Sistemas inteligentes de embalagens utilizando filmes de quitosana como indicador colorimétrico de temperatura

Abstract

Resumo: Clorofila, um pigmento natural termossensível, foi incorporado à matriz de filmes de quitosana visando a obter sistemas inteligentes de indicação de variação de temperatura. A quitosana é um polímero biodegradável que forma filmes flexíveis com eficiente barreira ao oxigênio, podendo ser alternativa ao uso de polímeros sintéticos. Clorofila foi adicionada (0,25 g/100 g) à suspensão de quitosana (2,00 g/100 g) formando filmes inteligentes de quitosana (FIQ). Os efeitos da temperatura (10 °C a 50 °C) e luminosidade (0 a 1000 lx) foram estudados utilizando um planejamento experimental, avaliando os parâmetros de cor (L*, a*, b*) e propriedades mecânicas. As suspensões de quitosana contendo clorofila foram aplicadas como revestimento em superfície de papel cartão formando o sistema de material flexível filme-papel cartão (S-FP), reduzindo significativamente o tempo de secagem. Os filmes caracterizaram-se pela homogeneidade, flexibilidade, coloração esverdeada e fácil manuseio. A variação de cor foi visualmente observada no sistema S-FP, alterando irreversivelmente de verde para amarelo quando submetido a temperaturas acima de 50 °C, independentemente da luminosidade. Desta forma, o sistema proposto tem potencial de aplicação como indicador colorimétrico de temperatura na faixa de 50 °C a 75 °C, com a vantagem de simples fabricação, biodegradabilidade e uso de materiais seguros para aplicação em contato direto com alimentos e fármacos, além do baixo custo. Palavras-chave: Embalagem inteligente, quitosana, clorofila, indicadores de temperatura. Alternative Intelligent Material for Packaging Using Chitosan Films as Colorimetric Temperature IndicatorsAbstract: Chlorophyll was incorporated into chitosan films, forming intelligent systems able to detect variations in temperature. Chitosan is a biodegradable polymer that forms flexible, resistant films with an efficient oxygen barrier. Chlorophyll was added (0.25 g/100 g) into chitosan suspension (2.00 g/100 g) and intelligent films (FIQ) were cast. The effects of temperature (10 °C to 50 °C) and luminosity (0 to 1000 lx) on the films were studied using an experimental design with two variables, analyzing the color parameters L*, a*, b* and mechanical properties. The films were characterized according to their homogeneity, flexibility, color and handling. Chitosan suspensions containing chlorophyll were also applied as coating on the surface of pieces of card-paper, forming a card paper film system (S-FP). By visual inspection we observed the color of the S-FP changing irreversibly from green to yellow when the temperature was above 50 °C. Therefore, the S-FP system can potentially be used as a colorimetric indicator for the 50 °C to 70 °C range, being advantageous owing to the ease of fabrication, biodegradability, safe use for food and low cost. Keywords: Intelligent packaging, chitosan, chlorophyll, temperature indicator. IntroduçãoO potencial de aplicação de novos sistemas de acondicionamento vem aumentando devido às exigências do consumidor e preocupação sobre...

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