Optimisation of Plantain - Brewers’ Spent Grain Biscuit Using Response Surface Methodology

Abstract

Aim: To optimize the formulation of plantain – brewers’ spent grain biscuits using Response Surface Methodology with the purpose of achieving the maximum quality and overall acceptability of produced biscuits. Study Design: Central composite design model of Response surface methodology was employed to design the work. This produced thirteen experimental runs, the variables considered were Brewer’s spent grain (94-97 %) and plantain flour (3-6 %) while the responses were percentage soluble dietary fibre, percentage insoluble dietary fibre and iron contents. Place and Duration of Study: Department of Food science and Technology, Federal University of Technology, Akure, Nigeria, between January to December 2012. Methodology: The variables considered for the research were Brewer’s spent grain (94-97 %) and plantain flour (3-6 %) while the responses were percentage soluble dietary fibre, percentage insoluble dietary fibre and iron contents. Thirteen (13) runs were obtained.The optimization was carried out on plantain flour and brewer’s spent grain in order to know which of the combinations will give best total dietary fibre and iron content. Results: Optimized values, which are the highest total dietary fibre and iron values of 68.55 % and 0.80 mg /100g respectively, were obtained from blends of 95.5 % and 4. 5 % of plantain flours and Brewer’s spent grains respectively (PS 4). The best response surface model for the insoluble dietary fibre was quadratic that of soluble dietary fibre was linear while it was quadratic also for iron content. The lack of fit, (p=0.4208) is non significant. A non significant lack of fit is required confirming that, the model of is adequate. The R2 value of 52 % signifies a good model. This is in view of the fact that R2 must be at least 50 % to be a good model. Conclusion: Response Surface Methodology was effective in optimizing iron and dietary fibre in the formulation of plantain-spent grain biscuit. The nutritional composition of the plantain-spent grain biscuit indicated good levels of dietary fibre (IDF, SDF and TDF), Iron.