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Variation in fermentation time may be an essential alternative to provide coffee beverages with different and unique sensory profiles. This work investigated the microbiological, chemical, and sensory changes in coffees submitted to different fermentation durations (0, 24, 48, 72, and 96 h). Self-induced anaerobiosis fermentation (SIAF) was used, and two treatments were performed: spontaneous fermentation and inoculation with S. cerevisiae CCMA0543. Microbiological analyses were performed, and the permanence of the inoculum was monitored. Chromatography (sugars, organic acids, and volatile compounds) was analyzed, and sensory analysis (temporal dominance of sensations - TDS) was performed. A total of 228 isolates were identified during spontaneous fermentation. The dominant bacteria and yeasts were Leuconostoc mesenteroides, Lactiplantibacillus plantarum, Staphylococcus warneri, Bacillus sp., Torulaspora delbrueckii, Hanseniaspora uvarum, and Meyerozyma caribbica. High concentrations of citric (18.67 mg.g- 1) and succinic (5.04 mg.g- 1) acids were detected at 96 h in SIAF fermentation. One hundred twenty-one volatile compounds were detected, but 22 were detected only in inoculated coffees. In spontaneous fermentation, 48 h of fermentation showed woody notes, while 72 h showed chestnuts. However, in the inoculated coffee, 72 h of fermentation showed high fruity dominance, and 96 h of fermentation was the only one with herbaceous notes. In addition, yeast inoculation increased the intensity of caramel notes in the first 48 h and increased the fruity flavor after 72 h of fermentation. Therefore, the type of fermentation (with or without inoculation) and the chosen fermentation time will depend on the sensorial profile the producer intends to obtain.

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This study has innovative aspects related to the use of sequential inoculation technique in the coffee bean fermentation process: the inoculation of Lactiplantibacillus plantarum followed by Saccharomyces cerevisiae, in the fermentation of coffee fruit for the production of specialty natural coffees. The objective was to evaluate the effect of this technique and of the total fermentation time on the sensory attributes of the coffee beverage and on the organic acid profile, bioactive compounds, and fatty acid profile of the beans. The fermentation of coffee fruit with sequential inoculation resulted in greater acidity of the beverage and contributed to increases of up to 2 points in coffee fermented. The total fermentation time was directly related to the organic acid content, and the longer the total fermentation time was, the greater the organic acid content. The fatty acid content and bioactive compound content showed little variation among treatments.

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All coffee production stages occur in a microbiome, which is generally composed of bacteria, yeasts, and filamentous fungi. The use of starter cultures in post-harvest processing stages is an interesting alternative, since they promote faster removal of mucilage and incorporation of compounds that improve sensory quality, which can result in diverse sensory attributes for the beverage. This study was therefore developed with the objective of evaluating the effect of the following processing procedures on the chemical and sensory characteristics of the coffee beverage: first, fermentation of coffee fruit of the yellow Catucaí variety of Coffea arabica with indigenous microorganisms, followed by inoculation of the starter culture Torulaspora delbrueckii CCMA 0684 during the drying stage. The fruit was divided into two lots, which were differentiated by a natural fermentation process before drying began. The starter culture was inoculated on the coffee at different times during the drying process: at 0 h, 24 h, 48 h, or 72 h after drying began. The sensory attributes, the volatile compound composition of the roasted beans, the organic acid profile, the bioactive compounds, and the fatty acid profile of the green coffee beans were analyzed. The fatty acid and bioactive compound content showed little variation among treatments. Analysis of volatile compounds and organic acids and evaluation of sensory attributes made it possible to distinguish the two treatments. We conclude that natural fermentation of coffee fruit improve the chemical and sensory quality of the coffee beverage. The effect of natural fermentation may be before inoculation of the starter cultures or even during drying.

