SDS-PAGE of proteins in goat milk cheeses ripened under different conditions

Proteolytic characteristics of five varieties of commercial goal milk cheeses and a cow milk Cheddar aged under different conditions were evaluated by SDS-PAGE and an advanced densitometry system. All fresh goat cheeses had distinctively lower intensities of alpha(s1)-casein (CN) bands than those of cow milk Cheddar, whereas intensities of beta-CN were much greater in the goat cheeses. The PAGE patterns clearly displayed alpha(s2)-CN in all goat cheese, but it was negligible in cow milk Cheddar. The greater protein degradation in hard goat cheeses than cow milk Cheddar at 4 degrees C and 22 degrees C strongly correlated with water-soluble nitrogen compound concentrations and densitometric values of corresponding cheeses.