Comparative Study of Dextrose Production from Locally Sourced Cassava, Tigernut and Yam

Abstract

Starch was extracted after sedimentation from seven samples, TME 419, TMS 30572, Provitamin, Tigernut, Boko, Mumuyi and Onitsha. The first three samples were cassava varieties while the last three samples were species of yam variety Dioscorea rotundata. The extracted starch were gelatinized and hydrolyzed enzymatically to produce 250ml of dextrose from each sample. From spectrometer analysis it showed that Mumuyi dextrose has the highest glucose concentration of 0.72mg/ml when compared to the standard 0.506mg/ml of ASTMD6406 at pH5, with a viscosity, specific gravity and refractive index of 1.2Cst, 1.030 and 1.3378 respectively all within the range of their standards. Its water content was 19.6% and 75.75% carbohydrate content. It was closely followed by Onitsha with 0.63mg/ml of glucose concentration and Boko with 0.57gm/ml while TME 419 had 0.55gm/ml, Tigernut 0.52gm/ml, Provitamin 0.50gm/ml and TMS 30572 having 0.49gm/ml. There viscosities were 1.0Cst, 1.3Cst, 0.16Cst, 2.7Cst, 7.0Cst and 28.2Cst; Specific gravity 1.028, 1.030, 1.034, 1.029, 1.032, 1.037; Refractive index as 1.33636, 1.33638, 1.33936, 1.33738, 1.34035 and 1.33937; water content as 18%, 21%, 18%, 21.2%, 20% and 18.8%; Carbohydrate as 73%, 71.5%, 69%, 62.5%, 65% and 66% respectively. There functional parameters were obtained at an operational temperature of 55⁰C and time interval of 5 hours on each pH considered. The effect of temperature on the varied pHs above the operational temperature was not favourable to the reactions. The hydrolysis was most favoured at the operational temperature and at pH5 when considered and compared with the activity profile of the enzyme amyloglucosidase.   

Key words: Comparative Study, Dextrose Production, Locally Sourced Cassava, Tigernut, Yam, Cassav
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