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1.
J Agric Food Chem ; 68(49): 14643-14651, 2020 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-33252222

RESUMO

In response to the need from the food industry for new analytical solutions, a fit-for-purpose quantitative 1H NMR methodology was developed to authenticate pure coffee (100% arabica or robusta) as well as predict the percentage of robusta in blends through the study of 292 roasted coffee samples in triplicate. Methanol was chosen as the extraction solvent, which led to the quantitation of 12 coffee constituents: caffeine, trigonelline, 3- and 5-caffeoylquinic acid, lipids, cafestol, nicotinic acid, N-methylpyridinium, formic acid, acetic acid, kahweol, and 16-O-methylcafestol. To overcome the chemical complexity of the methanolic extract, quantitative analysis was performed using a combination of traditional integration and spectral deconvolution methods. As a result, the proposed methodology provides a systematic methodology and a linear regression model to support the classification of known and unknown roasted coffees and their blends.


Assuntos
Coffea/química , Espectroscopia de Ressonância Magnética/métodos , Alcaloides/análise , Cafeína/análise , Coffea/classificação , Café/química , Culinária , Análise Discriminante , Diterpenos/análise , Contaminação de Alimentos/análise , Sementes/química , Sementes/classificação
2.
Food Res Int ; 121: 612-621, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31108788

RESUMO

In most previous studies, brewed coffee samples were served at specific serving temperatures for sensory evaluation. While several recent studies have illustrated that serving temperature does have an impact on sensory attribute intensities of brewed coffee, more elaboration is needed. By focusing on knowledge gaps between earlier studies, this study sought to determine whether and how sensory attributes of brewed coffee can vary as a function of serving temperature and coffee variety. In this study, 6 trained panelists rated intensities of 32 sensory attributes (3 appearances, 12 aromas, 2 tastes, 13 flavors, and 2 mouthfeels) with respect to brewed coffee samples, of each of three varieties (Ethiopian, Kenyan, and Colombian) served at four different serving temperatures: 70, 55, 40, and 25 °C, respectively. The results indicated that intensities of 18 and 7 attributes, respectively, differed significantly with serving temperature and coffee variety. A principal component analysis (PCA) showed the greater amount of data variation could be attributed to serving temperature (63.28%) rather than coffee variety (21.24%), much like the result of a hierarchical clustering analysis. Regression vector (RV) coefficients, determined by a factor score matrix of brewed coffee samples served at different temperatures, revealed that brewed coffee samples served at 70 and 55 °C were perceived differently from those served at 40 and 25 °C. In conclusion, the findings emphasize that sensory attributes of brewed coffee samples should be evaluated at multiple serving temperatures, both higher (70 to 55 °C) and lower (40 to 25 °C) ones, to better capture sensory attributes of brewed coffee than those from a traditional sensory evaluation. Further study is needed to characterize different coffee samples with respect to lessening an overwhelming effect of serving temperature.


Assuntos
Café/química , Temperatura Alta , Paladar , Coffea/química , Coffea/classificação , Café/classificação , Comportamento do Consumidor , Culinária , Aromatizantes/análise , Manipulação de Alimentos/métodos , Humanos , Odorantes/análise , Percepção , Extratos Vegetais/análise
3.
J Sci Food Agric ; 99(9): 4267-4275, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30816557

RESUMO

BACKGROUND: Silverskin is a by-product obtained from coffee roasting. It is characterized by a high content of dietary fibre, phenolic compounds and caffeine. The aim of this study was to assess the silverskin obtained from two species of Coffea (Arabica and Robusta) at three percentages (2%, 4%, or 6%) into cow whole-milk yogurt to raise the nutraceutical value of the products and to verify the bioaccessibility of bioactive compounds during the shelf-life of 3 weeks. RESULTS: The amount and origin of silverskin significantly influenced all the physicochemical parameters. Concerning the bioactive compounds, the highest levels were observed in yogurt supplemented with 6% of silverskin. Between the coffee species, Arabica yielded the highest 5-caffeoylquinic acid content and the strongest antioxidant activity, whereas Robusta gave the highest caffeine content. The digestion increased antioxidant activity in the yogurt, possibly because of greater accessibility of compounds. CONCLUSION: The results obtained highlighted that silverskin can be used in yogurt production to increase the nutraceutical value of the products and that the bioactive compounds are bioaccessible during the digestion process. The characteristics and bioaccessibility of the resulting yogurt were strongly correlated with the coffee species and with the percentage added. © 2019 Society of Chemical Industry.


