|DONELSON, JOHN - USDA ARS SOFT WHEAT QUAL.
Submitted to: Cereal Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/4/1998
Publication Date: N/A
Interpretive Summary: Starch is the primary component of wheat flour. Isolated starch from hard and soft wheats are usually considered similar, but are difficult to study in cookie formulas. More starch granules of hard wheat than soft wheat are damaged during milling. Cookie diameters are reduced if starch damage is elevated in either hard or soft wheat flour. In this study, levels of damaged starch were adjusted and sugar-snap cookies were produced from hard and soft wheat flours and from all-starch cookies, made from starches isolated from hard or soft wheats. Structure and appearance of 100%-starch cookies were equivalent to flour cookies when damaged starch was elevated to 8%. Soft wheat starch made larger cookies than hard wheat starch, but at any cookie size, the hard wheat flour or starch had less damaged starch. That indicates that hard wheat starch is fundamentally different from soft wheat starch. Likely, some aspect of hard wheat starch creates higher viscosity in the dough during baking, perhaps because it has greater affinity for water in cookie formulations. Additionally, soft wheat flour is treated with chlorine gas to reduce cookie spreading during baking is some cookie formulations. A level of pregelatinized (damaged) starch was determined that effected cookie quality like chlorine gas treatment did. Those findings will assist researchers in evaluating baking quality differences among soft wheats. They also show a practical way to reduce the amount of chlorine used in cookie flour.
Technical Abstract: Prime starch was extracted from soft and hard wheat flours and ball-milled to produce 100% damage starch. Small amounts of the ball-milled starch or a pregelatinized starch (also 100% damage) were added to sugar-snap cookie formulations. Other cookie doughs were produced from prime starch only (no flour) with small amounts of the ball-milled starch added. Starch damages of the resulting substituted soft and hard wheat flours and soft and hard wheat prime starches were determined and compared to diameters of sugar-snap cookies produced from the control and treatments. Soft wheat flour and starches produced larger diameter cookies than their hard wheat counterpart at all levels of damaged starch. Either source of damaged starch (ball-milled or pregelatinized starch) had similar effects on cookie diameter. Cookies produced from all starch (no flour) were similar to their respective flour controls at about 8% damaged starch. To produce the same size cookie as that produced by soft wheat flour and starch, hard wheat flour and starch cookie formulations required less damage starch and lower alkaline water retention than did the soft wheat flour and starch cookie formulations. Other flours were treated with chlorine gas to pH 4.8. About 5% pregelatinized starch was required to reduce the cookie diameter as much as chlorine treatment did. Results suggest quality differences between soft and hard wheat starch as they function in sugar-snap cookie baking.