Glutamate isn't actually bad despite its dubious connection to the "china food syndrome". It doesn't cause allergies (which would be pretty bad for one of the amino acids that is widely used to build proteins).

I may change the taste of food in a strange way, since people have different numbers of receptors for tasting it (the taste is called umami).

Glutamate isn't actually bad despite its dubious connection to the "china food syndrome". It doesn't cause allergies (which would be pretty bad for one of the amino acids that is widely used to build proteins).

I may change the taste of food in a strange way, since people have different numbers of receptors for tasting it (the taste is called umami).

The LD50 of the substance, around 15-18g/kg, is much higher than that of, say, natriumchloride.

The bad reputation of mono-sodium glutamate is due to incomplete research, for example overlooking the use of alcohol in in the food and high salt levels. Double-blind trials up to now have shown that placebos create the same effect in "sensitive" people, as for example in the study in the links below. It can therefore be considered harmless.

http://www.sciencedirect.com/science/article/pii/027869159390012N

Do tomatoes actually contain mono sodium glutamate or naturally occurring "free" glutamate?

MSG had been linked to headaches, asthma as well as a "bad tummy syndrome" and I have always been a little cautious about this, especially as its often added to very highly processed foods.

You are right Kalpana, natural foods contain free glutamate rather than MSG (I would reframe my question), but its gluatamate that people are sensitive to, isn't it. The sodium level in glutamate is only one third of what we have in common salt. Glutamate is the one which gives the peculiar taste to food. Dr. Praetorius intoduced us to its name "umami". The information is new to me, so thank you Dr. Praetorius. To best of my knowledge, the human body treats MSG the same way as natural glutamate and does not distinguish between free glutamate and MSG. I would like to add that the intention of raising this question was not to promote the usage of MSG but to discover the "myths and truths" through discussion.

In tomatoes you will find free glutamate because the salt is in solution there. The same is true for foods which contain enough liquid to dissociate this into sodium and free glutamate. The way our body processes this is in the dissociated form.

@Kalpna: I haven't followed up this in detail, but to my knowledge all these links are at least weak or not prvable.

@Naveen: Wikipedia has interesting articles (and links to references) about umami and MSG.

I have just been delving into this, and it appears that manufactured free glutamic acid (ie MSG) is made up of both L-glutamic acid and D-glutamic acid (and may may also contain some impurities from the manufacturing process like pyroglutamic acid, mono and dichloro propanols , heterocyclic amines)

"Natural" food protein, as well as protein in the human body, contains only L-forms of amino acids.

I wonder if these different isometric forms are metabolised differently by the body? This could be the key reason - what do you think?

Hey Kalpana, that's a very good point for discussion. High levels of these impurities are definitely not good. I will do some research on that.

Good point raised by Kalpana but as far as D form of glutamate is concerned that may be taken care of by racemases? Can anyone shed light on this, please.

@Naveen: There are n number of bioproducts as well as synthetic products which has been given a bad name by some bad scientific studies where they have not conducted a thorough work and produced their half baked results which media has blown out of proportion.