Efeito das condições de manejo nas características sensoriais de banana (Musa spp.) cv. Pacovan

Estudou-se o efeito de quatro condições de manejo sobre a aceitação de banana 'Pacovan'. Os frutos foram colhidos no ponto de maturação fisiológica ideal para o armazenamento, em quatro propriedades rurais do município de Bananeiras - PB, seguindo-se delineamento inteiramente casualizado. Os tratamentos foram identificados como: P1: irrigação+adubação química e orgânica +controle químico de plantas invasoras; P2: controle manual de plantas invasoras; P3: irrigação+adubação química+controle manual de plantas invasoras; P4: controle manual e químico de plantas invasoras. Em cada propriedade, foram colhidos cinco cachos de banana que foram submetidos à climatização com carbureto de cálcio por 12 horas para uniformização da maturação. Após esse período, foram mantidos à temperatura ambiente até sua completa maturação. O painel sensorial foi composto por 62 julgadores não treinados, com idade média de 18 anos. Os atributos aroma, sabor, textura e cor da polpa foram avaliados por meio de teste de aceitação, utilizando-se de escala hedônica estruturada de 9 pontos. Para o teste de intenção de compra, foi utilizada escala estruturada de 5 pontos. As amostras foram apresentadas aos julgadores na forma de rodelas, com espessura aproximada de 1,5 cm. Os resultados foram submetidos à análise de variância (ANOVA), e as médias, comparadas pelo teste de Tukey, ao nível de 5% de probabilidade. Para todos os atributos avaliados,os valores situaram-se entre 7,34 e 7,68, posicionando-se na escala hedônica entre os termos 'gostei moderadamente' e 'gostei muito'. Para intenção de compra, o percentual de aceitação foi de 74,19; 72,58; 72,58 e 70,97%, respectivamente, para as amostras P1, P2, P3 e P4. O tipo de manejo não influenciou na aceitação da banana 'Pacovan', sendo os frutos considerados pelos julgadores como produto de boa aceitação.

Manejo da poda de raízes no transplantio de mudas de fruteiras nativas

Com o intuito de se avaliar o efeito da poda de raízes no transplantio de mudas de jabuticabeira, cerejeira-da-mata e uvaieira, realizou-se o presente trabalho por meio do manejo da poda do sistema radicular em diferentes proporções. O experimento foi conduzido na Universidade Tecnológica Federal do Paraná (UTFPR) - Câmpus Dois Vizinhos-PR. O delineamento experimental utilizado foi o inteiramente casualizado, em fatorial duplo 3 x 4 (fruteira nativa x percentual de poda de raiz), contendo quatro repetições, utilizandose de 10 mudas por unidade experimental. Após 180 dias de implantação do experimento, avaliaram-se o percentual de sobrevivência, o comprimento da parte aérea (cm) e o número de folhas, sendo para estas duas últimas variáveis considerada somente a diferença de valores obtidos do transplantio até esta análise. A realização da poda radicular em mudas de jabuticabeira, cerejeira-da-mata e uvaieira interfere de forma negativa para a sobrevivência e o desenvolvimento destas, não sendo aconselhada sua aplicação.

DESENVOLVIMENTO E PRODUÇÃO DE BANANEIRA ‘GRANDE NAINE’ EM DIFERENTES SISTEMAS DE MANEJO PARA A CONVIVÊNCIA COM A SIGATOKA-NEGRA NO VALE DO RIBEIRA-SP

RESUMO Objetivou-se avaliar o desenvolvimento e a produção de bananeira da cultivar Grande Naine submetidos a diferentes sistemas de manejo para a convivência com a Sigatoka-negra no Vale do Ribeira-SP (Brasil). Utilizou-se de mudas de ‘Grande Naine’ micropropagadas e conduzidas em delineamento inteiramente casualizado, com cinco tratamentos (sistemas de manejo): plantio intercalado; fungicida; desfolha+plantio intercalado; desfolha+fungicida; testemunha e subdividida no tempo (dois ciclos de produção), com oito repetições, considerando uma planta por repetição. Foram avaliados os seguintes parâmetros: altura da planta, diâmetro do pseudocaule, número de folhas ativas no florescimento e na colheita, massa fresca dos frutos comercializáveis, produtividade, número de pencas, número total de frutos, massa fresca total e por frutos da 2ª penca, comprimento e diâmetro de frutos da 2ª penca. Os dados foram submetidos a análises de variâncias, pelo teste F; e as médias, quando significativas, foram submetidas ao teste de Tukey (5 % de probabilidade). Conclui-se que as aplicações de fungicidas foram eficientes para o controle da Sigatoka-negra, com melhores resultados no desenvolvimento, na produção e na qualidade dos frutos da cultivar Grande Naine, porém sem apresentar diferenças quando associados com a desfolha. O plantio intercalado afetou negativamente em todos os parâmetro de desenvolvimento e produção da cultivar Grande Naine.

