number of measurements was crucial to obtain accurate curves. The systems analyzed show good potential for both performance and cost use, and may have the advantage of using systems for small dairy farmers, who can use the equipment used in the technological development of the property, producing quality and safety.