Obtenção de frações proteicas de sangue bovino : composição, valor nutritivo e propriedades funcionais

AUTOR(ES)
DATA DE PUBLICAÇÃO

1997

RESUMO

The objective of this thesis was to obtain bovine blood proteins and to study their functional and nutritional properties to be used in human foods. Blood of healthy bovines was collected from a slaughterhouse using sodium citrate to prevent coagulation and subsequently it was fractionated in a centrifuge separator into plasma and blood cell concentrate. The plasma was spray dried after concentration by ultrafiltration to obtain an dehydrated blood plasma concentrate (CPP). Blood cells concentrate was hemolyzed by suspending in water and the separation of hemoglobin to heme and globin was done under acidic solution (pH<3). Fallowed precipitation of the heme group with diluted carboxymethyl cellulose solution at pH <3. The globin isolate (IPG) was obtained by adjusting the supernatant to pH 6 with I N HCI and then liofilized. The dehydrated fractions were characterizated chemically through determination of proximate percent composition, mineral and amino acids determination. The protein nutritional quality of CPP, IPG and mixtures of CPP:IPG was assessed in vivo through determination of net protein ratio (NPR) and nitrogen balance. Functional properties such as solubility, water absorption, foam formation and stability, emulsifying capacity and stability, and gelationwere also studied under various conditions. The yield of globin preparation from hemoglobin solution was 61.26% and the iron removed represented 96%. The amino aid composition of CPP was considered adequate when compared with the FAO theorical standard. However the IPG was limited in isoleucine and in sulphur-containing amino acids. The mixture CPP:IPG (2: 1 w/w) showed the highest NPR (4.12) and a true digestibility of 95.03%, similar to casein (94.77%). The CPP showed the highest nitrogen balance (1.13), true biological value (85.46%) and true net protein utilization (81.05%). The CPP showed high water solubility at pHs 2 to 9 while the highest solubility of IPG was in the acidic pH region and above pH 9. The CPP was superior to IPG on foam formation at pH 7, on emulsifying capacity above pH 6 and on gelation. The IPG showed the highest water absorption, foam formation at pH 4 and emulsifying capacity at pHs 3 and 4.

ASSUNTO(S)

sangue aspectos nutricionais plasma sanguineo

ACESSO AO ARTIGO

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