Biblioteca do Café

URI permanente desta comunidadehttps://thoth.dti.ufv.br/handle/123456789/1

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2004 - 200952010 - 2019152020 - 20233

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Autor: search.filters.author.Borém, Flávio MeiraAssunto: search.filters.subject.Qualidade de bebida

Resultados da Pesquisa

Agora exibindo 1 - 10 de 23
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    Case study of modeling covariance between external factors and sensory perception of coffee
    (Universidade Federal de Lavras, 2023-08-18) Resende, Mariana; Borém, Flávio Meira; Cirillo, Marcelo Ângelo
    Analysis and inference of sensory perceptions in coffee beverages are complex due to numerous random causes intrinsic to productivity, preparation, and especially consumer and/or taster subjectivity. In this context, latent variables often composed of a combination of other observed variables are discarded from conventional analyses. Following this argument, this study aimed to propose a model of structural equations applied to a database, geographical indication of coffees in Serra da Mantiqueira, with a methodological contribution characterized by inclusion of a treatment effect, contemplated by different altitudes at which coffees were produced. From the methodology used, a covariance structure was estimated, and used in another statistical methodology to discriminate the effects. It is concluded that the proposed model proved to be advantageous for allowing the analysis of the relationship of latent variables, production and environmental variations, which are not considered in a sensorial analysis, and showed that, in fact, they influence the sensorial perception, for the coffees produced in the Serra da Mantiqueira region. The correlation structure generated from the covariance matrix adjusted by the model resulted in estimates that could be used in other statistical methodologies more appropriate to discriminate the effects, exemplifying the use of principal components.
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    A mixed model applied to joint analysis in experiments with coffee blends using the least squares method
    (Universidade Federal do Ceará, 2019) Paulino, Allana Lívia Beserra; Cirillo, Marcelo Angelo; Ribeiro, Diego Egídio; Borém, Flávio Meira; Matias, Gabriel Carvalho
    The aim of the present study was to propose a mixed model for a sensory analysis of four experiments with blends of different standards of quality, including the species Coffea Arabica L. and Coffea Canephora. Each experiment differed in the proportions used to formulate the blends and the concentrations used in preparing the beverages, these being 7% and 10% coffee powder for each 100 ml of water. The response variables under analysis were the sensory characteristics of the beverage found in an assessment made by a group of trained tasters, considering taste, bitterness and a final score. Each description followed a numerical rating scale of intensity that ranged from 0 to 10. The model was implemented using the least squares method; this led to the conclusion that including random parameters in the model, represented by the experiments, made it possible to compare the effect of each component simultaneously for each of the experiments.
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    Monte Carlo simulation and importance sampling applied to sensory analysis validation of specialty coffees
    (Universidade Federal do Ceará, 2021) Ferreira, Haiany Aparecida; Liska, Gilberto Rodrigues; Cirillo, Marcelo Ângelo; Borém, Flávio Meira; Ribeiro, Diego Egídio; Cortez, Ricardo Miguel
    Coffee sensory analysis is usually made by a sensory panel, which is formed by trained tasters, following the recommendations of the Specialty Coffee Association of America. However, the preference for a coffee is commonly determined by experimentation with consumers, who typically have no special skills in terms of sensory characteristics. Therefore, this study aimed at applying an intensive computational method to study sensory notes given by an untrained sensory panel, considering the probability distributions of the class of extreme values. Four types of specialty coffees produced under different processes and in varied altitudes in the mountainous region of Mantiqueira, Minas Gerais, were considered. We concluded that the generalized Pareto distribution can be applied to sensory analysis to discriminate types of specialty coffees. Furthermore, the method of importance sampling by Monte Carlo simulation showed greater variability considering a probabilistic model adjusted to identify specialty coffees.
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    Statistical procedure for the composition of a sensory panel of blends of coffee with different qualities using the distribution of the extremes of the highest scores
    (Editora da Universidade Estadual de Maringá - EDUEM, 2019) Cirillo, Marcelo Ângelo; Ramos, Mariana Figueira; Borém, Flávio Meira; Miranda, Felipe Mesquita de; Ribeiro, Diego Egídio; Menezes, Fortunato Silva de
