Proteolysis of Cacioricotta cheese made from goat milk coagulated with caprifig (Ficus carica sylvestris) or calf rennet

摘要

A study was undertaken on Cacioricotta, a traditional Italian goat’s cheese obtained from overheated milk (90 °C) without use of starter. The profile of proteolysis in the artisanal type, made with vegetable coagulant (latex released from caprifig branches) as milk clotting agent, was compared to that of the “industrial” one, manufactured with calf rennet. Particular aim of the investigation was to study the differences and, possibly, establish a useful tool for distinguishing the two types of cheese. The study was based on the quantification of the water soluble, 15% TCA soluble and amino acid nitrogen fractions, RP-HPLC separation of low molecular weight peptides and their identification by mass spectrometry (MALDI-ToF MS). The use of fig latex was associated to higher amounts of the nitrogen fractions and to RP-HPLC chromatograms very rich in peptides, in contrast to an almost complete lack of peptides in the industrial counterpart. These results confirm the strong proteolyitic activity exerted by the caprifig clotting enzymes in spite of the intense overheating of the milk, which is considered to cause reduction of the rate of casein degradation in cheese. The MS-based identification of several peptides provided a support at the molecular level for the characterization of Cacioricotta made with this vegetable coagulant and could be useful for “tracing back” purposes. In conclusion, the peptide pattern determined by the use of caprifig for milk coagulation can be considered a particular feature of the artisanal Cacioricotta, giving confirmation of its vocation to EU protection as typical product.