Aplicação de ultrassom e avaliação da qualidade de alginato de sódio de Sargassum spp.
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Data
2020-03-27
Autores
Chica, Letícia Rustici
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Universidade Estadual Paulista (Unesp)
Resumo
As algas marinhas marrons possuem diversos biocompostos de interesse econômico. Dentre eles, o alginato é um composto que apresenta aplicação em diferentes setores industriais devido a suas propriedades espessantes. Apesar de sua grande aplicabilidade, praticamente todo alginato utilizado no Brasil é importado. Desse modo, é de suma importância incentivar a produção nacional desse polissacarídeo, visto que a alga Sargassum está presente em abundância no litoral brasileiro. No presente estudo, foi utilizado o delineamento Box-Behnken para otimizar a etapa de extração do alginato com aplicação de ultrassom, em substituição parcial à etapa ácida tradicionalmente aplicada no processo, a qual normalmente utiliza ácido clorídrico, pelo ácido cítrico, que é um ácido mais fraco e ecológico. Foram obtidas 17 combinações a fim de avaliar o efeito de três fatores, potência do ultrassom, pH e tempo de aplicação do ultrassom, sobre o rendimento, capacidade antioxidante, viscosidade dinâmica, viscosidade intrínseca e peso molecular. A condição otimizada (176 W, pH 1, 15 minutos) gerou rendimento de 54,20%, capacidade antioxidante de 80,81 µM trolox/g de alginato, viscosidade intrínseca de 4,28 dL/g e peso molecular de 202,56 kDa. Dentre os parâmetros estudados, o pH apresentou maior influência sobre as respostas estudadas. Na condição otimizada, foi avaliado o efeito do emprego do ácido clorídrico no rendimento e parâmetros de qualidade do alginato. Os resultados mostraram maiores rendimento e capacidade antioxidante na extração com ácido cítrico, e valores próximos de viscosidade intrínseca e peso molecular do alginato extraído com os dois ácidos, mostrando que o ácido cítrico é uma alternativa interessante na substituição do ácido clorídrico, quando combinado com ultrassom. Assim, a aplicação de ultrassom é um método promissor para a extração de alginato de sódio, podendo o ácido cítrico ser satisfatoriamente empregado na etapa ácida.
Brown algae have several bio composites of economic interest. Among them is the alginate, a compound that, due to its thickening properties, has application in different industrial sectors. Despite its great applicability, all alginate used in Brazil is imported. Thus, it is extremely important to encourage the national production of this polysaccharide, since the Sargassum seaweed is present in abundance on the Brazilian coast. In the present study, the Box-Behnken design was used to optimize the alginate extraction with the application of ultrasound, partially replacing the acidic treatment with hydrochloric acid, with citric acid applied in the extraction process by an acidic treatment with citric acid, which is a weaker and more ecological option. 17 combinations were obtained in order to evaluate the effect of 3 factor, ultrasound potency, citric acid pH and ultrasound application time, on the yield, antioxidant capacity, dynamic viscosity, intrinsic viscosity and molecular weight. The optimized condition (176 W, pH 1, 15 minutes) resulted in a yield of 54.20%, antioxidant capacity of 80.81 µM trolox/g of alginate, intrinsic viscosity of 4.28 dL/g and molecular weight of 202.56 kDa. From the studied parameters, it was observed that the pH had a greater influence on the responses. In the optimized condition, the effect of the hydrochloric acid on alginate yield and quality parameters was evaluated. The extraction with citric acid showed higher yield and antioxidant capacity with close values of intrinsic viscosity and molecular weight to the alginate extracted with hydrochloric acid. This shows that citric acid is an interesting alternative in the replacement of hydrochloric acid, when combined with ultrasound. The results showed that the application of ultrasound is a promising method for the extraction of sodium alginate and that the acidic treatment can be satisfactorily replaced with citric acid.
Brown algae have several bio composites of economic interest. Among them is the alginate, a compound that, due to its thickening properties, has application in different industrial sectors. Despite its great applicability, all alginate used in Brazil is imported. Thus, it is extremely important to encourage the national production of this polysaccharide, since the Sargassum seaweed is present in abundance on the Brazilian coast. In the present study, the Box-Behnken design was used to optimize the alginate extraction with the application of ultrasound, partially replacing the acidic treatment with hydrochloric acid, with citric acid applied in the extraction process by an acidic treatment with citric acid, which is a weaker and more ecological option. 17 combinations were obtained in order to evaluate the effect of 3 factor, ultrasound potency, citric acid pH and ultrasound application time, on the yield, antioxidant capacity, dynamic viscosity, intrinsic viscosity and molecular weight. The optimized condition (176 W, pH 1, 15 minutes) resulted in a yield of 54.20%, antioxidant capacity of 80.81 µM trolox/g of alginate, intrinsic viscosity of 4.28 dL/g and molecular weight of 202.56 kDa. From the studied parameters, it was observed that the pH had a greater influence on the responses. In the optimized condition, the effect of the hydrochloric acid on alginate yield and quality parameters was evaluated. The extraction with citric acid showed higher yield and antioxidant capacity with close values of intrinsic viscosity and molecular weight to the alginate extracted with hydrochloric acid. This shows that citric acid is an interesting alternative in the replacement of hydrochloric acid, when combined with ultrasound. The results showed that the application of ultrasound is a promising method for the extraction of sodium alginate and that the acidic treatment can be satisfactorily replaced with citric acid.
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Palavras-chave
Algas marinhas, Alginatos, Ultrassom, Box-Behnken, Ácido cítrico