Resume of Dr. Abiodun Okunola, Post harvest / Agricultural/ Renewable Engineering

This contains academic profile of Dr. Abiodun Okunola (Associate Professor, Department of Agricultural & Biosysytems Engineering, Landmark University, Nigeria

Impact of some essential plant oils on viability of stored cowpea and maize seeds for food security

Essential oils from three aromatic spice plants were applied on cowpea and maize seeds in storage and viability on germination was investigated. Cowpea and maize seeds were subjected to treatment using essential oils from (Monodora myristica, Eugenia aromatic and Piper guineese) at concentrations of 0, 5, 10, 15 and 20 ml/kg of seeds. These were stored at a temperature of 27±2oC and 65 -70% r.h. in the laboratory. The viability test was conducted on the treated seeds at three and six months of storage, using Petri-dishes each containing 10 of randomly selected cowpea and maize seeds in three replicates, at the different levels of oil concentrations. The seeds were placed on moistened cotton wools and covered. Seeds germination occurred mainly within three to five days after commencement of experiment. The data obtained were subjected to two – way analysis of variance, at (p< 5%) using Ducan’s multiple range test. It was observed that among the three essential oils applied, seeds treated with Piper guineese oil ranked highest in germinations at a concentration of 5 ml/kg for both seeds, with cowpea seeds having 88.7 and 83.0% and maize seeds with 69.3 and 45.3% at three and six months respectively

Acceptability and Sensory Evaluation of Maize and Cowpea Products Stored with some Essential Oils

The sensory evaluation and processing qualities of cooked maize paste (pap) and cooked cowpea paste(moinmoin) products from treated maize and cowpea grains stored with essential oils of three plant spices (Eugenia aromatica, Piper guineesis and Monodora myristica),were investigated. Essential oils were applied at dosage rate of 0, 5, 10, 15 and 20 ml/kg of stored grains for six months. The products were processed, cooked and evaluated for processing and sensory qualities to access the spices and concentration effects of the essential oils extracted with n-hexane. A 9- point hedonic scale was used to evaluate the sensory parameters of taste, aroma and appearance ranging from dislike extremely to like extremely. Panelists were administered well-structured questionnaires to assess the effect of the essential oils, from spices concentration and interaction between spice and concentration on the parameters assessed on the grains. Sensory evaluation data were subjected to 3x5 factorial arrangements. Pap from maize and moinmoin (cooked cowpea paste) from cowpea grains stored with dosage rate of 5 -10 ml/kg grains, were significantly accepted and preferred by the panelists. Nutmeg spiced products at 5 ml/kg for the grains products was ranked highest among other spices

Performance evaluation of a rice cleaning and grading machine

Rice (Oryza sativa L.), that are locally produced and processed in Nigeria is characterized with high percentage of broken grains and impurities which impairs its quality and attracts low market value. To overcome this predicament, an appropriate technology machine was designed A three sieve cleaner-grader machine developed by the authors was tested for performance with a vibration speed of 240 r.p.m. Three rice varieties was used for testing the milling qualities such as milled rice yield, head rice yield and brokens at the moisture content of 12.2% ±1.4 An air blast of 4.8ms 1 was utilized to separate light materials while apertures diameter of 3, 5.5 and 7mm were selected for bottom, intermediate and top sieves to effect grading of whole kernels. Milled rice fed into the machine was tested at tilt angles of 2o, 4o and 6o and at blower inclinations of 0o and 5o. The brokens within 18.18 to 22.62% was reduced to 6.13 and 9.06%.with the utilization of the grading machine. Machine capacity ranges from 1000 – 1,200 kg/hr. The incorporation of the grading machine after milling has upgraded locally processed rice quality from grade III to grade I

Evaluation of an active evaporative cooling device for storage of fruits and vegetables

