Abstract

SBODIO, O.A et al. Desarrollo de un dispositivo para monitoreo en la línea del proceso de coagulación de la leche. RIA. Rev. investig. agropecu. [online]. 2017, vol.43, n.3, pp.312-327. ISSN 1669-2314.

In this investigation we studied a device for monitoring the enzymatic or acid coagulation of milk. The instrument consists of a platinum heater/sensor, a Platinum Resistance Temperature Detector (PRTD) temperature sensor, a pH electrode, a direct constant current source, a digital acquisition system that, with the developed software runs on a Personal Computer. The heater/sensor was build with a 0.025 mm diameter platinum wire coiled around a ceramic structure and immersed in a small protective thermowell, allowed monitoring the physical changes of milk. Under conditions of quiet air and room temperature (25°C), tests showed that this probe was able to withstand a DC current of at least 190 mA. Different tests performed with different values of DC constant current allowed to select the appropriate current (130 mA). Using this DC constant current, this experiment proved to be highly reproducible, with low signal to noise ratio. Heat transfer analysis also showed temperatures of <50°C on the heater/sensor thermowell surface, with no risk of soluble protein denaturation. The effects of temperature, pH, enzyme concentration and CaCl2 addition, on the responses CT, Tmax and firmness, were similar to those obtained with other methods. The small size of this sensor make it a non-invasive, though robust enough device, easy to clean in place or to sterilize using steam in place, which does not need to be removed during cheesemaking operations. In addition, the instrument meets the sanitary requirements of the 3-A and EHEDG standard, which allows it to be used on cheese or yogurt production lines.

Keywords : Instrument; Sensor; Behavior; Cheese; Yogurt.

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