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URI permanente desta comunidadehttps://thoth.dti.ufv.br/handle/123456789/3352
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Item 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 VazThis 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.Item Quality of natural coffee dried under different temperatures and drying rates(Editora UFLA, 2018-04) Borém, Flávio Meira; Isquierdo, Eder Pedroza; Alves, Guilherme Euripedes; Ribeiro, Diego Egídio; Siqueira, Valdiney Cambuy; Taveira, Jose Henrique da SilvaThe final quality of coffees depends on the preservation of the cell membranes of the coffee beans, which can be damaged during the drying. Thus, the aim of this study was to assess the immediate and latent effects of the air temperature and drying rate on the sensorial quality of natural coffees, as well as its relationship with the chemical e physiological characteristics of the coffee beans. Mature fruits of arabica coffee were harvested and sundried to moisture content of approximately 35% (wb) and then moved into a mechanical drier under different conditions of drying. This process involved the combination of three dry bulb temperatures – DBT (35°C, 40°C, and 45°C) and two dew point temperatures – DPT (2.6°C and 16.2°C). Thus, the relative humidity of the air used for drying was a dependent variable of DTB and DPT, and as consequences, different drying rates were achieved for each DBT. The increase in the drying rate for the temperatures 35°C and 40°C has a negative effect on the final quality of natural coffee beans. However, for the temperature of 45°C, the effects of the drying rate on the coffee beans are overlaid by the thermal damages that are caused at this level of heating. Higher sensory scores for coffee are linked to lower values of electrical conductivity and potassium leaching of the exudate of the coffee beans, as well as lower values of fatty acids. It is emphasized that while the temperature of 35o C is recommended for the production of specialty coffees the temperature of 45o C is not.Item Quality of natural coffee subjected to different rest periods during the drying process(Editora UFLA, 2012-07) Isquierdo, Eder Pedroza; Borém, Flávio Meira; Oliveira, Pedro Damasceno de; Siqueira, Valdiney Cambuy; Alves, Guilherme EuripedesRest periods during the coffee drying process may help improve the final coffee quality and reduce power consumption. The objective of the present study was to evaluate the effect of the moisture content of coffee fruit at the point when the drying process is temporarily interrupted on the quality of natural coffee using sensory analysis and electrical conductivity and potassium leaching tests. Ripe coffee fruits were manually and selectively harvested, sun-dried in a concrete yard for two days and subjected to mechanical drying in fixed-bed dryers. When the coffee reached moisture contents of 20%, 17% and 14% (wet basis, wb), the drying process was interrupted, and the coffee was allowed to remain at rest for 5, 15 or 30 days. Following this rest period, the coffee was dried in mechanical dryers until reaching a moisture content of 11% (wb). The control condition was complete drying in the yard. The combination of lowest moisture content with greatest period of rest and the combination of greatest moisture content and shortest period of rest resulted in the lowest values of potassium leaching. The beverage quality gradually improved as the duration of the rest period increased. Coffee subjected to a rest period at moisture contents of 17% and 20% (wb) did not alter the quality compared to that from drying in the yard.Item Qualidade do café cereja desmucilado submetido ao parcelamento da secagem(Editora UFLA, 2011-01) Isquierdo, Eder Pedroza; Borém, Flávio Meira; Cirillo, Marcelo Ângelo; Oliveira, Pedro Damasceno de; Cardoso, Rennan Alves; Fortunato, Valquíria AparecidaA interrupção do processo de secagem do café (Coffea arabica L.) com elevados teores de água, e a conclusão da secagem após um determinado período de repouso, já é uma técnica comumente adotada pelos cafeicultores. Porém, são escassos os relatos científicos que recomendem essa técnica. Objetivou-se, no presente trabalho, avaliar os efeitos da secagem na qualidade do café. Após a pré-secagem em terreiro, o café foi secado mecanicamente até atingir os teores de água de 16%, 20% e 24% (bu); em seguida, o café permaneceu em repouso durante dois, seis e doze dias em caixas de madeira. Após cada período de repouso, a secagem foi completada até que o café atingisse o teor de água de 11% (bu). A testemunha constituiu-se na secagem contínua até 11% (bu). Para a caracterização da qualidade do café foram realizadas as análises de condutividade elétrica, lixiviação de potássio, açúcares totais, redutores e não redutores, coloração dos grãos beneficiados e análise sensorial. Verificou-se que os valores de condutividade elétrica e de lixiviação de potássio foram significativamente menores quando a secagem do grão foi interrompida com o teor de água de 24% independente do tempo de repouso, indicando que, para esse tratamento, os danos ao sistema de membranas foram menores em relação aos demais. Verificou-se também que, para as análises de açúcares totais, redutores e não redutores, análise de coloração dos grãos e análise sensorial não houve diferença significativa entre os tratamentos. Conclui-se que, para as condições desse experimento, não foram observadas alterações indesejáveis na qualidade do café cuja secagem foi interrompida com o teor de água de até 24% (bu) e que permaneceu em repouso por até 12 dias.