Caracterização da fração amilácea da farinha obtida a partir do fruto da castanha portuguesa (castanea sativa) modificada por hidrólise parcial enzimática

• Ano de defesa: 2016
• Autor(a) principal: Lopes, Bruna de Mônaco
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Positivo; Brasil; Pós-Graduação; Programa de Pós-Graduação em Biotecnologia Industrial; UP
• Palavras-chave em Português: Análise térmica; Amido - castanha portuguesa; Hidrólise; CNPQ::CIENCIAS BIOLOGICAS::BIOLOGIA GERAL
• Link de acesso: https://repositorio.cruzeirodosul.edu.br/handle/123456789/2612

The Portuguese chestnut fruit (Castanea sativa Mill) is a derived fruit of the chestnut tree, a fruit tree native from the northern hemisphere. At present, the species is commercially used in Brazil mainly for landscaping. This fruit has an important nutritional value by presenting several essential nutrients to the human diet. Among these nutrients, starch figure as the main component with a content between 38% - 80%, according to the technical literature. Starch is composed by around 33% of amylose and 67% of amylopectin. Starch is a component which can be changed regarding its composition in order to generate a final product with physico-chemical characteristics desirable for industrial processes. Starch samples were subjected to partial enzymatic hydrolysis for 12, 24 and 36 h, in order to check the behavior of the granules and to study the thermal phase transition by DSC analysis and TG-DTA. The variation obtained was around 3° C of temperature to start gelatinization. The larger range of variation was between 62 to 65 ° C, corresponding to native starch sample and sample with 12 h of treatment. Morphological and structural analyzes were performed using the techniques of scanning electron microscopy and apparent viscosity. With the enzymatic hydrolysis it was initially obtained an increase of starch particles due to surface erosion process of the granules. Gradually, with the action of enzymes in certain periods of time, the particles were breaking and detaching from the grain resulting in fractionated starch grains, which caused changes in the gelatinization temperature, detected in DSC analysis. There was an enthalpy variation between untreated and treated samples, possibly indicating a higher granule strength, with the enthalpy variation values of native starch 12, 24 and 36 h of treatment being, respectively, 4.85 J.g-1, 6.11 J.g-1, 4.96 J.g-1, 7.82 J.g-1. The images obtained by scanning electron microscopy show the erosion in the granules caused by enzymatic treatment. The treated samples featured lower peak viscosity (167.18 cP, 91.27 cP 66.09 cP, 46.14 cP) and low tendency to retrogradation (44.37 cP, 6.82 cP, 25 cP, 18.53 cP), whereas treatment showed changes in starch properties, which allow the consideration of their use in industrial applications.