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

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 BG 0 (control), BG 1 (3% ginger), BG 2 (4% ginger), BG 3 (3% turmeric), BG 4 (4% turmeric), BG 5 (1.5% ginger + 1.5% turmeric) and BG 6 (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 a W (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 (3.810 1 to 210 2 ). The highest mean value for ash was recorded for treatment BG 4 (0.98), water activity in BG 0 (0.91), moisture in BG 0 (29.69), pH in BG 4 (6.34) Microbial count in BG 0 (1.5 10 2 cfu/g), color in BG 3 (6.98), texture in BG 0 (7.04), flavor in BG 0 (6.90) and overall acceptability in BG 0 and BG 3 (6.96). The overall results showed that BG 3 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.