Re: Would biolgical washing powders be better at removing stuborn stains

Sarah,
 Enzymes can help to remove certain  kinds of stains from clothing, 
particularly protein stains.  The type of enzymes that are used in washing 
powders are the same as some digestive enzymes, which help in the digestion 
of proteins.  These enzymes are lumped under the general name "proteases" 
because they all function to digest proteins by breaking them up into 
smaller units.  Proteins themselves are often less water soluble than the 
smaller pieces that are left after digestion by a protease.  Hence, it makes 
sense that these enzymes might help to wash out stains if the stains are 
made up of proteins. 

There are several possible reasons why you don’t see much of a difference 
between washing powders that contain enzymes and those that don’t.  Many 
stains are from materials that are not proteins.  The enzymes in washing 
powders will not be effective on such stains.  Secondly, modern detergents 
are very effective at removing normally insoluble materials such as oils and 
grease, and protein, from clothing.  Lastly, the results might depend on 
what temperature you do the washing.  Most enzymes function best at room 
temperature or slightly above.  Not very many enzymes retain activity for 
long at high temperatures; they will denature and become inactive. 

Your experiment also demonstrates another fact about marketing of consumer 
products.  Often the advantages of particular products are not what they are 
advertised to be.