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The present study had the objective to evaluate the effect of blends of KCl and K2SO4 fertilizers and their influence on the yield and the nutritional state of coffee plants, as well as on the chemical composition and quality of the coffee beverage. The experimental design was in randomized blocks with four repetitions and six treatments (T1: 100% KCl; T2: 75% KCl + 25% K2SO4; T3: 50% KCl + 50% K2SO4; T4: 25% KCl + 75% K2SO4; T5: 100% K2SO4; and a control, without application of K). The following analyses were performed: K and Cl content in the leaves and the soil, stocks of Cl in soil, yield, removal of K and Cl with the beans, cup quality of the beverage, polyphenol oxidase activity (PPO), electric conductivity (EC), potassium leaching (KL), the content of phenolic compounds, the content of total sugars (TS), and total titratable acidity (TTA). The stocks of Cl in the soil decreased as the proportion of KCl in the fertilizer was reduced. The fertilization with KCl reduces the cup quality and the activity of the polyphenol oxidase, probably due to the ion Cl. The increase in the application of Cl directly relates to the increase in potassium leaching, electric conductivity, and titratable acidity. Indirectly, these variables indicate damages to the cells by the use of Cl in the fertilizer. The activity of the polyphenol oxidase enzyme and the cup quality indicate that the ion Cl- reduces the quality of the coffee beverage. K content in the leaves was not influenced by the application of blends of K fertilizer while Cl content increased linearly with KCl applied. The application of KCl and K2SO4 blends influenced coffee yield and the optimum proportion was 25% of KCl and 75% of K2SO4. The highest score in the cup quality test was observed with 100% K2SO4.

RESUMO

The final quality of pre-processed coffees is influenced by the applied drying technology. Thus, the aim of the study was to develop and validate a heated air flow diffusion system to optimize and reduce the drying time of rotary dryers and improve the final quality of coffee. Computational fluid dynamics was used for the simulation of the air fluid dynamics in the combustion chamber of the heat generator. It was observed that the energy losses in the upper and lower walls of the heat generator chamber were higher with an increase in the convective heat transfer coefficient. It was found that the rate of fluid flow presented a fully developed profile, in which the higher speed value was found in the central region of the outlet. The reduction in moisture content during coffee drying was directly proportional to the increase in temperature. The Midilli model shows the best fit to describe the drying curves of the coffee. The effective diffusion coefficient increases with increasing temperature of the drying air. It was observed that the adjustments of the fluid dynamics in the burning of gas and the adaptation of the diffuser system significantly influenced the drying time and final quality of naturally processed and pulped coffees. In conclusion, the adapted technological set, a rotary dryer with gas heating and diffusion of heated air, had a high performance in the final quality of the coffee, and for this reason it is recommended to producers and the industry.

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Starter cultures during fermentation of Coffea arabica var. Mundo Novo processed in open stainless-steel vessels by natural and pulped natural methods were studied. The yeasts Meyerozyma caribbica (CCMA 0198), Saccharomyces cerevisiae (CCMA 0543), Candida parapsilosis (CCMA 0544), and Torulaspora delbrueckii (CCMA 0684) were inoculated separately in two different coffee processes: natural and pulped natural. The qPCR (real-time quantitative polymerase chain reaction) was used as a culture-independent method to monitor the inoculum's permanence. Changes in microbial metabolites (organic acids and volatile) production were evaluated by high-performance liquid chromatography (HPLC) and gas chromatograph-mass spectrometry (GC-MS), respectively. The sensory analysis was assessed in roasted beans. The fermentation lasted 27 h, and the coffee temperature ranged from 16.5 to 24.0 °C. The starter culture population was dominant throughout fermentation. S. cerevisiae (CCMA 0543) and T. delbrueckii (CCMA 0684) presented a higher population in natural processing. However, in pulped natural processing, M. caribbica (CCMA 0198) and C. parapsilosis (CCMA 0544) were the dominant populations. Citric, malic, and succinic acids were naturally present in coffee. Lactic, isobutyric, and isovaleric acids were detected at the end of the fermentation in different treatments. Lactic acid was detected in samples at the end of fermentation in Control and CCMA 0198 treatment. NAT coffee inoculated with CCMA 0684 presented isobutyric acid and isovaleric acid concentrations. Volatile compounds, such as 2,6-diethylpyrazine was detected in treatments inoculated with yeasts, but not in Controls. 2-acetoxymethylfuran was only detected in samples inoculated with CCMA 0198 from both NAT and PN methods. Samples fermented with S. cerevisiae (CCMA 0543) presented the highest sensorial scores in both processing (84.75 and 84.92). The inoculated coffee beans showed higher scores of sweetness, long aftertaste, and greater complexity. The starter cultures influenced the sensorial profiles through the synthesis of specific volatile constituents. However, considering all parameters analyzed, S. cerevisiae (CCMA 0543) would be the most suitable yeast for the var. Mundo Novo processed by both fermentation methods.

