Production of Biscuits from Quality Protein Maize Enriched with Dried Fluted Pumpkin Leaves and Cocoa Powder

摘要

Biscuits are ready-to eat snacks and a good source of energy. Most snackfoods are often considered as "junk food" or empty foods because they contain high levels of calories with little protein, vitamin and minerals. Due to high importation costs of wheat, biscuits have been developed from non-wheat products. The quality protein maize (QPM) grown locally in Nigeria is a popular alternative to wheat. Studies have been conducted to enrich biscuits using some plant materials. Fluted Pumpkin leaves (Telfairia occidentalis) 'ugu' leaves is a cheap source of minerals and vitamins. In Nigeria, the range of industrial products from cocoa beans is small hence the need to explore other uses for the cocoa powder. This study investigated the effects of enriching biscuits from QPM with dried 'ugu' leaves (DUL) and cocoa powder (CP) with the aim of increasing their utilization.Ugu leaves were washed, shredded, dried and milled to fine powder. QPM were cleaned, decorticated, dried and milled into fine powder. The flours were formulated into biscuits: QPM flour: xanthan gum: DUL: CP (100:0:0, 99:1:0:0, 96:1:0:3, 93:1:3:3, 90:1:6:3, 87:1:9:3, 84:1:12:3). Biscuits were packed in a low density polyethylene bag and analyzed for proximate, minerals, amino acid composition, physical, functional and sensory properties on the samples using standard analytical methods.Addition of DUL and CP increased the protein, ash, fat, fibre amino acid content and mineral contents significantly but decreased the carbohydrate and metabolizable energy values for the biscuits. The water and oil absorption capacities of the samples increased with addition of CP. Bulk density, swelling capacity of the samples decreased with addition of DUL and CP. Functional properties varied with temperature and water absorption capacity and swelling capacity of the flour samples ranged between 169.66% to 197.33% and 121.00 to 183.33% respectively. Quadratic equations gave highest R2 values for swelling capacity (0.9339-0.9979) and water absorption capacity (0.9259-0.9817) at different temperatures compared to exponential, linear, or logarithmic equations. The physical properties of the biscuits: weight, and thickness increased while diameter, spread ratio and break strength reduced with enrichment. pH of the flour reduced with the addition of dried 'ugu' leaves but increased with the addition of cocoa powder. The in-vitro protein digestibility of the biscuits increased with enrichment (51.68 to 62.16%). QPM based biscuits had total amino acid values ranging between 88.83 and 98.33 g/100 g protein. The biscuits were of acceptable sensory qualitiesup to 12% level of cocoa powder substitution but the scores were lower than that of the control samples. Regression equations were developed for the relationships between breaking strength and storage time, moisture content and storage time.The study concluded that biscuits from QPM enriched with DUL and CP improved the nutritional properties without affecting the functional attributes thus enlarging their utilization potentials.