No abstract

The increase in demand of coffee in the world as well as high cost of imported coffee roasting machines has made many local fabricators to develop coffee roaster. Unfortunately, the roasted coffee from the machines is not too different from the locally roasted coffee in terms of qualities revealed during sensory and organoleptic tests. This paper presents the development of coffee roaster operational sequence which has a temperature controller, stirring and cooling mechanism embedded into it, which mitigate the effect of poor and irregular heating pattern of most traditional roasting methods. Optimum Coffee roasting temperature is 200°C. However, the roaster can attain a temperature of 400°C.The evaluation of the coffee roaster revealed that the machine attained a steady temperature of 200°C, 250°C and 300°C at 6, 7 and 10 minutes respectively. It was observed that uniform and even roasting was achieved by proper stirring of the coffee bean inside the roaster at the desired temperature which reduced the drudgery, operators’ interference and contamination of the roasted coffee.

This paper describes the design and construction of a device for measuring compressive force during oil expression from oil bearing seeds or nuts. The device consist of a 10 tons load cell and an amplifier with display unit. The device was calibrated and tested. The result obtained from the test shows that the device is adequate for measuring dead load and compressive force, ranging from 0-100kN in a situation where a percentage error of up to 0.2% is permissible. In addition, test result of oil yield obtained by using the device to measure compressive force during oil expression from grounded Palm Kernel was compared to the result of oil yield measured using the Universal Testing Machine (UTM) of 50KN capacity. The results were subjected to a statistical analysis using T-test. The comparative analysis of the two independent results confirmed that there is no significant difference between the two devices at 5% level of confidence (P>.05).