Valorization of sheep offal as a source of milk clotting enzyme

Despite their significant potential for recovery, animal by-products such as offal are often considered waste in the meat industry. Our study focused on extracting pepsin from sheep abomasa and analyzing its catalytic activity in milk from different species. Using sheep pepsin instead of recombinant bovine chymosin in the milk coagulation process affects the clotting kinetics and curds consistency; but does not noticeably impact ewe's milk. Proteolytic analysis of bovine caseins revealed that sheep pepsin promoted more pronounced hydrolysis of α-casein than β-casein, whereas bovine chymosin hydrolyzed both fractions equally. Comparative analysis of the resulting peptide profiles from the hydrolysis of bovine, ovine, and caprine caseins revealed differences in the action of sheep pepsin and chymosin. However, the results obtained for caprine caseins remained comparable. Overall, these results suggest that sheep pepsin could be a more suitable substitute for chymosin in the production of artisanal cheeses made from goat's or sheep's milk.