Oke M.O.,LAUTECH |
Awonorin S.O.,UNAAB |
Sanni L.O.,UNAAB |
Asiedu R.,International Institute Of Tropical Agriculture |
Journal of Food Processing and Preservation | Year: 2013
Water yam (Dioscorea alata) flour was processed using standard wet milling procedure prior to the extrusion process, which led to the determination of extrudate properties of the flours. A single-screw extruder (DCE 330, NJ) was used in evaluating the extrudate properties, which included torque, mass flow rate, residence time, specific mechanical energy and expansion ratio of the flours from the water yam samples. The effect of extrusion and process variables: feed moisture content, screw speed and barrel temperature on the extruder torque, residence time, mass flow rate, specific mechanical energy and expansion ratio for the variety were determined and predictive models were also developed using response surface methodology. It was observed that changing the feed moisture content, barrel temperature and screw speed significantly (P<0.05) affected expansion ratio, torque, mass flow rate, residence time and specific mechanical energy of all the extrudates. Increasing the feed moisture content (18-28% db) and screw speed (80-180rpm) resulted in a substantial decrease in expansion ratio (46.6%), residence time (27.5%) and specific mechanical energy (83.6%); whereas, increasing the screw speed significantly increased the mass flow rate (64.5%) of extrudates. Regression analysis indicated that screw speed and feed moisture content were the major process variables showing significant (P<0.05) linear, quadratic and interaction influences on mass flow rate, expansion ratio and specific mechanical energy. © 2012 Wiley Periodicals, Inc.
Odedara O.O.,Abeokuta Federal University of Agriculture |
Ayo-John E.I.,Abeokuta Federal University of Agriculture |
Gbuyiro M.M.,UNAAB |
Falade F.O.,Abeokuta Federal University of Agriculture |
Archives of Phytopathology and Plant Protection | Year: 2012
A field survey was conducted in eight local government areas (LGA) of Ogun state, Nigeria to assess the incidence of viral diseases of yams in the areas. Leaf samples were collected from 90 yam plants which were either symptomatic or asymptomatic. These were bulked into 45 during serological tests and the viruses indexed include yam mosaic virus (YMV); Dioscorea alata bacilliform virus (DaBV) and cucumber mosaic virus (CMV). DaBV was the most prevalent virus on the field with incidence of 48.9% (22/45) followed by YMV which occurred in 42.2% (19/45). CMV had the lowest percentage of incidence; 2.2% (1/45). Of all the LGAs visited, Abeokuta north and Abeokuta south had the highest incidence of YMV and DaBV, respectively. Mixed virus infections were also detected. © 2012 Taylor and Francis Group, LLC.