Effect of Transglutaminase Enzyme on the Preparation and Quality of Gluten Free Composite Flour Bread

Abstract

The aim of this work was to determine the impact of adding transglutaminase (TGase), to sorghum, corn and rice composite flour on the physicochemical and sensory properties of gluten-free breads. Samples were produced from flour containing of 0.0 (A), 5.0 (B), 10.0 (C) and 15.0 (D) μg TGase /g of protien. The chemical composition of gluten free bread flour has moisture, ash, fat, fiber, protein and carbohydrate contents of 9.66, 1.93, 2.09, 7.28, 11.35 and 67.60 % respectively. Also the gluten free mixture was found to be good in magnesium (17.04 mg), calcium (12.73 mg) and low in potassium (0.519 mg) and phosphorus (0.658 mg) while it was free of Iron. The samples were weighed in the following portions to prepare gluten free bread: White rice flour 34.5 %, Sorghum 30 % ,Corn flour 22 % ,Skimmed milk 12.5 % ,Xanthan gum 1%, Yeast .5% , Salt .25% and Sugar .25%. The functional properties of gluten free bread were determined and the water absorption capacity of the samples ( control (A) 0.0μg TGase /g of protien, (B) 5.0μg TGase /g of protien, (C) 10μg TGase /g of protien ,(D) 15μg TGase /g of protien and (E) wheat flour were 81, 79, 80, 81 and 78 % respectively, The emulsification capacity results were 40.9, 40.9 ,41.9 , 42.9 and 42.9 % respectively . Foaming capacity results were 6, 9.6 , 7.5 , 5.35 and 5 , Foaming stability results were 1, 1.9 ,0.95 , 0.54, and 5.0 % respectively. Bulk density results were 0.84, 0.83, 0.82, 0.81 and 0.82 % respectively. Swelling capacity results were 6, 7, 8, 10 and 8 % respectively. TGase has an impact on the waterholding capacity. It is presumed that the protein network formed by TGase has the ability to trap water and, hence, cause an increase in the water-holding capacity. The protein fractions were determined and the albumin content of the samples A,B,C,D and E were 2.70, 2,20, 2.10, 2.80 and 1.80 % respectively, V Prolamin were 1.30, 1.0 , 1.9, 1.30 and 1.90 % respectively. Globulin were 2.70, 1.70, 2.90, 3.00 and 4.60 % respectively. Glutelin were 1.70, 2.60, 2.80, 2.30 and 2.40 % respectively. The protein solubility were determined and the solubility of the samples A, B, C, D, and E at pH 4 were 4.00 , 3.1 , 4.9, 3.5 and 2.2 % respectively, while, at pH 6 were 3.00 , 6.30, 5.30, 3.10 and 2.20 % respectively. Addition of TGase in different percentages to gluten free flour significantely changed the values of farinograph . The water absorption of the samples A,B,C and D were 39.2, 39.2, 38.0 and 39.4 % respectively. The dough stability values of the samples A,B,C and D blend were 1.1, 0.1 , 0.9 and 0.0min respectively. The dough development time of the samples A, B, C and D were 10.2, 8.6 9.9, and 9.5min respectively.There is positive correlation between addition of TGase and water absorbtion when compared with wheat flour. Sensory evaluation of loaf bread showed that loaf bread made from gluten free flour with 15μg/g of protein gained the highest score of general acceptibility among the GF bread 3.05