The nutritive value of porcine blood plasma concentrates prepared by ultrafiltration and spray drying.

Abstract

AbstractConcentrated solutions of porcine blood plasma proteins, prepared by centrifugation and ultrafiltration4 were spray dried directly at air inlet temperatures of 154, 170.3, 225 and 243.2 °C. Spray dried concentrates contained ca 86–90% protein, ca 2–7% moisture and ca 5% minerals. The overall amino acid composition of the plasma proteins compared favourably with that of FAO whole egg protein.12 Although the values of essential amino acids generally fell below the egg values, the only serious limitations were in the content of isoleucine (less than half of the egg value). The chemical score (CS) and essential amino acid index (EAAI) were 49.1 and 70.1 respectively. Rats fed on a diet containing plasma concentrate as the sole protein source showed a net weight increase. NPU carcass for plasma protein was 65.8 ± 1.9 compared with a value of 72.1 ± 0.4 for a casein control. An inverse correlation between denaturation status of plasma proteins and spray drying temperature was found. The percent denaturation as measured on pH 4.0 filtrates increased from 8.4% at an air inlet temperature of 154 °C to 48.6% at a temperature of 243.2 °C. A similar inverse relationship was found between the available lysine content of plasma proteins and spray drying temperature. A maximum decrease in percent lysine availability of 16% was found at an air inlet drying temperature of 243.4 °C.