Feasibility study into the use of a micro-machined grating spectrometer to measure fat and protein content in liquid milk products

A study was undertaken to determine the feasibility of building a system capable of measuring the protein and fat content in dairy based samples. The system would be based upon a micro-spectrometer. Using Beers-Lambert law, spectral absorption changes due to protein and fat variation in dairy samples are obtained, over the spectral region 800 to 1100 nm. Samples representing a range of liquid milk products, manufactured in the dairy industry were fabricated. These samples spanned typical fat and protein ranges. Each sample after preparation, was chemically analysed using standard Mojennier and Kjeldahl tests, for fat and protein content. The optical set-up required to optimise the collection from the sample is discussed.