Extração e caracterização de alginato de sódio da macroalga Sargassum cymosum C. Agardh
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Data
2017-03-09
Autores
Nogueira, Marcela Tiemi [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
As algas marinhas pardas são as principais fontes de alginato de sódio utilizados na indústria alimentícia. O Brasil não possui o processamento de alginato, sendo assim dependente de produtos importados para suprir a demanda. A macroalga Sargassum sp. é comumente encontrada nas regiões costeiras do litoral de São Paulo, a extração de alginato dessa alga possibilitaria autonomia brasileira na produção de alginato de sódio. O meio ambiente e as condições climáticas em que as algas marinhas vivem influencia no rendimento de alginato, na massa molecular e na capacidade antioxidante. No primeiro capítulo foi realizado a otimização da extração de alginato de sódio por delineamento Box-Behnken e também o estudo da influência dos parâmetros de pH, temperatura e tempo de extração sobre o rendimento, viscosidade intrínseca e massa molecular. O pH influencia no rendimento, viscosidade intrínseca e massa molecular, enquanto que o tempo apresentou baixo efeito sobre o rendimento e a temperatura não influenciou nas respostas avaliadas. Os resultados da otimização mostraram que máximo rendimento (46,04%), viscosidade intrínseca (4,89 dL/g) e massa molecular (231,78 kDa) podem ser obtidos utilizando na extração a temperatura de 80°C, pH 10 por 90,08 minutos. No segundo capítulo foram estudados alginatos extraídos de Sargassum cymosum C. Agardh coletadas em duas localidades diferentes do litoral de São Paulo (Ubatuba-ASU e São Sebastião-ASS) com relação ao rendimento, massa molecular, comportamento reológico e atividade antioxidante, verificando a diferença entre os alginatos extraídos. O rendimento apresentou maior valor para os alginatos da alga coletada em ASS, porém as maiores massa moleculares foram observadas nas algas de Ubatuba (ASU). A maior atividade antioxidante foi verificada no alginato de ASU, que pode ser devido ao meio ambiente e condições climáticas em que a alga estava exposta durante seu crescimento. O estudo de comportamento reológico para as ASU apresentaram alginatos com características de fluido newtoniano, enquanto para ASS, fluido psedoplástico.
Brown seaweeds are the main sources of sodium alginate used in the food industry. Brazil doesn’t have alginate processing, so it is dependent on imported products to supply the demand. The macroalgae Sargassum sp. is commonly found in the coastal regions of São Paulo, the extraction of alginate from this alga would allow Brazilian autonomy in the production of sodium alginate. The environment and climatic conditions in which marine algae live influence alginate yield, molecular weight and antioxidant capacity. In the first chapter, the optimization of the sodium alginate extraction by the Box-Behnken design was carried out, as well as the influence of pH, temperature and extraction time parameters on yield, intrinsic viscosity and viscosimetric molecular mass. pH influenced yield, intrinsic viscosity and molecular mass, while time had low effect and temperature did not influence the responses evaluated. The optimization results showed that maximum yield (46.04%), intrinsic viscosity (4.89 dL / g) and viscosimetric molecular weight (231.78 kDa) can be obtained using the extraction at temperature of 80 ° C, pH 10 and 90 minutes. In the second chapter, alginates extracted from Sargassum cymosum C. Agardh were studied in two different locations along the coast of São Paulo (Ubatuba-ASU and São Sebastião-SSA) and were studied the difference between them in the yield, molecular mass, rheological behavior and antioxidant activity. The yield presented higher values for the alginates of the algae collected in ASS, but the highest molecular weight were observed in the algae of Ubatuba (ASU). The highest antioxidant capacity was observed in ASU alginate, which may be due to the environmental and climatic conditions in which the algae were exposed during its growth. The study of rheological behavior for ASU presented alginates with characteristics of Newtonian fluid, while for ASS, psedoplastic fluid.
Brown seaweeds are the main sources of sodium alginate used in the food industry. Brazil doesn’t have alginate processing, so it is dependent on imported products to supply the demand. The macroalgae Sargassum sp. is commonly found in the coastal regions of São Paulo, the extraction of alginate from this alga would allow Brazilian autonomy in the production of sodium alginate. The environment and climatic conditions in which marine algae live influence alginate yield, molecular weight and antioxidant capacity. In the first chapter, the optimization of the sodium alginate extraction by the Box-Behnken design was carried out, as well as the influence of pH, temperature and extraction time parameters on yield, intrinsic viscosity and viscosimetric molecular mass. pH influenced yield, intrinsic viscosity and molecular mass, while time had low effect and temperature did not influence the responses evaluated. The optimization results showed that maximum yield (46.04%), intrinsic viscosity (4.89 dL / g) and viscosimetric molecular weight (231.78 kDa) can be obtained using the extraction at temperature of 80 ° C, pH 10 and 90 minutes. In the second chapter, alginates extracted from Sargassum cymosum C. Agardh were studied in two different locations along the coast of São Paulo (Ubatuba-ASU and São Sebastião-SSA) and were studied the difference between them in the yield, molecular mass, rheological behavior and antioxidant activity. The yield presented higher values for the alginates of the algae collected in ASS, but the highest molecular weight were observed in the algae of Ubatuba (ASU). The highest antioxidant capacity was observed in ASU alginate, which may be due to the environmental and climatic conditions in which the algae were exposed during its growth. The study of rheological behavior for ASU presented alginates with characteristics of Newtonian fluid, while for ASS, psedoplastic fluid.
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Palavras-chave
Alginato de sódio, Box Behnken, Capacidade antioxidante, Comportamento reológico, Otimização