RESUMO
The commercial value of Peruvian hake (Merluccius gayi peruanus) meat is low because of its soft texture. This study investigated the major factor contributing to the gel-forming ability of Peruvian hake surimi by comparing the effects of endogenous protease activity and parasitic infection. Heat-induced gels could not be obtained at 50 °C-90 °C. Surimi with severe parasitic infection showed a stronger gel-forming ability. The endogenous protease activities were the main factor influencing the Peruvian hake meat proteolysis and contributed to the low gel-forming ability, rather than parasitic infection. Specifically, endogenous cysteine proteases played an essential role in protein degradation and low gel-forming ability. Moreover, endogenous transglutaminase was also shown to be involved in the gel-forming ability upon heating at 40 °C. These results suggested that Peruvian hake meat could be used as a raw material of frozen surimi for fish gel by inhibiting the activity of endogenous proteases.
Assuntos
Cisteína Proteases , Gadiformes , Perciformes , Animais , Gadiformes/metabolismo , Temperatura Alta , Peru , Peixes/metabolismo , Perciformes/metabolismo , Produtos Pesqueiros/análise , Proteínas de Peixes/metabolismoRESUMO
ABSTRACT: The effect of methods to remove protein content on the properties of glucosamine hydrochloride from the shells of white leg shrimp (Litopenaeus vannamei) and black tiger shrimp (Penaeus monodon) was investigated. Chitin from shrimp shells was obtained by demineralization in 6% HCl for 12h, deproteinization by two different methods (first group soaked in 8% NaOH for 36h and second group treated in Alcalase enzyme at the concentration of 0.2% for 36h). Two group samples were converted to glucosamine hydrochloride by soaking in 36.76% HCl solution for 5h at 85 °C. The results of fourier transform infrared spectroscopy (FTIR), solubility and recovery yield analysis showed that deproteinization methods did not significantly affect the properties of glucosamine hydrochloride. However, glucosamine hydrochloride from white leg shrimp shells contained higher recovery yield and solubility than black tiger shrimp shells.
RESUMO: Investigou-se o efeito de métodos para remover o conteúdo de proteínas nas propriedades do cloridrato de glucosamina das conchas de camarão de pernas brancas (Litopenaeus vannamei) e camarão de tigre preto (Penaeus monodon). A quitina das cascas de camarão foi obtida por desmineralização em HCl a 6% por 12 h, desproteinização por dois métodos diferentes (primeiro grupo embebido em NaOH a 8% por 36 h e segundo grupo tratado na enzima Alcalase na concentração de 0,2% por 36 h). Duas amostras de grupo foram convertidas em cloridrato de glucosamina por imersão em solução de 12M HCl por 5 h a 85 °C. Os resultados das análises de FTIR, solubilidade e rendimento de recuperação mostraram que os métodos de desproteinização não afetaram significativamente as propriedades do cloridrato de glucosamina. No entanto, o cloridrato de glucosamina de cascas de camarão de pernas brancas continha maior rendimento e solubilidade de recuperação do que as cascas de camarão tigre preto.