Aplicação da cromatografia por exclusão e da cromatografia gasosa de alta resolução na análise do café

The combination of high performance exclusion chromatography (HPEC) and gas chromatography (GC) was applied to the analysis of six coffee samples that were previously characterized by sensory tests as of good or poor quality. The data obtained by the two techniques were statistically evaluated by "Principal Components Analysis" (PCA) using selected peak areas. The results showed the potential of the described techniques for coffee analysis. The HPEC technique monitored with the U.V. detector at 272 nm and followed by PCA may be correlated with sensorial data, particularly if a wider group of samples is used.

Componentes voláteis do café torrado. Parte I: compostos heterocíclicos

A review of heterocyclic compounds in roasted coffee is presented. The contents, precursors and sensorial properties of furans, pyrroles, oxazoles, thiazoles, thiophenes, pyrazines and pyridines are discussed. The impact heterocyclic compounds of coffee aroma are described.

Componentes voláteis do café torrado. Parte II. Compostos alifáticos, alicíclicos e aromáticos

This review is about the aliphatic, alicyclic and aromatic compounds (non-heterocyclic compounds) that are present in the volatile fractions of roasted coffees. Herein, the contents, aroma precursors and the sensorial properties of volatile phenols, aldehydes, ketones, alcohols, ethers, hydrocarbons, carboxylic acids, anhydrides, esters, lactones, amines and sulphur compounds are discussed. Special attention is given to the compounds of these groups that are actually important to the final aroma of roasted coffees.

Determinação de compostos bioativos em amostras comerciais de café torrado

Coffee is a product consumed all around the world, Brazil being the biggest exporter. However, little is known about the difference in composition of the different brands in terms of bioactive substances. In the present study, ten of the most consumed brands of coffee in Rio de Janeiro were analyzed. Caffeine contents, trigonelline and total chlorogenic acid varied from 0.8 g/100g to 1.4 g/100g; 0.2 g/100g to 0.5 g/100g and from 3.5 g kg-1 to 15.9 g kg-1, respectively. The large heterogeneity observed in the amounts of the bioactive compounds can be attributed to different formulations of the various brands, as well as to different roasting conditions.

Metodologia para análise simultânea de ácido nicotínico, trigonelina, ácido clorogênico e cafeína em café torrado por cromatografia líquida de alta eficiência

A reverse phase liquid chromatography method was developed for simultaneous determination of trigonelline, caffeine, nicotinic and chlorogenic (5-CQA) acids in roasted coffee. A gradient of acetic acid/acetonitrile was used as mobile phase and detection was carried out in the UV. The samples were extracted with acetonitrile/water (5:95 v/v) at 80 ºC/10 min. Good recovery (89 to 104%), repeatability and linearity were obtained. Detection limits of 0.01, 0.15, 0.04 and 0.04 mg mL-1 were observed for nicotinic acid, trigonelline, 5-CQA and caffeine. The method, applied to arabica and robusta coffees with different degrees of roasting, was efficient and fast (~35 min) and also allowed identification of cinnamic acids.

Determinação de açúcar total em café cru por espectroscopia no infravermelho próximo e regressão por mínimos quadrados parciais

In this work a fast method for the determination of the total sugar levels in samples of raw coffee was developed using the near infrared spectroscopy technique and multivariate regression. The sugar levels were initially obtained using gravimety as the reference method. Later on, the regression models were built from the near infrared spectra of the coffee samples. The original spectra were pre-treated according to the Kubelka-Munk transformation and multiplicative signal correction. The proposed analytical method made possible the direct determination of the total sugar levels in the samples with an error lower by 8% with respect to the conventional methodology.