Assuntos
Coffea/química , Suplementos Nutricionais/análise , Aditivos Alimentares/análise , Extratos Vegetais/análise , Iogurte/análise , Animais , Bovinos , Coffea/classificação , Leite/química , Sementes/química , Resíduos/análise
4.
J Texture Stud ; 50(2): 172-184, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30676645

RESUMO

When it comes to the sensory analysis of specialty coffees, it is necessary to discuss the protocol of tests of the Specialty Coffee Association (SCA) and the formation of Q-Graders as reliable parameters in the sensory analysis. However, the training of these Q-Graders and the use of the SCA protocol has generated discussions in the scientific community and demonstrated the importance of talking about the level of professional precision as well as the use of the protocol. This study sought to understand the relation of accuracy and efficiency of the Q-Graders and protocol in the sensory analysis of coffees. Three experiments were carried out to evaluate and test the hypotheses regarding the level of precision in relation to the shift, the number of samples and the judgment abilities of Q-Graders due to the quality of the specialty coffee and nonspecialty coffee. These three experiments were performed by seven Q-Graders in an isolated environment during three consecutive days with 137 specialty coffee samples and 7 nonspecialty coffee samples as defined by the SCA. The results indicate that the Q-Graders present high precision when evaluating excellent and outstanding coffees, as defined by the SCA. In addition, the effect of the shift did not exert fatigue on the Q-Graders. However, evaluation errors were made by the Q-Graders on very good coffee (77.00-80.00 points), which are considered as nonspecialty by the SCA, thus allowing a more in-depth discussion on what would be the boundary between a specialty and nonspecialty coffee. PRACTICAL APPLICATIONS: The article deals with the sensory evaluation process of coffees, and it has great importance to teaching and research institutions in Brazil, the largest producer, largest exporter and the country with the highest concentration of coffee scholars in the world. The article focuses on a new approach and a new way of looking at the sensory evaluation process of coffees, using the methodology of the Specialty Coffee Association to analyze the accuracy and efficiency of the Q-Graders.


Assuntos
Café/química , Análise de Alimentos/métodos , Qualidade dos Alimentos , Paladar , Brasil , Coffea/química , Coffea/classificação , Café/classificação , Humanos , Sementes
5.
Food Res Int ; 115: 227-233, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30599935

RESUMO

To produce specific desirable coffee blends, Coffea arabica and C. canephora are mixed each other, in some cases to suit consumer preference, but in others to reduce production costs. In this scenario, the aim of this work was to evaluate standard candidate reference materials (RMc) for analysis of different blends of roasted and ground coffee. For this purpose, we analyzed different percentages of C. arabica and C. canephora (100:0; 50:50; 25:75; and 0:100, respectively). These RMc samples were developed in a previous study with green coffee beans submitted to medium roasting. In this work, coffee species differentiation (C. arabica and C. canephora) was analyzed by real-time PCR, using specific primers previously developed, called ARA primers. The RMc material with 100% C. canephora did not present amplification, in contrast with the samples containing C. arabica, which all presented amplification. These results indicate the specificity of ARA primers for C. arabica and that the detection system assay can be used as a promising molecular tool to identify and quantify percentages of C. arabica in different coffee blends.


