Celery can enhance the flavour of chicken soup, and could offer novel flavour enhancers for food formulations, suggests new research from Japan.

Researchers from Ochanomizu University in Tokyo and the Technical Research Centre at T Hasegawa Co Ltd have reported that low concentrations of the volatile compounds 3-n-butylphthalide, sedanenolide, and sedanolide found in celery enhance the umami (the flavour associated with a non-essential amino acid, glutamate, and other nitrogen compounds) and sweet properties of chicken broth.

Researchers assumed that certain odour compounds could enhance the intensity of flavour in a complex food matrix and set about testing the celery extracts in chicken broth.

Chicken broth was formulated to include celery extracts containing both volatile and non-volatile compounds. Female volunteers were then recruited to evaluate the formulated broth and from this researchers found that celery's volatile compounds enhanced the complex flavour more than non-volatile compounds.

“We considered that the increase of intensity of umami and sweet perceived in the samples containing phthalides were not actual values, but rather the increase of intensity of impression of umami and sweet, which was induced by olfactory sensations brought about by the retronasally delivered phthalides,” researchers told the Journal of Agricultural and Food Chemistry. “The mechanism is hard to understand and needs further study.”