Artisanal Minas cheese produced in the Campos das Vertentes/MG region: microbiota and volatile compounds profile

Abstract

The artisanal cheese produced in Minas Gerais is a product of extreme economic and cultural importance for the region and has been recognized as intangible Brazilian heritage. Its manufacture takes place in rural properties, using freshly milked raw milk, rennet, endogenous yeast (pingo) and salt. The Campos das Vertentes region was recognized in 2009 as a producer of Artisanal Minas Cheese (AMC) and the cheeses must be matured for a minimum period of 22 days to ensure their microbiological safety. The present work was carried out with the objective of revealing the microbiota and the profile of Volatile Organic Compounds, present in the AMC produced in the Campos das Vertentes/MG region. The isolation and identification of the microbiota was carried out using a culture-dependent methodology, through MALDI - TOF, and culture-independent, through the sequencing of conserved 16S and ITS regions of the rRNA, extracted directly from the cheeses, the centesimal composition, pH and profile of volatile organic compounds, using GC/MS, of AMC produced by 4 certified cheese dairies located in the Campos das Vertentes/MG region. The samples showed moisture between 38.7 and 44.7%, and fat content on average between 33 and 37%, which is equivalent to 57% of fat in the dry extract, classifying the cheese as fat. The protein content varied between 22.3 and 25.02 and the pH varied between 5.0 and 5.5. In the culture-dependent analyses, the yeasts identified in the cheeses were Geotrichum candidum, Kluyveryomyces lactis, Diutina catenulata and some candida species and through metagenomics it was revealed the predominance of G. candidum, Corynebacterium variabile, D. catenulata, K. lactis and Debaryomyces prosopidis. The species Yarrowia lipolitica and Debaryomyces hansenii, widely described in artisanal cheeses, were not identified, suggesting that their absence may be a marker of authenticity for the cheeses produced in this region. For volatile compounds, a greater relative area was found for acetic, decanoic, hexanoic and octanoic acids, 3-methylbutanol alcohol, 2-heptanone, 2-nonenone and 2-butanone ketones, and ethyl hexanoate and ethyl octanoate esters. The cheese produced in this region is expected to have aromatic notes of vinegar, oily, rancid, sweet, fruity, malty, burnt and green. The results obtained in this work expand the knowledge about the microbiota naturally present in artisanal cheeses and the main volatile compounds produced in the maturation of cheeses from the Campos das Vertentes region and are configured as an important step to ensure the manufacture of cheeses with a flowering rind, to support new legislation aimed at regulating the production of these cheeses and endorsing the request for Denomination of Origin certification for the region.