Comparison of bench-scale decortication devices to fractionate bran from sorghum

Authors: Hums, Megan; Moreau, Robert; Yadav, Madhav; Powell, Michael; Simon, Stefanie

Submitted to: Cereal Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/17/2018
Publication Date: 8/20/2018
Citation: Hums, M.E., Moreau, R.A., Yadav, M.P., Powell, M.J., Simon, S. 2018. Comparison of bench-scale decortication devices to fractionate bran from sorghum. Cereal Chemistry. 95:720-733. https://doi.org/10.1002/cche.10087.
DOI: https://doi.org/10.1002/cche.10087

Interpretive Summary: Decortication of sorghum grain is a process that uses abrasion to separate the external surface (bran) from the starchy interior (endosperm). Decortication could have beneficial impacts on ethanol production, while producing value-added co-products. The goal of this study was to compare three bench-scale devices (barley pearler, scarifier, and rice polisher) to decorticate sorghum grain and analyze the composition of each fraction. The scarifier and barley pearler produced bran with similar contents of protein, starch, and total dietary fiber. The rice polisher produced bran with higher content of oil, protein, ash, and starch, but total dietary fiber was lower. The scarifier bran had the highest wax content while the rice polisher and barley pearler brans had similar lower wax content. The composition of bran from the rice polisher indicated that more germ and some endosperm were removed during decortication as compared to the other devices. There is a need for producing bran between lab- and pilot-scale with efficient separation of the pericarp from the endosperm. This research is the first to compare the composition of all sorghum fractions, including a wax analysis, from three types of bench-scale decortication devices.

Technical Abstract: Decortication of sorghum grain is a process that uses abrasion to separate the bran (including pericarp and germ) from the endosperm. Decortication could have beneficial impacts on ethanol production, while producing value-added co-products. The goal of this study was to compare three bench-scale devices (barley pearler, scarifier, and rice polisher) to decorticate sorghum grain and analyze the composition of each fraction. In a single batch to produce 10 g bran per 100 g sorghum, the scarifier processed more sorghum to produce more bran (12 g bran per 150 g input) than the barley pearler (7 g bran per 75 g input). The scarifier and barley pearler produced bran with similar contents of protein (10 g per 100 g bran), starch (40 g per 100 g bran), and total dietary fiber (40 g per 100 g bran). The rice polisher produced bran (43 g bran per 500 g input) with higher content of oil (12 g per 100 g bran), protein (11 g per 100 g bran), ash (6 g per 100 g bran), and starch (47 g per 100 g bran), but total dietary fiber was lower (29 g per 100 g bran). The scarifier bran had the highest wax content (1.9 g per 100 g bran) while the rice polisher and barley pearler brans had similar lower wax content (1.6 g per 100 g bran). The composition of bran from the rice polisher indicated that more germ and some endosperm were removed during decortication as compared to the other devices. There is a need for producing bran between lab- and pilot-scale with efficient separation of the pericarp from the endosperm. This research is the first to compare the composition of all sorghum fractions, including a wax analysis, from three types of bench-scale decortication devices.