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5-HMF as a versatile organic compound is considered as a promising biomass-derived value-added product via dehydration of saccharide. A large amount of research has been carried out on its production and separation. In this research, three single and three mixed solvents were tested to separate 5-HMF via liquid-liquid extraction from simulated HTC products. The mixed solvents were made up of DCM-THF, DCM-2-butanol and 2-butanol-THF with different mixing ratio of 1:4, 1:1, and 4:1. 20wt% and 10wt% NaCl were added in to help phase separation and to improve the performance of extraction. The simulated HTC product was composed of 5-HMF, levulinic acid and furfural. The extraction was carried out in vial and the phase separation was accomplished in a separatory funnel. The aqueous phase was analyzed with HPLC-UV to determine the solute concentrations in the aqueous phase. The solute concentrations in organic phase, partition coefficients, separation factors, solute recovery rates and purities of 5-HMF in separated products were calculated accordingly. The separation performance of mixed solvents was compared with theoretical values. In addition, the effects of pH and NaCl concentration on extraction and separation were investigated. It was found that the partition coefficients of 5-HMF were always higher than those of levulinic acid. 20 wt% of NaCl improved 5-HMF extraction significantly, and the corresponding partition coefficient was 6.87. Extraction of levulinic acid was found more sensitive to solvent pH value than 5-HMF and furfural. For 5-HMF extraction, pH 2.4 was more favorable than pH 2.0. Meanwhile, mixed solvents had better extraction performance than each single solvent for 5-HMF. The performance of the mixed solvents depended on mixing ratio; partition coefficient showed linear correlation with mixing fraction. More furfural was extracted into organic phase than 5-HMF, and the partition coefficients of levulinic acid were very close to that of 5-HMF. In general, however, mixed solvent extraction was able to improve the extraction efficiency rather than separation efficiency of 5-HMF.

5-HMF as a versatile organic compound is considered as a promising biomass-derived value-added product via dehydration of saccharide. A large amount of research has been carried out on its production and separation. In this research, three single and three mixed solvents were tested to separate 5-HMF via liquid-liquid extraction from simulated HTC products. The mixed solvents were made up of DCM-THF, DCM-2-butanol and 2-butanol-THF with different mixing ratio of 1:4, 1:1, and 4:1. 20wt% and 10wt% NaCl were added in to help phase separation and to improve the performance of extraction. The simulated HTC product was composed of 5-HMF, levulinic acid and furfural. The extraction was carried out in vial and the phase separation was accomplished in a separatory funnel. The aqueous phase was analyzed with HPLC-UV to determine the solute concentrations in the aqueous phase. The solute concentrations in organic phase, partition coefficients, separation factors, solute recovery rates and purities of 5-HMF in separated products were calculated accordingly. The separation performance of mixed solvents was compared with theoretical values. In addition, the effects of pH and NaCl concentration on extraction and separation were investigated. It was found that the partition coefficients of 5-HMF were always higher than those of levulinic acid. 20 wt% of NaCl improved 5-HMF extraction significantly, and the corresponding partition coefficient was 6.87. Extraction of levulinic acid was found more sensitive to solvent pH value than 5-HMF and furfural. For 5-HMF extraction, pH 2.4 was more favorable than pH 2.0. Meanwhile, mixed solvents had better extraction performance than each single solvent for 5-HMF. The performance of the mixed solvents depended on mixing ratio; partition coefficient showed linear correlation with mixing fraction. More furfural was extracted into organic phase than 5-HMF, and the partition coefficients of levulinic acid were very close to that of 5-HMF. In general, however, mixed solvent extraction was able to improve the extraction efficiency rather than separation efficiency of 5-HMF.

