Chemical Profiling to Discriminate Geographical Origin and Varietal  Type of Teff (Eragrostis tef (Zucc)) grown in the Western Part of  Amhara Regional State, Ethiopia

Chaltu Reta

dc.contributor.author	Chaltu Reta
dc.date.accessioned	2023-07-12T10:14:12Z
dc.date.available	2023-07-12T10:14:12Z
dc.date.issued	2023-07
dc.identifier.uri	http://ir.bdu.edu.et/handle/123456789/15491
dc.description.abstract	Teff is one of the most stable food crops that originated and diversified in Ethiopia. It is highly preferred by Ethiopian people for consumption as food, especially since it has good nutritional content and cereal grains. Discriminating the geographical origins of foodstuff is a good mechanism to get the right product for consumers and traders. The objective of this study was to profile the chemical composition and assess the nutritional qualities of teff and develop chemometric models to find out marker chemicals in teff cereal grain grown in the Amhara regional state, Ethiopia. For this study, about 72 teff samples were directly collected from farmers in the 2020 harvesting season in the three administrative zones (East Gojjam, West Gojjam, and Awi zones) of Amhara Regional state, Ethiopia. The total phenolic content (TPC), and, total flavonoid content (TFC), for selected mineral and fatty acid compositions, were investigated following the standard procedures. Statistical packages were used to discriminate the region's teff samples based on the studied chemical constituents. Based on the Gallic acid equivalent, the TPC was in the range of 46.21 - 133.3 mg/100g G.A.E across the sub-district. In the current study, the TFC expressed as catechin equivalent, CE (under the alkaline condition) and quercetin equivalent, QE (under the acidic condition) was found to be in the ranges of 7.6 -57.3 mg C.E and 15.4 -113.1 mg Q.E per 100 g of teff sample. ANOVA result shows that there was a significant variation in data of TPC and TFC. Based on the hierarchical cluster analysis (HCA) and biplots teff samples were clustered into their geographical origins. In biplot analysis, the first two principal components explained a total variation of about 87.2% in the data set. Concerning the mineral composition, the average concentration of major elements ranged from 203.8- 3164.1 mg/kg of the teff sample with K > Mg > Ca > Na. The mean concentrations of the trace metals in the teff samples collected from the three sampling zones can be ordered as 662.9 to 2.1 mg/ kg of teff samples with Fe > Mn >Zn > Cu > Cr > Ni > Co. In principal component analysis (PCA), the first two principal components explained 82.8% of the total variation in the data. Linear discriminant analysis (LDA) for the classification of teff samples was used, and two discriminant ii functions were computed, where the first accounted for 69% and the second 31% of the variance present in the data. The most discriminate elements in the teff samples were Mg, Ca, Fe, Mn, and, Zn. The discriminant elements for the Awi zone were Ca and Fe whereas the most discriminant elements for West Gojjam were Cr and that of East Gojjam were Ni and Na. Based on the varieties of teff samples Tseday variety was distinguished from Kuncho by its higher content of Ca and Fe. On the other hand, the concentration of fatty acid in teff cereal grains from three zones are ordered Palmitic acid > Oleic acid > Linoleic acid > Stearic acid > Sciadonic acid >Azelaiacid > Trans vaccenic acid > Capric acid. The total average concentration of fatty acid content in teff samples varied from 739.85 to 938.06 mg/100g across the districts. In the principal component analysis, component 1 accounted for 44% while the second 22% of the variation in the teff data. Linear discriminant analysis was applied to construct classification models for teff grains cultivated in the studied three zones and two discriminant functions were computed, 98.6% of samples were correctly classified into their respective production zone Oleic acid, Linoleic acid, Palmitic acid, and Stearic acid were identified fatty acids and the most discriminating compounds among the production zones. Stearic acid, Trans vaccenic acid, linoleic acid, Azelaic acid, and, Capric acid are the fatty acids that discriminate teff samples from East Gojjam to West Gojjam zones while, Palmitic acid, Palmitoleic acid, and Oleic acid discriminate the Awi zone teff samples from the other two zones. Keywords: Teff, polyphenol, Fatty acid, Element, Geographical Origin, Amhara Ethiopia	en_US
dc.language.iso	en_US	en_US
dc.subject	Chemistry	en_US
dc.title	Chemical Profiling to Discriminate Geographical Origin and Varietal Type of Teff (Eragrostis tef (Zucc)) grown in the Western Part of Amhara Regional State, Ethiopia	en_US
dc.type	Dissartation	en_US