Effects of Various Viscosity Enhancers and pH on Separating Haem from Porcine Red Blood Cells

Abstract

Haem derived from animal blood is a valuable source of organic iron which may be used as a supplement in foods. The purpose of this study was to examine the effects of sodium carboxymethyl cellulose (NaCMC), propylene glycol alginate (PGA) and sodium alginate (SA) as viscosity enhancers on the separation of haem from porcine red blood cells, and on the distribution of iron between the haem and non-haem fractions of the extracts. Iron determinations were carried out spectrophotometrically on the supernatants obtained by centrifuging the cell suspensions and on two successive washings of the cells. In the first washings the total extracted iron content using NaCMC was highest when a high-viscosity grade was used ; there were no significant differences (P > 0.05) between the results obtained with this material and those obtained using PGA or SA. There were also no significant differences (P > 0.05) among the three treatments in terms of non-haem content. The absorbances at 540 nm of the first washings were lower when the washing was carried out at pH 1.4 rather than at pH 1.0 or 2.0. There were no significant differences associated with changes in the viscosity enhancer in the absorbances of the second washings, but the absorbances at pH 1.4 were generally higher than those at pH 1.0 or 2.0. Enhancement of the absorbances on the addition of 1,10-o-phenanthroline indicated that the extracted iron was present in the ferrous form.