Enhanced flavour formation by combination of selected lactococci from industrial and artisanal origin with focus on completion of a metabolic pathway

Combinations of lactococcal strains from various origins with divers proper ties were developed as new starters for new dairy products. Flavour formati on by such tailor-made cultures was studied. In some cases, a strongly enha nced flavour was observed. For instance, the combination of B1157 and SK110 strains in milk resulted in a very strong chocolate-like flavour. B1157 pr oduces only a moderate chocolate-like flavour, whereas SK110 alone fails to produce this flavour. Headspace gas chromatography results corroborate the organoleptic evaluations. High levels of branched-chain aldehydes were fou nd when B1157 and SK110 were grown together. The enzyme activities involved in this pathway were studied; both strains contain transaminase activity. Although B1157 had a very high amino acid decarboxylating activity, its rel ease of amino acids from milk protein was limited. SK110 was strongly limit ed in decarboxylating activity, although this strain is very active in prot eolysis. By combining these strains, the substrates released by SK110 can d irectly be used by the other strain, resulting in the completion of the who le flavour-formation pathway. This opens new avenues for the preparation of tailor-made cultures.