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Authors
Abstract(s)
Com o aumento da consciencializaĆ§Ć£o da populaĆ§Ć£o em geral relativamente aos problemas
ambientais causados pelo uso exagerado dos derivados do petrĆ³leo, como Ć© o caso dos
plĆ”sticos nas embalagens alimentares, nos Ćŗltimos anos tĆŖm-se procurado materiais
naturais como uma alternativa ecolĆ³gica e que garanta a seguranƧa alimentar. A utilizaĆ§Ć£o
de biopolĆmeros na produĆ§Ć£o de embalagens alimentares tem sido amplamente estudada,
por estes materiais serem de origem natural e apresentarem uma elevada
biodegradabilidade. Este trabalho teve como principal objetivo o desenvolvimento de
laminados de celulose/zeĆna para embalagem alimentar. Numa fase inicial estudou-se a
composiĆ§Ć£o e propriedades antioxidantes e antibacterianas do Ć³leo essencial de cipreste
(OC) com a finalidade de o incorporar em filmes Ć base de zeĆna. Foram produzidos dois
tipos de filmes zeĆna, o filme controlo (FC) contendo zeĆna, glicerol (GLY) e Ć”cido oleico
(AO), e o filme com Ć³leo essencial de cipreste (FOC), com a restante composiĆ§Ć£o idĆŖntica ao
FC. Posteriormente foram produzidos os laminados, usando papel e os filmes preparados
anteriormente e recorrendo a uma tĆ©cnica de moldagem por compressĆ£o em condiƧƵes prĆ©definidas. Os filmes, papel e laminados, foram caracterizados quanto Ć s suas propriedades
mecĆ¢nicas, Ć³ticas, tĆ©rmicas, barreira e atividades antioxidante e antibacteriana. Quanto Ć s
propriedades antibacterianas, os filmes e laminados com OC, FOC e LFOC, respetivamente,
apresentaram os melhores resultados, inibindo o crescimento de todas as bactƩrias
utilizadas (Enterococcus faecalis ATCC 29212, Listeria monocytogenes LMG 16779,
Bacillus cereus ATCC 11778, Staphylococcus aureus ATCC 25923, Salmonella
Typhimurium ATCC 13311, Pseudomonas aeruginosa ATCC 27853, e Escherichia coli ATCC
25922). Quanto as propriedades antioxidantes, mecĆ¢nicas, permeabilidade ao vapor de
Ɣgua e oxigƩnio, os LFOC apresentaram os melhores resultados comparativamente ao
controlo. A incorporaĆ§Ć£o do OC aumentou a resistĆŖncia tĆ©rmica dos filmes e laminados e
melhorou a sua microestrutura, proporcionando homogeneidade comparativamente aos
respetivos controlos. Na globalidade, os LFOC apresentaram melhores propriedades como
material de embalagem.
With the increasing awareness of the general human population concerning the environmental problems caused for the exaggerated use of oil derivatives, such as the plastics used in food packaging, the last years have been about searching for natural materials that can be an ecological alternative without compromising food safety. The use of biopolymers in the manufacturing of food packages has been widely studied because these materials have a natural origin and present an elevated biodegradability. The main goal of this work was the development of cellulose laminates/zein for food packaging. In a preliminary phase, the composition and the antioxidant and antibacterial properties of cypress essential oil (OC) were studied for the purpose of incorporating the essential oil in zein based films. Then were produced two types of zein films, the control film (FC) containing zein, glycerol (GLY) and oleic acid (AO), and the film with the cypress essential oil (FOC) which has the remaining composition identical to FC. Posteriorly, the laminates were produced, using paper and the films previously prepared and using a compression molding technique in pre-established conditions. The films, paper, and laminates were characterized for their mechanical, optic, thermal, barrier, antioxidant and antibacterial properties. As for the antibacterial properties, the films and the laminates with OC, FOC and LFOC, respectively, show the best results, inhibiting the growth of every bacteria used in this study (Enterococcus faecalis ATCC 29212, Listeria monocytogenes LMG 16779, Bacillus cereus ATCC 11778, Staphylococcus aureus ATCC 25923, Salmonella Typhimurium ATCC 13311, Pseudomonas aeruginosa ATCC 27853, e Escherichia coli ATCC 25922). As for the antioxidant and mechanical properties, water vapor and oxygen permeability, the LFOC presented the best results comparing with the control. The incorporation of OC increased the thermal resistance of films and laminates and improved their microstructure, providing homogeneity comparatively to control. Globally, the LFOC presented the best properties as packaging material.
With the increasing awareness of the general human population concerning the environmental problems caused for the exaggerated use of oil derivatives, such as the plastics used in food packaging, the last years have been about searching for natural materials that can be an ecological alternative without compromising food safety. The use of biopolymers in the manufacturing of food packages has been widely studied because these materials have a natural origin and present an elevated biodegradability. The main goal of this work was the development of cellulose laminates/zein for food packaging. In a preliminary phase, the composition and the antioxidant and antibacterial properties of cypress essential oil (OC) were studied for the purpose of incorporating the essential oil in zein based films. Then were produced two types of zein films, the control film (FC) containing zein, glycerol (GLY) and oleic acid (AO), and the film with the cypress essential oil (FOC) which has the remaining composition identical to FC. Posteriorly, the laminates were produced, using paper and the films previously prepared and using a compression molding technique in pre-established conditions. The films, paper, and laminates were characterized for their mechanical, optic, thermal, barrier, antioxidant and antibacterial properties. As for the antibacterial properties, the films and the laminates with OC, FOC and LFOC, respectively, show the best results, inhibiting the growth of every bacteria used in this study (Enterococcus faecalis ATCC 29212, Listeria monocytogenes LMG 16779, Bacillus cereus ATCC 11778, Staphylococcus aureus ATCC 25923, Salmonella Typhimurium ATCC 13311, Pseudomonas aeruginosa ATCC 27853, e Escherichia coli ATCC 25922). As for the antioxidant and mechanical properties, water vapor and oxygen permeability, the LFOC presented the best results comparing with the control. The incorporation of OC increased the thermal resistance of films and laminates and improved their microstructure, providing homogeneity comparatively to control. Globally, the LFOC presented the best properties as packaging material.
Description
Keywords
Celulose Embalagens Alimentares Filmes Laminados Ćleo Essencial de Cipreste ZeĆna