Partially substitution of wheat flour by coconut residues in bakery products and their physical and sensorial properties

The food process generates certain amounts of agricultural wastes and by-products. Thesematerials are considerably non-valuable and normally sold for livestock feed. Coconutresidue is one of the by-products obtained from coconut milk extraction. Thus, this studywas aimed to valorise coconut residue powder (CRP) by partial substitution of wheat flourin deep fried donut and butter cookies and to investigate how different CRP substitutionlevels affect the physical and sensorial qualities of these bakery products. CRP wasprepared by drying coconut residues at 55oC for 9 hrs, size reducing with a blender at24,000 rpm for 40 s and sieving through a 35-mesh sifter. Protein, ash, fat andcarbohydrate contents of coconut flour were 3.82, 0.72, 39.83 and 55.64% on dry basis,respectively. After the utilization of CRP by partial substitution wheat flour in deep frieddonut (5%, 10% and 15%) and butter cookies (10%, 15% and 20%), it was found thatCRP can substitute wheat flour in the donut and cookies productions by 10% and 15%,respectively. Donuts with higher substitution levels had lower specific volume but higherL*, a*, ∆E*-values, hardness and chewiness. For butter cookies, an increase in CRPsubstitution level led to higher hardness but it did not significantly affect the fracturabilityand the ∆E*-value. An increase in CRP substitution level also reduced the overall-likingscore. The overall-liking scores of fried donuts with 10% CRP substitution level andbutter cookies with 15% CRP substitution level were 6.43 (slightly like) and 7.00(moderately like), respectively. This study showed the value-adding of agricultural wastesuch as coconut residue by its application in food production.