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1.
Molecules ; 26(13)2021 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-34198992

RESUMO

Wet coffee processing generates a large amount of coffee pulp waste that is mostly disposed of in the processing units. To reduce this waste and the associated environmental burden, an alternative strategy would be to exploit the coffee pulp to produce a durable and stable consumable product. Accordingly, a puree produced from Robusta coffee pulp was investigated in relation to its physicochemical and sensory properties. After thermal and chemical stabilization, the obtained puree (pH 3.6) was found to exhibit a multimodal particle size distribution, shear-thinning behavior, and lower discoloration, as well as an antioxidant capacity of 87.9 µmolTE/gDM. The flavor of the puree was examined by sensory evaluation and the corresponding analyses of aroma-active volatile compounds, as determined using aroma extract dilution analyses (AEDA) and gas chromatography-mass spectrometry/olfactometry (GC-MS/O). The puree was characterized by dominant fruity (4.4), floral (3.4), citrusy (3.3) and hay-like (3.3) odor impressions. The aroma-active compounds were predominantly aldehydes, acids, and lactones, whereby (E)-ß-damascenone, geraniol, 4-methylphenol, 3-hydroxy-4,5-dimethylfuran-2(5H)-one, and 4-hydroxy-3-methoxybenzaldehyde exhibited the highest flavor dilution (FD) factor (1024), thereby indicating their high impact on the overall aroma of the puree. This study demonstrates an approach to stabilize coffee pulp to produce a sweet, fruity puree with comparable physical properties to other fruit purees and that can be used as a new and versatile flavoring ingredient for various food applications.


Assuntos
Café/química , Odorantes/análise , Compostos Orgânicos Voláteis/análise , Café/classificação , Cromatografia Gasosa-Espectrometria de Massas , Estrutura Molecular , Olfatometria , Extratos Vegetais/análise , Extratos Vegetais/química , Compostos Orgânicos Voláteis/química
2.
J Sci Food Agric ; 101(11): 4705-4714, 2021 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-33491774

RESUMO

BACKGROUND: Specialty coffee fascinates people with its bountiful flavors. Currently, flavor descriptions of specialty coffee beans are only offered by certified coffee cuppers. However, such professionals are rare, and the market demand is tremendous. The hypothesis of this study was to investigate the feasibility to train machine learning (ML) and deep learning (DL) models for predicting the flavors of specialty coffee using near-infrared spectra of ground coffee as the input. Successful model development would provide a new and objective framework to predict complex flavors in food and beverage products. RESULTS: In predicting seven categories of coffee flavors, the models developed using the ML method (i.e. support vector machine) and the deep convolutional neural network (DCNN) achieved similar performance, with the recall and accuracy being 70-73% and 75-77% respectively. Through the proposed visualization method - a focusing plot - the potential correlation among the highly weighted spectral region of the DCNN model, the predicted flavor categories, and the corresponding chemical composition are presented. CONCLUSION: This study has proven the feasibility of applying ML and DL methods on the near-infrared spectra of ground coffee to predict specialty coffee flavors. The effective models provided moderate prediction for seven flavor categories based on 266 samples. The results of classification and visualization indicate that the DCNN model developed is a promising and explainable method for coffee flavor prediction. © 2021 Society of Chemical Industry.


Assuntos
Café/química , Aprendizado Profundo , Aromatizantes/química , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Café/classificação , Humanos , Redes Neurais de Computação , Paladar
3.
Lett Appl Microbiol ; 63(1): 25-9, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27203680

