Effect of calcium and thrombin on the turbidity changes and the gelation properties of swine plasma

Abstract

Swine plasma solution containing 5.8% protein and 0.4% Na-citrate was supplemented with 800–2000 ppm of calcium to investigate the time-dependent changes of turbidity and gel strength. Maximal absorbance (660 nm) slopes change with time ( S m ) were calculated by the first derivatives from the turbidity curves. It was found that plasma solution supplemented with 1200 and 1500 ppm calcium had the maximal S m value (Max S m ), while that supplemented with 1350 ppm calcium exhibited the minimal S m value (Min S m ). The minimal time period for activation of blood clotting-related enzymes (Min TS m ) was found to be 8.0 min in plasma supplemented with 1200 ppm calcium. Linear relationships of Max S m and Min TS m between calcium content and 1/protein concentration were observed. Maximal activation of thrombin was obtained by the addition of 800–1200 ppm calcium. Addition of thrombin (0–8 U/ml plasma solution) decreased the gel strength of plasma in the presence of 1000 ppm calcium.