The effect of alpha-ketoglutaric acid on amino acid utilization by nonstarter Lactobacillus spp. isolated from Cheddar cheese.

Aims:  To examine the effect of α-ketoglutaric acid (α-KG) on the utilization and catabolism of amino acids by strains of nonstarter lactobacilli isolated from Cheddar cheese. Methods and Results:  The effect of α-KG in the growth medium of nonstarter lactobacilli on amino acid metabolism, catabolite levels, peptide hydrolase and aminotransferase activities was examined. The pattern of amino acid utilization, catabolite formation and aminotransferase activity was affected by keto acid. Conclusions:  Amino acid conversion into cheese aroma and flavour compounds by nonstarter lactobacilli is enhanced in the presence of α-ketoglutarate. Significance and Impact of the Study:  Increasing the availability of α-ketoglutarate in cheese offers a possible method of reducing the maturation period by accelerating the rate of character compound formation from amino acids by the nonstarter lactobacilli.