RESUMO

UNLABELLED: The objective of this study was to evaluate the effect of different caffeine concentrations (0-4%) on (i) lag phase prior to growth, (ii) growth rates and (iii) ochratoxin A (OTA) production by strains from the Aspergillus section Circumdati and Aspergillus section Nigri groups, isolated from coffee, when grown on a conducive medium at 0·98 water activity and 30°C. The lag phases prior to growth increased with caffeine concentration. A strain of Aspergillus niger and Aspergillus carbonarius were the most sensitive to caffeine with growth being inhibited by <1% caffeine. For strains of Aspergillus westerdijkiae, Aspergillus ochraceus and Aspergillus steynii, although growth was inhibited significantly, some growth (10-15% of controls) occurred in 4% caffeine. OTA production was significantly inhibited by only 0·5% caffeine for strains of A. westerdijkiae, A. niger and A. carbonarius. For A. steynii at least 1·5% caffeine was required to inhibit OTA production. In contrast, for the strain of A. ochraceus there was a stimulation of OTA at 3% with a reduction at 4% caffeine. These results are discussed in the context of the different concentrations of caffeine found in Arabica and Robusta coffee and the development of minimization strategies. SIGNIFICANCE AND IMPACT OF THE STUDY: Arabic (0·6%) and Robusta coffee (4%) have significantly different amounts of endogenous caffeine. The growth of six ochratoxigenic fungi which contaminate coffee with ochratoxin A (OTA) had differential tolerance/sensitivity to concentrations of caffeine in vitro in this range. However, low concentrations of caffeine (<0·5%) was inhibitory to OTA production. These results are discussed in the context of the potential for using such information for the design of minimization strategies to control mycotoxin production in such products.


Assuntos
Aspergillus/crescimento & desenvolvimento , Aspergillus/metabolismo , Cafeína/farmacologia , Coffea/microbiologia , Café/metabolismo , Ocratoxinas/biossíntese , Aspergillus/classificação , Café/classificação , Água
4.
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
5.
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
6.
Sensors (Basel) ; 14(9): 17770-85, 2014 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-25254303

RESUMO

This paper describes a new method based on a voltammetric electronic tongue (ET) for the recognition of distinctive features in coffee samples. An ET was directly applied to different samples from the main Mexican coffee regions without any pretreatment before the analysis. The resulting electrochemical information was modeled with two different mathematical tools, namely Linear Discriminant Analysis (LDA) and Support Vector Machines (SVM). Growing conditions (i.e., organic or non-organic practices and altitude of crops) were considered for a first classification. LDA results showed an average discrimination rate of 88% ± 6.53% while SVM successfully accomplished an overall accuracy of 96.4% ± 3.50% for the same task. A second classification based on geographical origin of samples was carried out. Results showed an overall accuracy of 87.5% ± 7.79% for LDA and a superior performance of 97.5% ± 3.22% for SVM. Given the complexity of coffee samples, the high accuracy percentages achieved by ET coupled with SVM in both classification problems suggested a potential applicability of ET in the assessment of selected coffee features with a simpler and faster methodology along with a null sample pretreatment. In addition, the proposed method can be applied to authentication assessment while improving cost, time and accuracy of the general procedure.


Assuntos
Café/classificação , Análise Discriminante , Máquina de Vetores de Suporte , Inteligência Artificial , Café/normas , Eletrônica , Humanos , México
7.
J Chromatogr A ; 1731: 465171, 2024 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-39059306

RESUMO

This paper presents a study that assesses the application of chemometrics for classifying coffee samples in a quality control context. High-resolution and accurate mass measurements were utilized as input for pixel-based orthogonal partial least squares discriminant analysis (OPLS-DA) models. The compositional data were acquired through a fully automated workflow combining headspace solid-phase microextraction and gas chromatography-high-resolution mass spectrometry (GC-HRMS) using an FT-Orbitrap® mass analyzer. A workflow centered on accurate mass measurements was successfully utilized for group-type analysis, offering an alternative to methods relying solely on MS similarity searches. The predictive models underwent thorough evaluation, demonstrating robust multivariate classification performance. Five key coffee attributes, bitterness, acidity, body, intensity, and roasting level were successfully predicted using GC-HRMS data. The results revealed strong predictive accuracy across all models, ranging from 88.9 % (bitterness) to 94.4 % (roasting level). This study represents a significant advancement in automating methods for coffee quality control, notably increasing the predictive ability of the models compared to existing literature.