With increased worries of our Nations’ reliance on fossil fuels and their deleterious effects on the environment, researchers are concentrating on developing sustainable alternative sources for energy and chemicals. One potential starting resource that is worldwide distributed and renewable is biomass. Cellulose, the most plentiful source of biomass on earth, can be hydrolyzed into biofuel precursors such as 5-hydroxymethylfurfural (HMF). However, due to the poor solubility of cellulose and its robust crystalline structure, current methods available to degrade cellulose into these biofuel precursors are costly, result in low yields along with a large amount of waste. Generally, fructose is the preferred feedstock for the synthesis of HMF with high efficiency and selectivity. However, the large-scale production of HMF from fructose is limited due to the scarcity and the high cost of fructose. Therefore, it is desirable to use a cheaper renewable starting material for the synthesis of HMF such as sucrose. This study is conducted to develop an efficient one-pot process to synthesize HMF from biomass, particularly sucrose, using various sulfonated heterogeneous catalysts such as ordered mesoporous silica, bridged periodic mesoporous organosilicas (PMO) and carbon materials. The HMF yields in the presence of such acidic nanoporous materials were comparable to those using much less environmentally-friendly metal-based catalysts.

Avec la disparition progressive des réserves de carbone fossile, un intérêt tout particulier est aujourd’hui porté sur la valorisation de la biomasse notamment la cellulose. Elle représente une source importante (1,3 Millions de tonnes) et peu onéreuse (< 10 €/kg) de carbone renouvelable. L’utilisation de la cellulose en tant que matière première pour la chimie fine apparait comme une solution attractive tant sur le plan économique qu’environnemental. Néanmoins, la présence de liaisons hydrogène intra et extra réseau lui confère une stabilité élevée (forte cristallinité) la rendant insoluble dans les solvants organiques usuels et dans l’eau. Ainsi, l’hydrolyse de ce polymère en glucose ou oligosaccharides, en présence d’un catalyseur solide est limitée par les interactions catalyseur/cellulose. C’est pourquoi, des prétraitements de la cellulose sont souvent utilisés permettant alors d’augmenter les interactions avec les catalyseurs solides. Toutefois, les méthodes développées dans la littérature sont coûteuses ou néfastes pour l’environnement. L’objectif de cette étude est le développement d’activations physiques de la cellulose, respectueuses de l’environnement, permettant l’hydrolyse de ce polymère en présence d’un catalyseur solide. L’activation de la cellulose est effectuée par ultrasons ou par plasma atmosphérique non thermique. Ces méthodes d’activation permettent d’augmenter considérablement le rendement en glucose en modifiant i) la taille des particules et/ou ii) le degré de polymérisation et/ou iii) la cristallinité de la cellulose. Enfin, à partir des sucres issus de la dépolymérisation de la cellulose, le 5- hydroxyméthylfurfural (molécule plateforme) peut être obtenu. Cette synthèse sera étudiée et plus particulièrement la nature du solvant, qui impacte la sélectivité de cette réaction. Lors de ces travaux, un intérêt tout particulier est porté sur l’utilisation de glycérol et de carbonate de glycérol en tant que solvant. / With the depletion of fossil carbon resources, biomass (including cellulose) is widely introduced in the chemical industry, as a renewable source of carbon. Cellulose is a huge reservoir (1,3 Million tons) of cheap (< 10 €/kg) and non-edible carbon. So use cellulose as raw material has many advantages, as much as economic plan than environmental one. However, due to important inter and intra hydrogen bonds network, cellulose is highly crystalline and thus insoluble in common solvents (including water) and recalcitrant to hydrolysis by heterogeneous catalysis, due to solid/solid interactions. A preliminary step consists in the activation of cellulose to enhance the solid/solid interactions. However, the pretreatments used in the literature are limited by the cost, corrosiveness, and toxicity. The aim of this study is to develop physical pretreatments of cellulose in order to be environmentally friendly and promote cellulose/catalyst interactions. In this manuscript, two physical methods of cellulose activation will be explored. The first involves a sonic treatment and the second implies non-thermal atmospheric plasma technology. These methods lead to an increase of the glucose yield due to the change of i) the particle size, or/and ii) the degree of polymerization or/and iii) the cristallinity. From carbohydrate obtained via the depolymerisation of cellulose, 5-hydroxymethylfurfural (platform molecule) is achieved. This synthesis, including dehydration of fructose, will be studied and especially, the nature of the solvent which is a key point ofthis conversion will be discussed. In this work glycerol or glycerol carbonate-based media were studied, as co-solvent from renewable carbon.

