Cereal Chem. 71:64-68   |  VIEW ARTICLE


Distribution of (1-3),(1-4)-beta-D-Glucan in Kernels of Oats and Barley Using Microspectrofluorometry.

S. Shea Miller and R. G. Fulcher. Copyright 1994 by the American Association of Cereal Chemists, Inc. 

The distribution of (1-3),(1-4)-beta-D-glucan (beta-glucan) in grains was studied using scanning microspectrofluorometry of cell-wall-bound Calcofluor in selected cultivars of oats and barley. Microspectrofluorometric imaging showed a high concentration of beta-glucan in the depleted layer adjacent to the embryo in all oat cultivars examined. In the low beta-glucan oat OA516-2, a high concentration of beta-glucan was also seen in the subaleurone region in cross sections of the proximal, central, and distal areas of the kernel. In the high beta-glucan cultivar Marion, the relative fluorescence intensity of the bound Calcofluor was high throughout the central endosperm. Morphological differences were observed in the central endosperm of the two cultivars, with Marion having somewhat smaller cells and slightly thicker walls, which would result in a greater concentration of beta-glucan per unit volume than that in OA516-2. Very little beta-glucan was observed in the embryo in either oat cultivar. In a comparison of maps of central cross sections of five cultivars of differing beta-glucan content (range 3.7-6.4%), there was a trend for the high-subaleurone concentration of beta- glucan to become less distinct as the total beta- glucan content of the cultivars increased. The distribution of beta-glucan in barley was more uniform, with no high-subaleurone concentration of beta-glucan in any of the five cultivars examined (beta-glucan range: 2.8-11%). The highest concentration of beta-glucan was in the central endosperm.