Enhancement of amino acid catabolism in Cheddar cheese using α-ketoglutarate: amino acid degradation in relation to volatile compounds and aroma character

The effectiveness of the transaminase acceptor α-ketoglutarate in enhancing amino acid catabolism and manipulating the aroma profile of Cheddar cheese has been studied. Utilisation of α-ketoglutarate, catabolism of amino acids, volatiles production, and aroma profile of the cheese were monitored after 6, 12 and 24 weeks ripening. Glutamate and GABA were considerably enhanced on addition of the transaminase acceptor while levels of phenylalanine, leucine, isoleucine, alanine, valine, methionine and threonine were reduced. Addition of α-ketoglutarate increased volatile components originating from the catabolism of branched chain and aromatic amino acids. These compounds included acetic, propanoic, 2-methylpropanoic and 3-methylbutanoic acids, 3-methylbutanol, phenylacetaldehyde and benzaldehyde. Additionally enhanced production of 3-OH-2-butanone was evident. Addition of α-ketoglutarate increased aroma intensity, creamy and fruity aromas. Effects obtained must be verified by tasting cheeses made with food grade α-ketoglutarate, but results suggest potential benefits in accelerated maturation, low fat systems and manipulation of flavour profiles.