Publicação
Preparação de oligómeros de quitosano pela acção conjunta de peróxido de hidrogénio e radiação micro-ondas. Estudo das propriedades antioxidantes e antibacterianas
| Resumo: | Chitosan oligomers (OQ) have deserved particular attention due to their low viscosity and high solubility at neutral pH. Different studies have emphasized their ability to improve food quality and human health. Chemical and enzymatic methods have been widely used for the production of OQ but the chemical hydrolysis is more commonly used in the industrial-scale. The objective of this work was to prepare OQ from brown crab (Cancer pagurus) chitosan by an oxidative degradation method involving hydrogen peroxide (H2O2) and microwave radiation and to evaluate their antioxidant and antibacterial properties. Chitin was extracted from brown crab exoskeleton and deacetylated to chitosan. Several OQ with different molecular weight (MM) were prepared by making a mixture of chitosan and H2O2 followed by irradiation with microwave for different periods. The reducing power, the antiradicalar capacity (DPPH and ABTS) and the antibacterial activity of OQ were measured. The highest radical scavenging ability was recorded in OQ with the lowest MM (500 Da). Conversely the highest antibacterial activity was achieved by OQ with the highest MM (3 000 Da). It may be concluded that OQ can be conveniently and effectively obtained by oxidative degradation of chitosan with H2O2 and microwave radiation |
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| Autores principais: | Andrade, Inês Janine Palmeiro Ribeiro |
| Assunto: | Cancer pagurus chitosan oligomers microwave radiation antioxidant activity antibacterial activity |
| Ano: | 2014 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade de Lisboa |
| Idioma: | português |
| Origem: | Repositório da Universidade de Lisboa |
| Resumo: | Chitosan oligomers (OQ) have deserved particular attention due to their low viscosity and high solubility at neutral pH. Different studies have emphasized their ability to improve food quality and human health. Chemical and enzymatic methods have been widely used for the production of OQ but the chemical hydrolysis is more commonly used in the industrial-scale. The objective of this work was to prepare OQ from brown crab (Cancer pagurus) chitosan by an oxidative degradation method involving hydrogen peroxide (H2O2) and microwave radiation and to evaluate their antioxidant and antibacterial properties. Chitin was extracted from brown crab exoskeleton and deacetylated to chitosan. Several OQ with different molecular weight (MM) were prepared by making a mixture of chitosan and H2O2 followed by irradiation with microwave for different periods. The reducing power, the antiradicalar capacity (DPPH and ABTS) and the antibacterial activity of OQ were measured. The highest radical scavenging ability was recorded in OQ with the lowest MM (500 Da). Conversely the highest antibacterial activity was achieved by OQ with the highest MM (3 000 Da). It may be concluded that OQ can be conveniently and effectively obtained by oxidative degradation of chitosan with H2O2 and microwave radiation |
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