Abstract

The objective of this study was to optimise raw tooke flour-(RTF), vital gluten (VG) and water absorption (WA) with respect to bread-making quality and cost effectiveness of RTF/wheat composite flour. The hypothesis generated for this study was that optimal substitution of RTF and VG into wheat has no significant effect on baking quality of the resultant composite flour. A basic white wheat bread recipe was adopted and response surface methodology (RSM) procedures applied. A D-optimal design was employed with the following variables: RTF (x₁) 0-33%, WA (x₂) -2FWA to +2FWA and VG (x₃) 0 - 3%. Seven responses were modelled. Baking worth number, volume yield and cost were simultaneously optimized using desirability function approach. Models developed adequately described the relationships and were confirmed by validation studies. RTF showed the greatest effect on all models, which effect impaired baking performance of composite flour. VG and Farinograph water absorption (FWA) as well as their interaction improved bread quality. Vitality of VG was enhanced by RTF. The optimal formulation for maximum baking quality was 0.56%(x₁), 0.33%(x₂) and -1.24(x₃) while a formulation of 22%(x₁), 3%(x₂) and +1.13(x₃) maximized RTF incorporation in the respective and composite bread quality at lowest cost. Thus, the set hypothesis was not rejected.

Key words: Raw tooke flour, composite bread, baking quality, response surface methodology, Farinograph water absorption, vital gluten.