Doctoral Dissertations

Date of Award


Degree Type


Degree Name

Doctor of Philosophy


Food Science and Technology

Major Professor

Marjorie P. Penfield

Committee Members

Clark Brekke, Betsy Haughton, Lana Zivanovic


For part 1 of a 2-part study, a randomized balanced incomplete design, blocked on day, was used to test the effects of 4 flours at 5.8, 7.5, 8.8, and 10.4% protein, 3 fat replacers (Betatrim, Stardri, and Simplesse) at 0, 35, 55, 75% fat reduction, and 3 sugar replacers (Sucralose, Isomalt, and Maltitol) at 0, 45, and 65% sugar reduction on cookie quality. Cookie spread (width/thickness) and hardness (g) were measured. Full-fat and 35 and 55% reduced-fat cookie spread decreased as flour protein increased (p = 0.0102) as did flour hydration properties. Within each flour, cookies made with Betatrim at 55 and 75% were smaller than full-fat cookies; at similar fat levels, Stardri produced cookies larger than full-fat cookies. For all fat replacers, 75% reduced-fat cookies with 5.8% protein flour were larger than their respective 35% reduced-fat/10.4% protein flour cookies. Full-fat and 35% reduced-fat cookies were softer as flour protein increased from 7.5 to 10.4% (p = 0.0053). For each flour, Stardri fat replacement produced harder cookies than all reduced-fat cookies. For Part 2, a randomized incomplete design, blocked on day and panelist, was used to test 30 optimal wire-cut cookie formulas selected from Part 1. A trained panel (n=12) rated cookies made with the low-protein flour/full-fat and low-protein flour/Simplesse darker than all other treatments (p = 0.0045); Isomalt with any fat/fat replacer system produced cookies similar in baked color to control cookies (p = 0.0075). Full-fat/low-protein flour (p = 0.0007) and full-fat/full-sugar (p = 0.0025) were the driest cookies. Full-fat/full-sugar cookies and Stardri cookies with any sugar/sugar replacer system were harder than all other treatments (p = 0.0251). Cookies made with the low-protein flour had larger crumb cell size (p < 0.0001), were more brittle (p = 0.0005), had more intense browned flavor (p = 0.0150), and were sweeter (p = 0.0003) than cookies made with the higher protein flours. Bakers must recognize that low-protein flours can be used to optimize reduced fat cookie spread, texture, appearance, and flavor. Isomalt and Maltitol are also two sugar replacers that formulators can use in reduced-fat cookies that will produce cookie textures similar to full-fat/full-sugar versions.

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