Assuntos
Coffea/genética , Café/genética , Reação em Cadeia da Polimerase em Tempo Real/métodos , Sementes/genética , Coffea/química , Coffea/classificação , Café/química , DNA de Plantas/análise , DNA de Plantas/genética , Análise de Alimentos/métodos , Manipulação de Alimentos/métodos , Sementes/química , Sementes/classificação
6.
Nutr Health ; 25(1): 3-7, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30392444

RESUMO

BACKGROUND:: Little independent information on the caffeine content of the popular Nespresso® coffee pod range exists. AIM:: To quantify the caffeine content of Nespresso® pod coffees. METHODS:: Initially, three serves (ristretto (S), espresso (M), lungo (L)) of two pod varieties (Livanto and Roma) were prepared on three different Nespresso® machines (2 × U-Delonghi (1 × 5 years since purchase (old), 1 × recently purchased (new)), 1 × new Lattissima Pro (alternate)) using two different batches (sleeves). Caffeine content was then determined via triplicate samples using high-performance liquid chromatography. Differences in content (i.e. serve size, machine or sleeve) were determined via an analysis of variance or paired sample t-tests. RESULTS:: Coffees prepared on different machines or pods from different sleeves did not influence the caffeine content (old = 63 ± 13, new = 60 ± 8, alternate = 60 ± 10 mg·serve-1; p = 0.537, sleeveA = 63 ± 11, sleeveB = 59 ± 9 mg·serve-1; p = 0.134). Less caffeine was delivered in S (51 ± 7 mg·serve-1) compared to larger sizes (M = 66 ± 7 and L = 66 ± 10 mg·serve-1). Subsequently, the caffeine content from two serve sizes (S and L) from 17 other varieties within the Nespresso® range was determined and compared to the manufacturer's values. Caffeine content (all pods) ranged from 19 to 147 mg·serve-1, and represented 51-162% of manufacturer's values. CONCLUSION:: Nespresso® consumers are exposed to variable amounts of caffeine, which often differ from the manufacturer's reports.


Assuntos
Cafeína/análise , Coffea/química , Café/química , Cromatografia Líquida de Alta Pressão/métodos , Coffea/classificação , Humanos , Especificidade da Espécie
7.
Artigo em Inglês | MEDLINE | ID: mdl-29704991

RESUMO

Coffee is a highly consumed beverage throughout the world. Its popularity derives from its organoleptic properties that are a result of the roasting process. Roasting greatly alters a coffee bean's composition and possibly its bioactivity. In the current study, green as well as roasted extracts from both Coffea arabica (Brazil and Decaf) and Coffea canephora (Robusta) species were tested for their antimutagenic activity using the Ames test. In addition, a compositional analysis was conducted to identify the main components, mainly Chlorogenic acid isomers (CGA) and derivatives present in the extracts using UHPLC-ESI(±) and HRMS/MS methods According to the results, all extracts exhibited strong antimutagenic activity against the oxidizing factor tert-Butyl hydroperoxide, a Reactive Oxygen Species-producing compound. Roasting had a distinct effect on the antimutagenic activity of coffee, enhancing it in the Brazil variety and having no effect in the Decaf and Robusta varieties. In addition, all coffee extracts exhibited reducing activity as well as the ability to scavenge (albeit differentially) both the superoxide and hydroxyl radicals, implying that their potential antimutagenic effect can be partially attributed to their free radical scavenging activity.


Assuntos
Antimutagênicos/farmacologia , Ácido Clorogênico/farmacologia , Coffea/classificação , Antimutagênicos/química , Antioxidantes/farmacologia , Ácido Clorogênico/química , Coffea/química , Temperatura Alta , Isomerismo , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Especificidade da Espécie , terc-Butil Hidroperóxido/metabolismo
8.
Food Chem ; 245: 603-612, 2018 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-29287415

RESUMO

Coffee bean extracts are consumed all over the world as beverage and there is a growing interest in coffee leaf extracts as food supplements. The wild diversity in Coffea (Rubiaceae) genus is large and could offer new opportunities and challenges. In the present work, a metabolomics approach was implemented to examine leaf chemical composition of 9 Coffea species grown in the same environmental conditions. Leaves were analyzed by LC-HRMS and a comprehensive statistical workflow was designed. It served for univariate hypothesis testing and multivariate modeling by PCA and partial PLS-DA on the Workflow4Metabolomics infrastructure. The first two axes of PCA and PLS-DA describes more than 40% of variances with good values of explained variances. This strategy permitted to investigate the metabolomics data and their relation with botanic and genetic informations. Finally, the identification of several key metabolites for the discrimination between species was further characterized.


