Effect of Monascus sp. as an adjunct starter on physicochemical properties and proteolysis in semi-hard cheeses during ripening.

Two kinds of semi-hard cheeses, with Monascus purpureus and without M. purpureus, were manufactured, and effects of M. purpureus on physicochemical properties and proteolysis were evaluated during 36 days of ripening. Addition of M. purpureus changed the microbial survival and showed no significant effect on physicochemical properties of the cheeses, including dry matter and pH. Regardless on the rind or in the core, the indices of proteolysis had no significant difference (p>0.05), whereas there were significant differences of total free amino acid (FAA) and individual FAA between cheeses; this indicated that M. purpureus had no significant effect on the primary proteolysis, but affected the content and ratio of individual FAAs during maturation. Electrophoretic analysis showed strong degradation of αs1-casein in the core and on the rind of cheeses, while β-casein was highly degraded on the rind but less in the core. Thus, Monascus spp. might have a potential application in the manufacture of cheeses.