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Fermenting in bioreactors can improve coffee quality, standardize the fermentation process, and generate specialty coffees. This work aimed to evaluate novel stainless steel bioreactors with inoculated and non-inoculated coffees processed via natural and pulped natural. Yeast and bacteria populations were evaluated and grown on Yeast Extract Peptone Glucose; De Man, Rogosa, and Sharpe; and Nutrient agar media. Volatile compounds from roasted beans were analyzed in a Gas Chromatography-Mass Spectrometry equipment, and the sensory perception was evaluated through a cup test. The mesophilic bacteria population was statistically significant in pulped natural coffee compared to yeast and lactic acid bacteria. Furans had the highest concentration among the chemical groups. Beverage inoculated with CCMA 0535 presented the highest SCA score. Prune, peach, and floral attributes were only perceived in Nat CCMA 0535. The sensory perception indicated that the inoculated yeasts modified the flavor attributes, enhanced the quality, and increase their SCA scores.

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Fermentation is one of the post-harvest steps that influence coffee quality. This work evaluated the effect of Saccharomyces cerevisiae (CCMA 0543) and Torulaspora delbrueckii (CCMA 0684) inoculation on the quality of natural and pulped natural processed coffee in different producing regions. Yeast populations were assessed by the real-time polymerase chain reaction. Volatile and nonvolatile compounds were evaluated by gas chromatography-mass spectrometry and high-performance liquid chromatography, respectively. S. cerevisiae was predominant during spontaneous (average of 4 log cells/g) and inoculated (average of 7 log cells/g) fermentations in both processes. T. delbrueckii showed a similar population (3.79 log cells/g) in all assays. Glucose and fructose were the most detected sugars in coffee beans. Succinic acid was found at the end of the fermentative process. The lactic acid concentration was inversely proportional to ethanol concentration. Pyrrole and furan, which are volatile groups, allowed to differentiate the coffee processing methods. Yeast inoculation modified the sensorial profile and increased the coffee beverage scores by up to 5 points. S. cerevisiae inoculation was most suitable for pulped natural coffee, and T. delbrueckii inoculation showed the best performance in natural coffee.

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Correspondence analysis is a multivariate dimensionality-reduction technique applied to data structured into contingency tables. The main outcome of this approach is the generation of perceptual maps aimed at the study of similarity between categorical levels. In most cases, interpretations of these similarities present subjectivity when different metrics are considered; e.g., Hellinger distance and Chi-square. Thus, in an attempt to minimize this subjectivity, the present study proposes an index that quantifies the shortest distance between those levels. A simulation study was undertaken in which the generated maps were discussed in relation to real data involving the similarity of blends formed by coffees of different species, with sensory evaluations considering the flavor and acidity attributes. In conclusion, the proposed indexnamed metric selection index (MSI)made it possible to include a statistic that justifies the most suitable metric for correspondence analysis, thus preventing subjectivity in interpretations of similarities between blend types and grade classes. In the simulation studies, with the metric proposed by Hellinger distance, MSI showed stabler results regarding total inertia distribution on the first two axes.(AU)

A análise de correspondência é uma técnica multivariada de redução de dimensionalidade aplicada a dados estruturados em tabelas de contingência. Como principal resultado, mapas perceptuais são gerados com o propósito de estudar a similaridade entre os níveis categóricos. Na maioria das vezes, as interpretações dessas similaridades apresentam certa subjetividade, ao considerar diferentes métricas, como por exemplo, a distância de Hellinger e Qui-quadrado. Assim, com o intuito de minimizar essa subjetividade, esse trabalho teve como objetivo propor um índice que quantifique a menor distância entre esses níveis. Foi realizado um estudo de simulação, discutindo-se os mapas gerados em relação a dados reais envolvendo a similaridade de blends formados por cafés de diferentes espécies com avaliações sensoriais considerando os atributos sabor e acidez. Concluiu-se que a proposta do índice, denominado índice de seleção de métrica (ISM), permitiu agregar uma estatística que justifique a métrica mais adequada na análise de correspondência, evitando a subjetividade nas interpretações das similaridades entre os tipos de blends e classe de notas. Em relação aos estudos de simulação a métrica proposta pela distância de Hellinger, o ISM apresentou resultados mais estáveis em relação à distribuição da inércia total nos dois primeiros eixos.(AU)