京都大学 / 新制・課程博士 / 博士(エネルギー科学) / 甲第23394号 / エネ博第421号 / 新制||エネ||80(附属図書館) / 京都大学大学院エネルギー科学研究科エネルギー社会・環境科学専攻 / (主査)教授 河本 晴雄, 教授 髙野 俊幸, 准教授 奥村 英之 / 学位規則第4条第1項該当 / Doctor of Energy Science / Kyoto University / DFAM

Alkylierte polyzyklische aromatische Kohlenwasserstoffe (alk-PAK) kommen zusammen mit rein aromatischen polyzyklischen Kohlenwasserstoffen u.a. im Zigarettenrauch, Dieselabgasen sowie einigen Lebensmitteln (z.B. Freilandgemüse, planzliche Öle und Fette) vor. Benzylische Hydroxylierung und nachfolgende Sulfokonjugation ist ein wichtiger Bioaktivierungsweg für einige alk-PAK. Oxidation der benzylischen Alkohole durch Alkoholdehydrogenasen (ADH) und Aldehyddehydrogenasen (ALDH) zur Carbonsäure könnte einen wichtigen Detoxifizierungsweg in Konkurrenz zur Aktivierung durch Sulfotransferasen (SULT) darstellen, was für 1-Hydroxymethylpyren in der Ratte bereits gezeigt wurde (Ma, L., Kuhlow, A. & Glatt, H. (2002). Polycyclic Aromat Compnds 22, 933-946). Durch Hemmung der ADH und/oder ALDH ist eine verstärkte Aktivierung zu erwarten, wie in der besagten Studie ebenfalls nachgewiesen wurde. Insbesondere Ethanol kommt in diesem Zusammenhang eine Rolle als möglicher Risikofaktor für alk-PAK induzierte Kanzerogenese zu. Menschen konsumieren häufig große Mengen Ethanol und oft besteht eine Koexposition mit alk-PAK (z.B. durch Rauchen). Ähnliches gilt für 5-(Hydroxymethyl)-2-furfural (HMF), einem Pyrolyseprodukt reduzierender Zucker, dem gegenüber Menschen in recht hohen Mengen exponiert sind. Auch bei HMF steht der ADH- und ALDH-vermittelte oxidative Metabolismus in Konkurrenz zu einer Aktivierung durch Sulfokonjugation. Um die Bedeutung humaner ADH und ALDH im Metabolismus von alk-PAK und von HMF aufzuklären, wurden alle bekannten humanen ADH sowie die humanen ALDH2 und 3A1 (aus theoretischen Überlegungen heraus die vielversprechendsten Formen) für kinetische Analysen in Bakterien exprimiert. Als Enzymquelle dienten zytosolische Präparationen und durch Anionenaustauschchromatographie partiell gereinigte Enzyme. In der vorliegenden Arbeit wurde nachgewiesen, dass primäre benzylische Alkohole von Methyl- und Dimethylpyrenen gute Substrate humaner ADH sind. Sekundäre benzylische Alkohole und benzylische Alkohole von alk-PAK mit größerem Kohlenwasserstoffgrundgerüst erwiesen sich dagegen als schlechte Substrate. Vier Formen (ADH1C, 2, 3 und 4) wurden näher analysiert. Dazu wurden sie partiell gereinigt, primär um die störende endogene Bakterien-ADH zu eliminieren. Alle untersuchten ADH waren in der Lage Pyrenylmethanole zu oxidieren. Insbesondere ADH2 katalysierte die Oxidation der Pyrenylmethanole effizient, aber auch für ADH1C und 4 waren die Pyrenylmethanole gute Substrate. ADH3 oxidierte die Pyrenylmethanole mit geringer katalytischer Effizienz. Die Reduktion der entsprechenden Pyrenaldehyde durch ADH1C, 2 und 4 wurde mit noch höherer Effizienz katalysiert als die Oxidation der Pyrenylmethanole, was die Bedeutung von ALDH für die effiziente Detoxifizierung dieser Verbindungen unterstreicht. In einer an diese Arbeit angelehnten Diplomarbeit (Rost, K. (2007). Universität Potsdam, Mathematisch-Naturwissenschaftliche Fakultät) wurde auch tatsächlich gezeigt, dass humane ALDH2 aber auch ALDH3A1 in der Lage sind, die Pyrenaldehyde zu Pyrenylcarbonsäuren zu oxidieren. Die bestimmten kinetischen Parameter legen nahe, dass insbesondere ALDH2 von Bedeutung für die Detoxifizierung von Methyl- und Dimethylpyrenen ist. Schon allein auf Grund der an der Detoxifizierung beteiligten Enzyme ist Ethanolaufnahme bei Koexposition mit Pyrenderivaten als Risiokofaktor anzusehen. Es ist wahrscheinlich, dass Ethanol und, nach dessen Oxidation, Acetaldehyd als konkurrierende Substrate die ADH- und ALDH-katalysierte Oxidation von Pyrenylmethanolen bzw. Pyrenaldehyden inhibieren und somit zu einer verstärkten SULT-vermittelten Aktivierung der