Influence of the interaction of milk and starters on the ripening and quality of Comte cheeses

To study the influence of milk x starter interactions on the physico-chemical and sensory characteristics of Comte cheese, twelve typical Comte' cheeses were made in duplicate with raw milk fr om three different sources. Four different starters were used with each type of milk. Throughout the ripening period, different physico-chemical and sensory characteristics correlated not only with the origin of the milk or starters but also with the interaction between milk and starter. After 4 weeks of ripening, 30% of the variation in amino acid and peptide composition resulted from the interaction between milk and starter. After 13 weeks, 36% of proteolysis was due to the milk, while at the end of ripening the influence of the starter on proteolysis prevailed. Rheological measurement showed different behaviour between cheeses according to the level of proteolysis: the cheeses with a lower level of proteolysis showed a higher degree of cohesion. At 13 weeks, 44% of the variation in the level of acetic acid production was due to the interaction between milk and starter. Comte' cheeses made from the same milk but with different starters showed different acetic and propionic acid levels. The lower propionic acid level observed with one starter seemed to correlate with its lower proteolytic activity. The sensory, analysis showed the importance of the milk on cheese texture, in particular on firmness and heterogeneity and also on cheese taste, in particular pungency. Bitterness seemed to be correlated with interactions between milk and starter.