Assuntos
Café , Cromatografia Gasosa-Espectrometria de Massas , Microextração em Fase Sólida , Café/química , Café/classificação , Cromatografia Gasosa-Espectrometria de Massas/métodos , Microextração em Fase Sólida/métodos , Análise Discriminante , Análise dos Mínimos Quadrados , Quimiometria/métodos , Estudo de Prova de Conceito , Controle de Qualidade , Coffea/química , Coffea/classificação
8.
J Contemp Dent Pract ; 14(4): 681-90, 2013 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-24309349

RESUMO

OBJECTIVE: To evaluate the effect of Arabic coffee, Turkish coffee and Nescafe on the color stability of four different composite resins after a period of aging time 1, 7 and 30 days. MATERIALS AND METHODS: Twenty specimens from each type of tested composite resin material were prepared. Five specimens from each tested material (Z350 XT, Artist, GC and Z250) was evaluated after storage in Arabic coffee, Turkish coffee, Nescafe and distil water (control) at 37°C in a dark container for 1, 7 and 30 days. Color measurement was done using colorimeter based on the CIE L* a* b* color scale. Color differences ΔE*ab, Δb* and Δa* among specimens immersed in distil water and staining coffee beverages were evaluated overtime. Mean values were statistically analyzed with one-way analysis of variance (ANOVA), followed by Tukey test with p < 0.05 as significance level. RESULTS: All tested composite resins showed increase color change after a period of 1, 7 and 30 days. The color change ΔE*ab , Δb* and Δa* exhibited by Arabic coffee, in Turkish coffee and Nescafe except Δa*. The highest total color difference ΔE*ab after 30 days was in group A Arabic coffee (ΔE > 1.5 perceivable) and not perceivable in group B Turkish coffee and group C Nescafe. For Δb* all materials discolored toward yellowness after 30 days except Arabic coffee group which shifted from yellowness toward blueness (Δb*> 1.5 perceivable). CONCLUSION: The effect of staining beverages on the resin composite materials increases with time of aging toward yellowness and not perceivable in all groups except with Arabic coffee which had highest effect after 30 days and the discoloration shifted from yellowness to blueness perceivable.


Assuntos
Café/classificação , Resinas Compostas/química , Materiais Dentários/química , Nanocompostos/química , Cor , Colorimetria , Cimentos de Ionômeros de Vidro/química , Humanos , Teste de Materiais , Cimentos de Resina/química , Propriedades de Superfície , Fatores de Tempo , Água/química
9.
J Hepatol ; 57(5): 1090-6, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22820478

RESUMO

BACKGROUND & AIMS: The aim of this study was to determine the influence of coffee and other caffeinated drinks on liver fibrosis of severely obese European patients. METHODS: A specific questionnaire exploring various types of coffee (regular filtrated coffee and espresso), caffeinated drinks, and chocolate was filled in by 195 severely obese patients. All patients had liver biopsies that were analyzed according to the NASH Clinical Research Network Scoring System. Univariate and multivariate analyses of significant fibrosis were performed. RESULTS: Caffeine came mainly from coffee-containing beverages (77.5%). Regular coffee and espresso were consumed in 30.8% and 50.2% of the patients, respectively. Regular coffee, espresso, and total caffeine consumption was similar between patients with and without NASH. While consumption of espresso, caffeinated soft drinks, and chocolate was similar among patients, with respect to the level of fibrosis, regular coffee consumption was lower in patients with significant fibrosis (F ≥2). According to logistic regression analysis, consumption of regular coffee was an independent protective factor for fibrosis (OR: 0.752 [0.578-0.980], p=0.035) in a model including level of AST (OR: 1.04 [1.004-1.076], p=0.029), presence of NASH (OR: 2.41 [1.007-5.782], p=0.048), presence of the metabolic syndrome (NS), and level of HOMA-IR (NS). Espresso, but not regular coffee consumption was higher in patients with lower HDL cholesterol level, higher triglyceride level, and the metabolic syndrome. CONCLUSIONS: Consumption of regular coffee but not espresso is an independent protective factor for liver fibrosis in severely obese European patients.