Influência do processamento e da torrefação sobre a atividade antioxidante do café (Coffea arabica)

The aim of this work is to evaluate the influence of processing (semi-dry and dry) and roasting (light, medium and dark) on the antioxidant activity of coffee brews, using tests to determine the reducing power and the DPPH scavenging, Fe+2 chelating and lipid peroxidation inhibition activities. All of the coffee brews presented concentration-dependent antioxidant activity. The light coffee samples presented the higher reducing power and DPPH scavenging activity. Its ion chelating capacity was similar to the medium samples, but was less than the green coffee chelating capacity. The semi-dry processing was more efficient than the dry processing only for the reducing power. All of the samples presented high lipid peroxidation inhibition activity. Based on the results the degree of coffee roasting seems to be more important than the processing to determine the antioxidant activity of brews.

Utilização do índice de retenção linear para caracterização de compostos voláteis em café solúvel utilizando GC-MS e coluna HP-Innowax

Gas chromatography coupled with mass spectrometry (GC-MS) is widely used for the characterization of volatile compounds. However, due to the complexity of the soluble coffee matrix, a complete identification of the components should not be based on mass spectra interpretation only. The linear index of retention (LRI) is frequently used to give support to mass spectra. The aim of this work is to investigate the characterization of the volatile compounds in soluble coffee samples by GC-MS using LRI values found with a HP-INNOWAX column. The method used allows a significant increase of the reliability of identifying compounds.

Preparação e caracterização de carvão ativado produzido a partir de resíduos do beneficiamento do café

Coffee fruit processing is one of the most polluting activities in agriculture due to the large amount of waste generated in the process. In this work, coffee parchment was employed as precursor for the production of carbons activated with ZnCl2 (CAP). The material was characterized using N2 adsorption/desorption at 77 K, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The material showed a surface area of 521.6 m²g-1 and microporous structure. CAP was applied as adsorbent for the removal of methylene blue dye in aqueous medium. The adsorption capacity was found to be about 188.7 mg g-1.

Preparação de carvão ativado em baixas temperaturas de carbonização a partir de rejeitos de café: utilização de FeCl3 como agente ativante

Ferric chloride as a new activating agent was used to obtain activated carbons from agroindustrial waste. This material was prepared at three temperatures of pyrolysis, 200, 280 and 400 ºC. The carbonaceous materials obtained after the activation processes showed high specific surface areas (BET), with values higher than 900 m² g-1. The materials showed different behaviors in the adsorption of methylene blue dye and reactive red textile dye in water solutions. An important fact in the use of FeCl3 as an activating agent is that the activation temperature is at 280 ºC, well below of those commonly employed in chemical or physical activations described in the literature.

Materiais à base de óxido de ferro para oxidação de compostos presentes no efluente da despolpa do café

Materials based on pure iron oxide and impregnated with niobia (Nb2O5) were prepared. Their catalytic activities were tested on the oxidation of compounds present in the wastewater from the processing of coffee berries. Particularly caffeine and catechol were tested. The oxidation reactions were carried out with the following systems (i) UV/H2O2, (ii) photo-Fenton and (iii) heterogeneous Fenton. All materials were characterized with X-ray diffraction, Mössbauer and infrared spectroscopy. Iron was mainly in the forms of goethite and maghemite. The oxidation kinetics were monitored by UV-vis and the oxidation products were monitored by mass spectrometry. The photo-Fenton reaction presented highest oxidation efficiency, removing 98% of all caffeine and catechol contents.

Composição volátil dos defeitos intrínsecos do café por CG/EM-headspace

About 20% of Brazilian raw coffee production is considered inappropriate for exportation. Consequently, these beans are incorporated to good quality beans in the Brazilian market. This by-product of coffee industry is called PVA due to the presence of black (P), green (V) and sour (A) defective beans which are known to contribute considerably for cup quality decrease. Data on the volatile composition of Brazilian defective coffee beans are scarce. In this study, we evaluated the volatile composition of immature, black-immature, black defective beans and PVA compared to good quality beans. Potential defective beans markers were identified.