Assuntos
Coffea/química , Café/química , Cromatografia Líquida de Alta Pressão , Coffea/classificação , Interpretação Estatística de Dados , Análise Discriminante , Espectrometria de Massas , Metabolômica
9.
Rocz Panstw Zakl Hig ; 68(4): 347-353, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29265388

RESUMO

Background: The roasting stage constitutes a key component in the manufacturing process of natural coffee because temperature elicits changes in bioactive compounds such as polyphenols and that Maillard-reaction compounds appear, thus affecting the product's sensory and antioxidant properties. Actual contents of these compounds may depend on which region the coffee is cultivated as well as the extent to which the beans are roasted Objectives: To determine polyphenols content and antioxidant activity in the 'Arabica' coffee type coming from various world regions of its cultivation and which have undergone industrial roasting. Also to establish which coffee, taking into account the degree of roasting (ie. light, medium and strong), is nutritionally the most beneficial Materials and Methods: The study material was natural coffee beans (100% Arabica) roasted to various degrees, as aforementioned, that had been cultivated in Brazil, Ethiopia, Columbia and India. Polyphenols were measured in the coffee beans by spectrophotometric means based on the Folin-Ciocalteu reaction, whereas antioxidant activity was measured colourimetrically using ABTS+ cat-ionic radicals Results: Polyphenol content and antioxidant activity were found to depend both on the coffee's origin and degree of roasting. Longer roasting times resulted in greater polyphenol degradation. The highest polyphenol concentrations were found in lightly roasted coffee, ranging 39.27 to 43.0 mg/g, whereas levels in medium and strongly roasted coffee respectively ranged 34.06 to 38.43 mg/g and 29.21 to 36.89 mg/g. Antioxidant activity however significantly rose with the degree of roasting, where strongly roasted coffee had higher such activity than lightly roasted coffee. This can be explained by the formation of Maillard-reaction compounds during roasting, leading then to the formation of antioxidant melanoidin compounds which, to a large extent, compensate for the decrease in polyphenols during roasting Conclusions: Polyphenols levels and antioxidant activities in the studied Arabica coffee beans that had undergone roasting depended on the cultivation region of the world. Longer roasting caused a significant decline in polyphenols compound levels (from 7.3% to 32.1%) in the coffee beans. Antioxidant activities of coffee increased with roasting, despite reduced levels of natural antioxidants. From a nutritional standpoint, the most favoured coffees are those lightly or medium roasted


Assuntos
Antioxidantes/análise , Coffea/química , Café/química , Manipulação de Alimentos/métodos , Polifenóis/análise , Coffea/classificação , Produtos Finais de Glicação Avançada , Temperatura Alta , Humanos , Sementes/química
10.
Food Res Int ; 99(Pt 1): 155-165, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28784472

RESUMO

A deeper knowledge of the chemical composition of coffee silverskin (CS) is needed due to the growing interest in its use as a food additive or an ingredient of dietary supplements. Accordingly, the aim of this paper was to investigate the metabolic profile of aqueous extracts of two varieties of CS, Coffee arabica (CS-A), Coffee canephora var. robusta (CS-R) and of a blend of the two (CS-b) and to compare it to the profile of Coffee arabica green coffee (GC). Chlorogenic acids, caffeine, furokauranes, and atractyligenins, phytotoxins not previously detected in CS, were either identified or tentatively assigned. An unknown compound, presumably a carboxyatractyligenin glycoside was detected only in GC. Caffeine and chlorogenic acids were quantified while the content of furokauranes and atractyligens was estimated. GC and CS were also characterized in terms of total polyphenols and antioxidant capacity. Differences in the metabolites distribution, polyphenols and antioxidant capacity in GC and CS were detailed.


