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Since ancient times, coffee has been a savory drink for most of the world's population. It is the second most widely distributed commodity after crude oil in the world. Hence, there has always been a pressure on the coffee industry to produce more volume of good quality coffee. The coffee industry has not been able to meet this increasing coffee demand due to various reasons, such as low crop yield, high coffee rejection rate etc. Historically, the coffee production industry has had high rejection rates due to inadequate knowledge about the defects that plague coffee and the lack of research to detect and eliminate the defective coffee beans. In this thesis, an attempt has been made to minimize the rejection rate of coffee beans due to a specific defect called "Potato Defect". Potato defect is very prominent in East African countries for reasons not yet known. It is caused by an increase in the concentration of 2-isopropyl -3-methoxypyrazine (IPMP), present in parts per billion concentration in coffee beans. In this thesis, various techniques have been evaluated to detect the increased concentration of IPMP, and then eliminate the 'potato defect' infected coffee beans. As these proposed techniques need to be implemented on an industrial scale, special care has been taken to keep the inspection time of coffee beans as low as possible to minimize its negative impact on the overall coffee production rate. Considering both sensitivity and time, non destructive methods such as ion mobility spectrometry, cavity ring down spectrometry and electronic nose were assessed for their suitability to identify low concentrations of IPMP in the complex matrix of coffee volatiles. Experiments were also conducted by Solid Phase Micro Extraction (SPME), followed by multidimensional gas chromatography with simultaneous olfactory and mass spectrometric detection (GC- MS-O) technology to validate information related to the 'potato defect'. GC-MS-O could detect IPMP present in whole green coffee beans while other researchers only detected IPMP in ground coffee. The findings of this thesis opens the doors for the coffee industry to establish non destructive, sensitive methodology to analyze further coffee aroma.

