Taste was the theme of the 5th Tomato Conference held in the Netherlands.

Most of us would identify salty, sweet, sour and bitter as tastes, but may be unaware of the fifth basic taste: umami. Described by Dr Kikunae Ikeda of the Tokyo Imperial University 100 years ago, umami is a dominant flavour in meat and other foods such as cheese, mushrooms …and tomatoes. Otherwise described as savouriness, succulence or ‘deliciousness’, umami is due mainly to monosodium glutamate (adenosine monophosphate and glutamate in tomatoes). When mixed, umami compounds appear to behave synergistically, which explains why meat and tomatoes are often cooked together. Tomatoes, which are relatively high in glutamate, enhance the savoury, meaty flavour of meat.

Chemical analyses of tomato flavour by Don Mottram’s team at the University of Reading have shown differences in concentrations of umami compounds in different tomato varieties, and an interesting piece of work carried out in response to a request by celebrity chef Heston Blumenthal (renowned for his acute sense of taste) showed much higher levels (up to 10- to- 12-fold) of umami compounds in the centre (pulp and seeds) than in the outer flesh of tomatoes (1). The results confirmed the differences in strength of umami taste between the outer flesh and the centre which the chef had perceived. Think twice before you discard the seeds!

The conference was all about taste – so of course there had to be a tasting session. We all had to choose which wine we preferred with various different types of tomato. The results corroborated the interesting theory that northern Europeans like harmony in taste (a dry, slightly acid wine with a sharp tomato) whereas southern Europeans prefer contrast (a sweet wine with a sharp tomato, and a dry wine with a sweet tomato). The tasting didn’t end there – the chef had to meet the challenging task of preparing a 3-course meal based on tomatoes – which ended with tomato ice cream (delicious??!)

Search the CAB Abstracts database for hundreds of records on research into tomato taste and flavour and how this can be improved.

1. Oruna-Concha, M. J.; Methven, L.; Blumenthal, H.; Young,
C.; Mottram, D. S. (2007) Differences in glutamic acid and 5´-ribonucleotide contents between
flesh and pulp of tomatoes and the relationship with umami taste. Journal of
Agricultural and Food Chemistry 55(14) 5776-5780

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