The Application of On-line Sensors and Novel Control Technologies for Food Processing

Abstract

The objective of this research was to apply on-line continuous sensors in food processing, in particular in cheese and milk powder manufacture, in order to improve process control, for example, by achieving higher quality, increased yields, reduced losses and less downgrading of product. This project focused on technologies for monitoring rheologyrelated parameters. The main conclusions were as follows: * Seven systems for monitoring curd formation in cheesemaking were evaluated in the laboratory. * Two on-line systems for monitoring curd firmness (hot-wire and NIR reflectance) have been deployed in a commercial cheese plant with promising results. * Experimental results demonstrated that NIR reflectance / transmission probes have a potential for on-line application in cheesemaking. Despite the difference in scale, the commercial sensors compared well with the cheesemaker s observation of curd firming and look promising as an objective means of predicting curd cut time in an industrial cheese plan. * A detailed knowledge of the rheological variation in cheese curd has been developed and a means of investigating factors which influence the rheology of cheese curd (e.g. effect of heat treatment or fortification of cheesemilk) has been determined. * Technologies available for monitoring concentrate viscosity changes in the production of milk powder have been assembled at pilot scale, and initial trials have been encouraging. Further evaluation of the MTL plant to assess on-line performance, ruggedness and cleanability are planned.