Assuntos
Antioxidantes/análise , Cromatografia Líquida de Alta Pressão , Coffea/química , Análise de Alimentos/métodos , Metabolômica/métodos , Compostos Fitoquímicos/análise , Sementes/química , Espectrometria de Massas por Ionização por Electrospray , Toxinas Biológicas/análise , Atractilosídeo/análogos & derivados , Atractilosídeo/análise , Cafeína/análise , Ácido Clorogênico/análise , Coffea/classificação , Sementes/classificação
11.
BMC Plant Biol ; 16: 94, 2016 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-27095276

RESUMO

BACKGROUND: Drought is a widespread limiting factor in coffee plants. It affects plant development, fruit production, bean development and consequently beverage quality. Genetic diversity for drought tolerance exists within the coffee genus. However, the molecular mechanisms underlying the adaptation of coffee plants to drought are largely unknown. In this study, we compared the molecular responses to drought in two commercial cultivars (IAPAR59, drought-tolerant and Rubi, drought-susceptible) of Coffea arabica grown in the field under control (irrigation) and drought conditions using the pyrosequencing of RNA extracted from shoot apices and analysing the expression of 38 candidate genes. RESULTS: Pyrosequencing from shoot apices generated a total of 34.7 Mbp and 535,544 reads enabling the identification of 43,087 clusters (41,512 contigs and 1,575 singletons). These data included 17,719 clusters (16,238 contigs and 1,575 singletons) exclusively from 454 sequencing reads, along with 25,368 hybrid clusters assembled with 454 sequences. The comparison of DNA libraries identified new candidate genes (n = 20) presenting differential expression between IAPAR59 and Rubi and/or drought conditions. Their expression was monitored in plagiotropic buds, together with those of other (n = 18) candidates genes. Under drought conditions, up-regulated expression was observed in IAPAR59 but not in Rubi for CaSTK1 (protein kinase), CaSAMT1 (SAM-dependent methyltransferase), CaSLP1 (plant development) and CaMAS1 (ABA biosynthesis). Interestingly, the expression of lipid-transfer protein (nsLTP) genes was also highly up-regulated under drought conditions in IAPAR59. This may have been related to the thicker cuticle observed on the abaxial leaf surface in IAPAR59 compared to Rubi. CONCLUSIONS: The full transcriptome assembly of C. arabica, followed by functional annotation, enabled us to identify differentially expressed genes related to drought conditions. Using these data, candidate genes were selected and their differential expression profiles were confirmed by qPCR experiments in plagiotropic buds of IAPAR59 and Rubi under drought conditions. As regards the genes up-regulated under drought conditions, specifically in the drought-tolerant IAPAR59, several corresponded to orphan genes but also to genes coding proteins involved in signal transduction pathways, as well as ABA and lipid metabolism, for example. The identification of these genes should help advance our understanding of the genetic determinism of drought tolerance in coffee.


Assuntos
Adaptação Fisiológica/genética , Coffea/genética , Secas , Genes de Plantas/genética , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Brotos de Planta/genética , Coffea/classificação , Coffea/fisiologia , Café/genética , Café/fisiologia , Perfilação da Expressão Gênica/métodos , Regulação da Expressão Gênica de Plantas , Biblioteca Gênica , Ontologia Genética , Folhas de Planta/genética , Folhas de Planta/fisiologia , Brotos de Planta/fisiologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Especificidade da Espécie
12.
J Sci Food Agric ; 96(10): 3543-51, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26592362