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Volatile and non-volatile compounds in coffee directly affect the beverage's quality. This study aimed to demonstrate how the organic acids and volatile profiles were impacted by coffee fermentation using four starter cultures (Meyerozyma caribbica (CCMA 0198), Saccharomyces cerevisiae (CCMA 0543), Candida parapsilosis (CCMA0544), and Torulaspora delbrueckii (CCMA 0684)) inoculated in two varieties of coffee (Bourbon Amarelo and Canário Amarelo) using natural and pulped natural processing methods and sensory perception. Real-time PCR (qPCR) was used to verify the dynamic behavior of yeast populations. Organic acids were detected using high performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS) was used to detected volatile compounds. Sensory analysis was performed on the roasted coffee. Citric, malic, succinic, lactic, oxalic, isobutyric, and propionic acids and 105 volatile compounds were detected. At the beginning of fermentation, treatments with natural processing presented higher number of volatiles compounds. After fermentation, the main compounds groups were acids, alcohols, and aldehydes. The perception of sensory attribute (fruity, nutty, cocoa) varied with the coffee variety, type of processing, and type of inoculum. The use of yeasts is an alternative for sensorial differentiation of coffee variety Canário Amarelo and Bourbon Amarelo. The stainless-steel containers showed good results for coffee fermentation.

Assuntos

RESUMO

Correspondence analysis is a multivariate dimensionality-reduction technique applied to data structured into contingency tables. The main outcome of this approach is the generation of perceptual maps aimed at the study of similarity between categorical levels. In most cases, interpretations of these similarities present subjectivity when different metrics are considered; e.g., Hellinger distance and Chi-square. Thus, in an attempt to minimize this subjectivity, the present study proposes an index that quantifies the shortest distance between those levels. A simulation study was undertaken in which the generated maps were discussed in relation to real data involving the similarity of blends formed by coffees of different species, with sensory evaluations considering the flavor and acidity attributes. In conclusion, the proposed indexnamed metric selection index (MSI)made it possible to include a statistic that justifies the most suitable metric for correspondence analysis, thus preventing subjectivity in interpretations of similarities between blend types and grade classes. In the simulation studies, with the metric proposed by Hellinger distance, MSI showed stabler results regarding total inertia distribution on the first two axes.

A análise de correspondência é uma técnica multivariada de redução de dimensionalidade aplicada a dados estruturados em tabelas de contingência. Como principal resultado, mapas perceptuais são gerados com o propósito de estudar a similaridade entre os níveis categóricos. Na maioria das vezes, as interpretações dessas similaridades apresentam certa subjetividade, ao considerar diferentes métricas, como por exemplo, a distância de Hellinger e Qui-quadrado. Assim, com o intuito de minimizar essa subjetividade, esse trabalho teve como objetivo propor um índice que quantifique a menor distância entre esses níveis. Foi realizado um estudo de simulação, discutindo-se os mapas gerados em relação a dados reais envolvendo a similaridade de blends formados por cafés de diferentes espécies com avaliações sensoriais considerando os atributos sabor e acidez. Concluiu-se que a proposta do índice, denominado índice de seleção de métrica (ISM), permitiu agregar uma estatística que justifique a métrica mais adequada na análise de correspondência, evitando a subjetividade nas interpretações das similaridades entre os tipos de blends e classe de notas. Em relação aos estudos de simulação a métrica proposta pela distância de Hellinger, o ISM apresentou resultados mais estáveis em relação à distribuição da inércia total nos dois primeiros eixos.

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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.

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Automatic classification methods have been widely used in numerous situations and the boosting method has become known for use of a classification algorithm, which considers a set of training data and, from that set, constructs a classifier with reweighted versions of the training set. Given this characteristic, the aim of this study is to assess a sensory experiment related to acceptance tests with specialty coffees, with reference to both trained and untrained consumer groups. For the consumer group, four sensory characteristics were evaluated, such as aroma, body, sweetness, and final score, attributed to four types of specialty coffees. In order to obtain a classification rule that discriminates trained and untrained tasters, we used the conventional Fishers Linear Discriminant Analysis (LDA) and discriminant analysis via boosting algorithm (AdaBoost). The criteria used in the comparison of the two approaches were sensitivity, specificity, false positive rate, false negative rate, and accuracy of classification methods. Additionally, to evaluate the performance of the classifiers, the success rates and error rates were obtained by Monte Carlo simulation, considering 100 replicas of a random partition of 70% for the training set, and the remaining for the test set. It was concluded that the boosting method applied to discriminant analysis yielded a higher sensitivity rate in regard to the trained panel, at a value of 80.63% and, hence, reduction in the rate of false negatives, at 19.37%. Thus, the boosting method may be used as a means of improving the LDA classifier for discrimination of trained tasters.(AU)

