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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Desenvolvimento de bioblendas polim?ricas a partir de gelatina bovina e de til?pia com amido de milho

Nunes, Yana Luck 15 August 2014 (has links)
Made available in DSpace on 2014-12-17T14:07:19Z (GMT). No. of bitstreams: 1 YanaLN_DISSERT.pdf: 5775270 bytes, checksum: f47a012d46ef867169583aea0a586ef2 (MD5) Previous issue date: 2014-08-15 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The natural raw materials acquired special importance beside the mineral raw materials with the need for using alternative sources to oil, because they can be used to produce biopolymers. Gelatin, produced from the denaturation of collagen, and starch, an abundant polysaccharide in various plants, are examples of biopolymers which have several technological applications, especially in films. The objective of this work is to produce polymeric bioblends with gelatin and corn starch using two types of gelatin: commercial bovine gelatin and gelatin produced from mechanically separated flesh of tilapia (Oreochromis niloticus). For the extraction of tilapia gelatin 3 distinct pretreatments, followed by extraction in distilled water under heating were performed. The properties of gelatin extracted were similar to bovine gelatin, and the differences can be explained by the difference in extraction processes and sources. Blends of commercial gelatin and starch were produced in an internal mixer from a Haake torque rheometer, to study the behavior of the gelatin mixture with starch, thus, the same compositions were processed by twin screw extrusion, to define the mixing parameters. Subsequently, the extrusion of blends of tilapia gelatin and corn starch was carried out in the same twin screw extruder. The physico-chemical, rheological and morphological properties of the blends with thermoplastic starch and gelatin were studied. It was found that various properties vary linearly with increasing concentration of the components. The blends produced are immiscible, and among the two gelatins, tilapia gelatin showed a better interfacial adhesion with the corn starch. Regarding the morphology, gelatins formed the dispersed phase in all compositions studied, even in compositions rich in starch. Can be concluded that the procedure for tilapia gelatin extraction is feasible and advantageous, and the increasing in its scale to a reactor of 30 liters is possible, with a satisfactory yield. The bioblends of bovine gelatin/corn starch and tilapia gelatin/corn starch were successfully produced, and the processing conditions were appropriate / Com a necessidade da utiliza??o de fontes alternativas ao petr?leo, as mat?rias-primas naturais adquiriram uma import?ncia especial ao lado das mat?rias-primas minerais, pois podem ser utilizadas na produ??o de biopol?meros. Como exemplo disso tem-se a gelatina, um biopol?mero produzido a partir da desnatura??o do col?geno de fontes animais, e o amido, um polissacar?deo abundante em diversas fontes vegetais, que apresentam diversas aplica??es tecnol?gicas, sobretudo, na produ??o de filmes. O objetivo deste trabalho ? produzir bioblendas polim?ricas de gelatina e amido de milho utilizando dois tipos de gelatina: gelatina bovina comercial e gelatina obtida a partir de res?duos de carne mecanicamente separada de til?pia (Oreochromis niloticus). Para a extra??o da gelatina de til?pia foram realizados 3 pr?-tratamentos distintos, seguidos da extra??o em ?gua destilada sob aquecimento. As propriedades da gelatina extra?da foram semelhantes ?s da gelatina bovina estudada, e as diferen?as observadas podem ser justificadas pela diferen?a de processos de extra??o e de fontes de obten??o. Foram produzidas blendas de gelatina e amido de milho comercial em uma c?mara de mistura de um re?metro de torque tipo Haake com o objetivo de avaliar o comportamento de mistura da gelatina com o amido. Posteriormente, ap?s definidos os par?metros de mistura, realizou-se a extrus?o das blendas de gelatina de til?pia e amido de milho. As propriedades f?sico-qu?micas, reol?gicas e morfol?gicas das blendas de gelatina com amido termopl?stico foram estudadas. Observou-se que diversas propriedades variam linearmente com o aumento da concentra??o de um dos componentes. As blendas produzidas se mostraram imisc?veis, e, dentre as duas gelatinas, a gelatina de til?pia apresentou uma melhor ades?o interfacial com o amido de milho. Quanto ? morfologia, as gelatinas formaram a fase dispersa em todas as composi??es estudadas, mesmo nas composi??es ricas em amido. Conclui-se que o procedimento para a extra??o da gelatina de til?pia ? vantajoso e vi?vel, sendo poss?vel o aumento de sua escala para um reator de 30 litros com rendimento satisfat?rio. Foi poss?vel produzir, com sucesso, as bioblendas de gelatina bovina /amido de milho e de gelatina de til?pia/amido de milho, e as condi??es de processamento utilizadas foram adequadas

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