Cereal Chem 68:272-275   |  VIEW ARTICLE

Chemical and Spectral Quantification of Mold in Contaminated Barley.

C. A. Roberts, R. R. Marquardt, A. A. Frohlich, R. L. McGraw, R. G. Rotter, and J. C. Henning. Copyright 1991 by the American Association of Cereal Chemists, Inc. 

This work was conducted to estimate mold in barley by N-acetyl-D-glucosamine determined by ion- exchange chromatography and near-infrared reflectance spectroscopy (NIRS). In one study, barley fungal contamination was assessed visually using a scale of 0 (no mycelia or spores) to 5 (prolific mycelial growth or spore production). The contaminated barley was then analyzed for glucosamine using ion-exchange chromatography. Glucosamine correlated highly (P less than 0.01) with mycelia and spores; correlation coefficients were 0.86 and 0.85, respectively. Glucosamine was quantified by NIRS; coefficients of determination for calibration and performance exceeded 0.92. In a second study, a population of artificially contaminated barley was created by mixing mycelial dry matter with noncontaminated barley. Mycelial tissue in these samples was quantified by NIRS; the performance coefficient of determination was 0.94. Based on results with naturally incubated samples, we concluded that glucosamine determined by ion- exchange chromatography represented fungal contamination in barley and that it could be determined by NIRS. Based on the successful artificial calibration, we concluded that mycelia at naturally occurring levels could be quantified by NIRS and that NIR spectrophotometers can detect mycelia directly, despite the empirical nature of NIRS technology.