Colour stabilization of spray-dried porcine red blood cells using nicotinic acid and nicotinamide

The effect of nicotinic acid (NA) and nicotinamide (NAm) on colour parameters (CIE L*, a*, b*) of spray dried red blood cells and colour stability during a 7-weeks storage period at room temperature were investigated. The influence of pH on the colour of powder stabilized with NA or NAm was also determined by using starch gels as a model matrix. The results showed that nicotinic acid at 2% (w/v) considerably prevented colour deterioration of haemoglobin concentrate during spray-drying as well as during the storage period. The powder obtained was clearer, redder and more yellow than the control. A positive effect was also detected with 2.5% (w/v) nicotinamide, but the improvement achieved was never as high as it was when nicotinic acid was used. However, powder containing nicotinamide at 2.5% (w/v) showed higher capacity as a red colourant than nicotinic acid at 2% (w/v) when added to starch gels either at pH 7.5 or 4.5.