Optical online measurement technique used for process control of the drying step during pasta production

Abstract

The presented paper concentrates on the development of a fuzzy system to control the drying process of pasta plates. The system adjusts drying temperature as well as humidity by including knowledge of experts or from research in setting up models of the actual process respectively product state. As a basis the research led to the development of an appropriate online measurement setup that was implemented in a climate test chamber. Here relevant product information like – in this case – moisture content, colour and surface temperature of the pasta right during the running process are obtained. These three selected parameters are measured by an optical non-invasive approach with fast data acquisition. In addition to gravimetric measurements for referencing the spectroscopic approach resulting in values of the water content of pasta, magnetic resonance imaging is used to gain information of the moisture distribution within the cross section of a pasta plate. In combination with further product characteristics the quality of the product is evaluated and used in a fuzzy logic system that determines a situative and adjusted control strategy by correlating the product state with the suitable drying parameters temperature and moisture in the dryer. Adjusting the drying process with respect to the current process respectively product state realises an individual optimisation and leads to a high product quality, less product losses (due to e.g. internal thermal stresses or unwanted colour changes) and an improved energy usage.