Os métodos automáticos de classificação têm sido amplamente utilizados em inúmeras situações, nas quais o método boosting tem se destacado por utilizar um algoritmo de classificação que considera um conjunto de dados de treinamento e, a partir desse conjunto, constrói um classificador com versões reponderadas do conjunto de treinamento. Dada essa característica, esse trabalho tem por objetivo avaliar um experimento sensorial relacionado a testes de aceitação com cafés especiais, tendo como referência grupos de consumidores, treinados e não treinados. Ao grupo de consumidores, foram avaliadas quatro características sensoriais, tais como aroma, corpo, doçura e nota final, atribuídos a quatro tipos de cafés especiais. Com o propósito de obter uma regra de classificação que discrimine provadores treinados e não treinados, utilizaram-se a análise discriminante de Fisher convencional (LDA) e a análise de discriminante via algoritmo de boosting (Adaboost). Os critérios utilizados na comparação das duas abordagens foram sensibilidade, especificidade, taxa de falsos positivos, taxa de falsos negativos e acurácia dos métodos classificatórios. Adicionalmente, para avaliar o desempenho dos classificadores, as referidas taxas de acerto e erro foram obtidas por simulação Monte Carlo, considerando-se 100 réplicas de uma partição aleatória de 70% para a amostra de treinamento e o restante para o conjunto de teste. Concluiu-se que o método de boosting aplicado na análise discriminante proporcionou maior taxa de acerto quanto aos provadores treinados, cujo valor foi 80,63% e, consequentemente, redução na taxa de falsos negativos, cujo valor foi 19,37%. Dessa forma, o método de boosting pode ser utilizado como uma forma de aperfeiçoar o classificador LDA para a discriminação de provadores treinados.(AU)

Assuntos

RESUMO

Automatic classification methods have been widely used in numerous situations and the boosting method has become known for use of a classification algorithm, which considers a set of training data and, from that set, constructs a classifier with reweighted versions of the training set. Given this characteristic, the aim of this study is to assess a sensory experiment related to acceptance tests with specialty coffees, with reference to both trained and untrained consumer groups. For the consumer group, four sensory characteristics were evaluated, such as aroma, body, sweetness, and final score, attributed to four types of specialty coffees. In order to obtain a classification rule that discriminates trained and untrained tasters, we used the conventional Fisher’s Linear Discriminant Analysis (LDA) and discriminant analysis via boosting algorithm (AdaBoost). The criteria used in the comparison of the two approaches were sensitivity, specificity, false positive rate, false negative rate, and accuracy of classification methods. Additionally, to evaluate the performance of the classifiers, the success rates and error rates were obtained by Monte Carlo simulation, considering 100 replicas of a random partition of 70% for the training set, and the remaining for the test set. It was concluded that the boosting method applied to discriminant analysis yielded a higher sensitivity rate in regard to the trained panel, at a value of 80.63% and, hence, reduction in the rate of false negatives, at 19.37%. Thus, the boosting method may be used as a means of improving the LDA classifier for discrimination of trained tasters.

Os métodos automáticos de classificação têm sido amplamente utilizados em inúmeras situações, nas quais o método boosting tem se destacado por utilizar um algoritmo de classificação que considera um conjunto de dados de treinamento e, a partir desse conjunto, constrói um classificador com versões reponderadas do conjunto de treinamento. Dada essa característica, esse trabalho tem por objetivo avaliar um experimento sensorial relacionado a testes de aceitação com cafés especiais, tendo como referência grupos de consumidores, treinados e não treinados. Ao grupo de consumidores, foram avaliadas quatro características sensoriais, tais como aroma, corpo, doçura e nota final, atribuídos a quatro tipos de cafés especiais. Com o propósito de obter uma regra de classificação que discrimine provadores treinados e não treinados, utilizaram-se a análise discriminante de Fisher convencional (LDA) e a análise de discriminante via algoritmo de boosting (Adaboost). Os critérios utilizados na comparação das duas abordagens foram sensibilidade, especificidade, taxa de falsos positivos, taxa de falsos negativos e acurácia dos métodos classificatórios. Adicionalmente, para avaliar o desempenho dos classificadores, as referidas taxas de acerto e erro foram obtidas por simulação Monte Carlo, considerando-se 100 réplicas de uma partição aleatória de 70% para a amostra de treinamento e o restante para o conjunto de teste. Concluiu-se que o método de boosting aplicado na análise discriminante proporcionou maior taxa de acerto quanto aos provadores treinados, cujo valor foi 80,63% e, consequentemente, redução na taxa de falsos negativos, cujo valor foi 19,37%. Dessa forma, o método de boosting pode ser utilizado como uma forma de aperfeiçoar o classificador LDA para a discriminação de provadores treinados.

