109 Effect of sorghum flour and gelatinized starch on the structure and texture of cookies.

M. LEON, C. M. McDonough, and L. W. Rooney. Cereal Quality Lab, Soil and Crop Sciences, Texas A&M University, College Station, TX 77843-2474.

Cookies were prepared from 100% sorghum flour (SF), a combination of 50:50 wheat/SF, and 95:5 SF/gelatinized corn starch, using 100% wheat flour as a control, to determine what effect the flours had on cookie texture and structure. The internal structure was characterized using environmental scanning electron microscopy; hardness of the cookies was measured using a TA.XT2 texture analyzer. Acceptability of the cookies as well as external appearance was also evaluated. Fragility of the 100% sorghum cookie and low values for the peak force were a result of the crumb having a discontinuous starchy phase without gluten network to hold the crumb together. Particles in the crumb were only slightly associated in the 100% sorghum flour cookies. The 50:50 wheat/SF cookie had a stronger crumb, higher peak force value and similar appearance to the control; a continuous phase/gluten network was present, but was thin and insufficient to hold the crumb together. The cookie prepared with 95:5 SF/gelatinized corn starch was harder in texture than the 100% SF cookie and was similar in appearance to the controls. The pre-gelatinized starch provided enough of a continuous starchy phase or matrix to hold the sorghum flour particles in the cookie together which strengthened the crumb. The SF/gelatinized corn starch cookies were as acceptable in appearance and texture as the control cookies.