Orientadores: Fernando Antonio Cabral, Losiane Cristina Paviani / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-21T23:56:25Z (GMT). No. of bitstreams: 1 Paula_JuliaTeixeirade_M.pdf: 2661007 bytes, checksum: 54793467279c439979f86fae6e09b9c5 (MD5) Previous issue date: 2013 / Resumo: Extratos de folhas de Arrabidaea chica (Humb. Bonpl.) Verlot foram obtidos usando dióxido de carbono supercrítico (scCO2), etanol e água como solventes. Dois tipos de extração sequencial em leito fixo foram realizados: o primeiro tipo em três etapas, usando o scCO2 na primeira etapa, o etanol na segunda e a água na terceira, nas temperaturas de 40 °C e 50 °C e pressões de 300 bar e 400 bar; o segundo tipo em duas etapas, usando o dióxido de carbono supercrítico em uma primeira etapa, seguida de uma segunda extração com uma mistura de scCO2/etanol/água em diferentes proporções, a 40 °C e 300 bar. Para comparação, foram realizadas algumas extrações convencionais: uma extração convencional etanólica a temperatura ambiente, uma extração convencional hidroalcoólica com uma mistura de etanol, água 70:30 (v:v) a temperatura ambiente, uma extração hidroalcoólica com uma mistura de etanol, água 70:30 (v:v) a 40 °C e 300 bar e três extrações aquosas convencionais (40 °C, 50 °C e 80 °C). Todos os extratos foram caracterizados quanto ao rendimento global, às respectivas cinéticas de extração, conteúdo de compostos fenólicos totais, flavonoides totais, antocianinas monoméricas totais, carajurina e luteolina. A cromatografia líquida de alta eficiência (CLAE) foi empregada na determinação quantitativa de dois compostos selecionados: 6,7-dihidroxi-5,4'-dimetoxi flavilium (carajurina) e luteolina, além do monitoramento qualitativo dos outros dois pigmentos presentes na A. chica: pigmento (1) 6,7,3',4'- tetra-hidroxi-5-metoxi flavilium e pigmento (2) 6,7,4'- trihidroxi-5-metoxi flavilium. Nos processos de extração em leito fixo em três etapas, o rendimento total acumulado das três etapas, nas quatro condições operacionais de temperatura e pressão, variaram entre 22 % e 27 %, sendo o maior rendimento global alcançado na condição de 50 °C e 300 bar. O maior teor de compostos fenólicos totais (178,2 mg EAG/g extrato) e flavonoides totais (373,2 mg EC/ g extrato) foi obtido pelo processo realizado com a mistura 80,8 % scCO2, 19,2 % de etanol e 0 % de água. Os extratos etanólicos apresentaram maior teor de carajurina e a maior concentração de luteolina foi obtida no extrato convencional hidroalcoólico com uma mistura de etanol, água 70:30 (v:v). Na extração com scCO2 puro, obteve-se o menor rendimento de extração e foi seletiva para extrair carajurina / Abstract: Extracts from Arrabidaea chica (Humb. Bonpl.) Verlot leaves were obtained using supercritical carbon dioxide (scCO2), ethanol and water as solvents. Two types of sequential extraction were carried out in a fixed bed: the first type in three stages, using scCO2 in the first step, the ethanol in the second step and water in the third step at temperatures of 40 °C and 50 °C and pressures of 300 bar and 400 bar; the second type in two steps, using supercritical carbon dioxide in a first step, followed by a second extraction with a mixture of scCO2/ethanol/water in different proportions, at 40 °C and 300 bar. For comparison, some conventional extractions were performed: an ethanolic extract conventional at room temperature, a conventional hydroalcoholic extraction with a mixture of ethanol, water 70:30 (v: v) at room temperature, a hydroalcoholic extraction with a mixture of ethanol, water 70:30 (v: v) at 40 °C and 300 bar and three extractions conventional aqueous (40 °C, 50 °C and 80 °C). All extracts were analyzed for global yield, the respective kinetics of extraction, total phenolic compounds, total flavonoid, anthocyanins monomeric total, carajurin and luteolin. The high performance liquid chromatography (HPLC) was used for quantitative determination of two selected compounds: 6,7-dihydroxy-5, 4'-dimethoxy flavilium (carajurina) and luteolin, besides for monitoring qualitatively the other two pigments present in A. chica: pigment (1) 6,7,3 ', 4'-tetrahydroxy-5-methoxy flavilium and pigment (2) 6,7,4' - trihydroxy-5-methoxy flavilium. In the three stages extraction processes in fixed bed, the global yield of the three steps accumulated in the four operational conditions of temperature and pressure ranged between 22 % and 27 %, with the highest overall efficiency achieved in the condition of 50 °C and 300 bar. The highest content of total phenolic compounds (178.2 mg GAE / g extract) and total flavonoid (373.2 mg CE / g extract) was obtained by the process performed with the mixture scCO2 80.8 %, 19.2 % ethanol and 0 % water. The ethanol extracts showed a high level of carajurin and the highest concentration of luteolin was obtained in conventional hydroalcoholic with a mixture of ethanol, water 70:30 (v: v). In pure scCO2 extraction, the lowest extraction yield was achieved and it selective to extract carajurin / Mestrado / Engenharia de Alimentos / Mestra em Engenharia de Alimentos

<div>Shifts in the human diet to more refined foods and ingredients have contributed to the rise in metabolic disease rates associated with long-term consumption of foods causing swift rises in blood glucose response. Foods which result in a more moderate blood glucose curve are considered healthier by increasing satiety and reducing oxidative stress. Sorghum products contain naturally slowly digested starch. The matrix of sorghum porridges contains kafirin protein bodies which cross link around gelatinizing starch molecules, while similar nascent matrices in other cereals aggregate and collapse. The 3-deoxyanthocyanidin pigments unique to sorghum may be accountable for the difference in matrix stability. The density of the starch entrapped in the matrices is thought to partially inhibit α-amylase access to the starch, reducing overall starch digestion and thereby mitigating glucose response. The purpose of this work was to increase our understanding of how phenolic compounds in sorghum interact with endosperm proteins to create a stable matrix, and to explore if the knowledge might be translated to other starchy cereal products. In the first study, phenolic extracts from flours (sorghum, corn masa, white rice) were characterized for phenolic content, antioxidant activity, phenolic components, and their ability to interact with a model protein system (ovalbumin) in order to examine protein polymerization. In the second study, specific phenolic compounds in sorghums (<i>p</i>-coumaric, sinapic, and gallic acids; (+)-catechin; and apigeninidin, a 3-deoxyanthocyanidin found in sorghums) were interacted in the model protein system at different concentrations to observe extent and type of protein polymerization, and promising compounds subjected to fluorescence quenching spectroscopy to examine the nature of the interactions. The final study explored the effects of apigeninidin addition to a yellow corn flour and naturally present anthocyanin (blue corn) on starch digestion and microstructure of porridges by utilizing an <i>in vitro</i> α-amylase assay and confocal microscopy. </div><div>The slow digestion of starch in cooked sorghum products can be attributed to the 3-deoxyanthocyanidin compounds present in the grain participating in sulfhydryl-disulfide interchanges which results in extensive kafirin cross-linking surrounding starch granules. While other phenolic and redox-active components may affect matrix formation and stability, 3-deoxyanthocyanidins appear to have the most direct influence, and their ability to modify food protein matrices appears to have a direct result on starch digestion <i>in vitro</i>.</div>