KSEF: Sensor Technology Development for Monitoring and Control of Curd Syneresis.

Cheese processing consists of a coagulation step which converts milk into a gel, a cutting step which cuts the gel into small pieces, and a syneresis step in which the coagulum water (whey) weeps out of the pieces (1). Whey separation is promoted by applying mechanical and/or thermal treatment. At the end of the syneresis, the two-phase mixture consists of approximately 10-20% curd and 80-90% whey. The curd is separated ftom the whey and further processed into cheese. The final curd moisture content depends on pH, syneresis duration and mechanical/thermal treatments applied (2). Rate and extent of syneresis regulate the moisture, mineral and lactose content of the curd, which in turn affects cheese ripening (2) (3) and subsequently the final cheese pH, texture and flavor. There are currently no sensors available for monitoring curd syneresis. A sensor technology that is able to control curd moisture content would have a large impact on cheese manufacturing worldwide in terms of product quality, consistency and production efficiency. Successful development of the proposed technology will require: 1) a sensor designed to measure diffuse reflectance from a two phase mixture of curd and whey; 2) the determination of the light wavelength(s) that best characterizes the kinetics of syneresis; and 3) the development of an algorithm that uses the kinetic parameters to predict the endpoint of the syneresis step and thus control cheese moisture content. In 1992 the University of Kentucky patented optical technology for automatically selecting cutting time. This CoAguLiteTMtechnology has been commercialized by Reflectronics, Inc., Lexington, KY and is currently being used by six large cheese plants and is being investigated by five cheese research organizations around the world. The proposed technology would complement and enhance the CoAguLite technology by extending control over two of the critical steps in cheesemaking. .