RESUMO

BACKGROUND: Knowledge of the sensory profile of coffee quality, associated with genetic and environmental factors, is of utmost importance for the international market, as well as for the productive sector. In this context, the goal of this study was to classify the quality of Coffea arabica L., cv. Yellow Bourbon, according to different scores obtained through sensory evaluations based on the Specialty Coffee Association of America protocol (SCAA), and by means of decision trees resulting from applying the CHAID method (chi-square automatic interaction detection). To that end, we used a database with the sensory characteristics of cv. Yellow Bourbon and the environmental characteristics of the Mantiqueira de Minas region, State of Minas Gerais, Brazil. RESULTS: The method used exhibited promising results regarding accuracy and success rates in order to discriminate coffee sensory quality as a function of the production environment. The results obtained clearly show the effect of the coffee growing environment on the Yellow Bourbon variety, resulting in notable sensory differences in the beverage. CONCLUSION: It was possible to discriminate cv. Yellow Bourbon coffee samples, the sensory evaluations of which resulted in scores of ≥88 points, which are associated with growing environments at altitudes of ≥1200 m. © 2015 Society of Chemical Industry.


Assuntos
Altitude , Coffea/química , Café/química , Brasil , Coffea/classificação , Árvores de Decisões , Olfato , Paladar
13.
J Sci Food Agric ; 96(9): 3098-108, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26439192

RESUMO

BACKGROUND: Detailed knowledge of coffee production systems enables optimization of crop management, harvesting and post-harvest techniques. In this study, coffee quality is mapped as a function of coffee variety, altitude and terrain aspect attributes. The work was performed in the Zona da Mata, Minas Gerais, Brazil. RESULTS: A large range of coffee quality grades was observed for the Red Catuai variety. For the Yellow Catuai variety, no quality grades lower than 70 were observed. Regarding the terrain aspect, samples from the southeast-facing slope (SEFS) and the northwest-facing slope (NWFS) exhibited distinct behaviors. The SEFS samples had a greater range of quality grades than did the NWFS samples. The highest grade was obtained from an NWFS point. The lowest quality values and the largest range of grades were observed at lower altitudes. The extracts from the highest-altitude samples did not produce any low-quality coffee. CONCLUSIONS: The production site's position and altitude are the primary variables that influenced the coffee quality. The study area has micro-regions with grades ranging from 80 to 94. These areas have the potential for producing specialty coffees. © 2015 Society of Chemical Industry.


Assuntos
Bebidas/normas , Coffea/anatomia & histologia , Café/normas , Agricultura/métodos , Altitude , Análise de Variância , Bebidas/análise , Brasil , Coffea/química , Coffea/classificação , Café/química , Café/classificação , Qualidade dos Alimentos , Mapeamento Geográfico , Controle de Qualidade , Paladar
14.
Molecules ; 20(9): 16687-708, 2015 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-26389867

RESUMO

Compositions of fatty acid, amino acids, and volatile compound were investigated in green coffee beans of seven cultivars of Coffea robusta grown in Hainan Province, China. The chlorogenic acids, trigonelline, caffeine, total lipid, and total protein contents as well as color parameters were measured. Chemometric techniques, principal component analysis (PCA), hierarchical cluster analysis (HCA), and analysis of one-way variance (ANOVA) were performed on the complete data set to reveal chemical differences among all cultivars and identify markers characteristic of a particular botanical origin of the coffee. The major fatty acids of coffee were linoleic acid, palmitic acid, oleic acid, and arachic acid. Leucine (0.84 g/100 g DW), lysine (0.63 g/100 g DW), and arginine (0.61 g/100 g DW) were the predominant essential amino acids (EAAs) in the coffee samples. Seventy-nine volatile compounds were identified and semi-quantified by HS-SPME/GC-MS. PCA of the complete data matrix demonstrated that there were significant differences among all cultivars, HCA supported the results of PCA and achieved a satisfactory classification performance.


