Effect of sorghum sourdough and nabag (zizyphus spina-christi) pulp powder on dough fermentation and quality characteristics of bread

Abstract

Sorghum sourdough made with lactic acid bacteria (LAB) and fruit products are of interest in the preparation of a variety of fermented baked products. In this study, different levels (10, 20, and 30%) of sorghum sourdough were fermented by a blend of L. plantarum and L. brevis and various levels of dry nabag pulp powder (1, 3, 5, and 7%). Physicochemical properties of dough and bread as well as the sensory evaluation were determined. Sorghum sourdough' pH decreased from 6.30 to 3.54, total titratable acidity (TTA) increased from 2.8 to 15 mL and bacteria count increased from 6.00E + 08 to 1.14E + 09, CFU/mL after 24 h of fermentation. The addition of sorghum sourdough and nabag powder progressively decreased pH and increased TTA values of bread and dough compared to the controls. Nabag powder significantly (p < 0.05) increased maximum dough fermentation height (Hm), compared to the control, however the other samples were lower (p < 0.05). The maximum gas fermentation height (H’m) and gas properties increased (p < 0.05) for all samples with different addition levels. Crust and crumb color were not affected by sorghum sourdough and nabag pulp powder except for 30% sorghum sourdough and 7% nabag pulp powder. These results showed sorghum sourdough and nabag pulp powder can be used in the bread formulations.