Publication no. C-2000-0212-07R |  VIEW ARTICLE

Relationships Among Grain Hardness, Pentosan Fractions, and End-Use Quality of Wheat.

A. D. Bettge (1,2) and Craig F. Morris (1). (1) USDA-ARS Western Wheat Quality Laboratory, E-202 Food Science and Human Nutrition Facility East, P.O. Box 646394, Washington State University, Pullman, WA 99164-6394. Phone: 509-335-4062; Fax: 509-335-8573. Mention of trademark or proprietary product does not constitute a guarantee or warranty of the product by the U.S. Department of Agriculture and does not imply its approval to the exclusion of other products that also may be suitable. (2) Corresponding author. E-mail: <abettge@wsu.edu> Cereal Chem. 77(2):241-247. Accepted December 23, 1999. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. American Association of Cereal Chemists, Inc., 2000.

Grain texture (hardness) in wheat (Triticum aestivum L.) is a major determinant of end-usage. Variation in grain texture can be conceptually assigned to the two major hardness classes that result from the action of one major gene (Hardness) or to as-yet undetermined factors contributing to residual variation within hardness classes. Identifying the physicochemical basis of both sources of texture variation could provide a means of better controlling or manipulating this quality trait. Pursuant to this objective, the role of pentosans was examined. Pentosan fractions (membrane-associated, total, and soluble) were isolated from 13 hard and 13 soft wheat samples and their flours. Among the hard wheat samples, pentosans had a minimal role in modifying grain hardness. However, among the soft wheat samples, pentosans appeared to have a significant hardness-modifying effect that carried over into end-use quality. Among the soft wheat samples, pentosan fractions, along with wheat protein, accounted for 53-76% of the variation in grain texture, depending on the method used to quantify texture. Membrane-associated pentosans were the most influential single parameter in modeling grain texture for the soft wheat samples. Membrane-associated pentosans were most influential in accounting for variation (69%) in alkaline water retention capacity. Total pentosans, together with flour protein, accounted for 87% of the variation in cookie diameter for soft wheat samples, with the total pentosan fraction being the more influential.