The cheese ripening is the result of several biochemical processes that are steered by production technology and aging, and induce the modification of milk and curd leading to the production of new and more simple compounds that characterise the different cheese varieties.
More specifically, lactose is consumed by lactic acid bacteria that ferment it producing lactic acid; proteins are partially transformed into lower molecular weight compounds, such as peptides and amino acids; and fats release fatty acids. The combination of these modifications turn cheese into a food that is more digestible and easier to assimilate compared to the initial milk.
Blue cheeses, such as Gorgonzola DOP, are produced by using selected moulds, in particular the Penicillium roqueforti, that grow in the cheese and create its typical veins. The growth of the mould represents the most important and distinctive feature of Gorgonzola, because the proteolytic and lipolytic activities of Penicillium roqueforti induce a deep transformation of milk proteins and fats, as well as of the several compounds of the curd.
The biochemical phenomena involved during the Gorgonzola ripening are rather complex, as they depend on the development of the micro-flora, that in turn is affected by the intermediate products obtained by the degradation of milk ingredients. In particular, in Gorgonzola cheese, the main ripening agents are the introduced lactic acid bacteria that dominate the first stage of ripening by creating a suitable habitat for the mould to grow.
At the beginning of ripening, acidity is high, but it is then gradually neutralised. As the mould develops, the low molecular weight nitrogen fractions increase and lipids release fatty acids in various quantities that, in turn, act like a substrate for other enzyme transformations releasing volatile compounds with a strong aromatic impact.
The combination of these biochemical processes that accompany the Gorgonzola DOP Cheese ripening, leads to the change of its structure – that becomes creamy for the Dolce (Sweet) type, and more textured for the Piccante (Spicy) type – and to the development of the distinctive and prised aromatic compounds, that are shared by both types.
Therefore, we can conclude saying that the ripening process of the Gorgonzola cheese involves a deep transformation of the initial milk compounds that, in a nutshell, produce taste, aroma and structure of the cheese, making the Gorgonzola easier to digest and assimilate.