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Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/4005

Title: Thermal properties of selected species of banana grown in Ghana
Authors: Ofori, Hayford
Keywords: Gros michel ‘asante kwadu’
Medium cavendish ‘broni kwadu’
Thermal conductivity
Specific heat
Thermal diffusivity
Bulk density
Moisture content
Issue Date: 19-Jun-2011
Abstract: Banana (Musa acuminata) is an important fruit eaten by most Ghanaians in raw state. The fruit has a very short life span after ripening, hence most are discarded during bumper harvest. Processing will increase its shelf-life and also add value to the product. In order to design equipment, facilities and determine the amount of heat to be added or removed from banana during processing, knowledge of thermal properties of these locally grown bananas of which specific heat, thermal conductivity and thermal diffusivity are vital. The selected varieties for the study were dried to moisture content (MC) ranging from 18.5 – 50.0%wb for gros michel and 34.4 – 65.9 %wb for the medium cavendish. Specific heat was measured by the method of mixtures while the thermal conductivity was measured by the line heat source probe method. Thermal diffusivity was then calculated from the experimental results obtained from specific heat, thermal conductivity and bulk density. Bulk density was measured by the mass per unit change in volume of the sample. The bulk densities for both varieties of banana were found to be in a range of 1376.2 – 1130.0 kg. m-3 and 1233.5 -1065.3 kg. m-3 for the gros michel and medium cavendish varieties respectively, which was found to decrease in with increasing MC. The coefficients of determination were 94.1% and 96.4% respectively for the gros michel and medium cavendish. The specific heat for gros michel variety ranged from 1574 – 2506.8 Jkg-1 oC-1 and that of the medium cavendish variety was 1982.9 – 2970.6 J kg-1 oC-1. The coefficients of determination were 95.4% and 99.9% for the gros michel and medium cavendish varieties of banana respectively. The thermal conductivity of gros michel varied from 0.249 – 0.458Wm-1 oC-1 and that of the medium cavendish also varied from 0.317 – 0.543 Wm-1 oC-1. The LSD and coefficient of determination were 0.0091 and 0.0084; and 98.1% and 97.2% for gros michel and medium cavendish respectively. The thermal diffusivity range for gros michel was 1.15 х10-7–1.62 х10-7m2s-1 and that of the medium cavendish also ranged from 1.29 х10-7-1.7х10-7m2s-1. Specific heat, thermal conductivity and thermal diffusivity were found to increase with increasing MC for both varieties. The effects of MC on all parameters studied were significant at p ≥ 0.05. Regression equations of second order of polynomials were established which could be used to reasonably estimate the values of bulk density, specific heat, thermal conductivity and thermal diffusivity respectively.
Description: A Thesis submitted to the Department of Agricultural Engineering,Kwame Nkrumah University of Science and Technology in partial fulfillment of the requirement for the degree of Master of Science in Food and Postharvest Engineering, 2011
URI: http://hdl.handle.net/123456789/4005
Appears in Collections:College of Engineering

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