Purification and characterisation of a lectin from the red marine alga Pterocladiella capillacea (S.G. Gmel.) Santel. & Hommers.

A lectin present in the marine red alga Pterocladiella capillacea was purified and characterised by extraction of soluble proteins (crude extract) in 20 mM Tris-HCl buffer, pH 7.5. Among the analysed erythrocytes (human blood group A, B and O and the animals ox, goat, chicken and rabbit) the lectin agglutinated specifically rabbit erythrocytes. The hemagglutinating activity assay showed that the lectin was not dependent on divalent cations and was shown to be inhibited by the glycoproteins avidin and mucin. The purification procedure was conduced by precipitation of the crude extract with 80% saturation ammonium sulfate (F0/80) followed by affinity chromatography on guar-gum column. The lectin of P. capillacea was purified 14.5 fold and had a recovery of 27.4% of the original total specific activity present in the crude extract. The absence of carbohydrate suggested that the lectin is not a glycoprotein. The molecular mass of P. capillacea lectin, determined by gel filtration, was 5.8 kDa. SDS-PAGE in the presence of ß-mercaptoethanol gave one band, indicating that the native lectin is a monomeric protein. The activation energy of denaturation process (D G') was calculated to be 106.87 kJ . mol-1 at 70 ºC.

Replacement of mechanically deboned chicken meat with its protein hydrolysate in mortadella-type sausages

Mortadella-type sausage manufactured using mechanically deboned chicken meat were reformulated replacing MDCM with increasing amounts of MDCM protein hydrolysates (10%, 20%, and 30%), and their physicochemical, microbiological, and sensorial characteristics were evaluated for 60 days of storage at 4 °C. The higher substitutions resulted in sausages more susceptible to lipid oxidation with higher TBARS values during storage; however, these values were lower than the organoleptic perception threshold. The sausages were darker and less red, with lower lightness (L*) and redness (a*) values than those of the control treatment. They had soft texture, which was evidenced by both the instrumental and sensory analysis. Therefore, the formulation containing 10% of MDCM protein hydrolysates proved to be the most suitable for mortadella-type sausage elaboration.