    The identification and interpretation of discrepant observations in sensory experiments are difficult to implement since the external effects are associated with the individual consumer. This fact becomes more relevant in experiments that involve blends, which scrutinize coffees with different qualities, varieties, origins, and forms of processing and preparation. This work proposes a statistical procedure that facilitates the identification of outliers while also evaluating the discriminatory powers of a sensory panel concerning the differentiation of pure blends and coffees. For this purpose, four experiments were performed that tested coffees with different qualities and varieties. The results suggest that the statistical procedure proposed in this work was effective for discriminating the blends relative to the pure coffees and that the effects of the concentrations and types of processing did not interfere with the statistical evaluations.
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    Unsupervised classification of specialty coffees in homogeneous sensory attributes through machine learning
    (Editora UFLA, 2020) Ossani, Paulo César; Rossoni, Diogo Francisco; Cirillo, Marcelo Ângelo; Borém, Flávio Meira
    Brazil is the largest exporter of coffee beans, 29% world exports, 15% this volume in specialty coffees. Thereby researches are done, so that identify different segments in the market, in order to direct the end consumer to a better quality product. New technologies are explored to meet an increasing demand for high quality coffees. Therefore, in this article has an objective to propose the use of machine learning techniques combined with projection pursuit in the construction of unsupervised classification models, in a sensory acceptance experiment, applied to four groups of trained and untrained consumers, in four classes of specialty coffees in which they were evaluated sensory characteristics: aroma, body coffee, sweetness and general note. For evaluating classifier performance, in the data with reduced dimension, all instances were used, and considering four groupings, the models were adjusted. The results obtained from the groupings formed were compared with pre-established classes to confirm the model. Success and error rates were obtained, considering the rate of false positives and false negatives, sensitivity and classification methods accuracy. It was concluded that, machine learning use in data with reduced dimensions is feasible, as it allows unsupervised classification of specialty coffees, produced at different altitudes and processes, considering the heterogeneity among consumers involved in sensory analysis, and the high homogeneity of sensory attributes among the analyzed classes, obtaining good hit rates in some classifiers.
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    Avaliação sensorial do café cereja descascado, armazenado sob atmosfera artificial e convencional
    (Editora UFLA, 2008-11) Borém, Flávio Meira; Nobre, Gilberto Westin; Fernandes, Simone Miranda; Pereira, Rosemary Gualberto F. A.; Oliveira, Pedro Damasceno de
    Objetivou-se, com o presente trabalho, avaliar sensorialmente as bebidas e classificar quanto ao tipo o café cereja descascado submetido a diferentes acondicionamentos, ao longo do armazenamento. O experimento foi instalado em delineamento inteiramente casualizado (DIC), em esquema fatorial 2x5x5, com três repetições. Foram testados cinco acondicionamentos, com e sem modificação de atmosfera, em cinco épocas de avaliação, em dois lotes de café cereja descascado, sendo um em pergaminho e o outro beneficiado. Os acondicionamentos em embalagens impermeáveis (sacos de náilon, sacos de náilon com 40% de CO 2 e sacos aluminizados a vácuo) apresentaram capacidade de preservar a qualidade de bebida do café cereja descascado, na duração e nas condições do experimento. Os cafés acondicionados em embalagens permeáveis (sacos de juta e sacos de juta com casca de café picada) apresentaram alterações sensoriais que depreciaram a qualidade do café. Na classificação física, o tipo do café não sofreu alteração nos diversos acondicionamentos usados durante o experimento.
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    Composição química de grãos crus de de cultivares de Coffea arabica suscetíveis e resistentes à Hemileia vastatrix Berg et Br.
    (Editora UFLA, 2007-03) Mendonça, Luciana Maria Vieira Lopes; Pereira, Rosemary Gualberto Fonseca Alvarenga; Mendes, Antônio Nazareno Guimarães; Borém, Flávio Meira; Marques, Elizabeth Rosemeire
    Com este trabalho, buscou-se caracterizar a composição química e físico-química dos grãos crus de 16 cultivares de café Coffea arabica L., com o intuito de avaliar novos materiais desenvolvidos com resistência à ferrugem (Hemileia vastatrix Berg. et Br.) em comparação aos tradicionais. Desta forma, frutos provenientes do ensaio de melhoramento genético do MAPA/PROCAFÉ, localizado na Fazenda Experimental de Varginha em MG foram colhidos e transportados imediatamente para o Pólo de Tecnologia em Pós- Colheita do Café da UFLA, onde foram lavados, descascados e secados em terreiro de concreto. Após o beneficiamento, os grãos foram acondicionados em latas de alumínio e armazenados a 15 o C. Os frutos avaliados correspondiam às cultivares Acaiá , Acauã , Bourbon Amarelo , Canário , Catuaí Amarelo , Catuaí Vermelho , Catucaí Amarelo , Catucaí Vermelho , Icatu Amarelo , Icatu Vermelho Mundo Novo , Palma , Rubi , Sabiá 398 , Siriema e Topázio , do ano safra 2002. Os grãos crus foram moídos em moinho de bola com nitrogênio líquido. As análises realizadas foram: açúcares totais, redutores e não-redutores, extrato etéreo, polifenóis e cafeína. Diferenças foram consideradas significativas e as cultivares apresentaram variações para os teores de todos os compostos avaliados, indicando haver uma influência do genótipo sobre esses constituintes.
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    Qualidade do café-cereja descascado produzido na região sul de Minas Gerais
