Changes in the physical and biochemical properties of pearl millet (Pennisetum americanum) on conversion to ogi

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Abstract

Millet was converted into ogi, a naturally fermented cereal product, by the traditional wet milling/wet sieving process and by fermenting millet meal and ground millet malt. Proximate chemical composition, flavanol content, vitamin A and B2 contents, energy value, protein and starch availabilities and Brabender paste viscosity of millet grain and ogi were determined. Yields of ogi ranged from 67.5 to 96.5%. Protein, ether extract, ash and crude fibre contents were reduced in ogi by 2.3–24, 3.9–25.5, 14.3–28.6 and 6.6–42.3% respectively, while the soluble carbohydrate content of the grain (68.2 ± 12 g kg−1) was retained. Flavanol content of millet (1.025 g c-glycosylflavanol equivalent kg−1 grain) was reduced in ogi (0.643–0.872 g c-glycosylflavanol equivalent kg−1 grain). Vitamin A content was reduced by 21.4–53.4% and vitamin B2 content was increased by 85.7–242.8% on conversion of millet into ogi. Apparent protein availability increased by 91.3–144.9% with papain digestion and by 47.6–109.5% without papain. However, changes in tryptophan (5.6%) and lysine (5.2%) were less marked, except in ogi from malt, which showed 22.2 and 20.8% increases in tryptophan and lysine contents respectively. Apparent carbohydrate availability increased (by 17–93%) but energy value generally remained the same (highest increase 3.4%) when millet was converted to ogi. Conversion of grain to ogi reduced paste viscosity.

© 2002 Society of Chemical Industry

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