How can I avoid getting swindled? How can I detect polyphosphates in fish fillets?
Fish fillets are treated with polyphosphates for several reasons, but mainly to increase their weight (and hence the profit).
According to this FAO paper:
- The first and universal effect of all polyphosphate treatment is to increase the weight of the fish by retaining water
- Application of polyphosphate to ...(high quality fish) ... is generally only of slight value
- The dull surface of poor quality fillets from stale fish can also be given a gloss by treatment with polyphosphate.
- Excessive treatment of small products such as shellfish or thin fillets can even result in undesirable flavour changes and sloppy texture.
So ... is there a way to know if a fillet has been treated with polyphosphate without buying it first and lending it to your chemist cousin?
Best Answer
Put the fish under a blacklight and dab a bit of 4',6-diamidino-2-phenylindole stain on it. If it changes glow from blue to green, its been treated with polyphosphate.
You can purchase DAPI stain here: http://www.sigmaaldrich.com/catalog/product/sigma/d9542?lang=en®ion=US
I would suggest cutting a piece of the fish that you will not be eating, dabbing the stain on that piece and tossing it in the bin after.
Or lend it to your chemist cousin :)
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