Publicação
Caracterização e recuperação de proteínas de subprodutos de pescado
| Resumo: | Fish byproducts are a source of proteins and lipids liable to improvement. The aims of this work were: protein recovery by the shifting pH method and isoelectric precipitation; phospholipids removal on soluble proteins by adding CaCl2 and citric acid; characterization of functional, textural and rheological properties of recovered proteins. Alkaline recovered proteins (PR_ALC) contained 75.9 % protein and 14.4 % fat and acidic recovered proteins (PR_AC) contained 47.8 % e 17.0 %, respectively. PR_ALC had higher water holding capacity (2.97 g/ g-sample) and emulsion stability (88,5 %), but none of them exhibited foaming capacity. Fat absorption was 2.95 and 3.28 g/g-sample of PR_ALC e PR_AC, respectively. Emulsifying activity index was respectively 3.19 and 3.67 m2/g for PR_AC and PR_AC respectively. The gel strength of PR_ALC was 381.83 g.cm and hardness was 24.37 N. Rheological behavior of recovery proteins was similar, but the G’ and G’’ moduli were higher in PR_ALC. The L* and a* value were higher in PR_ALC but had a lower b* value. PR_ALC was also whiter than PR_AC. The acid solubilization led to a decrease of 90 % of phospholipids with 1:6 fish:water ratio and 82 % with 1:9 ratio. At alkali solubilization the phospholipids removal was about 75 % with 1:9 relation. At 5-10 mM CaCl2 and 1-5 mM citric acid showed an optimal effect on phospholipids removal. In the presence of citric acid and CaCl2 phospholipid removal from PR_AC was 59 % (1:6 ratio) and 41 % (1:9 ratio) and 74 % for PR_ALC (1:9 ratio). |
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| Autores principais: | Salgado, Rita Alexandra Fernandes |
| Assunto: | acid and alkaline solubilization recovered proteins functional properties texture rheological properties phospholopids removal |
| Ano: | 2015 |
| 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: | Fish byproducts are a source of proteins and lipids liable to improvement. The aims of this work were: protein recovery by the shifting pH method and isoelectric precipitation; phospholipids removal on soluble proteins by adding CaCl2 and citric acid; characterization of functional, textural and rheological properties of recovered proteins. Alkaline recovered proteins (PR_ALC) contained 75.9 % protein and 14.4 % fat and acidic recovered proteins (PR_AC) contained 47.8 % e 17.0 %, respectively. PR_ALC had higher water holding capacity (2.97 g/ g-sample) and emulsion stability (88,5 %), but none of them exhibited foaming capacity. Fat absorption was 2.95 and 3.28 g/g-sample of PR_ALC e PR_AC, respectively. Emulsifying activity index was respectively 3.19 and 3.67 m2/g for PR_AC and PR_AC respectively. The gel strength of PR_ALC was 381.83 g.cm and hardness was 24.37 N. Rheological behavior of recovery proteins was similar, but the G’ and G’’ moduli were higher in PR_ALC. The L* and a* value were higher in PR_ALC but had a lower b* value. PR_ALC was also whiter than PR_AC. The acid solubilization led to a decrease of 90 % of phospholipids with 1:6 fish:water ratio and 82 % with 1:9 ratio. At alkali solubilization the phospholipids removal was about 75 % with 1:9 relation. At 5-10 mM CaCl2 and 1-5 mM citric acid showed an optimal effect on phospholipids removal. In the presence of citric acid and CaCl2 phospholipid removal from PR_AC was 59 % (1:6 ratio) and 41 % (1:9 ratio) and 74 % for PR_ALC (1:9 ratio). |
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