Posts Tagged ‘tomato’

Gelling ketchup with horseradish

Friday, December 17th, 2010


Mixing tomato ketchup with horseradish causes it to gel over night

A while ago a reader sent me a very interesting question regarding a gelled seafood sauce. It is made by mixing tomato ketchup with horseradish and his question was very simple: Why and how does this sauce gel? He speculated about pectin (which is present in tomatoes), but wondered why ketchup then doesn’t gel on it’s own? And he also noted that horseradish ground with water does not have any gel like properties. So how come they can form a gel when mixed together?
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TGRWT #19: Tomato and black tea

Monday, September 7th, 2009

tgrwt-19

This month’s round of TGRWT is hosted by Pablo over at Medellitin, and the foods to pair this time are tomato and black tea. As always you can find instructions on how to participate in the announcement post. If you are new to TGRWT (which stands for They Go Really Well Together), check out the round-ups of the previous 18 rounds! And if you are chemically inclined, you may want to read on to learn more about the compounds behind this months pairing.
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Glutamic acid in tomatoes and parmesan

Friday, July 6th, 2007

mono-sodium-glutamate.jpg
Pure mono sodium glutamate from Taiwan

A recent article (found via Harold McGee’s News for curious cooks) featuring Heston Blumenthal as a co-author emphasizes the huge difference in glutamic acid contents between the flesh and pulp of tomatoes. Glutamic acid and it’s sodium salt (mono sodium glutamate or MSG) are responsible for the characteristic umami taste. On average the flesh contains 1.26 g/kg glutamic acid whereas the pulp on average contains 4.56 g/kg glutamic acid. Similar differences are found for several nucleotides which posess similar taste qualities. These differences can explain the perceived difference in umami taste between the flesh and pulp of tomatoes – and is worthwhile considering when cooking.

Those concerned about food with added MSG should read the chapter about MSG in John Emsley’s excellent book “Was it something you ate?”. First thing to note is that you can’t be allergic to MSG because our body needs glutamic acid to function properly. Emsley retraces the history of the Chinese restaurant syndrome (CRS) back to it’s roots in 1968 when a letter was published (R.H.M. Kwok, New Engl. J. Med. 1968, 278, 796) describing a series of symptoms experienced after having eaten at a Chinese restaurant. To make a long story short, in 1993 Tarasoff and Kelly reviewed previous studies and conducted a double blind test which led to the following conclusion:

… ‘Chinese Restaurant Syndrome’ is an anecdote applied to a variety of postprandial illnesses; rigorous and realistic scientific evidence linking the syndrome to MSG could not be found.

Following the publication, a critical reply was published by Adrianne Samuels, to which the authors have replied.

Anyway, it was in John Emsley’s book that I first read about the record levels of glutamic acid found in parmesan cheese: 12 g/kg! That’s nearly three times the amount found in tomato pulp. In some cheeses there is so much that it crystallises out in small white crystals visible to the naked eye. Think about this when you sprinkle your food with parmesan. And if you ever wondered why Italian food tastes so nice, now you know that MSG is one reason (but of course not the only one …).

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