Assuntos
Cirurgia Bariátrica , Café/classificação , Fígado Gorduroso/epidemiologia , Cirrose Hepática/prevenção & controle , Obesidade Mórbida/epidemiologia , Obesidade Mórbida/cirurgia , Adulto , Biópsia , Cacau , Cafeína , Estudos de Coortes , Cola , Comorbidade , Europa (Continente)/epidemiologia , Fígado Gorduroso/patologia , Feminino , Humanos , Fígado/patologia , Masculino , Pessoa de Meia-Idade , Hepatopatia Gordurosa não Alcoólica , Inquéritos e Questionários , Chá
10.
Rocz Panstw Zakl Hig ; 63(1): 25-30, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22642066

RESUMO

BACKGROUND: Tea and coffee are the potentially rich source of oxalic acid, which can act as a antinutrient. OBJECTIVE: The aim of this study was to determine and evaluate the content of soluble oxalates in teas and coffees available on the Polish market. MATERIAL AND METHOD: The green, red and black teas, and black natural ground and instant coffees were used for preparing the infusions. The manganometric method was used for the determination of the oxalates in the infusions. RESULTS: The mean oxalates content in the infusions from 3 g of black teas was 115.68 mg/100 cm3 and was higher as compared to red teas (101.91 mg/100 cm3) and green teas (87.64 mg/100 cm3). Disregarding the variety of analyzed teas, the largest oxalates content was in infusions of pure one-component tea--"Sir Roger" (164.82-174.22 mg/100 cm3), while the lowest oxalates content was noted in the tea containing the components from other plants ("Bio-Active" with grapefruit juice--reaching as low level as 39.00 mg/100 cm3). Instant coffees contained larger amount of oxalates than natural ground coffees. Irrespective of the kind of the tested coffees, the lowest oxalates content was found in the infusions from the following coffees: Tchibo Exclusive--19.62 mg/100 cm3, Gala ulubiona--37.32 mg/100 cm3, and Maxwell House--38.40 mg/100 cm3, while the highest oxalates content in instant coffee--Nescafe Espiro 51.80 mg/100 cm3. CONCLUSIONS: The results revealed a significant relation between phytochemical composition of analyzed teas and coffees and the level of soluble oxalates in infusions prepared from the tested products.


Assuntos
Bebidas/análise , Café/química , Oxalatos/análise , Chá/química , Cromatografia Gasosa/métodos , Café/classificação , Contaminação de Alimentos/análise , Humanos , Polônia , Solubilidade , Chá/classificação
11.
Mol Biotechnol ; 64(3): 263-277, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34595725

RESUMO

Coffea arabica is the most economically important coffee species worldwide. However, its production is severely limited by diseases such as rust. The mechanisms underlying constitutive defense responses in coffee are still poorly understood, compared with induced defense mechanisms. We aimed to characterize constitutive defense responses of thirteen cultivars of C. arabica. Cultivars were classified under field conditions according to the level of resistance to rust: resistant (R), moderately resistant (MR), and susceptible (S). Based on this classification, the stability of eight reference genes (RGs) was evaluated. The most stable RGs were EF1α, APT1, and 24S. We also evaluated the expression of CaWRKY1, CaPAL1, CaCAD1, and CaPOX1, and activities of PAL, CAD, and POX, which are involved in lignin biosynthesis, and leaf content of total phenolic compounds and lignin. Gene expression and enzymatic activity were not correlated with defense metabolites in the R cultivar group but showed a negative correlation with phenolic compounds in MR cultivars. Cultivar S showed positive correlations of gene expression and enzyme activity with phenolic compounds. These results may assist coffee breeding programs regarding selection of genotypes and in optimization of rust resistance.


Assuntos
Café/crescimento & desenvolvimento , Resistência à Doença , Proteínas de Plantas/genética , Café/classificação , Café/genética , Café/microbiologia , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Lignina/biossíntese , Fenóis/metabolismo , Folhas de Planta/classificação , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/microbiologia
12.
Genome ; 54(5): 377-90, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21539438

