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ARS Home » Plains Area » Manhattan, Kansas » Center for Grain and Animal Health Research » Grain Quality and Structure Research » Research » Publications at this Location » Publication #263205
Title: Factors Governing Pasting Properties of Waxy Wheat Flours

Author
item GARIMELLA PURNA, SHIVANANDA - Kansas State University
item SHI, YOUNG-CHENG - Kansas State University
item GUAN, LAN - Kansas State University
item Wilson, Jeff
item Graybosch, Robert

Submitted to: Cereal Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/11/2015
Publication Date: 9/2/2015
Citation: Garimella Purna, S.K., Shi, Y., Guan, L., Wilson, J.D., Graybosch, R.A. 2015. Factors Governing Pasting Properties of Waxy Wheat Flours. Cereal Chemistry. http://dx.doi.org/10.1094/CCHEM-10-14-0209-R. 92(5):529-535.

Interpretive Summary: Starch in endosperm of normal wheat consists of ca. 25% amylose (mostly linear) and ca. 75% amylopectin (highly branched), whereas starch in waxy wheat, a valuable specialty wheat, endosperm is comprised of essentially all amylopectin. This waxy trait in wheat flour is responsible for differences in how starch melts, or pastes in excess water. This study was undertaken to determine the factors governing the pasting properties of waxy wheat flours and compare their pasting properties to those of normal and partial waxy wheat flours. Starches isolated from six hard waxy wheat flours had similar pasting properties, yet their corresponding normal and partial waxy flours had very different pasting properties. The differences in pasting properties were narrowed once endogenous a-amylase (a starch degrading enzyme) activity in the waxy wheat flours was inhibited by silver nitrate. Upon the action of protease, the extent of protein digestibility determined the viscosity profile in waxy wheat flours. Waxy wheat starch granules swelled more extensively and were more prone to a-amylase degradation than normal wheat starch. The protein matrix of the flour also affected the swelling of the starch granules which in turn also caused variations in pasting properties of waxy wheat flours.

Technical Abstract: To realize the full potential of waxy wheat, the pasting properties of hard waxy wheat flours as well as factors governing the pasting properties were investigated and compared with normal and partial waxy wheat flours. Starches isolated from six hard waxy wheat flours had similar pasting properties, yet their corresponding flours had very different pasting properties. The differences in pasting properties were narrowed once endogenous a-amylase activity in waxy wheat flours was inhibited by silver nitrate. Upon action of protease, the extent of protein digestibility determined viscosity profile in waxy wheat flours. Waxy wheat starch granules swelled more extensively and were more prone to a-amylase degradation than normal wheat starch. A combination of endogenous a-amylase activity and protein matrix contributed to a large variation in pasting properties of waxy wheat flours.