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RESUMO

O tempo despendido na secagem é fundamental para manter a qualidade do produto e escolher o procedimento de secagem a ser adotado. Esse trabalho teve como objetivo quantificar a redução do tempo de secagem com beneficiamento prévio do café conilon (Coffea canephora) em terreiro de estufa, bem como avaliar a qualidade dos grãos secos. O café conilon foi colhido com mais de 80% de frutos maduros e colocados, simultaneamente, em terreiros de estufas. Assim, as parcelas foram beneficiadas no momento em que atingiram 22%, 19%, 16% e 13% de umidade (bu). As parcelas com 22%, 19% e 16% (bu), foram levadas de volta ao terreiro até que atingissem o nível de umidade ideal de 13% (bu). O tempo de secagem foi quantificado e a qualidade do produto avaliada através análise sensorial, química e fisiológica. O trabalho foi realizado em blocos ao acaso, com quatro repetições, e os resultados submetidos ao teste F (ANOVA) e teste de média (Tukey a 5% de probabilidade). Houve diminuição de 6 dias na secagem do café beneficiado a 22% de umidade, comparado ao café beneficiado a 13%. O beneficiamento prévio do café conilon não afetou a qualidade final. Assim, conclui-se que o beneficiamento prévio do café com 22% (bu), com posterior secagem até atingir 13% é uma prática que favorece de maneira significativa o cafeicultor, pois diminui o tempo de secagem e maximiza o uso de área no terreiro, sem...(AU)

The time spent in coffee drying is quite important for keeping the product quality and therefore choosing the appropriate method to be used. This study was performed to quantify the decrease in drying time as a result of early hulling of conilon coffee (Coffea canephora) dried on a concrete terrace in a greenhouse, as well as to determine the quality of the dried coffee. The coffee was harvested at more than 80% ripe fruits and immediately placed on concrete terraces in greenhouses for drying. The parcels were hulled when 22%, 19%, 16% and 13% (wb) moisture levels were reached. Then, the parcels hulled at 22%, 19% and 16% moisture were returned to the greenhouse until they reached the desired moisture level of 13% (wb). The time spent on drying was quantified, and coffee quality was assessed through sensory, chemical and physiological analyses. This procedure was performed in four distinct periods during the harvest, and four repetitions were performed in blocks. The F (ANOVA) and Tukey (at 5% of probability) tests were performed to compare the evaluated characteristics among groups. The coffee hulled at 22% (wb) moisture content presented a considerably shorter drying time (6 days shorter) than the coffee hulled at 13% (wb) moisture content. The early hulling of conilon coffee did not affect the final quality. Thus, early hulling is a practical and significantly favorable...(AU)

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RESUMO

This work aimed to evaluate the effects of intermittent drying on the quality of the coffee, after twelve months of storage. The parchment coffee was submitted to two days of pre-drying on the ground, and soon afterwards, mechanically dried until reaching a moisture of 16%, 20% and 24% (wb); later, the coffee remained under tempering for two, six and twelve days in wooden boxes. After each tempering period, the drying was completed until the coffee reached a moisture of 11% (wb). The control consisted of continuous drying up to 11% (wb). After the drying until an 11% (wb) moisture, the coffee was stored for twelve months. After that period electric conductivity, potassium leaching, total reducing and non-reducing sugars, total titratable acidity analyses and sensorial analysis of the coffee were conducted. The values of electric conductivity indicated that the coffees submitted to two and six days of tempering until the restart of the drying, independent of the moisture when the drying was interrupted, presented lower degradation levels of the cellular membrane system, when compared with the coffees submitted to the continuous and intermittent drying, with twelve days of tempering until the resumption of drying. It was verified that, for the other analysis there was no significant difference among the treatments.

Objetivou-se, no presente trabalho, avaliar os efeitos do parcelamento da secagem na qualidade do café, após doze meses de armazenamento. O café cereja desmucilado foi submetido a dois dias de pré-secagem em terreiro, e em seguida, secado mecanicamente até atingir os teores de água de 16%, 20% e 24% (bu); posteriormente, o café permaneceu em repouso durante dois, seis e doze dias em caixas de madeira e após cada período de repouso, secado até o teor de água de 11% (bu). A testemunha constituiu-se na secagem contínua até 11% (bu). Após a secagem completa o café foi armazenado por doze meses; e então submetido às análises de condutividade elétrica, lixiviação de potássio, açúcares totais, redutores e não redutores, acidez titulável total e análise sensorial. Os valores de condutividade elétrica indicaram que os cafés submetidos a dois e seis dias de repouso até o reinício da secagem, independente do teor de água quando a secagem foi interrompida, apresentaram menores níveis de degradação ao sistema de membranas celulares, quando comparados com os cafés submetidos à secagem contínua e ao parcelamento da secagem, com doze dias de repouso até a retomada da secagem. As demais análises não indicaram diferença significativa entre os tratamentos.