RESUMO

Biotic or abiotic stress can cause considerable damage to crop plants that can be managed by building disease resistance in the cultivated gene pool through breeding for disease resistance genes (R-genes). R-genes, conferring resistance to diverse pathogens or pests share a high level of similarity at the DNA and protein levels in different plant species. This property of R-genes has been successfully employed to isolate putative resistance gene analogues (RGAs) using a PCR-based approach from new plant sources. Using a similar approach, in the present study, we have successfully amplified putative RGAs having nucleotide-binding-site leucine-rich repeats (NBS-LRR-type RGAs) from seven different sources: two cultivated coffee species (Coffea arabica L. and Coffea canephora Pierre ex. A. Froehner), four related taxa endemic to India (wild tree coffee species: Psilanthus bengalensis (Roem. & Schuttles) J.-F. Leroy, Psilanthus khasiana , Psilanthus travencorensis (Wight & Arn.) J.-F. Leroy, Psilanthus weightiana (Wall. ex Wight & Arn.) J.-F. Leroy), and a cDNA pool originally prepared from light- and drought-stressed Coffea arabica L. leaves. The total PCR amplicons obtained using NBS-LRR-specific primers from each source were cloned and transformed to construct seven independent libraries, from which 434 randomly picked clones were sequenced. In silico analysis of the sequenced clones revealed 27 sequences that contained characteristic RGA motifs, of which 24 had complete uninterrupted open reading frames. Comparisons of these with published RGAs showed several of these to be novel RGA sequences. Interestingly, most of such novel RGAs belonged to the related wild Psilanthus species. The data thus suggest the potential of the secondary gene pool as possible untapped donors of resistance genes to the present day cultivated species of coffee.


Assuntos
Café/genética , Genes de Plantas/genética , Imunidade Inata/genética , Sequência de Aminoácidos , Sequência de Bases , Clonagem Molecular , Café/classificação , Índia , Dados de Sequência Molecular , Filogenia , Doenças das Plantas/genética , Reação em Cadeia da Polimerase , Alinhamento de Sequência
13.
Int J Food Sci Nutr ; 62(8): 865-71, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22032554

RESUMO

Arabica and Robusta coffee beans were roasted at 220 ± 10°C for 7, 9 and 11 min to identify chemical descriptors in the beverages. The pH of the beverages showed the lowest value in the medium roasting level. In each degree of browning, the soluble solids content remained slightly higher in Arabica drinks. The contents of caffeine did not vary, but trigonelline decreased with burning up intensity. Chlorogenic acids also decreased with increasing roasting time. The 5-O-caffeoylquinic acid prevailed in Arabica and Robusta beverages, but the isomers of dicaffeoylquinic and feruolilquínic acids remained higher in Robusta. It was concluded that trigonelline and total caffeoylquinic, fatty dicaffeoylquinic and fatty feruolilquínic acids detached the beverages according to roasting intensity. Caffeine and pH allowed drinks separation between both species. Soluble solids take apart Arabica and Robusta drinks in each degree of roasting. All the individual groups of chlorogenic acids also explained 90% of the variance among samples.


Assuntos
Alcaloides/análise , Cafeína/análise , Ácido Clorogênico/análogos & derivados , Café/química , Culinária , Ácidos Cumáricos/análise , Ácido Quínico/análogos & derivados , Ácido Clorogênico/análise , Coffea , Café/classificação , Temperatura Alta , Concentração de Íons de Hidrogênio , Extratos Vegetais/análise , Ácido Quínico/análise , Sementes/química , Solubilidade , Especificidade da Espécie
14.
Acta Sci Pol Technol Aliment ; 20(2): 179-188, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33884855

RESUMO

BACKGROUND: The aim of the study was to evaluate the caffeine level and antioxidant activity of brews of specialty grade coffee compared to popular coffee brands. METHODS: Ten types of coffee were used, including 7 specialty Arabica, 1 Robusta and 2 popular cheap coffee brands. For caffeine determination, HPLC analysis and the spectrophotometric method were used as reference. The total polyphenol content and antioxidant capacity (DPPH and FRAP methods) were evaluated. For two selected high-quality coffees, the influence of the brewing method on the antioxidant activity and caffeine content in the brews was assayed. RESULTS: Regarding the caffeine content, differences between specialty coffee brews and popular products were not found, and an average level amounted to 56 and 40 mg/ml, respectively. In contrast, the antioxidant capacity of specialty coffee brews was significantly higher than for popular ones, independently of the test used. The highest scavenging ability and total phenolic content was found for S3 specialty coffee (46.15% of DPPH inhibition and 58.7 mg GAE/ml, respectively), whereas the lowest was found for popular coffee (about 35% of DPPH inhibition and about 41 mg/GAE/ml). For two selected high-quality coffees, the influence of the brewing method on the antioxidant activity and caffeine content in the brews was tested. It was found that the use of a dripper (overflow brewing method) provides the brew with the best antioxidant properties but with moderate caffeine levels. CONCLUSIONS: It was found that 'specialty' quality coffees do not differ from popular brands in terms of caffeine content, but significantly outweigh them in terms of antioxidant activity. This property can be beneficial in the case of a high consumption of coffee, due to antiradical protective effects without the risk of caffeine overdose.


