Microwaves action on milk for infants (fwd)
haoxiao at cc.UManitoba.CA
Thu Jan 12 00:23:45 EST 1995
> Contrary to what other respondents have stated,
> there is some theory behind this concern. Amino acids,
> which are the building blocks of proteins in all living organisms,
> occur in two spatial configurations that are often referred to as
> D and L. However, the form used with very few exceptions in
> organisms is the L form; that is the form that occurs in milk
> as a nutrient.
> However, microwaves can "racemize" amino acids, that is, interconvert
> the D and L forms. I do not know the theoretcial basis of this
What is the % of free amino acids in milk as compared to protein? Or how
the microwave can "racemize" peptide bonded amino acids?
> as I'd have expected the microwave energy to be too low to do this,
> but I've seen reports of it being done and it has been proposed as the
> basis of an industrial method for interconversion. Indeed, I did get
> a student of mine to check it out a few years ago, and she did
> manage to get it to occur.
> To get back to the milk, I did see a letter to Lancet a few years back
> reporting that D amino acids could be detected in microwaved milk.
> Right at this moment I can't find the reference. Of course, what
> you want to know is how important is this. The loss of nutrient
> quality is probably small; the D amino acids formed from essential
> amino acids will be unavailable for use in making proteins in the baby.
> Normally, we destroy any D amino acids we encounter. The only concern
> is that babies almost certainly have a more limited ability to cope
> with D amino acids, and one of them, D - proline is somewhat
> neurotoxic. The risk might be entirely hypothetical, but there is
> a potential mechanism for it. Why microwave the milk anyway? It's easy
> to warm the amounts required for a baby by standing it in hot water.
> David Fell
> David Fell,
> School of Biological & Molecular Sciences,
> Oxford Brookes University,
> Oxford OX3 0BP, Tel. +44 (0)1865 483247
> UK FAX +44 (0)1865 484017
> daf at bms.brookes.ac.uk
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