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RESUMO

O tempo despendido na secagem é fundamental para manter a qualidade do produto e escolher o procedimento de secagem a ser adotado. Esse trabalho teve como objetivo quantificar a redução do tempo de secagem com beneficiamento prévio do café conilon (Coffea canephora) em terreiro de estufa, bem como avaliar a qualidade dos grãos secos. O café conilon foi colhido com mais de 80% de frutos maduros e colocados, simultaneamente, em terreiros de estufas. Assim, as parcelas foram beneficiadas no momento em que atingiram 22%, 19%, 16% e 13% de umidade (bu). As parcelas com 22%, 19% e 16% (bu), foram levadas de volta ao terreiro até que atingissem o nível de umidade ideal de 13% (bu). O tempo de secagem foi quantificado e a qualidade do produto avaliada através análise sensorial, química e fisiológica. O trabalho foi realizado em blocos ao acaso, com quatro repetições, e os resultados submetidos ao teste F (ANOVA) e teste de média (Tukey a 5% de probabilidade). Houve diminuição de 6 dias na secagem do café beneficiado a 22% de umidade, comparado ao café beneficiado a 13%. O beneficiamento prévio do café conilon não afetou a qualidade final. Assim, conclui-se que o beneficiamento prévio do café com 22% (bu), com posterior secagem até atingir 13% é uma prática que favorece de maneira significativa o cafeicultor, pois diminui o tempo de secagem e maximiza o uso de área no terreiro, sem...

The time spent in coffee drying is quite important for keeping the product quality and therefore choosing the appropriate method to be used. This study was performed to quantify the decrease in drying time as a result of early hulling of conilon coffee (Coffea canephora) dried on a concrete terrace in a greenhouse, as well as to determine the quality of the dried coffee. The coffee was harvested at more than 80% ripe fruits and immediately placed on concrete terraces in greenhouses for drying. The parcels were hulled when 22%, 19%, 16% and 13% (wb) moisture levels were reached. Then, the parcels hulled at 22%, 19% and 16% moisture were returned to the greenhouse until they reached the desired moisture level of 13% (wb). The time spent on drying was quantified, and coffee quality was assessed through sensory, chemical and physiological analyses. This procedure was performed in four distinct periods during the harvest, and four repetitions were performed in blocks. The F (ANOVA) and Tukey (at 5% of probability) tests were performed to compare the evaluated characteristics among groups. The coffee hulled at 22% (wb) moisture content presented a considerably shorter drying time (6 days shorter) than the coffee hulled at 13% (wb) moisture content. The early hulling of conilon coffee did not affect the final quality. Thus, early hulling is a practical and significantly favorable...

Assuntos

RESUMO

A manutenção da integridade das membranas celulares, entre outros eventos, é um forte indicativo de que a qualidade do café foi preservada na pós-colheita. Objetivou-se neste trabalho, analisar o efeito de diferentes métodos de secagem na manutenção da integridade da parede celular e da membrana plasmática de café natural e café despolpado, buscando determinar as condições e o momento em que ocorrem as rupturas microscópicas. Os cafés foram submetidos a um período de pré-secagem em terreiro. Após este, uma parcela de cada tipo de café foi desidratada no terreiro e, outra, à temperatura de 40ºC e 60ºC em secadores de camada fixa, monitorando-se a temperatura e o teor de água até 11 por cento (bu). Nesse período, grãos foram aleatoriamente amostrados e fragmentos do endosperma preparados para a microscopia eletrônica de varredura, registrando-se diversas eletromicrografias, avaliando-se as alterações na membrana plasmática da célula do endosperma dos grãos de cafés em função do teor de água e tempo de secagem. O citoplasma das células a 11 por cento (bu) de teor de água não foi comprometido na secagem em terreiro e a 40°C; na secagem a 60°C, observou-se comprometimento nas estruturas celulares nos cafés com teor de água de 20 por cento (bu).

