Effect of Orange Peel Flour on the Quality Characteristics of Bread

Aims: This study was carried out to investigate the effects of orange peel flour (OPF) substitution with wheat flour in bread production (substitution levels of 3, 6 and 9%) on the proximate composition, phytochemicals content, baking and sensory characteristics.
Place and Duration of Study: Department of Food Science and Technology, Ebonyi State University, Abakaliki, Ebonyi State, Nigeria for seven months.
Methodology: Oranges were washed thoroughly and peeled. Peels were boiled in water, sundried and ground into flour. Bread was produced by replacing wheat flour with 3, 6 and 9% OPF. Bread samples were analyzed for proximate composition (fat, moisture, protein, ash, fibre and carbohydrates), phytochemicals (tannins, saponins and alkaloids), baking characteristics (oven spring, loaf volume, specific volume and weight) and sensory quality.
Results: The addition of orange peel flour led to reduction in protein (8.2-2.7%) and fat (1.7-0.8%) but increased the ash (2.3-4.3%), fibre (0.6-5.8%) and carbohydrates (59.9-62.1%) contents. Phytochemicals levels also increased with increased levels of orange peel flour in the samples. Tannins ranged from 3.6-8.0mg/g, saponins from 0.9-1.4mg/g and alkaloids from 3.6-4.8mg/g. Oven spring decreased from 2.0 to 0.2cm, loaf volume from 8.0 to 4.8cm3 and specific volume from 5.3 to 3.2cm3/g. Sensory quality decreased with increase in orange peel flour for all the attributes studied. However sensory quality of bread made with 3% OPF did not differ from that made with 100% wheat flour.
Conclusion: The use of orange peel flour in bread has the advantage of improving the fibre, ash and phytochemicals levels in bread. However only bread produced with 3% OPF had sensory quality comparable to that produced with 100% wheat. Orange peel flour in bread production will not only add value to food but will also reduce environmental pollution as well as reduce the cost of importation of wheat.