Química Nova
URI permanente para esta coleçãohttps://thoth.dti.ufv.br/handle/123456789/13323
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Resultados da Pesquisa
Item Teores de compostos bioativos em cafés torrados e moídos comerciais(Sociedade Brasileira de Química, 2010) Souza, Romilaine Mansano Nicolau de; Canuto, Gisele André Baptista; Dias, Rafael Carlos Eloy; Benassi, Marta de ToledoThe amounts of nicotinic acid, trigonelline, 5-CQA, caffeine, kahweol and cafestol in 38 commercial roasted coffees ranged from 0.02 to 0.04; 0.22 to 0.96; 0.14 to 1.20; 1.00 to 2.02; 0.10 to 0.80 and 0.25 to 0.55 g/100 g, respectively. Evaluation of color and content of thermo-labile compounds indicated similarity in roasting degree. Differences in the levels of diterpenes and caffeine, components less influenced by the roasting degree, could be mainly explained by the species used (arabica and robusta). Gourmet coffees showed high concentrations of diterpenes, trigonelline and 5-CQA and low levels of caffeine, indicating high proportion of arabica coffee.Item Main minerals and organic compounds in commercial roasted and ground coffee: an exploratory data analysis(Sociedade Brasileira de Química, 2021) Kalschnea, Daneysa Lahis; Silva, Nathalia Karen; Canan, Cristiane; Benassi, Marta de Toledo; Flores, Eder Lisandro Moraes; Leite, Oldair DonizeteCoffee is one of the most popular beverages in the world, however, little information is found regarding the mineral composition of commercial roasted and ground coffees (RG) and its correlation with organic bioactive compounds. 21 commercial Brazilian RG coffee brands - 9 traditional (T) and 12 extra strong (ES) roasted ones - were analyzed for the Cu, Ca, Mn, Mg, K, Zn, and Fe minerals, caffeine, 5-caffeoylquinic acid (5-CQA) and melanoidins contents. For minerals determination by flame atomic absorption spectrometry (FAAS), the samples were decomposed by microwave-assisted wet digestion. Caffeine and 5-CQA were determined by liquid chromatography and melanoidins by molecular absorption spectrometry. The minerals and organic compounds contents association in RG coffee was observed by a principal component analysis. The thermostable compounds (minerals and caffeine) were related to dimension 1 and 2, while 5-CQA and melanoidins were related to dimension 3, allowing for the T coffees segmentation from ES ones.Item Análises quali- e quantitativa de cafés comerciais via ressonância magnética nuclear(Sociedade Brasileira de Química, 2006) Tavares, Leila Aley; Ferreira, Antonio GilbertoCoffee is one of the beverages most widely consumed in the world and the "cafezinho" is normally prepared from a blend of roasted powder of two species, Coffea arabica and Coffea canephora. Each one exhibits differences in their taste and in the chemical composition, especially in the caffeine percentage. There are several procedures proposed in the literature for caffeine determination in different samples like soft drinks, coffee, medicines, etc but most of them need a sample workup which involves at least one step of purification. This work describes the quantitative analysis of caffeine using ¹H NMR and the identification of the major components in commercial coffee samples using 1D and 2D NMR techniques without any sample pre-treatment.