The maintenance of the integrity of cellular membranes, among other events, is a strong indicator that the quality of the coffee was preserved in the post-harvesting process. Therefore, this work aimed to analyze the effect of different drying methods on the maintenance of the integrity of cell walls and plasma membrane of natural and de-pulped coffee in order to determine the conditions and the moment that microscopic ruptures take place. The coffee was submitted to a pre-drying period on a concrete patio. After this, a sample of each type of coffee was dehydrated outdoors and another, with heated air at 40ºC and 60ºC in fixed-layer dryers, controlling the grain temperature and the moisture content to 11 percent (bu). During the drying process the coffee grains were randomly sampled and fragments of the endosperm were prepared for scanning electron microscopy and eletromicrographs were taken. Measurements of the cells were taken for evaluating changes in the plasma membrane of the endosperm cells in relation to the moisture content and drying period. The cell cytoplasm of the coffee grains with 11 percent moisture content was not affected when dried under sun light and at the temperature of 40°C. When dried at 60°C, changes in the cellular structures of the cytoplasm were observed for coffees with moisture content of 20 percent.

RESUMO

O manejo adequado de doenças foliares, como a ferrugem e a cercosporiose do cafeeiro, é fator primordial para a produção de bebidas de qualidade. Nesse sentido, torna-se de extrema importância o conhecimento dos procedimentos técnicos e de produtos fitossanitários, bem como o efeito exercido pelos mesmos na qualidade do café. Objetivou-se, com este trabalho, estudar a qualidade dos grãos de café cereja descascado e bóia procedentes de tratamentos fungicidas, em duas safras agrícolas. Foram conduzidos ensaios nos anos agrícolas 2002/03 e 2003/04. O delineamento utilizado foi o inteiramente casualizado com parcelas subdivididas, utilizando-se quatro repetições, em esquema fatorial 2 x 3 x 2, compreendendo duas safras, três tratamentos fungicidas (fungicida sistêmico, nome comercial Ópera®, fungicida de contato, nome comercial Cobox®, e testemunha não tratada com fungicidas) e dois tipos de processamento, cereja descascado e bóia. As avaliações da qualidade dos grãos foram realizadas por meio das análises químicas: acidez titulável, pH, lixiviação de potássio e condutividade elétrica. Os resultados indicaram que os tratamentos fungicidas afetaram apenas a lixiviação de potássio para o café bóia, no qual o Cobox® apresentou menor lixiviação comparado aos demais. Em ambos os processamentos estudados, o segundo ano de ensaio apresentou maior condutividade elétrica, e quando considerado o café bóia, maior lixiviação de potássio. O resultados apontam ainda que, no primeiro ano de ensaio o café cereja descascado apresentou efeito superior para a acidez titulável.

The appropriate management of leaf diseases, such as rust and cercospora of the coffee plant, has become extremely important to the production of good quality coffee. In this context, the knowledge of technical procedures and phytosanitary products become extremely important, as well as the effect caused by them in the coffee quality. The objective of this work was to verify the influence of different methods of controlling fungal diseases in coffee plant on the grain quality of parchment and floater coffee. Trials were carried out in 2002/2003 and 2003/2004. The experimental design was the randomized complete block design subdivided into plots, using four replications, in a 2 x 3 x 2 factorial structure, involving two harvests, three fungicide treatments (Ópera®systemic fungicide, Cobox® cupric fungicide, and non-treated control), and two kinds of processing, parchment and floaters. The evaluation of the quality of the grains was performed through chemical analyses: titrable acidity, pH, leaching of potassium, and electrical conductivity. The results showed that the fungicide treatments just affect the leaching of potassium in floater coffee, in which Cobox® presented superior effect. In both processing methods studied the second year presented better electrical conductivity and better leaching of potassium in floater coffee. In the first year the parchment coffee presented superior effect for the titrable acidity.

RESUMO

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 CO2 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.

The present work aimed to give a sensorial evaluation to the coffee (Coffea arabica L.) beverage and to classify the shelled cherry-colored type coffee submitted to different packaging during storage. The experiment was installed entirely at random in a factorial outline 2x5x5, with three repetitions. Five packages were tested, with and without atmosphere modification, in five evaluation times, in two lots of shelled cherry-colored coffee, with one dried and the other processed. The impermeable packages (nylon sacks, nylon sacks with 40% of CO2 and foil vacuum packs) presented a capacity of preserving the quality of the drink of the shelled cherry-colored coffee, throughout the duration and conditions of the experiment. The coffee conditioned in permeable packing (jute sacks and jute sacks with ground coffee shells) presented sensorial alterations that depreciated the quality of the coffee. In the physical classification, the type of coffee didn't suffer alteration in the several packages used during the experiment.