Monitoring of rancidity of milk by means of an electronic nose and a dynamic PCA analysis

This paper reports the use of a semiconductor thin films based electronic nose to recognise the rancidity of two different kinds of milk (UHT and pasteurised) during their ageing days. The employed sensor array consists of five different SnO2 thin films prepared by means of the sol–gel technology. The data coming from the response of the sensors have been elaborated by principal component analysis (PCA) in order to obtain a classification of the data clusters related to different milk ageing days and so track the dynamic evolution of milk rancidity. The obtained results could lead to industrial applications in dairying for the quality control of starting milk and the rancidity check during the different stages of production.