Cheese flavour development by enzymatic conversions of peptides and amino acids

During ripening of cheese, many biochemical processes take place, which are essential for flavour development. The breakdown of caseins is a prerequisite for flavour development. A good balance between proteolysis and peptidolysis prevents the formation of bitterness in the cheese. For this reason, it is necessary to focus on starter cultures with highly active peptidases, which should be active in the cheese matrix. Amino-acid-converting enzymes (AACEs) are involved in the degradation of amino acids, which are liberated during proteolysis. Their activity results in various volatile (flavour) components; most notably the degradation of methionine results in flavour-active sulphur compounds. AACEs involved in degradation of methionine and other amino acids were identified and their role in (cheese) flavour formation is described. At least two pathways leading to the formation of sulphur compounds were identified. Overproduction of one of the enzymes involved, results specifically in a higher formation of sulphur compounds. This result, together with the observation that flavour production is highly strain-specific amongst Various lactococcal bacteria, offers a new potential for industrial applications. (C) 2000 Elsevier Science Ltd. All rights reserved.