Effect of supercritical carbon dioxide on protein structure modification and antimicrobial peptides production of Mongolian cheese and its in vitro digestion.

The aim of this research was to investigate the effects of supercritical carbon dioxide (SC-CO) treatment on protein structure in Mongolian cheese. The peptides during the digestive process of the SC-CO treated cheese were also studied. SC-CO technology was utilized to treat Mongolian cheese at three temperatures (45, 55 and 65 °C) and three pressures (7.5, 12.5 and 17.5 MPa). The results of fluorescence, ultraviolet-visible, Fourier transform infrared spectroscopy and free sulfhydryl groups showed that SC-CO, particularly at 65 °C and 17.5 MPa, modified the protein structure in Mongolian cheese effectively. The data of LC-MS/MS-based peptidomics showed that the content of antimicrobial peptides found in the SC-CO treated Mongolian cheese was 1.55 times that of the untreated Mongolian cheese; the content of unique antimicrobial peptides in the digested SC-CO treated Mongolian cheese was 1.46 times that of the digested untreated Mongolian cheese, which proved that SC-CO could help produce antimicrobial peptides in cheese not only during the process of SC-CO treatment but during subsequent simulated gastrointestinal digestion as well. In conclusion, SC-CO could be considered a promising method to develop cheese products with potential health benefits.