Effect Of Steeping Period On Yield And Acceptability Of Starch Extracted From Sorghum (Sorghum Bicolor, White Variety And Red Variety)
Effect Of Steeping Period On Yield And Acceptability Of Starch Extracted From Sorghum (Sorghum Bicolor, White Variety And Red Variety) Starch was extracted from two varieties of sorghum bicolor grains (white and red varieties) steeped for 6, 8 and 12 hours by wet milling method, the starch samples were analysed for yield, functional properties and overall acceptability. The yield of the white variety ranged from 0.45 – 0.70kg and the red variety was 0.40 – 0.50kg. The result of their functional properties were as follows; Bulk density, white (0.700 – 0.733g/ml), red (0.723 – 0.753g/ml) Gelation temperature; white (70 – 72oc) red (73 – 74oc). Least gelation concentration; white (0.60 – 0.90g/10ml), red (0.70 – 1.00g/10ml). Metabolisable energy value, white (3.12 –3.82kcal/g), red (3.73 – 3.82 kcal.g).
Glycosidic cyanide content, white (4.5 – 8.5%), red (8.5 – 10.5%). The starchy samples with shorter steeping periods gave better results in terms of functional properties, metabolisable energy value, and percentage moisture content. The starch samples steeped for longer periods had greater yield but poorer functional properties. The white variety tested cyanide free and had better results than the red variety. The result of the sensory evaluation revealed that the samples had significant difference at p(0.05) and p(0.01) in colour and consistency. But there was no significant difference at p(0.05) and p(0.01) in flavour, texture and overall acceptability.
Field sprouting damaged starch granules, protein matrices, and cell walls in sorghum kernels, consequently decreasing kernel hardness, kernel weight, and kernel size. Field sprouting also changed the chemical composition and pasting properties of field-sprouted grain sorghum, which could shorten fermentation time without decreasing ethanol yield. Field-sprouted grain sorghum had relatively high FAN content. The FAN provided efficient buffering capacity and optimal yeast performance, and field-sprouted sorghum had a more rapid fermentation rate than non-sprouted sorghum.
FAN played a key role in increasing conversion efficiency for ethanol production. Using weathered and/or sprouted sorghum from regions affected by unusually high moisture events during grain fill and harvest may provide an opportunity for ethanol producers to maintain ethanol production efficiency, while shortening processing time. This could offer sorghum producers an opportunity to receive a premium, or at least a fair market, value for sorghum when such environmental events occur.