Affordable Time-Domain Reflectometry System for Rapid Food Analysis

The development of an inexpensive instrumental chain based on time-domain reflectometry is presented. The attention paid to the choice of the components allowed purchase costs reduction compared to the instruments available on commerce. The chain is composed by a hand-made 30-mm needle probe, a square wave fast rise time pulses generator on board, and a digital sampling USB oscilloscope with bandwidth of 11 GHz. Stability measurements and sodium chloride, sucrose, and cow milk were conducted to assess device repeatability and evaluate the predictive potential of estimation for some food parameters. The traditional geometrical-mathematical approach was replaced by multivariate investigation of the time-domain signal. Good results in terms of coefficient of determination up to 0.983 were obtained. The results disclosed show how a cheap and easy-to-use instrumental chain can be very promising for attributes determinations of liquid materials, such as foodstuff.