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Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/3743

Title: Effects of blanching and dehydration methods on the quality of moringa leaf powder used as herbal green tea
Authors: Tetteh, Olivia Naa Ayorkor
Issue Date: 11-Sep-2009
Abstract: In order to determine the best processing and preservation method that will minimize nutrient loss of Moringa leaves used for the production of herbal tea, the effect of blanching and three different drying methods on the nutritional and physicochemical composition of Moringa oleifera and Moringa stenopetala were studied. Part of the harvested leaves (both species) was panellisted to steam blanching and part Un- blanched, and three different drying methods (shade, solar and oven) applied. Parameters assessed were water insoluble ash (WIS), water soluble extractives (WSE), pH, stalks, 13-carotene, light petroleum extractives (LPE), polyphenolics, proximate analysis, zinc and iron using standard methods. Sensory evaluation was also carried out to determine the best processing method resulting in best sensorial properties. Results revealed that among the three drying methods (solar, shade and oven), oven drying at 60 °C for 6hrs resulted in the best nutritional and physicochemical properties of the Moringa leaf powder. Blanching had variable effects on processed tea leaves with significant (p < 0.05) reductions in crude ash contents and a significant increase in 13-carotene, fibre, WIS and pH values in both species. Sensory results showed that tea infusions of blanched and oven-dried leaf powder infusions received significantly higher sensory scores. Results also revealed that Moringa herbal green teas (mean scores ranging between 6.47 and 7.73) were preferred to the commercial green tea (mean score 5.87). It is therefore evident that different methods of processing could have an effect on the nutritional, physicochemical and sensorial properties of Moringa leaves and the overall acceptability by consumers.
Description: A thesis submitted to the Board of Postgraduate Studies, Kwame Nkrumah University of Science and Technology, Kumasi, in partial fulfilment of the requirements for the award of the Degree of Master of Science in Biochemistry,February-2009
URI: http://hdl.handle.net/123456789/3743
Appears in Collections:College of Science

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