Made available in DSpace on 2014-06-11T19:24:46Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-09-21Bitstream added on 2014-06-13T20:32:11Z : No. of bitstreams: 1 huamanimelendez_vj_me_sjrp_parcial.pdf: 569064 bytes, checksum: a421744f281164e37617b166ac6f3843 (MD5) Bitstreams deleted on 2014-10-03T16:24:34Z: huamanimelendez_vj_me_sjrp_parcial.pdf,Bitstream added on 2014-10-03T16:27:33Z : No. of bitstreams: 2 huamanimelendez_vj_me_sjrp_parcial.pdf.txt: 53713 bytes, checksum: 111b3a17f7877d22607c79773592bd40 (MD5) 000698203.pdf: 2310634 bytes, checksum: 632d409df815fe5814967be2a2659bf4 (MD5) Bitstreams deleted on 2014-10-03T16:33:11Z: 000698203.pdf,Bitstream added on 2014-10-03T16:43:25Z : No. of bitstreams: 2 huamanimelendez_vj_me_sjrp_parcial.pdf.txt: 53713 bytes, checksum: 111b3a17f7877d22607c79773592bd40 (MD5) 000698203.pdf: 2310634 bytes, checksum: 632d409df815fe5814967be2a2659bf4 (MD5) Bitstreams deleted on 2014-10-03T16:48:51Z: 000698203.pdf,Bitstream added on 2014-10-03T16:49:44Z : No. of bitstreams: 1 000698203.pdf: 2310634 bytes, checksum: 632d409df815fe5814967be2a2659bf4 (MD5) Bitstreams deleted on 2014-10-27T11:47:01Z: 000698203.pdf,Bitstream added on 2014-10-27T11:48:02Z : No. of bitstreams: 1 000698203.pdf: 2310634 bytes, checksum: 632d409df815fe5814967be2a2659bf4 (MD5) / Oea / A presente pesquisa propõe como alternativa melhorar o processo de extração da cafeína dos grãos de café de variedade arábica utilizando água como solvente com auxílio de ultrassom de alta intensidade. Na primeira etapa da pesquisa foram avaliadas propriedades físicas do grão no processo de hidratação e a proposição da solução analítica para a semiesfera da equação de Fick. Na segunda etapa foi avaliado o coeficiente de difusão da cafeína no processo de extração com água em diferentes temperaturas (30, 40, 50 e 60 °C). Na terceira etapa foi empregado um delineamento composto central rotacional para avaliar a porcentagem de recuperação e o coeficiente de difusão de cafeína nos grãos de café, para os tempos de 15, 30 e 60 minutos sob a influência do ultrassom de alta intensidade (30, 45, 65, 85 e 100% da amplitude da potência) em diferentes ciclos de aplicação (30, 45, 65, 85 e 100%) e em função da temperatura de extração (30, 36, 45, 53 e 60 °C). O modelo matemático para geometria semiesférica apresentou melhor ajuste aos dados experimentais, tanto para a difusão de água nos grãos de café no processo de hidratação, como para o processo de extração de cafeína em meio aquoso. O coeficiente de difusão de água no grão de café no processo de hidratação variou de 6,901 .10-11 m2 s-1 a 30 °C até 3,119 .10-10 m2 s-1 a 60 °C, com energia de ativação de 41,243 kJ mol-1. Para a difusão da cafeína, o modelo matemático para semiesfera também resultou ser ligeiramente superior na maioria dos casos, onde o coeficiente de difusão variou de 1,026 .10-11 m2 s-1 a 30 °C até 9,004 .10-11 m2 s-1 a 60 °C com uma energia de ativação de 59,933 kJ mol-1. Na aplicação de ultrassom de alta intensidade, os fatores de potência de ultrassom e a temperatura... / This research proposes as an alternative to improve the process of extracting caffeine from coffee beans, arabica variety, using water as solvent, assisted by high-intensity ultrasound. In the first stage of the research, physical properties of the grain were evaluated in the hydration process and the proposition of an analytical solution for the semi-sphere of the Fick equation. In the second stage, it was determined the diffusion coefficient of caffeine in the extraction process with water at different temperatures (30, 40, 50 and 60 °C). In the third stage, a central composite rotational design was used to assess the percentage of recovery and the diffusion coefficient of caffeine in coffee beans, for caffeine extraction upon different treatment times (15, 30 and 60 minutes) under the influence of high-intensity ultrasound (30, 45, 65, 85 and 100% of the power amplitude), different application cycles (30, 45, 65, 85 and 100%), as a function of the temperature (30, 36, 45, 53 and 60 °C). The mathematical model presented by the semispherical geometry showed the best fit to the experimental data, in comparison to Fick's sphere geometry approach, both for the diffusion of water in the coffee beans in the hydration process, and for the extraction process of caffeine in aqueous media. The diffusion coefficient of water in the coffee bean in the hydration process ranged from 6.901 ×10-11 m2 s-1 at 30°C to 3.119 ×10-10 m2 s-1 at 60°C, with and activation energy of 41.243 kJ mol-1. For the diffusion of caffeine in the grain, the semi-sphere mathematical model also resulted slightly better fitting in most cases, with a diffusion coefficient ranged from 1.026 ×10-11 m2 s-1 at 30°C to 9.004 10-11 m2 s-1 at 60°C, and an activation energy of 59.933 kJ mol-1. In the high-intensity ultrasound assisted extraction process, the ultrasound... (Complete abstract click electronic access below)

O presente trabalho experimental focaliza o tema \"compostos fenólicos no café\". Dentre estes compostos se destacam os flavonóides, os ácidos clorogênico, cafêico, cafeilquinico, e seus isômeros. Na pesquisa foram avaliados quantitativamente, por espectrofotometria UV/VIS, as espécies fenólicas presentes após extração e complexação em amostras de cafés (cascas e sementes) com grãos em vários estágios de maturação. Foram obtidos valores na faixa de 10-6 mol.L-1 para fenóis totais nas cascas e nos grãos. O método de extração aqui proposto tornou-se bastante viável, sendo possível sua aplicação com tempo de preparo de amostras secas para análise de cerca de 40 minutos. As evidências experimentais decorrentes dessa pesquisa sugerem que tais espécies fenólicas (anti-oxidantes) podem ser aproveitadas de um material que é descartado (a casca do café), sendo, portanto um grande benefício econômico para a sustentabilidade do cultivo do café. / This experimental work has focused the theme \"Phelonic Compound in Coffee Beans\". Among these compounds have been shown flavonoids species, chlorogenic acid, caffeic acid, caffeinic acid and their isomer. The phelonic species has presented after extraction and complexation from coffee samples (peels and beans) using coffee beans in different grown and developed process has been evaluated in quantitative research by using UV/VIS Spectrophotometry Values have been got about 10-6 mol.L-1 in peels and beans. The proposed extraction method has been not only viable but its use possible with preparing time of dried samples for analyses in about 40 minutes. The experimental evidence resulting from this research has proposed that such phenolic antioxidant species can be made a good use of discarded material (the peel of coffee beans) therefore a great economical benefit for sustainable coffee cultivation.

