Cereal Chem 69:413-418   |  VIEW ARTICLE

Characterization and Estimation of Barley Polysaccharides by Near-Infrared Spectroscopy. I. Barleys, Starches, and Beta-D-Glucans.

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

Large and small starch granules were isolated from regular amylose (about 25%), high-amylose (44- 49%),and high-amylopectin (traces of amylose) barleys. Their near-infrared reflectance (NIR) spectra were compared with those of relatively pure (1-3),(1-4)-beta-D-glucans from barley and oats and with NIR spectra of ground barleys-naked and covered, regular, high-amylose, and high-amylopectin. The objective was to obtain detailed information on NIR spectra of barleys, isolated starches, and isolated beta-D-glucans to serve as a basis for development of a near-infrared spectrocsopy method for beta-glucan assay in barleys. There was little difference in NIR spectra of hull-less and covered barleys; whole meals of regular, high- amylose, and high-amylopectin barleys showed similar spectra. Small differences were recorded between spectra from high-amylose and regular or high-amylopectin starches. Spectra of starches and whole meals from which the starches were obtained differed widely. Major differences were recorded in three areas over the whole range of 1,600 to 2,400 nm for whole meals, isolated starches, and isolated beta-glucans. They included 1) wavelengths 1,702, 1,707, 1,772, and 1,773 nm, principal bands of starches, cellulose, and hemicellulose; 2) 2,060, 2,096, and 2,132 nm, bands associated with the interaction between starch and protein; and, foremost, 3) 2,268, 2,282 and 2,335 nm, bands that typify starch, beta-glucans, and cellulose.