Navegando por Autor "Dias, Rafael Carlos Eloy"

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Bioactive compounds in blends of coffee defects originating from the harvesting
(Universidade Federal de Lavras, 2023-01-11) Dias, Rafael Carlos Eloy; Opitz, Sebastian Ed Wieland; Yeretzian, Chahan
A coffee crop may consist of up to 1/5 of defective beans and finding a suitable destination for this material is economically interesting. Many coffee industries collect the selections - material containing coffee defects - and blend them with non-defective coffee fruits in specific proportions to obtain a marketable product. Studies on the composition of selections are scarce. Hydro- and liposoluble bioactive compounds were determined in five types of roasted and ground selections of coffee Arabica and in healthy Arabica and Robusta coffee species throughout an optimized HPLC-UV/Vis-MS-based method. Nicotinic acid and 4-CQA were not detected. Black and sour beans seem to increase the level of caffeine (variation from 1.3 to 2.4 g 100 g-1 of sample) in the selections. The occurrence of defects decreases the level of 5-CQA, the main representative chlorogenic acid. Trigonelline content is high in Arabica coffee, and the presence of defects does not promote a clear variation in its amount. Kahweol concentration (~74.6 to 76.9 mg g-1 of oil) was practically the same up the Arabica sample set; this diterpene was absent in Robusta coffee. Cafestol (variation between 12.4 and 16.4 mg g-1 of oil) is a good quality indicator. Kahweol and 16-O-methyl cafestol are species indicators, and caffeine can point out the species of coffee. PCA revealed that sour beans were associated with the presence of kahweol, while cafestol and trigonelline were correlated to the occurrence of coffee skin. The higher the proportion of black beans, the more balanced the contents of water-soluble and liposoluble compounds.
Discrimination of coffee species using kahweol and cafestol: effects of roasting and of defects
(Editora UFLA, 2010-01) Campanha, Fernanda Gonçalves; Dias, Rafael Carlos Eloy; Benassi, Marta de Toledo
The two most commercialized coffee species worldwide are: Coffea arabica L. (arabica) and Coffea canephora Pierre ex A. Froehner (robusta). Since these coffees differ in their commercial value and acceptability, adulteration and mislabeling are major concerns. The diterpenes kahweol and cafestol are considered potential indicators of conilon coffee addition, as they are present in different contents in the species. The degree of roasting and the presence of defective beans may affect the theor of several coffee constituents. The aim of this work was to evaluate the possibility of discriminating the coffee species arabica and robusta through their kahweol and cafestol contents. Samples of arabica, robusta, and of their blends, with different amounts of defects and degrees of roasting (light, medium and dark) were studied. After direct saponification and extraction with terc-butyl methyl ether, the samples were analyzed by reverse-phase HPLC with UV detection. The kahweol content varied between 661 and 923 mg/100 g in the arabica coffee, and its presence was not observed in the conilon. Cafestol ranged from 360 to 478 mg in arabica, and from 163 to 275 mg/100 g in conilon coffee. The addition of conilon coffee reduced diterpene contents, but this effect varied according to the amount of defects and roasting degrees. A higher intensity roast did not affect diterpene degradation. No differences in the kahweol and cafestol levels, comparing defective or regular beans, were observed. In the analysis of coffee samples with different degrees of roasting and defects, the parameters kahweol and cafestol showed potential for discriminating between the species.
Kahweol and cafestol in coffee brews: comparison of preparation methods
(Universidade Federal do Ceará, 2020) Wuerges, Karla Leticia; Dias, Rafael Carlos Eloy; Viegas, Marcelo Caldeira; Benassi, Marta de Toledo
The profile of bioactive compounds in coffee brews depends on the coffee bean species and varieties, harvesting and post-harvesting practices, roasting processes, and also on the brewing method. The present research aimed to study the contents of cafestol and kahweol - coffee diterpenes with a known impact on human health – comparing coffee beverages prepared using common brewing methods (filtered, espresso, and instant coffee brews). Filtered (cloth-filtered and paper-filtered), espresso and instant brews were obtained from a medium-roasted Coffea arabica coffee (NY 2). Five genuine replicates of each coffee brew were prepared, and the extracts were lyophilized. A validated UPLC-based method provided the content of diterpenes. The results were reported in mg of diterpene per g of solids or per a standard dose of 50 mL of coffee brew. Solids content of coffee brews ranged from 2.06 to 2.46 g 100 mL-1. All coffee brews presented low diterpene contents: 0.05 to 0.16 mg of kahweol and 0.11 to 0.14 mg of cafestol 50 mL-1. Instant coffee brew showed the lowest content of kahweol and absence of cafestol; this reduction was related to the production process of soluble coffee. Diterpenes content was similar in espresso and paper-filtered brews. The cloth-filtered coffee had lower solids content, but higher levels of diterpenes (in mg g-1 of solids). Similar cafestol and kahweol contents (mg 50 mL-1) were observed in filtered and espresso brews.
Metodologia para análise simultânea de ácido nicotínico, trigonelina, ácido clorogênico e cafeína em café torrado por cromatografia líquida de alta eficiência
(Sociedade Brasileira de Química, 2006) Alves, Sandriel Trindade; Dias, Rafael Carlos Eloy; Benassi, Marta de Toledo; Scholz, Maria Brígida dos Santos
A reverse phase liquid chromatography method was developed for simultaneous determination of trigonelline, caffeine, nicotinic and chlorogenic (5-CQA) acids in roasted coffee. A gradient of acetic acid/acetonitrile was used as mobile phase and detection was carried out in the UV. The samples were extracted with acetonitrile/water (5:95 v/v) at 80 ºC/10 min. Good recovery (89 to 104%), repeatability and linearity were obtained. Detection limits of 0.01, 0.15, 0.04 and 0.04 mg mL-1 were observed for nicotinic acid, trigonelline, 5-CQA and caffeine. The method, applied to arabica and robusta coffees with different degrees of roasting, was efficient and fast (~35 min) and also allowed identification of cinnamic acids.
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 Toledo
The 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.