Microbiological and physicochemical properties of sourdough bread from sorghum flour

Sorghum is the world’s fifth most important cereal grain after wheat, maize, rice and barley. Sourdoughs have been successfully used to improve the quality of gluten-free bread. The production of a novel food product with improved health benefit for gluten intolerance individuals necessitated this study. Microbiological and physicochemical qualities of the bread samples were determined. Sorghum grains were germinated and processed into flour for the production of sourdough. Thirty-six lactic acid bacteria (LAB) and thirteen yeast isolates were obtained. Among the LAB and yeasts, Pediococcus pentosaceus and Saccharomyces cerevisiae were employed as starter cultures, singly and in combination for the production of sorghum bread samples. The moisture content of the sorghum flour was determined to be 7.52%; the crude protein was 10.62% while the crude fat, crude fibre, ash and carbohydrate contents were 1.99%, 2.0%, 1.29% and 78.58% respectively. There was a significant decrease in the pH (6.77 to 4.31), increase in the acid equivalent (0.47ml to 1.69ml) and leavening (0.00cm to 1.40cm) at the end of the fermentation period. The proximate composition of the sorghum bread samples showed that moisture content ranged from 34.68 to 50.40%; crude protein, 11.27 to 16.60%; crude fat, 2.98 to 10.97%; ash, 1.50 to 2.13% while carbohydrate, 65.58 to77.39%. The mineral compositions in (mg/100g) were Calcium (6.6-13.15), Magnesium (68.65-120.75), and Potassium (126.2-233.25). The nutritional properties and physical parameters of the sorghum bread samples were improved relative to the sorghum flour and met the expectation for sourdough bread.