Determination of the moisture content of starch using near infrared photoacoustic spectroscopy

Abstract

Near infrared photoacoustic spectroscopy has been used to measure the water content of wet starch samples (over the range 0–30% of water). The relationship between moisture content and observed intensity of the photoacoustic signal is analysed in terms of the theory of the photoacoustic effect. It is shown that the non-linear dependence of signal intensity on moisture content is consistent with theory and that this non-linearity is to be generally expected in high water content systems. A method of linearising the data is described.