Sapote gum polysaccharide was examined for homogeneity by ion-exchange chromatography on diethylaminoethyl (DEAE)-cellulose and by fractional precipitation of its propionate derivative. The polysaccharide showed essential homogeneity and was therefore suitable for structural analysis. The polysaccharide showed a low negative specific rotation and contained residues of L-arabinose, D-xylose, D-glucuronic and 4-O-methyl-D-glucuronic acids. A new method was developed for the simultaneous estimation of 4-O-methyl-D-glucuronic acid and other uronic acids by gas-liquid chromatography. Uronic acids in polysaccharides may be reduced by reaction with lithium borohydride in tetrahydrofuran. After hydrolysis and reduction of the monosaccharides the acetylated alditols may be separated by gas-liquid chromatography on a column of butanediol succinate. The method permits the simultaneous estimation of 4-O-methyl-D-glucuronic acid, D-glucuronic acid and D-galacturonic acids. It was found by this method that L-arabinose, D-xylose, D-glucuronic and 4-O-methyl-D-glucuronic acids were present in the ratio of 1:2.8:0.48:0.52. An examination of the O-methyl-derivative of the gum yielded 2,3,5- (+++) and 2,3,4- (+)- tri-O-methyl-L-arabinose, 2,3,4- (+)- tri-O-, 2,3- (+)- di-O-, 3-0- (+++)-methyl-D-xylose, 3,4- (++)- di-O-methyl-D-glucuronic and 2,3,4— (++)- tri-O-methyl-D-glucuronic acid. The methylation data indicates the high degree of branching in the polysaccharide. The presence of 3,4-di-O-methyl-D-glucuronic acid also indicates that a part of the total uronic acids is branched at C-2. Autohydrolysis of the gum yielded a series of oligouronic acids and a lesser branched polysaccharide. The polysaccharide after methylation, reduction and hydrolysis afforded 2,3,4-tri-O-methyl, 2,3-di-0-methyl, 3-O-methyl-D-xylose and 2,3,4~tri-O-methyl-D-glucose in a molar ratio of 2: 1.3: 1: 2 indicating that the degraded polysaccharide has a xylose backbone. Sapote gum polysaccharide after successive periodate oxidation, borohydride reduction and mild acid hydrolysis yielded a series of homologous glycosides, (xylosyl) n=1,2,3 glycerol, which were fully identified by methylation and periodate oxidation. The occurrence of these glycosides signifies a random branching in the polysaccharide. Periodate oxidation and subsequent complete acid hydrolysis of the carboxyl reduced polysaccharide afforded ethylene glycol, glycerol, 2-O-methyl-D-erythritol, D-xylose and 4-O-methyl-D-glucose whose molar ratios were determined by gas-liquid chromatography (g.l.c.). The presence of 4-O-methyl-D-glucose indicates that a major part.of 4-O- methyl-D-glucuronic acid is branched at C-2 (a conclusion supported by the methylation data) and 2-O-methyl-D-erythritol arises from a minor part of 4-O-methyl-D-glucuronic acid with no substituent at C-2. Partial acetolysis of the carboxyl-reduced polysaccharide afforded a new series of oligosaccharides [formula omitted] and [formula omitted]. The results confirm the presence of the oligouronic acids in the polysaccharide. A new method for the selective cleavage of glycosiduronic acids, Hofmann. degradation, was applied to sapote gum in order to study the resulting degraded polysaccharide and to find out the nature of the substituent on 4-O-methyl-D-glucuronic acid. The degraded polysaccharide after methylation and hydrolysis afforded 2,3,4-tri-O-methyl-, 2,3-di-O-methyl-, and mono-O-methyl-D-xylose in a molar ratio of 3: 11: 2. An oligosaccharide originally attached at C-2 of 4-O-methyl-D-glucuronic acid was isolated. Digestion of the polysaccharide with arabinofuranosidase yielded free arabinose indicating that a major part of the terminal non-reducing arabinose units are in the furanose form and linked with xylose in [symbol omitted] configuration. Some enzymes with known ‘xylanase’ activity did not degrade the gum because of the high degree of branching of the polysaccharide. The structural evidence suggests that sapote gum polysaccharide possesses a highly branched xylan framework to which are attached L-arabinose units, D-glucuronic acid and 4-O-methyl-D-glucuronic acid containing side chains. / Science, Faculty of / Chemistry, Department of / Graduate

Orientador: Antonio Baldo Geraldo Martins / Banca: Carlos Ruggiero / Banca: Eduardo Sanches Stuchi / Resumo: O mamey (Pouteria sapota) originário do México e América Central, sendo bastante comum em Cuba, Norte da América do Sul e nas Índias Ocidentais. Porém somente após sua introdução na Flórida passou a ser mais conhecido e procurado, principalmente pelos latino-americanos. Muito pouco se conhece sobre o mamey, não existem estudos sobre a caracterização das diferentes plantas desta frutífera no país e por isso são encontradas plantas com variados comportamentos fenotípicos, de produção e qualidade dos frutos. Para diversas frutíferas, a distinção entre variedades pode ser realizada com base em características dos frutos e folhas, permitindo a diferenciação dessas plantas. Diante disso, realizou-se o presente trabalho, verificando a possibilidade da distinção de plantas de mamey pertencentes à coleção do Banco Ativo de Germoplasma, da FCAV, Campus de Jaboticabal-SP, através de características físicas e químicas dos frutos e características morfológicas das folhas. Foram avaliadas: massa fresca (g), comprimento (cm), diâmetro (cm), rendimento de polpa (%), acidez titulável (AT), sólidos solúveis (SS), ácido ascórbico (AA), pH e "ratio"(SS/AT) de frutos de treze plantas de