Šio darbo tiksas - nustatyti ochratoksino A kiekius žaliose ir skrudintose kavos pupelėse. Mėginiai tyrimams buvo paimti iš dviejų Lietuvos kavos skrudinimo įmonių. Kavos pupelių mėginiai buvo iš Amerikos, Afrikos ir Azijos. Žalių kavos pupelių užterštumas ochratoksinu A buvo 1,0 – 3,5 µg/kg, o po skrudinimo jis padidėjo 14,12 – 63,64%. Taip pat buvo identifikuojami ochratoksiną A gaminantys grybai ir skaičiuojami jų kolonijas sudarantys vienetai. Nustatyta, kad kavos pupelės buvo užterštos A. niger, A. ochraceus, A. parasiticus, A. sydowii ir A. flavus. / The experiments was done in LUHS VA in the Animal Welfare Reaserch Laboratory. The aim of this study were to determinate ochratoxin A amounts in green and roasted coffee beans. Samples were taken from two coffee roasters companies in Lithuania. Coffee samples were from America, Asia and Africa. The determination of OTA in green coffee samples was 1,0 – 3,5 µg/kg, but after roasting it increase to 14,12 – 63,64%. Also were identified OTA-producing species of fungi and their colony formed quantities. It was found that determination of fungi were 50% of A. niger colonies, other 50% were of A. ochraceus, A. parasiticus, A. sydowii and A. flavus.

Orientador: Roger Darros Barbosa / Banca: Maria Aparecida Mauro / Banca: Fernando Antonio Cabral / Resumo: A presente pesquisa propõe como alternativa melhorar o processo de extração da cafeína dos grãos de café de variedade arábica utilizando água como solvente com auxílio de ultrassom de alta intensidade. Na primeira etapa da pesquisa foram avaliadas propriedades físicas do grão no processo de hidratação e a proposição da solução analítica para a semiesfera da equação de Fick. Na segunda etapa foi avaliado o coeficiente de difusão da cafeína no processo de extração com água em diferentes temperaturas (30, 40, 50 e 60 °C). Na terceira etapa foi empregado um delineamento composto central rotacional para avaliar a porcentagem de recuperação e o coeficiente de difusão de cafeína nos grãos de café, para os tempos de 15, 30 e 60 minutos sob a influência do ultrassom de alta intensidade (30, 45, 65, 85 e 100% da amplitude da potência) em diferentes ciclos de aplicação (30, 45, 65, 85 e 100%) e em função da temperatura de extração (30, 36, 45, 53 e 60 °C). O modelo matemático para geometria semiesférica apresentou melhor ajuste aos dados experimentais, tanto para a difusão de água nos grãos de café no processo de hidratação, como para o processo de extração de cafeína em meio aquoso. O coeficiente de difusão de água no grão de café no processo de hidratação variou de 6,901 .10-11 m2 s-1 a 30 °C até 3,119 .10-10 m2 s-1 a 60 °C, com energia de ativação de 41,243 kJ mol-1. Para a difusão da cafeína, o modelo matemático para semiesfera também resultou ser ligeiramente superior na maioria dos casos, onde o coeficiente de difusão variou de 1,026 .10-11 m2 s-1 a 30 °C até 9,004 .10-11 m2 s-1 a 60 °C com uma energia de ativação de 59,933 kJ mol-1. Na aplicação de ultrassom de alta intensidade, os fatores de potência de ultrassom e a temperatura... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This research proposes as an alternative to improve the process of extracting caffeine from coffee beans, arabica variety, using water as solvent, assisted by high-intensity ultrasound. In the first stage of the research, physical properties of the grain were evaluated in the hydration process and the proposition of an analytical solution for the semi-sphere of the Fick equation. In the second stage, it was determined the diffusion coefficient of caffeine in the extraction process with water at different temperatures (30, 40, 50 and 60 °C). In the third stage, a central composite rotational design was used to assess the percentage of recovery and the diffusion coefficient of caffeine in coffee beans, for caffeine extraction upon different treatment times (15, 30 and 60 minutes) under the influence of high-intensity ultrasound (30, 45, 65, 85 and 100% of the power amplitude), different application cycles (30, 45, 65, 85 and 100%), as a function of the temperature (30, 36, 45, 53 and 60 °C). The mathematical model presented by the semispherical geometry showed the best fit to the experimental data, in comparison to Fick's sphere geometry approach, both for the diffusion of water in the coffee beans in the hydration process, and for the extraction process of caffeine in aqueous media. The diffusion coefficient of water in the coffee bean in the hydration process ranged from 6.901 ×10-11 m2 s-1 at 30°C to 3.119 ×10-10 m2 s-1 at 60°C, with and activation energy of 41.243 kJ mol-1. For the diffusion of caffeine in the grain, the semi-sphere mathematical model also resulted slightly better fitting in most cases, with a diffusion coefficient ranged from 1.026 ×10-11 m2 s-1 at 30°C to 9.004 10-11 m2 s-1 at 60°C, and an activation energy of 59.933 kJ mol-1. In the high-intensity ultrasound assisted extraction process, the ultrasound... (Complete abstract click electronic access below) / Mestre

