Milk quality degradation sensor based on chitosan biopolymer

Abstract

Chitosan thin film used as sensing material because of its structure and properties where it consist of amine group which has free electron. Milk powder can undergo oxidation process when exposed in the air. In this study, chitosan powder was dissolved in 2% of acetic acid to form chitosan solution gel. It was subsequently deposited on Printed Circuit Board (PCB) by using electrochemical deposition technique. Electrical testing was done for fresh milk powder and milk powder that exposed in open air for certain time by using air exposure technique. Sensor properties which include sensitivity, stability, responsibility, recovery, selectivity and repeatability were studied. The electrical result shows that voltage increases as the number of exposure day of milk powder in open air increases. The voltage increased because volatile gas is released when the milk powder exposed in the open air for certain time due to an oxidation process. All the sensing properties were achieved. Scanning Electron Microscope (SEM) result showed that there was some white particle on the sample after exposed to milk particle which means there were some reaction have occurred. Fourier Transform Infrared Spectroscopy (FTIR) result showed that there were N-H bonding and O-H bonding in chitosan gel.