Cereal Chem 69:419-423   |  VIEW ARTICLE

Characterization and Estimation of Barley Polysaccharides by Near-Infrared Spectroscopy. II. Estimation of Total Beta-D-Glucans.

J. Szczodrak, Z. Czuchajowska, and Y. Pomeranz. Copyright 1992 by the American Association of Cereal Chemists, Inc. 

Total beta-glucans were determined in 139 barleys, 84 of which were used for calibration and 55 for validation. They included covered two- and six-rowed regular (about 25% amylose in the starch) barleys, covered and hull-less waxy (up to 100% amylopectin) and high-amylose (up to 49% amylopectin) barleys, and chemically treated and gamma-irradiated barleys. Both commercial and varietal samples (from three locations) were used. The total beta-glucan content ranged from 2.7 to 9.5% and was higher in waxy than in regular or high-amylose barleys. Equations for prediction of beta-glucan content by the best fit of three wavelengths and the single-wavelength (2,264 or 2,348 nm) method (using the step-up program) were developed. The standard error of prediction for both was slightly above 0.6%. The three selected wavelengths were in the 2,260- to 2,380-nm region, previously found by us to be typical for beta-glucans. In light of the highly heterogenous populations used in this study, the accuracy of predicting the beta-glucan contents in the validation samples was affected by the identity of barleys used for developing the prediction equations. Preliminary studies indicated that even for more homogenous populations, the results may be affected by kernel size, hardness, and protein contents. The above parameters may have to be included in developing equations to predict the beta-glucan contents of barleys.