Volatile extracts from celery can enhance the flavour of chicken soup, and could offer novel flavour enhancers for food formulations, suggests new research.
Low concentrations of the compounds were found to enhance the umami and sweet properties of chicken broth, report the researchers from Ochanomizu University (Tokyo) and the Technical Research Center at T. Hasegawa Co.
"We conclude that the volatile compounds in celery, i.e., 3-n-butylphthalide, sedanenolide, and sedanolide enhanced the complex flavour of chicken broth," wrote lead author Yoshiko Kurobayashi in the Journal of Agricultural and Food Chemistry.
Flavour, defined as combined sense of taste and odour, is a key driver in the €3.2 trillion global food industry. Kurobayashi and co-workers 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. The broth was evaluated in terms of "thick," "impactful," "mild," "lasting," "satisfied," "complex," "refined," and "clarified". The researchers considered these elements in terms of "sweet," "salty," and "umami" taste.
Six to ten female volunteers (average age 23.5) were recruited to evaluate the formulated broth, and found that celery's volatile compounds 3-n-butylphthalide (0.2 ppm), sedanenolide (0.7 ppm), and sedanolide (0.2 ppm) enhanced the complex flavour more than non-volatile compounds.
Indeed, the volatile compounds were associated with enhanced scored for seven of the eight terms, and for umami.
Moreover, the researchers state that sedanenolide was the most effective compound for flavour enhancement, particularly for "umami" and "sweet".
Four test solutions were prepared; (A) chicken broth (control), (B) broth with sedanenolide added (0.7 ppm), (C) broth with 3-n-butylphthalide added (0.2 ppm), and (D) broth with sedanolide added (0.2 ppm), separately.
"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," wrote the researchers.
"The mechanism is hard to understand and needs further study," they concluded.
Previous research into taste has revealed that the human tongue has about 10,000 taste buds with five taste sensations: sweet, bitter, and umami, which work with a signal through a G-protein coupled receptor; salty and sour which work with ion channels.
Contrary to popular understanding, taste is not experienced on different parts of the tongue. Though there are small differences in sensation, which can be measured with highly specific instruments, all taste buds, essentially clusters of 50 to 100 cells, can respond to all types of taste.
Taste buds (or lingual papillae) are small structures on the upper surface of the tongue that provide information about the taste of food being eaten.
Source: Journal of Agricultural and Food Chemistry
Published on-line ahead of print 29 December 2007, ASAP Article, doi: 10.1021/jf072242p
"Flavour Enhancement of Chicken Broth from Boiled Celery Constituents"
Authors: Y. Kurobayashi, Y. Katsumi, A. Fujita, Y. Morimitsu, K. Kubota