Preparação e caracterização de membranas microfibrosas de gelatina obtida de resíduo de Tilápia do Nilo (Oreochromis niloticus)
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Data
2019-09-09
Autores
Vilches, José Luiz
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Universidade Estadual Paulista (Unesp)
Resumo
Em 2018, o Brasil se consolidou como o 4º maior produtor mundial de tilápia. Em decorrência da sua larga produção, grande quantidade de subprodutos, como pele e ossos, resultantes do processamento da tilápia são descartados. Torna-se imperativo então buscar formas de aproveitar esses subprodutos, buscando aplicações como na área de alimentação, áreas da saúde, fármacos entre outras. Neste sentido, este trabalho focou na fabricação e caracterização de membranas microfibrosas de gelatina de tilápia (Oreochromis Niloticus), produzidas utilizando a técnica de fiação por sopro em solução (FSS). As fibras poliméricas foram obtidas a partir da gelatina de tilápia (GT) dissolvida em ácido acético/água (80/20 v/v), em diferentes concentrações. Verificou-se que aumentando a viscosidade da solução, aumentou-se o diâmetro médio das fibras de aproximadamente 280 ± 73 nm (0,086 Pa.s) para aproximadamente 1195 ± 365 nm (1,88 Pa.s). Os termogramas (TG) para diferentes concentrações apresentaram perfis similares, com estabilidade térmica abaixo de 180 °C. A curva de DSC apresentou dois eventos endotérmicos, sendo o segundo, no intervalo de 100-130 °C, fortemente influenciado pelo diâmetro das microfibras, deslocando para maiores temperaturas de acordo com o aumento do diâmetro médio das microfibras. Esse comportamento está associado à difusão da água, ou seja, microfibras com menor diâmetro facilitam a evaporação de água devido ao menor caminho de difusão. Membranas fibrosas de gelatina incorporadas com ácido tânico (AT) nas concentrações de 3, 5, 10, 15 e 20 % m/m também foram produzidas. Os mesmos perfis das curvas de TG e DSC foram obtidos, apresentando comportamento similar às fibras sem AT. A reticulação pelo AT foi verificada, medindo a massa seca das membranas depois de submersas em água e também por FT-IR. Foi observado um deslocamento da banda amida I para menor valor de número de onda, indicando a ocorrência de reticulação. Um aumento na massa remanescente (massa seca) foi observado com o aumento da concentração de AT, atingindo um valor em torno de 40 % em relação à massa inicial para a amostra contendo 20 % de AT, indicando a ocorrência de reticulação.
In 2018, Brazil consolidated itself as the 4th largest tilapia producer in the world. As a result of its large production, large amounts of by-products, such as skin and bones, resulting from the processing of tilapia are discarded. It is therefore imperative to look for ways to take advantage of these by-products seeking applications such as in the area of food, health, drugs and others. In this sense, this work focused on the manufacture and characterization of tilapia gelatin microfiber membranes (Oreochromis Niloticus), produced using the solution blow Spinning (FSS) technique. The concentration and viscosity of fish gelatin solution, in acid acetic/water (80 % v/v), were examined to investigate the effects on the morphology of the gelatin microfibers. It was found that increased solution viscosity leads to increase of fibers diameters from approximately 280 ± 73 nm at viscosity ~ 0.086 Pa.s. to approximately 1195 ± 365 nm at viscosity ~ 1.88 Pa.s. The TG thermograms showed similar thermal profiles for all fibrous mat gelatins with thermal stability at temperatures below 180°C. The DSC curve showed two endothermic peaks being the second one, in the range of 100-130°C, strongly influenced by the microfiber diameters. It shifts to higher temperature increasing the microfiber diameter. This behavior was associated to the diffusion of water. Microfibers with smaller diameters tend to saturate quickly in moist environments, but also facilitate water evaporation owing to the smaller diffusion pathways. Tannic acid (AT) incorporated fibrous gelatin membranes at concentrations of 3, 5, 10, 15 and 20 % w/w were also produced. The same profile of TG and DSC curves were obtained, presenting similar behavior to fibers without AT. The effect of tannic acid on gelatin was evaluated by measuring the dry mass of the membranes after being inserted into rest water at room temperature and also by FT-IR. A shift of the amide I band to a lower value of wave numbers was observed, indicating the occurrence of crosslinking. An increase in the remaining mass (dry mass) was observed with the increase of AT concentration reaching a value around 40 % (compared to the initial mass), for the sample containing 20 % AT, thus confirming the occurrence of crosslinking.
In 2018, Brazil consolidated itself as the 4th largest tilapia producer in the world. As a result of its large production, large amounts of by-products, such as skin and bones, resulting from the processing of tilapia are discarded. It is therefore imperative to look for ways to take advantage of these by-products seeking applications such as in the area of food, health, drugs and others. In this sense, this work focused on the manufacture and characterization of tilapia gelatin microfiber membranes (Oreochromis Niloticus), produced using the solution blow Spinning (FSS) technique. The concentration and viscosity of fish gelatin solution, in acid acetic/water (80 % v/v), were examined to investigate the effects on the morphology of the gelatin microfibers. It was found that increased solution viscosity leads to increase of fibers diameters from approximately 280 ± 73 nm at viscosity ~ 0.086 Pa.s. to approximately 1195 ± 365 nm at viscosity ~ 1.88 Pa.s. The TG thermograms showed similar thermal profiles for all fibrous mat gelatins with thermal stability at temperatures below 180°C. The DSC curve showed two endothermic peaks being the second one, in the range of 100-130°C, strongly influenced by the microfiber diameters. It shifts to higher temperature increasing the microfiber diameter. This behavior was associated to the diffusion of water. Microfibers with smaller diameters tend to saturate quickly in moist environments, but also facilitate water evaporation owing to the smaller diffusion pathways. Tannic acid (AT) incorporated fibrous gelatin membranes at concentrations of 3, 5, 10, 15 and 20 % w/w were also produced. The same profile of TG and DSC curves were obtained, presenting similar behavior to fibers without AT. The effect of tannic acid on gelatin was evaluated by measuring the dry mass of the membranes after being inserted into rest water at room temperature and also by FT-IR. A shift of the amide I band to a lower value of wave numbers was observed, indicating the occurrence of crosslinking. An increase in the remaining mass (dry mass) was observed with the increase of AT concentration reaching a value around 40 % (compared to the initial mass), for the sample containing 20 % AT, thus confirming the occurrence of crosslinking.
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Palavras-chave
Gelatina, Fiação, Fibras, Ácidos orgânicos, Nile Tilapia gelatin, Solution Blow Spinning, Tannic acid, Gelatin microfibers