Evaluation of the Phytochemical Composition and Pasting Characteristics of African Locust Bean Pulp Flour, Wheat Flour and Blends

Abstract

Aim: The study determined the phytochemical composition and pasting properties of locust bean pulp, wheat flour and the blends. Study Design: The experiments in carried out in three replications in completely randomized design. The data were analyzed were analyzed by analysis of variance. Significance was accepted at p<0.05. Place and Duration of the Study: The study was carried in 2016 at The Federal Polytechnic, Idah, Nigeria. Methodology: Flour was prepared from locust bean pulp and used to substitute 10, 20, 30, 40, 50, 60, 70, 80 and 90% wheat flour. The phytochemical composition and pasting properties of the locust bean pulp flour and wheat flour were determined. The pasting properties of the blends were also assessed. Results: The locust bean pulp flour contained 3.97 mg/100g flavonoids, 8.72 mg/100g carotenoids, 9.81 mg/100g tannins, 8.92 mg/100g saponins, 2.92 mg/100g alkaloids, 0.77 mg/100g glycosides, 2.81mg/100g phytates, 0.88mg/100g oxalates and 0.05 mg/100g hydrogen cyanide. The wheat flour contained 0.5 mg/100g flavonoids, 0.8 mg/100g carotenoids, 1.0 mg/100g tannins, 0.8 mg/100g saponins, 0.5 mg/100g alkaloids, 0.8 mg/100g glycosides, 2.0 mg/100g phytates, 1.0 mg/100g oxalates and 0.09 mg/100g hydrogen cyanide. Wheat flour had significantly higher (P<0.05) peak viscosity (157.83 RVU) and final viscosity (179.33 RVU) than the locust bean pulp flour. The peak viscosity and final viscosity of locust bean pulp flour were -3017 and -2.75 RVU, respectively. Similarly, the trough viscosity, breakdown viscosity and setback viscosity of locust bean pulp flour were lower than those of wheat flour. These properties increased in the blends with the level of wheat flour. The pasting temperatures of locust bean pulp flour and wheat flour were 95.05°C and 79.45°C, respectively and increased with the level of wheat flour in the blends. It took locust bean pulp flour 6.13 min to reach peak viscosity and wheat flour 6.20 min. The pasting time decreased as the level of locust bean pulp flour increased in the blends. Conclusion: The locust bean pulp flour had higher amounts of flavonoids, carotenoids, tannins, saponins and alkaloids but lower pasting properties than wheat flour. Based on the pasting properties, the locust bean pulp flour and wheat flour blends would find applications in various baked food products. The study showed that locust bean pulp flour has potential for use in various food systems.