Effect of artisanal liquid rennet from kids and lambs abomasa on the characteristics of Feta cheese

Feta cheeses were manufactured with commercial calf rennet and artisanal liquid rennet from kids and lambs abomasa with an aim to investigate the influence of rennet type on the characteristics of this cheese variety. The two rennets had similar chymosin to pepsin ratios and they were used in quantities with the same total milk coagulating activity. The use of traditional rennet had no significant effect on the evolution of physicochemical composition (pH, total solids, ash, NaCl, fat, total protein) or on the evolution of proteolysis (water-soluble nitrogen expressed as percentage of total nitrogen, free amino acids expressed as mmol Leu, residual αs-casein and reversed phase HPLC profiles) during the ripening. The textural characteristics of mature 60d-old cheeses were not significantly different. The microbiological quality of traditional rennet significantly affected the enterococci and coliform counts of 3d-old cheeses but this influence was eliminated in the mature 60d-old cheeses. The significantly higher flavour scores of mature Feta made with traditional artisanal liquid rennet were in accordance with the significantly higher C4:0 and C10:0 FFA contents resulting from the lipase activity of traditional rennet.