Made available in DSpace on 2017-07-21T18:53:09Z (GMT). No. of bitstreams: 1 SIMONE CRISTINE WOSNIACKI BICUDO.pdf: 856559 bytes, checksum: d069ed257c254bc2a62e80ada3a1d5a0 (MD5) Previous issue date: 2008-02-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Starch is a very imp ortant polysaccharide for food processing. It is extracted from different sources and presents very important particular thermal characteristics. The most important temperature for food industry applications is the gelatinization, investigated in this work by techniques of thermal analysis, Differential Scanning Calorimetry (DSC), in various native starches. The thermal behaviour of starch granules was investigated by Thermogravimetry (TG), Differential Thermogravimetry (DTG) and Differential Thermal Analysis (DTA). Also the amylose content was measured for characterization of the native starches. The native starch that presented the lowest gelatinization temperature was the pinhão seed, with peak temperature of 50.8ºC, whereas the lowest amylose content, among non waxy starches, was of banana, with apparent amylose content of 8.1% and total amylose of 9.0%. / O amido é um carboidrato muito importante para o processamento dos alimentos. Está presente em diferentes fontes e apresenta características térmicas também variadas. O intervalo de temperatura de maior importância para a indústria é a de gelatinização, investigada neste trabalho através da técnica de análise térmica, Calorimetria Exploratória Diferencial (DSC), em diversos amidos nativos. Como muitos fatores influenciam o processamento dos alimentos, outras análises foram feitas para auxiliar na obtenção de informações para caracterizar diferentes amidos nativos, como Termogravimetria (TG) Termogravimetria Derivada (DTG) e Análise Térmica Diferencial (DTA), para investigar a degradação térmica dos grânulos de amido e os teores de amilose. O amido nativo que apresentou as menores temperaturas de gelatinização foi o de pinhão, com temperatura de pico de 50,8ºC enquanto que, os menores teores de amilose apresentados, dentre os amidos nativos não cerosos, foi o de banana, com amilose aparente de 8,1% e amilose total de 9,0%.

Pour cette étude, dans un premier temps, une caractérisation physico-chimique et rhéologique des amidons natifs de deux cultivars locaux de pomme de terre (Sipiera et Tselefou) et de trois de manioc (2425, 4115 et Seedling) a été faite avant leur incorporation dans du pâté de bœuf à 20, 30, 40 et 50g/kg de mêlée. L’influence du type d’amidon et de leur taux d’incorporation sur les propriétés physico-chimiques et texturales des pâtés a été évaluée. Les résultats ont montré que les propriétés physiques, fonctionnelles et rhéologiques des amidons sont étroitement liées à leur origine botanique. L’Analyse en Composantes Principales (ACP) laisse paraître que de tous les amidons natifs, celui du cultivar de pomme de terre Sipiera se rapproche le plus du témoin. Une fois incorporé dans les pâtés ; l’ACP de tous les paramètres texturaux des pâtés aux amidons natifs indique que le pâté à l’amidon du cultivar de manioc Seedling à de 40g/kg de mêlée (PS40), est celui qui se rapproche le plus du pâté témoin. Dans un deuxième temps, les amidons de pomme de terre (Sipiera) et de manioc (2425) ont été sélectionnés pour la modification (acétylation). Ces amidons acétylés ont par la suite fait l’objet des mêmes analyses que les amidons natifs et incorporés dans les pâtés aux mêmes taux que les amidons natifs. Des résultats, il ressort que les propriétés fonctionnelles des amidons natifs sont fortement influencées par l’acétylation et le temps d’acétylation. Les essais d’incorporation des amidons acétylés dans les pâtés montrent que l’amidon Sipiera/20 à un taux d’incorporation de 40g/kg de mêlée ne se distingue pas significativement (p>0,05) du pâté témoin / The first part of this work deals with the physico-chemical and rheological characterisation of native starches of two local cultivars of Irish potatoes (Sipiera and Tselefou) and three cultivars of cassava (2425, 4115 and Seedling) before they are incorporated into beef patty at 20, 30, 40 and 50g/kg ground meat. The influence of the type of starch and the amount of incorporation on the physico-chemical and textural properties of patties was evaluated. Results show that the physical, functional and rheological properties of starches are closely related to their botanical origin. Principal Component Analysis (PCA) showed that Irish potato cultivar Sipiera had properties that were close to reference. The PCA of all the textural properties of patties with native starches show that patty from starch of cassava cultivar Seedling at 40g/kg (PS40) was closest to the reference. In the second part of the work, the starch Sipiera and 2425 were selected for modification. These two starches were then acetylated for 10 and 20min. and this permitted us to have Sipiera/10, Sipiera/20, 2425/10 and 2425/20. The functional properties of the native starches were however strongly influenced by acetylation and the time of acetylation. Incorporation trials of this acetylated starches at different amounts in patty showed that Sipiera/20 starch at an incorporation rate of 40g/kg ground meat is not significantly different from the reference patty