MULTIVARIATE FTIR ANALYSIS OF SUBSTRATES FOR PROTEIN, POLYSACCHARIDE,LIPID AND MICROBE CONTENT - POTENTIAL FOR SOLID-STATE FERMENTATIONS

Components of fermentation processes such as protein, polysaccharide a nd lipid, as well as microbes, such as fungi grown on solid substrates , are difficult to measure in situ. The potential of Fourier Transform Infrared (FTIR) analysis of solid-state fermentations from mid-infrar ed absorption spectra has been investigated. The problem under conside ration was to build a calibration model containing no irrelevant infor mation to enable a multivariate mathematical approach for prediction o f component concentrations. Methods for solid sample preparation and p reprocessing of FTIR data were developed to assure Beer-Lambert law co mpliance and produce a well-conditioned multivariate system. The model was tested using composite samples of zein protein, com starch and az olectin lipid, and com samples containing known levels of fungal conta mination. Preliminary concentration estimates were remarkably close to the correct values, with less than 5% standard error of prediction fo r all components measured.