Effect of Watermelon Rind (Citrullus lanatus) Addition on the Functional, Pasting and Microbiological Quality of Sorghum Based Mumu

ABSTRACT

The effect of watermelon rind powder addition on the functional, pasting and microbiological quality of Sorghum based mumu was evaluated. Sorghum-based mumu was prepared from composite flours of 8515, 7515, 7015 and 6515% roasted sorghum flour and roasted partially defatted groundnut flour respectively and included with 0, 10, 15 and 20% watermelon rind powder respectively which were known as sample A, B, C and D accordingly. Subsequently, the functional, pasting properties and microbial quality was assessed. Functional properties values; Bulk density (0.89 to 0.80mg/100g), reconstitution index (4.99 to 4.89) and swelling index (2.35 to 2.20) decreased significantly (p < 0.05) with increase in watermelon powder addition while water absorption (10.36 to 10.97g/g), oil absorption (10.33 to 10.79) and foam capacities (12.46 to 13.85%) increased with increase in watermelon rind powder. The pasting properties; peak (302.22 to 292.44 RVU), trough (156.44 to 150.00 RVU) and Final viscosities (412.69 to 400.76RVU), and breakdown (149.95 to 140.59RVU) decreased significantly (p < 0.05) with increased in watermelon rind powder while setback viscosity (101.05 to 115.59RVU), pasting temperature (59.32 to 62.02oC) and pasting time (4.93 to 5.13mins) increased. Microbial analysis revealed the following ranges Total viable count, 0.5x102 to1.0x102 cfu/g, fungi count of 6.1x101- 9.9x101 cfu/g and no coliform was detected. Overall, addition of watermelon rind powder showed good functional, pasting and microbiological qualities of sorghum based mumu.