Assuntos
Aminoácidos Essenciais/análise , Coffea/química , Coffea/classificação , Ácidos Graxos/análise , Compostos Orgânicos Voláteis/análise , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Sementes/química
15.
J Agric Food Chem ; 63(19): 4815-26, 2015 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-25910038

RESUMO

The influence of green coffee genotype on the bioactive compounds and the in vitro antioxidant capacity against the principal reactive oxygen (ROO(•), H2O2, HO(•), and HOCl) and nitrogen (NO(•) and ONOO(-)) species of biological relevance was investigated. This is the first report on the capacity of green coffee to scavenge H2O2, HOCl, and NO(•). Variations in the contents of total chlorogenic acids (22.9-37.9 g/100 g), cinnamoyl-amino acid conjugates (0.03-1.12 g/100 g), trigonelline (3.1-6.7 g/100 g), and caffeine (3.9-11.8 g/100 g) were found. Hydrophilic extracts of Coffea canephora and Coffea kapakata were the most potent scavengers of ROO(•), H2O2, HO(•), NO(•), and ONOO(-) due to their chlorogenic acid contents, which were, on average, 30% higher than those found in Coffea arabica and Coffea racemosa. The results showed that genotype is a determinant characteristic in the bioactive compound contents and consequently in the antioxidant capacity of green coffee.


Assuntos
Coffea/química , Sequestradores de Radicais Livres/química , Extratos Vegetais/química , Espécies Reativas de Nitrogênio/química , Espécies Reativas de Oxigênio/química , Cafeína/química , Ácido Clorogênico/química , Coffea/classificação , Coffea/genética , Genótipo , Sementes/química , Sementes/classificação , Sementes/genética
16.
Food Chem ; 177: 330-8, 2015 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-25660894

RESUMO

Espresso coffee beverages prepared from pure origin roasted ground coffees from the major world growing regions (Brazil, Ethiopia, Colombia, India, Mexico, Honduras, Guatemala, Papua New Guinea, Kenya, Cuba, Timor, Mussulo and China) were characterized and compared in terms of their mineral content. Regular consumption of one cup of espresso contributes to a daily mineral intake varying from 0.002% (sodium; Central America) to 8.73% (potassium; Asia). The mineral profiles of the espresso beverages revealed significant inter- and intra-continental differences. South American pure origin coffees are on average richer in the analyzed elements except for calcium, while samples from Central America have generally lower mineral amounts (except for manganese). Manganese displayed significant differences (p<0.05) among the countries of each characterized continent. Intercontinental and inter-country discrimination between the major world coffee producers were achieved by applying canonical discriminant analysis. Manganese and calcium were found to be the best chemical descriptors for origin.


Assuntos
Coffea/química , Café/química , Minerais/análise , Ásia , Brasil , China , Coffea/classificação , Café/classificação , Colômbia , Análise Discriminante , Etiópia , Índia , Indonésia , Quênia , México , Papua Nova Guiné , Sementes/química , Sementes/classificação
17.
J Sci Food Agric ; 95(11): 2192-200, 2015 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-25258213

RESUMO

BACKGROUND: The aim of this study is to investigate the feasibility of a 'holistic' approach, using near infrared (NIR) spectroscopy and electronic devices (electronic nose and electronic tongue), as instrumental tools for the classification of different coffee varieties. Analyses were performed on green coffee, on ground roasted coffee and on coffee beverage. Principal component analysis was applied on spectral and sensory data to uncover correlations between samples and variables. After variable selection, linear discriminant analysis was used to classify the samples on the basis of the three coffee classes: Robusta, natural Arabica and washed Arabica. RESULTS: Linear discriminant analysis demonstrates the practicability of this approach: the external test set validation performed with NIR data showed 100% of correctly classified samples. Moreover, a satisfying percentage of correct classification in cross-validation was obtained for the electronic devices: the average values of correctly classified samples were 81.83% and 78.76% for electronic nose and electronic tongue, respectively. CONCLUSION: NIR spectroscopy was shown to be a very reliable and useful tool to classify coffee samples in a fast, clean and inexpensive way compared to classical analysis, while the electronic devices could assume the role of investigating techniques to depict the aroma and taste of coffee samples.


