Optimization of the functional characteristics, pasting and rheological properties of pearl millet-based composite flour.

Olugbenga Olufemi Awolu

doi:10.1016/j.heliyon.2017.e00240

Abstract

Optimisation of composite flour comprising pearl millet, kidney beans and tigernut with xanthan gum was evaluated for rheological evaluations. The functional properties of the composite flour were optimized using optimal design of response surface methodology. The optimum blends, defined as blends with overall best functional characteristics were run 3 (75.956% pearl millet, 17.692% kidney beans, 6.352% tigernut flours), run 7 (85.000% pearl millet, 10.000% kidney beans, 5.000% tigernut flours) and run 13 (75.000% pearl millet, 20.000% kidney beans, 5.000% tigernut flours). The pasting characteristics and rheological evaluation of the optimized blends were further evaluated in rapid visco units (RVU). Run 7 had the overall best pasting characteristics; peak viscosity (462 RVU), trough (442 RVU), breakdown viscosity (20 RVU), final viscosity (975 RVU), setback (533 RVU), peak time (5.47 min) and pasting temperature (89.60 °C). These values were found to be better than several composite flours consisting mixture of wheat and non-wheat crops. In addition, the rheological characteristics (measured by Mixolab) showed that run 7 is the best in terms of dough stability, swelling, water absorption and shelf stability. Composite flour with 85% pearl millet flour in addition to kidney beans and tigernut flours could therefore serve as a viable alternative to 100% wheat flour in bread production.

Highlights

The use of cereals, tubers with or without legumes and fibres as viable sources of functional composite flours keeps on increasing (Bamigbola et al, 2016; Awolu et al, 2016b; Awolu et al, 2016a)
Increase in pearl millet content accounted for the high bulk density observed
The analysis of variance (ANOVA) showed that the model (Special quartic) and the model terms did not significantly (p ≥ 0.05) affect the bulk density, meaning that though there was an increase brought about by addition of pearl millet, the increase was not significant (p ≥ 0.05)

Summary

Introduction

The use of cereals, tubers with or without legumes and fibres as viable sources of functional composite flours keeps on increasing (Bamigbola et al, 2016; Awolu et al, 2016b; Awolu et al, 2016a). Cereals (rice, amaranth, tigernut), tubers (cocoyam, sweet potatoes), legumes (soybeans, African oil bean, bambara groundnut, kersting’s groundnut) and fibres sources (rice bran, brewer’s spent grains) have been utilized as credible sources of composite flours (Bamigbola et al, 2016; Awolu et al, 2016b; Awolu et al, 2016a; Awolu et al, 2015). Millets generally have been discovered to be rich in dietary fibre, minerals, phytochemicals (especially phenolic compounds) and vitamins which make them to be health promoting (Saleh et al, 2013). Millets have been incorporated into wheat in the production of bread, biscuits, and ready-to-eat snacks (Saha et al, 2011)

Methods

Results

Conclusion