Proteinas de soro de sangue bovino : propriedades nutritivas e funcionais

AUTOR(ES)
DATA DE PUBLICAÇÃO

2002

RESUMO

It has been a constant interest in the utilization of animal blood from slaughter houses not only because of the intrinsical value of their constituents, mainly the proteins, but also to solve environmental problems. In this research the two main bovine protein fractions, the albumin (BSA) and globulin (GB) were isolated by using respectively 50% and 80% saturation with ammonium sulphate. The isolated fractions were dehydrated by two methods of drying (freeze drying and spray drying) Chemical composition and technological properties (solubility, foaming, emulsifying capacity and stability) were studied in the dehydrated powders. Protein content of two fractions was respectively, BSA 83%, GB 84-85%. BSA was 30% limited in tryptophan and GB 12% in isoleucine and protein digestibility was above 95% for both fractions. Both fractions presented excellent protein solubility. BSA was less sensitive to changes in pH than GB. Foaming capacity was very high in both fractions (equal or better than egg white). The influence ofthe drying methods was relevant. The drying method did not influence significantly the composition and the functional properties studied, except for the emulsifying capacity of GB that was decreased in the spray dried sample. The data suggested that for industrial operation the spray drying could perfectly replace the freeze-drying method. A factorial planned experiment was performed to compare the fractions that come out naturally from the spray drying with the portion that remains inside the equipment during the entire drying period. It was demonstrated that the retained sample (called BSA residue) was significantly affected by prolonged heat treatment. Even dough the solubility and emulsifying properties of this sample remained high but significantly inferior BSAthat was collected naturally out of the spray drying. The nutritional index estimated (PDCAAS) ranged from 80% for Iyophilized BSA to 91% for the spray dried GB, compared to 86% for casein

ASSUNTO(S)

sangue proteinas

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