Pyrenylmethanole führen. In der Tat wurde eine effiziente Inhibition der ADH2-katalysierten Oxidation von 1-Hydroxymethylpyren und von 1-(Hydroxymethyl)-8-methylpyren durch physiologisch relevante Ethanolkonzentrationen nachgewiesen. Drei humane ADH (4, 2 und 3), die HMF effizient zum 2,5-Diformylfuran oxidieren können, wurden identifiziert. Durch ALDH-katalysierte Weiteroxidation dieser Substanz entsteht schließlich 2,5-Furandicarbonsäure, die nach HMF-Exposition auch tatsächlich im menschlichen Urin gefunden wurde (Jellum, E., Børresen, H. C. & Eldjarn, L. (1973). Clin Chim Acta 47, 191-201). Weiter wurde gezeigt, dass ALDH3A1, aber auch ALDH2 HMF effizient zur 5-(Hydroxymethyl)-2-furancarbonsäure (HMFA) oxidieren können, ein weiterer nachgewiesener HMF Metabolit in vivo. Dass die ADH-katalysierte Oxidation von HMFA und nachfolgende ALDH-katalysierte Oxidation zur Bildung von 2,5-Furandicarbonsäure einen nennenswerten Anteil beträgt, kann aufgrund der kinetischen Daten für HMFA als Substrat humaner ADH ausgeschlossen werden. Die beobachteten Enzymaktivitäten lassen den Schluss zu, dass Ethanolaufnahme zu einer Reduktion des oxidativen HMF Metabolismus führt und somit eine Aktivierung von HMF durch Sulfokonjugation begünstigt. / Alkylated polycyclic aromatic hydrocabons (alk-PAH), together with purely aromatic PAH, are present e.g. in tobacco smoke, diesel exhausts and also in some foods (e.g. outdoor vegetables, vegetable oils). Benzylic hydroxylation and subsequent sulfo conjugation is an important metabolic activation pathway for some of these compounds. Nevertheless, oxidation of the benzylic alcohols by alcohol dehydrogenases (ADH) and subsequently by aldehyde dehydrogenases (ALDH) can compete with the sulfo conjugation. Therefore, this pathway is probably important in the detoxification as could be shown for the representative compound 1-hydroxymethylpyrene in the rat (Ma, L., Kuhlow, A. & Glatt, H. (2002). Polycyclic Aromat Compnds 22, 933-946). Inhibition of ADH and/or ALDH should increase bioactivation as indeed was shown for 1-hydroxymethylpyrene in this study. Particularly ethanol, a competing ADH substrate, is of high interest in this context. Humans often consume large quantities of ethanol and often they are coexposed to alk-PAH (e.g. due to tobacco smoking). Similar relationships can be considered for 5-(hydroxymethyl)-2-furfural (HMF), a common pyrolysate of reducing sugars with high exposure to humans. Oxidative metabolism of HMF by ADH and ALDH also competes with its bioactivation by sulfotransferases (SULT). To clarify the importance of human ADH and ALDH in the metabolism of alk-PAH and HMF, all known human ADH as well as human ALDH2 and 3A1 (the most promising forms according to theoretical considerations) were expressed in bacteria for kinetic anlalyses. Cytosolic preparations or enzymes partially purified by anion exchange chromatography were used as enzyme source. In the present study it was shown that primary benzylic alcohols of methyl- and dimethylpyrenes were good substrates for human ADH. However, secondary benzylic alcohols and benzylic alcohols derived from alk-PAH with a bulkier hydrocarbon skeletal were poor substrates for human ADH. The most promising forms (ADH1C, 2, 3 and 4) were partially purified and further analysed. The purification step was necessary to eliminate the bacterial ADH. Particularly ADH2 was efficient for oxidation of pyrenylmethanols, although ADH1C and 4 were relatively efficient too. ADH3 was also capable of oxidising the tested pyrenylmethanols but with low catalytic efficiency. The reduction of the corresponding pyrene aldehydes was catalysed by ADH1C, 2 and 4 even with higher efficiency than the oxidation of the pyrenylmethanols emphasising the importance of ALDH for the detoxification of these compounds. In a diploma work related to the present study (Rost, K. (2007). University of Potsdam, Mathematisch-Naturwissenschaftliche Fakultät) it was shown that human ALDH2, but also ALDH3A1, can oxidise pyrene aldehydes to pyrenylcarboxylic acids. Particularly ALDH2 efficiently catalyse these reactions and, therefore, is probably of importance for the detoxification of methyl- and dimethylpyrenes. Due to the enzymes involved ethanol consumption could be a risk factor for methyl- and dimethylpyrene induced damage in the case of coexposure to methyl- and dimethylpyrenes. It is probable that ethanol and, after its oxidation, acetaldehyde will inhibit the ADH- and ALDH-catalysed oxidation of pyrenylmethanols and pyrenealdehydes. Indeed, it was shown that ADH2 catalysed oxidation of 1-hydroxymethylpyrene and of 1-(hydroxymethyl)-8-methylpyrene was efficiently inhibited by physiologically attainable concentrations of ethanol. Three human ADHs (4, 2 and 3) that efficiently oxidise HMF to 2,5-diformylfuran were identified. Further oxidation by ALDH leads to 2,5-furandicarboxylic acid, which was found in human urine after exposure to HMF (Jellum, E., Børresen, H. C. & Eldjarn, L. (1973). Clin Chim Acta 47, 191-201). Moreover, it was shown that human ALDH3A1 and also ALDH2 efficiently oxidise HMF to 5-(hydroxymethyl)-2-furancarboxylic acid (HMFA), which was also found in human urine. That 2,5-furandicarboxylic acid can be formed in significant amounts by ADH-catalysed oxidation of HMFA and subsequent oxidation by ALDH could be ruled out due to the kinetic data with HMFA as a substrate for human ADH. Due to the enzymes involved it is probable that ethanol consumption will inhibit the oxidative metabolism of HMF and, therefore, will increase the sulfo conjugation of HMF.

Given the volatile, generally high price of crude oil, as well as environmental concerns associated with its use as a fuel, development of alternative energy sources is currently of considerable interest. Lignocellulose-derived energy has the potential to supplant traditional fossil fuels in the future because of its economic and environmental advantages. Lignocellulosic biomass is abundant and renewable. Lignocellulose is primarily composed of cellulose, hemicellulose and lignin, which can be converted by acid hydrolysis to simple sugars used in fermentation to produce biofuels. In this study, hemicellulose was hydrolyzed with different concentrations of hydrochloric acid at different temperatures. The resulting components were analyzed by high performance liquid chromatography (HPLC). The hydrolysis of cellulose was similarly characterized, with two additional parameters, the degree of polymerization (DP) and the crystallinity index (CrI), which were analyzed by Ubbelohde viscometer and X-ray diffraction respectively. The experimental results indicate that the hydrolysis rate of hemicellulose and the generation rate of furfural and 5-hydroxymethylfurfural (HMF) increased with increasing hydrochloric acid concentrations and reaction temperatures. In the selected five monosaccharides, xylose, glucose, mannose, arabinose and galactose, xylose has the highest hydrolysis rate and the accumulation of furfural during xylose hydrolysis is also the highest. Moreover, the hydrolysis rate of cellulose and the generation rate of glucose also increased with increasing hydrochloric acid concentrations and reaction temperatures. DP and CrI, both decreased when the cellulose was treated in concentrated hydrochloric acid. The rate of change of DP increased with the concentrations of acid and the reaction temperatures. The change rate of CrI increases by increasing concentration of acid and the temperature when it is above 0℃, while the CrI index decrease sharply when the reaction temperature was kept below 0℃. Experimental results also show that the hydrolysis rate of cellulose is much lower than that of hemicellulose.