Assuntos
Antioxidantes/farmacologia , Cafeína/análise , Café/química , Manipulação de Alimentos/métodos , Polifenóis/farmacologia , Antioxidantes/análise , Compostos de Bifenilo/metabolismo , Coffea/química , Café/classificação , Humanos , Picratos/metabolismo , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Polifenóis/análise
15.
Sensors (Basel) ; 10(1): 36-46, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-22315525

RESUMO

Electronic noses (ENs), are used for many applications, but we must emphasize the importance of their application to foodstuffs like coffee. This paper presents a research study about the analysis of Colombian coffee samples for the detection and classification of defects (i.e., using "Cup Tests"), which was conducted at the Almacafé quality control laboratory in Cúcuta, Colombia. The results obtained show that the application of an electronic nose called "A-NOSE", may be used in the coffee industry for the cupping tests. The results show that e-nose technology can be a useful tool for quality control to evaluate the excellence of the Colombian coffee produced by National Federation of Coffee Growers.


Assuntos
Café/química , Café/classificação , Eletrônica/instrumentação , Análise de Alimentos/instrumentação , Calefação/instrumentação , Nariz , Transdutores , Compostos Orgânicos Voláteis/análise , Materiais Biomiméticos , Colômbia , Desenho de Equipamento , Análise de Falha de Equipamento , Humanos , Olfato
16.
Food Chem ; 320: 126602, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32222657

RESUMO

Determining coffee region-of-origin is most appropriately addressed through analyses of the product available to the consumer. We analyzed the concentrations of 44 trace elements in 53 samples of roasted Arabica coffee beans (Coffea arabica) from 21 different countries. Variations in absolute elemental concentrations of coffee beans arise through varying degrees of roasting (from green through dark roasts). Since trace elements are not volatilized at roasting temperatures, we conducted analyses of element ratios to evaluate concentration-related differences among beans of different origins. We used kernel density estimates to compare the distributions of 1892 element ratios for each of these countries with the combined distribution of coffee samples from the other countries. Using this quantitative approach, we demonstrated that many of the world's coffee-producing regions can be distinguished from other regions of the world on the basis of element ratios.


Assuntos
Café/química , Geografia , Oligoelementos/análise , Coffea , Café/classificação , Sementes/química
17.
PLoS One ; 15(7): e0222747, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32639982

RESUMO

Physiology-based differentiation of SH genes and Hemileia vastatrix races is the principal method employed for the characterization of coffee leaf rust resistance. Based on the gene-for-gene theory, nine major rust resistance genes (SH1-9) have been proposed. However, these genes have not been characterized at the molecular level. Consequently, the lack of molecular data regarding rust resistance genes or candidates is a major bottleneck in coffee breeding. To address this issue, we screened a BAC library with resistance gene analogs (RGAs), identified RGAs, characterized and explored for any SH related candidate genes. Herein, we report the identification and characterization of a gene (gene 11), which shares conserved sequences with other SH genes and displays a characteristic polymorphic allele conferring different resistance phenotypes. Furthermore, comparative analysis of the two RGAs belonging to CC-NBS-LRR revealed more intense diversifying selection in tomato and grape genomes than in coffee. For the first time, the present study has unveiled novel insights into the molecular nature of the SH genes, thereby opening new avenues for coffee rust resistance molecular breeding. The characterized candidate RGA is of particular importance for further biological function analysis in coffee.


Assuntos
Café/genética , Resistência à Doença/genética , Genoma de Planta , Sequência de Aminoácidos , Basidiomycota/fisiologia , Sítios de Ligação , Café/classificação , Biblioteca Gênica , Solanum lycopersicum/classificação , Solanum lycopersicum/genética , Fases de Leitura Aberta/genética , Filogenia , Doenças das Plantas/microbiologia , Proteínas de Plantas/química , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Polimorfismo Genético , Alinhamento de Sequência , Fatores de Virulência/genética , Fatores de Virulência/metabolismo , Vitis/classificação , Vitis/genética
18.
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
19.
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
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