An active evaporative cooling device for storage of fruits and vegetables was evaluated. The cooling device was developed to improve the shelf life of fruits and vegetables. It consists of an inner wall (aluminum of 0.6 mm thickness), external wall (galvanized steel of 1mm thickness), one suction fan, water pump and three trays. The walls were lagged by polyurethane of 25 mm, and three trays. Water distribution network contains two water tanks of 20 litres capacity each, a polyvinyl chloride (PVC) pipe of 25 mm diameter for conveying water, a 0.5 hp pump for circulating water from the tank to the overhead reservoir and a floated switch for controlling the pump. Water is discharged from the overhead tank through a tap and drains through a jute bag which serves as a cooling pad material. As water drips through the pad, a suction fan of 38 cm swept depth set air in motion and blow through the wetted part. The cooler was evaluated with sweet orange, green tomatoes and red tomatoes for 7 days to determine firmness, colour changes and weight loss of the crops. Weight loss in the red and green tomatoes stored in the ambient was observed to be 47.20% and 5.14% respectively while it was 8.65% for red tomatoes stored in the cooler. Cumulative weight loss recorded in sweet oranges was 9.25% for ambient and 4.27% for the cooling device. The cooler reduced the ambient temperature of 29.5o C to 22.8o C and increased ambient relative humidity to 95.7%. Keywords: evaporative cooling, storage, orange, tomato, post-harvest losse

Energy and Exergy Analysis

A forced convection automatic cabinet dryer integrated with a data logger was designed and fabricated. The okra samples were dried in the dryer at drying temperatures of 50, 60, and 70 °C and at three different load densities of 200, 300, and 400 g at a continuous air velocity of 0.7 m·s–1. Energy and exergy analyses of the drying process were performed. The obtained results showed that the energy efficiency, energy utilisation, and utilisation ratio increased from 26.59 to 68.24%, 5.47 to 114.36 W, and 0.36 to 0.71 as the temperature increased to 70 °C, respectively. The inflow, outflow, and exergy losses were in the range of 7.02 to 26.14 W, 4.43 to 14.16 W, and 2.59 to 11.98 W, respectively, while exergy efficiency varied from 49.15 to 63.47%. The findings show that exergy efficiencies decrease with an increase in the drying temperature, but increase with a lower load rate. The index of sustainability varies from 2.14 to 2.77, the value increases as the load density decreases while it decreases with a temperature increment

DETERMINATION OF THE BIOLOGICAL AND PHYSICO-CHEMICAL PARAMETERS OF BOREHOLE WATER IN OMU-ARAN, KWARA STATE

The reliance on groundwater for various activities ranging from domestic, agricultural and industrial activities is ever on the increase in developing countries. The groundwater sources will, therefore, need to be evaluated constantly and periodically to ensure its portability and fitness for use. There is little documentation about the quality of water sources in Omu-Aran. This study therefore, is to assess water quality of borehole present in the area. In order to carry out the purported objective of this project, twenty-four samples withdrawn from boreholes of eight different locations across Omu-Aran were taken into consideration. Precautions and standard procedures were taken in its collection, storage and transportation in order to preserve the sanctity of the water samples. The procedures, materials and equipment required to carry out the test for each parameter such as electrical conductivity, dissolved oxygen, pH, nitrate, sulphate, zinc, nickel, E. coli, total coliform etc. were all in line with laid down standards and procedures. Results from the research revealed that the value of analyzed parameters were within the acceptable limits for potable water recommended by World Health Organization and Standard Organization of Nigeria except for iron, nickel, E. coli and pH. Iron, E. coli and nickel were much to above the limit while pH did not fall within the minimum and maximum limit allowed. Water quality index and spatial analysis using ArcGIS highlight the significance of these parameters. Borehole water in this region can be considered safe and of good quality but face huge risk of contamination by heavy metals and raises the question of suitability and effect of the drinking in the long run

LOCUST BEANS SEED DEHULLING MACHINE

A locust bean dehulling machine was fabricated and evaluated using locally available materials. The machine performs dual operations of removing the seed coats and cleaning. Components of the machine include the frame, hopper, dehulling chamber, water container, discharge outlets, set of gears and bearings in operation. In operation, locust beans seeds introduced via the hopper moved to the auger which separates the soft pulp and conveys the material into the dehulling chamber. The seeds were washed in the dehulling chamber while the coat (residual waste) passes through the sieve into the water trough where it was discharged through the waste outlet. Throughput capacity, output capacity, recovery percentage and cleaning efficiency were 264.0kg/hr, 98.48%, and 98.75%, respectively. This machine may find applications in the processing of locust beans