Hygienic quality, lipolysis and sensory properties of Spanish Protected Designation of Origin ewe's milk cheeses manufactured with lamb rennet paste

A lamb rennet paste preparation was studied to determine its suitability for the manufacture of the three main Spanish raw ewe's milk cheeses with Protected Designation of Origin (Manchego, Idiazabal and Zamorano) from the hygienic and sensory points of view. Cheeses were manufactured with lamb rennet paste or with commercial rennets (bovine powder rennet for Manchego cheese and liquid lamb rennet for Zamorano and Idiazabal cheeses) at identical levels of coagulating strength. Free fatty acids and partial glycerides were also analysed to study lipolysis levels and to relate them to sensory properties. No statistically significant differences were detected in microbiological counts for any of the species analysed between cheeses manufactured with lamb rennet paste and cheeses manufactured with non-paste commercial rennet. We conclude that the hygienic quality of the cheeses made in this study with lamb rennet paste was comparable with that of cheeses made with non-paste commercial rennet. Cheeses made with lamb rennet paste showed a higher lipolysis level than cheeses made with non-paste commercial rennet. Sensory differences between cheeses made with either type of rennet were mainly detected in Idiazabal cheese, whereas the sensory profile of the cheeses made with lamb rennet paste or with non-paste commercial rennet was rather similar for Manchego and Zamorano cheeses. Idiazabal cheeses manufactured with lamb rennet paste showed the highest scores for odour and flavour intensities, sharp odour, rennet odour and flavour, butyric flavour and pungent character. On the other hand, Idiazabal cheeses made with non-paste commercial rennet had higher scores for milk and buttery odour attributes than cheeses made with lamb rennet paste.