|Baevre, Anne Birgit|
|Graybosch, Robert - Bob|
Submitted to: Cereal Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/24/2006
Publication Date: 11/30/2006
Citation: Sahlstrom, S., Baevre, A., Graybosch, R.A. 2006. Impact of Waxy, Partial Waxy, and Wildtype Wheat Starch Fraction Properties on Hearth Bread Characteristics. Cereal Chemistry 83: 647-654. Interpretive Summary: Starch is the primary component of wheat endosperm and the characteristics of the starch are important factors controlling bread weight and texture of noodles. Waxy (amylose-free) wheats have been developed through classical breeding and genetics. Many uses have been suggested for waxy wheat, including as a source of blending flour to improve shelf life stability, processing quality, or palatability of baked and sheeted wheat products, or as a substitute for waxy maize in the production of modified starches. Experiments were conducted to determine whether waxy (no amylose) or partial waxy (reduced amylose) wheats could be used in the production of hearth breads. Hearth bread loaves baked with waxy wheat flour had significantly lower form ratio, weight, a more open pore structure, and a bad overall appearance. Baking with waxy and partial waxy wheat flour had no significant effect on hearth bread loaf volume. Waxy wheat flour has a much higher water absorption and formed intermediate-strength doughs that requireless time and work to develop. Due to low amylose content, waxy starch is very sensitive to shear thinning and has a high breakdown property. Partial waxy wheat flour had no negative effect on hearth bread production. Waxy wheat flour did have a negative effect when used alone, but the results suggest flours produced by blends of waxy and non-waxy wheats could have positive effects on shelf-life and loaf appearance.
Technical Abstract: Thirteen different wheat (Triticum aestivum L.)cultivars were selected to represent GBSS mutations: three each of wildtype, axnull, and bxnull, and two each of 2xnull and waxy. Starch and A- and B-granules were purified from wheat flour. Hearth bread loaves were produced from the flours using a smallscale baking method. A-granules purified from wildtype and partial waxy (axnull, bxnull, and 2xnull) starches have significantly higher gelatinization enthalpy and peak viscosity compared with B-granules. A- and granules from waxy starch do not differ in gelatinization, pasting, and gelation properties. A- and B-granules from waxy starch have the highest enthalpy, peak temperature, peak viscosity, breakdown, and lowest pasting peak time and pasting temperature compared with A- and B-granules from partial waxy and wildtype starch. Waxy wheat flour has much higher water absorption compared with partial waxy and wildtype flour. No significant difference in hearth bread baking performance was observed between wildype and partial waxy wheat flour. Waxy wheat flour produced hearth bread with significantly lower form ratio, weight, a more open pore structure, and a bad overall appearance. Baking with waxy, partial waxy, and wildtype wheat flour had no significant effect on loaf volume.