Biblioteca do Café
URI permanente desta comunidadehttps://thoth.dti.ufv.br/handle/123456789/1
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Item 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 SantosA 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.Item 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 ToledoThe 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.Item 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 ToledoThe 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.