Orientador: Flávio Luis Schmidt / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-19T16:23:54Z (GMT). No. of bitstreams: 1 Vieira_LuanaReis_M.pdf: 12427431 bytes, checksum: 43cbcc66f7d6f2b06d12185e0be5c71d (MD5) Previous issue date: 2012 / Resumo: O mel pode ser definido como uma solução concentrada de açúcares. Possui enzimas,ácidos orgânicos e outros compostos. O aquecimento do mel é usualmente utilizado para descristalizar e facilitar o processamento. Atualmente na indústria o mel é aquecido por convecção forçada de ar e pode demorar de 4 a 7 dias, onerando o processamento. O emprego de altas temperaturas no mel pode alterar muitas de suas propriedades, como diminuição da enzima diastase e aumento do hidroximetilfurfural (HMF), importantes indicadores de qualidade. O objetivo do trabalho foi estudar o processo de descristalização do mel frente ao tratamento térmico em banho de água sob agitação,visando desenvolver métodos mais eficientes para a descristalização do produto. A partir dos dados da história térmica do mel, os parâmetros cinéticos de transferência de calor e os impactos do aquecimento nas propriedades do mel foram verificados. Foram utilizados três tipos de méis para avaliação de suas propriedades sob influência do aquecimento e determinação das cinéticas de reação. Avaliaram-se as alterações no pH, acidez, índice de formol e cor, além da atividade diastásica e conteúdo de HMF formados nas temperaturas de 50, 70 e 90ºC. Para os estudos de descristalização foram realizados 12 ensaios utilizando-se mel de eucalipto, safra 2010, aquecido nas temperaturas de 58, 75 e 95ºC e velocidades de rotação 0, 20, 30 e 40 rpm. O aquecimento a 50 e 70ºC não produziu importantes alterações na sua composição inicial, entretanto a 90ºC as alterações começaram a se evidenciar. Os resultados obtidos demonstraram que a formação de HMF e a destruição da diastase puderam ser descritos pelo modelo cinético de primeira ordem com Ea (energia de ativação) de 19,5 kcal/mol, z (índice térmico) de 27,7ºC e Q10 (quociente de velocidade) de 2,3; para a formação do HMF e Ea de 31,4 kcal/mol, z de 17,8ºC e Q10 de 4,3 para a degradação da diastase, sendo notada a maior dependência desta com a temperatura. Foram encontrados menores valores de fh (parâmetro do efeito da temperatura) com o aumento da agitação das embalagens e também com o aumento da temperatura empregada, sendo possível a partir da cinética das reações, estimarem as concentrações finais de HMF e diastase. O ensaio com melhores resultados para a descristalização do mel foi a 75ºC e 20 rpm onde o mel apresentou-se totalmente descristalizado e sem perdas significativas da qualidade. O fh encontrado para este ensaio foi de 16 min e coeficiente de transferência de calor 54,2 W/m2.ºC. Foi possível concluir que o uso de tratamento térmico em banho sob agitação para descristalização do mel melhora as propriedades de transferência de calor reduzindo o tempo total de processo, mantém as características de qualidade do mel em níveis aceitáveis, podendo ser empregado para otimização, rapidez de fluxo, eficiência da descristalização e aumento da produtividade nas indústrias / Abstract: Honey can be defined as a concentrated solution of sugars, containing many organic acids, pigments and other compounds. Heating of honey is usually utilized to dissolve the sugar crystals, making a more acceptable product. Nowadays, at big industries, honey is heated by forced air convection, which takes 4 to 7 days. This process is quite onerous,becoming a problem on honey processing. High temperatures can change many properties of honey, like decrease in diastase activity and increase in hydroxymetylfurfural (HMF) contents, important indicators of honey¿s quality. The aim of the present work was to study the liquefying crystallized honey process using thermal treatment in water bath under stirring, in order to develop more efficient methods of doing it. The work intended to verify, based on data from the thermal history of honey, the kinetic parameters of heat transfer and the consequences