|Starch-Gum Interactions in Gluten Free Sorghum Bread|
P. AKIN ARI (1), R. Miller (1) (1) Kansas State University, , U.S.A.; (2) Kansas State University, Manhattan, KS, U.S.A..
Sorghum is unique in terms of its resistance to drought, heat and insects and is grown and consumed around the globe. Moreover, sorghum does not contain gluten and has potential in the gluten-free market. A blend of non-wheat flour, starch and gum typically provide the structure of gluten-free products. Most research on sorghum bread uses a yeast leavened process, HPMC gum and corn, potato, rice or tapioca starch. Little is known about the functionality or interactions of different starches and gums in sorghum batter. The objective of this study was to examine the starch-gum interaction in chemically leavened gluten free sorghum bread. Potato, rice and tapioca starches and HPMC, xanthan and locust bean gums were used. Bread was baked as pup loaves. Volume index was measured using AACCI Method 10-91.01 with a modified template, crumb grain was evaluated using the C-Cell Imaging System and texture was determined with the TA.XTPlus Texture Analyzer. The base formula was commercial sorghum flour, water, starch, gum, sugar, salt, shortening and double acting baking powder. Sorghum flour:starch ratios of 70:30, 80:20 and 90:10 were tested. Loaves containing all levels of rice starch had the same volume index (~165) as 100% sorghum flour (168) while all levels of tapioca starch and potato produced significantly smaller loaves (~150). The ratio of 90% sorghum flour and 10% starch was selected. The type and level of gum significantly impacted loaf volume, grain and texture. Starch-gum combinations which produced the best loaves were tapioca starch + 3% HPMC, rice starch + 3% xanthan and potato starch + 4% xanthan. Additional work is being conducted to evaluate the effect of the starch-gum combinations on sorghum batter viscosity profile using the RVA.