    (Editora UFLA, 2004-11) Silva, Reginaldo Ferreira da; Pereira, Rosemary Gualberto F. A.; Borém, Flávio Meira; Muniz, Joel Augusto
    O café-cereja descascado vem conquistando cada vez mais espaço nas diversas regiões produtoras de café. Considerando os diversos questionamentos sobre a qualidade dos grãos resultantes desse tipo de processamento, os poucos estudos sobre o assunto e as contradições observadas nos resultados obtidos até o momento, com o presente estudo teve-se por objetivo caracterizar a qualidade do café-cereja descascado produzido na região sul do Estado de Minas Gerais, bem como averiguar a influência da altitude na qualidade desse café por meio de análises físicas, químicas e sensoriais das amostras em seu estado original e após a retirada de grãos defeituosos. Foram aleatoriamente selecionadas lavouras de empresas cafeeiras situadas em faixas de altitude que variaram de 720 a 920 metros e de 920 a 1120 metros. As amostras de café da safra 2001/2002 foram coletadas em 32 propriedades distribuídas em 10 municípios. No Pólo de Tecnologia em Qualidade do Café da Universidade Federal de Lavras (UFLA), foram realizadas as seguintes análises: teor de água, acidez titulável total, açúcares totais e análise sensorial. As análises físicas, químicas e sensoriais realizadas nos grãos de café demostraram que a maioria dos cafés descascados apresenta teor de água abaixo do valor recomendado; os valores médios de acidez titulável total e açúcares totais em todas as amostras analisadas encontram-se dentro dos valores característicos de bebidas finas; os cafés sem a presença dos defeitos, produzidos na faixa de altitude de 920 a 1120 metros, apresentam corpo e acidez mais fracos e doçura mais alta do que os produzidos na faixa de 720 a 920 metros; e que maiores altitudes possibilitam a produção de cafés de melhor qualidade.
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    Physiological and sensorial quality of Arabica coffee subjected to different temperatures and drying airflows
    (Editora da Universidade Estadual de Maringá - EDUEM, 2017-04) Alves, Guilherme Euripedes; Borém, Flávio Meira; Isquierdo, Eder Pedroza; Siqueira, Valdiney Cambuy; Cirillo, Marcelo Ângelo; Pinto, Afonso Celso Ferreira
    The objective of this study was to evaluate the correlation between a group of physiological variables (electrical conductivity, potassium leaching, and germination percentage) and a group of drying kinetics variables (drying time and drying rate) in addition to verifying the relation between drying kinetics variables and coffee quality as a function of processing type, temperature, and drying airflow. Coffee drying was conducted in a fixed-layer dryer at two temperatures and two airflows. After drying, an evaluation of the physiological and sensorial quality was conducted. Based on the results obtained, the following conclusions were drawn: coffee that is processed via a dry method is more sensitive to mechanical drying with heated air than coffee processed via a wet method, resulting in poor physiological performance; airflow does not interfere with the physiological quality of pulped and natural coffees; a temperature increase from 40 to 45°C resulted in a decrease in the physiological quality only for pulped coffee; and an increase in the drying rate as a result of an increase in the drying temperature to 40°C had a negative effect on the sensorial quality of pulped coffee.
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    Quality of natural and pulped coffee as a function of temperature changes during mechanical drying
    (Editora UFLA, 2018-10) Oliveira, Pedro Damasceno de; Biaggioni, Marco Antônio Martin; Borém, Flávio Meira; Isquierdo, Eder Pedroza; Damasceno, Mariana de Oliveira Vaz
    This research evaluated the sensory quality of processed and dried coffee beans in different ways. Two types of processing were used: dry and wet, besides seven drying methods: drying in yard and mechanical drying with heated air at 50 oC until coffee reached 30% (w.b.) moisture content, followed by drying with air heated to 35 oC until reaching 11% (w.b.) moisture content; drying in fixed-layer dryers with heated air at 45 °C until coffee reached 30% moisture content, followed by drying with heated air at 35 °C until reaching 11% (w.b.) moisture content; and drying in fixed-layer dryers with heated air at 40 °C until coffee reached 30% (w.b.) moisture content, followed by drying with heated air at 35 °C until reaching 11% (w.b.) moisture content; drying in fixed-layer dryers with heated air at 35 °C until coffee reached 30% (w.b.) moisture content, followed by drying with heated air at 50 °C until reaching 11% (w.b.) moisture content; drying in fixed-layer dryers with heated air at 35 °C until coffee reached 30% (w.b.) moisture content, followed by drying with heated air at 45 °C until reaching 11% (w.b.) moisture content; drying in fixed-layer dryers with heated air at 35 °C until coffee reached 30% (w.b.) moisture content, followed by drying with heated air at 40 °C until reaching 11% (w.b.) moisture content. The mechanical drying system consisted of three fixed-layer dryers, allowing the control of temperature and drying flow. Coffee was tasted according to the evaluation system proposed by the Specialty Coffee Association of America (SCAA). Physicochemical composition and physiological quality of the beans were analyzed, involving: grease acidity, potassium leaching, electrical conductivity, color and germination. The results show that pulped coffee is more tolerant to drying than natural coffee, regardless of how it was dried.