Characterization of Local Honey and Development of Honey Based Extrudate
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Date
2014
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Addis Ababa University
Abstract
Ethiopia ranks first in Africa and tenth in the world in honey production. This study aimed at developing honey-based extruded ready-to-eat products and determining the physico-chemical parameters of honey from three distinct areas of Ethiopia. Accordingly, honey samples obtained from Oromiya (yellow), Tigray (white) and Gonder (red) areas were analyzed. A blend of rice with wheat (60:40%) flour was first formulated, and thereafter, 5%, 10% and 15% of this composite flour was replaced by the same amount of honey for the preparation of extruded snack. The design experiment produced 20 different combinations using Response Surface Methodology to investigate the effect of the response variables, lateral expansion, bulk density, color, water absorption and solubility index characteristics. The effect of each honey sample was studied separately and multiple regression equations were obtained to describe the effects of each variable on product responses. The results of the yellow honey analysis showed that it has 22%moisture, 0.273%ash, 4.1pH, 31.5%fructose, 33.9%glucose, 0.7%sucrose, 2.7%maltose, 7meq/kg free acidity, 0.52%water insoluble matters and 0.61μS/cm electrical conductivity; White honey contained 19%moisture, 0.155%ash, 4.1pH, 35.9%fructose, 31.5%glucose, 1.4%sucrose, 0.0%maltose, 5meq/kg free acidity, 0.56%water insoluble matters and 0.41μS/cm electrical conductivity. Red honey contained 19%moisture, 0.039%ash, 4.2pH, 35.4%fructose, 31.4%glucose, 3.3%sucrose, 4.6%maltose, 6meq/kg free acidity, 0.62%water insoluble matters and 0.22μS/cm electrical conductivity. For the purpose of optimization, the process parameters of 115 to 135oC BT, 270 to 350rpm SS and 5 to 15% honey were selected as independent variables. Results showed that increasing the barrel temperature resulted in extrudate with higher expansion, water absorption index, a* value and lower bulk density and L* and b* values. Increasing screw speed resulted in higher expansion, water solubility index, L value and lower bulk density whereas, increasing honey proportion of feed composition resulted in higher a* value, bulk density, water solubility index and lower expansion, water absorption index and L*value. The graphical optimization studies resulted in temperatures of 124.68, 125.12, 124.19oC, screw speed of 310.35, 309.88, 309.79rpm and amount of honey 9.69, 9.89, 9.66% as optimum variables for yellow, white and red honeys respectively. This is similar with the value 125oC BT, 310rpmSS and 10%honey obtained by panelists during sensory analysis for all types of samples. Accordingly white honey-based extrudate was found to be the best and addition of this honey upto 10% was selected as ideal for snack making.
Key word: Extrusion, Extrudate, Honey, Response surface methodology
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Keywords
Extrusion, Extrudate, Honey, Response surface methodology