Effect of coconut (Cocos nucifera) flakes substitution on some quality parameters of wheat bread

Abstract

Coconut has a unique taste and aroma and excellent dietary fibre which has potential application in baked products and human nutrition. Bread was baked using wheat flour and coconut flakes at different substitution levels 100% wheat flour (AWB), 80% wheat and 20% coconut flakes (CWB8), 85% wheat flour and 15% coconut flakes (CWB8.5) and 90% wheat flour and 10% coconut flakes (CWB9). Some quality parameters such as proximate, mineral, pasting, sensory and microbiological analyses were determined to find out the most appropriate substitution level that can give better acceptability. The results showed that proximate contents of samples increased with substitution level. Protein content ranged from 12.63% to 10.26%, fat from 2.23% to 6.13% and fibre from 0.23% to 0.29% respectively. There was a significant difference (p< 0.05) in the Calcium content of the flour blends with 20% coconut flakes (CWB8) having the highest value of 16.94m/kg while the control had the lowest value of 10.93mg/kg. Same trend was observed in the magnesium and potassium contents. The pasting properties revealed that 20% blends (CWB8) had the highest peak viscosity, through breakdown and final viscosity. The peak viscosity ranged from 1681 RVU to 2580 RVU and final viscosity from 1689 RVU to 2645 RVU when compared with the control which has 1814 RVU. Sensory evaluation results showed that CWB8 is the most preferred for all attributes determined when compared with other samples. Microbiological study showed that microbial counts of CWB8 had the highest value of 2.66 x 105 cfu/g at ambient temperature which was higher than the permissible limit within one week while samples stored in the fridge and freezer had low microbial counts. From this study, enrichment with coconut flakes increased the nutritional benefits of the bread because of the increased protein and dietary fibre contents which acts as a prebiotic that helps probiotic bacteria thrive and encourages optimal digestion helping to prevent constipation.