Assuntos
Coffea , Café/química , Eletrônica/métodos , Odorantes , Sementes/química , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Paladar , Coffea/classificação , Café/classificação , Nariz Eletrônico , Humanos , Nariz , Análise de Componente Principal , Especificidade da Espécie , Língua
18.
Guang Pu Xue Yu Guang Pu Fen Xi ; 34(6): 1688-92, 2014 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-25358189

RESUMO

Spectroscopic analysis was applied to the determination of the nutrient quality of ground, instant and chicory coffees. By using inductively coupled plasma atomic emission spectrometry (ICP-ES), nine mineral elements were determined in solid coffee samples. Caffeine was determined by ultraviolet (UV) spectrometry and organic matter was investigated by Fourier transform infrared (FTIR) spectroscopy. Oxidation-reduction titration was utilized for measuring the oxalate. The differences between ground coffee and instant coffee was identified on the basis of the contents of caffeine, oxalate and mineral elements. Experimental evidence showed that, caffeine in instant coffee was 2-3 times higher than in ground coffee. Oxalate in instant coffee was significantly higher in ground coffee. Mineral elements of Mg, P and Zn in ground coffee is lower than in instant coffee, while Cu is several times higher. The mineral content in chicory coffee is overall lower than the instant coffee. In addition, we determined the content of Ti for different types of coffees, and simultaneously detected the elements of Cu, Ti and Zn in chicory coffee. As a fast detection technique, FTIR spectroscopy has the potential of detecting the differences between ground coffee and instant coffee, and is able to verify the presence of caffeine and oxalate.


Assuntos
Cafeína/análise , Coffea/classificação , Café/química , Ácido Oxálico/análise , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier , Oligoelementos/análise
19.
Food Funct ; 5(8): 1718-26, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25014672

RESUMO

The effect of roasting of coffee beans and the extraction of ground coffee with different volumes of hot pressurised water on the caffeine and the total caffeoylquinic acids (CQAs) content of the resultant beverages was investigated. While caffeine was stable higher roasting temperatures resulted in a loss of CQAs so that the caffeine/CQA ratio was a good marker of the degree of roasting. The caffeine and CQA content and volume was determined for 104 espresso coffees obtained from coffee shops in Scotland, Italy and Spain, limited numbers of cappuccino coffees from commercial outlets and several instant coffees. The caffeine content ranged from 48-317 mg per serving and CQAs from 6-188 mg. It is evident that the ingestion of 200 mg of caffeine per day can be readily and unwittingly exceeded by regular coffee drinkers. This is the upper limit of caffeine intake from all sources recommended by US and UK health agencies for pregnant women. In view of the variable volume of serving sizes, it is also clear that the term "one cup of coffee" is not a reproducible measurement for consumption, yet it is the prevailing unit used in epidemiology to assess coffee consumption and to link the potential effects of the beverage and its components on the outcome of diseases. More accurate measurement of the intake of coffee and its potentially bioactive components are required if epidemiological studies are to produce more reliable information.


Assuntos
Cafeína/análise , Ácido Clorogênico/análise , Café/química , Coffea/química , Coffea/classificação , Itália , Limite de Detecção , Ácido Quínico/análogos & derivados , Ácido Quínico/análise , Recomendações Nutricionais/legislação & jurisprudência , Escócia , Espanha
20.
Food Chem ; 141(1): 98-104, 2013 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-23768333

RESUMO

Statistical interpretation of the concentrations of 59 elements, determined using solution based inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma emission spectroscopy (ICP-AES), was used to establish the provenance of coffee samples from 15 countries across five continents. Data confirmed that the harvest year, degree of ripeness and whether the coffees were green or roasted had little effect on the elemental composition of the coffees. The application of linear discriminant analysis and principal component analysis of the elemental concentrations permitted up to 96.9% correct classification of the coffee samples according to their continent of origin. When samples from each continent were considered separately, up to 100% correct classification of coffee samples into their countries, and plantations of origin was achieved. This research demonstrates the potential of using elemental composition, in combination with statistical classification methods, for accurate provenance establishment of coffee.


Assuntos
Coffea/química , Espectrometria de Massas/métodos , Oligoelementos/análise , Coffea/classificação , Café/química , Café/classificação , Análise Discriminante , Análise de Componente Principal , Controle de Qualidade
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