O presente trabalho experimental focaliza o tema \"compostos fenólicos no café\". Dentre estes compostos se destacam os flavonóides, os ácidos clorogênico, cafêico, cafeilquinico, e seus isômeros. Na pesquisa foram avaliados quantitativamente, por espectrofotometria UV/VIS, as espécies fenólicas presentes após extração e complexação em amostras de cafés (cascas e sementes) com grãos em vários estágios de maturação. Foram obtidos valores na faixa de 10-6 mol.L-1 para fenóis totais nas cascas e nos grãos. O método de extração aqui proposto tornou-se bastante viável, sendo possível sua aplicação com tempo de preparo de amostras secas para análise de cerca de 40 minutos. As evidências experimentais decorrentes dessa pesquisa sugerem que tais espécies fenólicas (anti-oxidantes) podem ser aproveitadas de um material que é descartado (a casca do café), sendo, portanto um grande benefício econômico para a sustentabilidade do cultivo do café. / This experimental work has focused the theme \"Phelonic Compound in Coffee Beans\". Among these compounds have been shown flavonoids species, chlorogenic acid, caffeic acid, caffeinic acid and their isomer. The phelonic species has presented after extraction and complexation from coffee samples (peels and beans) using coffee beans in different grown and developed process has been evaluated in quantitative research by using UV/VIS Spectrophotometry Values have been got about 10-6 mol.L-1 in peels and beans. The proposed extraction method has been not only viable but its use possible with preparing time of dried samples for analyses in about 40 minutes. The experimental evidence resulting from this research has proposed that such phenolic antioxidant species can be made a good use of discarded material (the peel of coffee beans) therefore a great economical benefit for sustainable coffee cultivation.

My diploma work deals with the topic of The preparation of coffee and its culture which is becoming interesting issue in our modern society and it is connected with modern lifestyle. The aim of my diploma work is exploring people's knowledge of coffee, coffee culture and also of the right preparation of coffee beverages, their health effects and some alternative methods of making coffee. Next point is to survey people's attitudes and social influences on coffee culture. Theoretical part of my work is mainly focused on coffee as a plant, processing of coffee beans, making coffee and coffee culture. The facts have been excerpted from available specialized literature and online resources. I have also used my theoretical knowledge based on my experience with SCAE Speciallity Coffee Association of Europe, that has the seat in London. Empirical research can be used as an inspiration for setting up a coffee bar. My diploma work can serve as a resource for creating specialized publication aimed at either wide public interested in coffee culture or at professional barists.

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