of heating on honey properties. To evaluate these consequences and to determine the reaction kinetics, three kinds of honey were used. The parameters: pH, acidity, formaldehyde contents and color, besides diastase activity and HMF contents were evaluated at 50, 70 and 90oC. To study liquefying crystallized honey process only eucalyptu's honey, crop 2010, was used. It was submitted to 12 essays, using temperatures of 58, 75 and 95oC, and stirring speed of 0, 20, 30 and 40 rpm. At 50 and 70ºC the changes observed in honey properties were not important, becoming significant at 90ºC. The results obtained demonstrated that production of HMF and degradation of diastase could be described by the kinetic model of first order with Ea of 19,52 kcal/mol, z of 27,7oC and Q10 of 2,32 for HMF production and Ea de 31,4 kcal/mol, z de 17,8ºC e Q10 de 4,27 for diastase. It was noted that diastase had the great temperature dependency. Increase in temperature and stirring speed of honey container, leds to decrease in fh (parameter of temperature effect) values. The reaction kinetics provided, in addition to kinetic parameters, estimated values of final concentrations of HMF and diastase. The essay with best results for liquefy crystallized honey was that of 75oC and 20rpm, in which honey was fully liquefied with no significant loss of quality. In this essay a fh value of 16 min and a heat transfer coefficient of 54,2 W/m2.OC were found. It was possible to conclude that use of heating treatment in water bath under stirring for liquefying crystallized honey improve the heat transfer properties, reducing total processing time,keep quality characteristics of honey at acceptable levels and, therefore, can be employed at the honey processor industries for optimization, flow quickness, efficiency in liquefying crystallized honey and increase in productivity / Mestrado / Tecnologia de Alimentos / Mestre em Tecnologia de Alimentos

Given the volatile, generally high price of crude oil, as well as environmental concerns associated with its use as a fuel, development of alternative energy sources is currently of considerable interest. Lignocellulose-derived energy has the potential to supplant traditional fossil fuels in the future because of its economic and environmental advantages. Lignocellulosic biomass is abundant and renewable. Lignocellulose is primarily composed of cellulose, hemicellulose and lignin, which can be converted by acid hydrolysis to simple sugars used in fermentation to produce biofuels. In this study, hemicellulose was hydrolyzed with different concentrations of hydrochloric acid at different temperatures. The resulting components were analyzed by high performance liquid chromatography (HPLC). The hydrolysis of cellulose was similarly characterized, with two additional parameters, the degree of polymerization (DP) and the crystallinity index (CrI), which were analyzed by Ubbelohde viscometer and X-ray diffraction respectively. The experimental results indicate that the hydrolysis rate of hemicellulose and the generation rate of furfural and 5-hydroxymethylfurfural (HMF) increased with increasing hydrochloric acid concentrations and reaction temperatures. In the selected five monosaccharides, xylose, glucose, mannose, arabinose and galactose, xylose has the highest hydrolysis rate and the accumulation of furfural during xylose hydrolysis is also the highest. Moreover, the hydrolysis rate of cellulose and the generation rate of glucose also increased with increasing hydrochloric acid concentrations and reaction temperatures. DP and CrI, both decreased when the cellulose was treated in concentrated hydrochloric acid. The rate of change of DP increased with the concentrations of acid and the reaction temperatures. The change rate of CrI increases by increasing concentration of acid and the temperature when it is above 0℃, while the CrI index decrease sharply when the reaction temperature was kept below 0℃. Experimental results also show that the hydrolysis rate of cellulose is much lower than that of hemicellulose.