Sue's Blog

Good news: free glutamates are not produced by the glutaminase enzyme subject of our Petition

After several conversations with FSANZ, I have discovered that free glutamates are not produced by the enzyme glutaminase that was subject of our Network petition 

I apologise that I did not have these conversations with them earlier, nor they with me – but it is pretty complicated.


I would like to say a sincere thank you to everyone who supported us in making this an issue which produced the useful conversations.

But there is still a problem:

Anything classified as a 'processing aid' is not listed!

Food manufacturers are increasing applications for additives to be classified as ‘processing aids’. This means that such added materials will not appear on the ingredients label.

Our concern

We worry because some of these processing aids might produce chemicals in the food to which food intolerant people react. But because they are not listed on the label, consumers will have no chance to work out what might be causing their problem.

Hiding additives

This is all part of the move by manufacturers to hide additives, because they know consumers prefer so-called clean labels


That’s why there is increasing use of ingredients that are actually functioning as preservatives or flavour enhancers but are hidden from consumers under innocent-sounding names (see our blog posts on cultured dextrose and 129 ways to hide glutamates).

What’s next?

What will happen if a 'processing aid' produces lots of ribonucleotides (635, 627, 631) to boost hidden glutamates?
Such an enzyme exists. Will it be approved?

We would consider that a disaster, see our factsheet on MSG boosters 

What about the next application for approval of a glutaminase? Will it be approved because this one has been approved?

We hope not. But as Thomas Jefferson may have said 'eternal vigilance is the price of freedom'.

Thank you

Again, many thanks to those who signed our petition for helping us raise awareness of the issue of hidden components in our foods. I should have done more technical homework. The problem is, after working on these issues for 25 years, I am not very trusting.    

The science - When is the enzyme glutaminase not producing free glutamates?

Application A1136 called the enzyme 'protein glutaminase'. In science enzymes are systematically classified by their action.

The subject of this application is EC protein-glutamine glutaminase.

The Recommended name is protein-glutamine glutaminase and Systematic name is protein-L-glutamine amidohydrolase. It specifically catalyses the hydrolysis of the gamma-amide of glutamine substituted at the carboxyl position or both the alpha-amino and carboxyl positions. “Protein-glutaminase catalyzes only the deamidation of the side chain amido group of protein-bound glutaminyl residues to release ammonia without catalyzing the transglutamination and hydrolysis of asparaginyl residues or producing other undesirable changes in protein structure”.

However more usually the word glutaminase refers to EC glutaminase.

The Recommended name is glutaminase and Systematic name is L-glutamine amidohydrolase. This enzyme catalyses L-glutamine + H2O to L-glutamate (free glutamate) + NH3.

Read more

Introduction to food intolerance – factsheet