Browsing by Author "Davrieux, Fabrice"

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    Fat Content and Fatty Acid Profiles of Shea Tree (Vitellaria paradoxa subspecies nilotica) Ethno-Varieties in Uganda
    (Forests, Trees and Livelihoods, 2012) Gwali, Samson; Nakabonge, Grace; Okullo, John Bosco Lamoris; Eilu, Gerald; Forestier-Chiron, Nelly; Piombo, Georges; Davrieux, Fabrice
    Fat content and fatty acid composition are important nutritional properties of shea fruits. Farmers in Uganda report the presence of local shea tree ethno-varieties, but it is necessary to investigate their relative fat content and fatty acid composition to evaluate the economic importance of these ethno-varieties. Near infrared spectrophotometry (NIRS) was used to determine the fat content as well as the fatty acid composition of 44 ethno-varieties. Wet chemistry (soxtec petroleum – ether fat extraction and gas chromatography) methods were used to validate the results from NIRS. Fat content ranged from 43.9% to 58.4% while fatty acid composition was dominated by oleic (47–62%) and stearic acid (25–38%). Other fatty acids present were palmitic, vaccenic, linoleic, linolenic and arachidic acids. There was no significant difference in stearic, palmitic and oleic acid composition between ethno-varieties. However, significant variation of fat content, vaccenic and linoleic acids was observed between some ethno-varieties, perhaps due to locality, climatic and tree-to-tree differences. These findings can be utilized for the selection of ethno-varieties that are suitable for commercial production of shea oil in Uganda.
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    Predicting Sweepotato Sensory Attributes Using DigiEye and Image Analysis as a Breeding Tool
    (RTBfoods, 2022) Nakatumba-Nabende, Joyce; Nabiryo, Ann Lisa; Babirye, Claire; Tusubira, Jeremy Francis; Katumba, Andrew; Murindanyi, Sudi; Mutegeki, Henry; Nantongo, Judith; Sserunkuma, Edwin; Nakitto, Mariam; Ssali, Reuben; Davrieux, Fabrice
    The objective of the work was to develop, test and evaluate a color and mealiness classification model based on images of sweetpotato roots. A total of 3018 images were collected from 950 samples from October 2021 to November 2022. The captured image data samples were harvested from several sites, including Namulonge, Arua, Bulindi, Nassari, Serere, Rwebitaba, Iganga, Kabarole, Mbale, Mpigi, Busia, Kamuli, Hoima, Kabale and Kenya. Calibrations were done using reference data collected by a sensory panel. Up to twelve cooked roots per genotype were used for sensory evaluation of traits per session. Calibrations used various linear and non-linear models. Using linear regression, high performances were observed of the calibration for orange color intensity (R2 = 0.92, Mean Squared Error (MSE) =0.58), suggesting that the model is sufficient for field application. For mealiness-by-hand and positive area, the best model has a Mean Absolute Error (MAE) of 2.16 and 9.01 respectively