Differing effect of protein isolates from different cultivars of blue lupin [Lupinus angustifolius] on plasma lipoproteins of hypercholesterolemic rats

Protein from white lupin is capable of lowering plasma lipids. We investigated in this study the effect of total protein extracts (TPEs) from different cultivars of blue lupin (Probor, Vitabor and Boregine) and alpha-/beta-conglutin from Boregine on the plasma lipids of rats. Rats were fed on a hypercholesterolemic diet containing either lupin protein (50 g/kg) or casein (50 g/kg) for 17 d. The rats fed with TPE from Vitabor and alpha-/beta-conglutin had lower triglyceride concentrations in the plasma (-24% and -21%, respectively) and very-low-density lipoprotein (VLDL; -40% and -29%, respectively) than the rats fed with casein. TPE from Vitabor was also capable of lowering low-density lipoprotein (LDL) cholesterol (-37%). In the liver of the rats fed with TPE from Vitabor, the expression of the genes involved in triglyceride and cholesterol synthesis was down-regulated. This study shows that the Vitabor cultivar of blue lupin had the most beneficial effect on plasma lipids which was presumed to have been caused by the down-regulation of genes involved in lipid synthesis.