Abstract

Inhibitory Effect of Ginger and Turmeric on Rhizopus stolonifer Growth on Bread

Ali Muhammad, Ziaur Rahman, Ayub M, Durrani Y, Ali SA, Abroo Tabassum, Ashbala Shakoor, Majid Khan and Arsalan Khan

The inhibitory effect of ginger and turmeric was studied on the Rhizopus stolonifer growth on bread. Different ratios of ginger and turmeric were incorporated to bread dough formulation. The treatments were BG0 (control), BG1 (3% ginger), BG2 (4% ginger), BG3 (3% turmeric), BG4 (4% turmeric), BG5 (1.5% ginger + 1.5% turmeric) and BG6 (2% ginger + 2% turmeric). All the samples were analyzed physicochemically (moisture, ash, pH and water activity), microbiologically (colony count of Rhizopus stolonifer) and organoleptically (color, texture, flavor and overall acceptability). The results showed that overall moisture decreased (from 27.46 to 26.41), water activity aW (from 0.89 to 0.86), color (from 7.4 to 5.58), texture (from 6.94 to 5.34), flavor (from 7.75 to 5.54) and overall acceptability (from 7.38 to 5.48), while percent ash increased (from 0.84 to 0.86), pH (from 5.95 to 6.20) and microbial count of Rhizopus stolonifer (3.8×101 to 2×102). The highest mean value for ash was recorded for treatment BG4 (0.98), water activity in BG0 (0.91), moisture in BG0 (29.69), pH in BG4 (6.34) Microbial count in BG0 (1.5 × 102cfu/g), color in BG3 (6.98), texture in BG0 (7.04), flavor in BG0 (6.90) and overall acceptability in BG0 and BG3 (6.96). The overall results showed that BG3 gave the best inhibitory results against Rhizopus stolonifer as well as in physicochemical and sensory evaluation, while BG6 also presented better inhibitory results in microbial analysis but it was not satisfactory in terms of sensory characteristics.