ABSTRACT

The Chemical, microbial and sensory qualities of Ighu dried in locally constructed solar dryers were analyzed. Nine (9) locally constructed solar dryers were used for the drying of Ighu produced from three cassava varieties using three shredding plates (nko). Response surface analysis was adopted in investigating the interaction of independent variables-cassava varieties, drying height and sample thickness based on central composite design (CCD) in which 27 experimental runs were generated. Varieties of cassava used were TME 419, TMS 30572 and NR 8082. Drying height of the solar dryers used were 40 mm, 60 mm and 80 mm, while the sample thickness were 0.57 mm, 0.72 mm to 0.91 mm. Thirty (30) panelists were used for the sensory analysis. Moisture content ranged from 8.40% to 11.20%; ash ranged from 1.50% to 2.55%, fibre ranged from 6.70% to 7.90%, carbohydrate ranged from 77.18% to 79.68%, starch ranged from 26.43% to 30.32% and hydrogen cyanide 3.81 to 6.86 mg/kg, however from the optimization, an optimum value of 9.25682 % moisture, 2.26039 % ash, 7.75212 % fibre, 28.8944 % starch, 78.8229 % carbohydrate and 4.47357 mg/kg HCN content will be obtained from a combined optimum factor levels of 0.84 mm sample thickness, 79.43 mm drying height using TME 419 cassava variety. There was insignificant lack of fit (p>O.05) and R2 value ? 70% showing the predictability of all the responses (chemical composition) by the model. Microbial analysis showed that bacteria count of Ighu were within the range of 5.72 to 6.03 log10cfu/g; 5.81 to 6.04 log10cfu/g, and 5.66 to 6.15 log10cfu/g for samples TME 419, NR 8082 and TMS 30572, respectively. Fungi counts of the Ighu obtained in sample TME 419 ranged from 0.00 to 4.80 log10cfu/g, 0.00 to 4.731og10cfu1g and 0.00 to 4.561og10cfu!g for NR 8082 and TMS 30572 respectively. Total coliform count in Ighu samples ranged from 0.00 to 3.47log10cfug for samples TME 419, 0.00 to 4.44 log10cfu/g for NR 8082 and 0.00 to 5.32 log10cfu/g for TMS 30572. The bacteria and fungi load of most sundried samples were considerably low when compared to solar dried samples. There was significant difference (p<O.00l) in the physical and sensory properties of the Ighu. All physical properties had a model equation with exception of appearance. The mean score of general acceptability varied from 2.63 to 4.17, appearance mean score ranged from 2.33 to 4.40, thickness ranged from 2.60 to 4.23, while texture ranged from 2.60 to 4.87. Sensory evaluation showed that Ighu produced from cassava variety TME 419, 80mm drying height, 0.72mm thickness was more accepted to the panelists with reference to overall acceptability