mamey. E para folhas foram medidos: comprimento (cm), largura (cm) e área foliar (cm2). Com base nos resultados obtidos, pode-se concluir que existem diferenças significativas tanto para as características físico-químicas dos frutos, assim como para as características morfológicas das folhas, possibilitando a seleção de matrizes promissoras, para implantação de pomares comerciais. / Abstract: The mamey sapota (Pouteria sapota) is originating from Mexico and Central America, but is quite common in Cuba, North of South America and the West Indies. But only after its introduction in Florida, mamey has become more known and sought, especially by Latin Americans. In general, little research has been done on mamey. In Brazil, for instance, there is no published research conducted on the characterization of this particular plant, which explains the great differences in plant behavior, production, and fruit quality. The distinction among varieties can be done based on fruits and leaves characteristics, what permit the differentiation of these plants. In this context, was realized the present research, verifying the possibility to distinguish plants from mamey sapota belonging to the collection of the Active Germoplasm Bank, in the FCAV, Campus of Jaboticabal, São Paulo State, Brazil, by physical and chemical characteristics of the fruits and morphological aspects of the leaves. It was evaluated: weight, length, width, pulp percentage, soluble solid (SS), titratable acidity (TA), ascorbic acid (AA), pH and SS/TA rate, on fruits of thirteen plants of mamey sapota. And for foliar aspects it was evaluated: length, width and leaf area. The results showed statistical difference for the physical and chemical characteristics of the fruits and also for the foliar aspects between all the mamey sapota plants studied, making possible the selection of promising plants for implantation of commercial orchards, and distinguishing the plants which fruits present desirable characters for industrial use. / Mestre

Made available in DSpace on 2014-06-11T19:28:29Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-02-22Bitstream added on 2014-06-13T20:58:17Z : No. of bitstreams: 1 nascimento_ve_me_jabo.pdf: 316206 bytes, checksum: c55ad3336cc722c93636a60b3c2d67a8 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / O mamey (Pouteria sapota) originário do México e América Central, sendo bastante comum em Cuba, Norte da América do Sul e nas Índias Ocidentais. Porém somente após sua introdução na Flórida passou a ser mais conhecido e procurado, principalmente pelos latino-americanos. Muito pouco se conhece sobre o mamey, não existem estudos sobre a caracterização das diferentes plantas desta frutífera no país e por isso são encontradas plantas com variados comportamentos fenotípicos, de produção e qualidade dos frutos. Para diversas frutíferas, a distinção entre variedades pode ser realizada com base em características dos frutos e folhas, permitindo a diferenciação dessas plantas. Diante disso, realizou-se o presente trabalho, verificando a possibilidade da distinção de plantas de mamey pertencentes à coleção do Banco Ativo de Germoplasma, da FCAV, Campus de Jaboticabal-SP, através de características físicas e químicas dos frutos e características morfológicas das folhas. Foram avaliadas: massa fresca (g), comprimento (cm), diâmetro (cm), rendimento de polpa (%), acidez titulável (AT), sólidos solúveis (SS), ácido ascórbico (AA), pH e “ratio”(SS/AT) de frutos de treze plantas de mamey. E para folhas foram medidos: comprimento (cm), largura (cm) e área foliar (cm2). Com base nos resultados obtidos, pode-se concluir que existem diferenças significativas tanto para as características físico-químicas dos frutos, assim como para as características morfológicas das folhas, possibilitando a seleção de matrizes promissoras, para implantação de pomares comerciais. / The mamey sapota (Pouteria sapota) is originating from Mexico and Central America, but is quite common in Cuba, North of South America and the West Indies. But only after its introduction in Florida, mamey has become more known and sought, especially by Latin Americans. In general, little research has been done on mamey. In Brazil, for instance, there is no published research conducted on the characterization of this particular plant, which explains the great differences in plant behavior, production, and fruit quality. The distinction among varieties can be done based on fruits and leaves characteristics, what permit the differentiation of these plants. In this context, was realized the present research, verifying the possibility to distinguish plants from mamey sapota belonging to the collection of the Active Germoplasm Bank, in the FCAV, Campus of Jaboticabal, São Paulo State, Brazil, by physical and chemical characteristics of the fruits and morphological aspects of the leaves. It was evaluated: weight, length, width, pulp percentage, soluble solid (SS), titratable acidity (TA), ascorbic acid (AA), pH and SS/TA rate, on fruits of thirteen plants of mamey sapota. And for foliar aspects it was evaluated: length, width and leaf area. The results showed statistical difference for the physical and chemical characteristics of the fruits and also for the foliar aspects between all the mamey sapota plants studied, making possible the selection of promising plants for implantation of commercial orchards, and distinguishing the plants which fruits present desirable characters for industrial use.