of compounds (Fig. 2b). For example, the non-dairy strains produced
higher levels of the branched chain aldehydes (2- and 3-methyl butanal
and 2-methyl propanal) and their corresponding alcohols (2-and 3-
methyl butanol and 2-methyl-1-propanol) which are the degradation
products of leucine, isoleucine and valine respectively, and suggest
that the non-dairy strains have enhanced amino acid catabolic abilities.
In addition, higher levels of ethanol (and hence esters), diacetyl, acetoin
and 2,3 butanediol were produced by the non-dairy strains. In dairy
strains, these compounds are generally produced through citrate metabolism
(McSweeney and Sousa, 2000). The broad ability of the plant
lactococci isolates to utilize citrate is thus suggesting the higher potential
that exists in these isolates to produce flavour compounds. The plant
lactococci isolates were also associated with higher levels of sulphur