Another science question

I was washing up yesterday when it ocourred to me; biological washing powders have enzymes to get oil and stuff out right? And it seems to do a pretty dam good job of getting food out. (I’m a messy eater :wink: ) So, given that the I’m trying to get the same food off my clothes and my dishes, why are there no enzymes in washing up liquid? Is it just cost, or are there reasons why it won’t work?

“Washing up” is a UK expression that I am not familiar with, being an American (who only spent 1 week in Newport-on-Tay, a few miles from Edinburgh.) What does it refer to?

Sorry…

My flatmate informs me that the american equivalent would be “doing the dishes”

There are (or at least used to be) laundry detergents with enzymes. However, they also have a lot of phosphates, and many places have restrictions on the amount of phosphates in laundry detergents because they cause IIRC algae blooms and fish kills. So these laundry detergents have fallen out of faor.

Oh, and thanks a lot for getting Fab’s “Oh Fab I’m glad they put enzyme-active lemon-freshened Borax in you” in my head.

Being an American male, I don’t know what THAT is, either.

Are you sure about the “enzyme active” part? I don’t remember that part of the jingle.

The “classic” Fab jingle is simply -

“Oh Fab! I’m glad! They put lemon-freshened Borax in you!”

Thank God for Borax! No clogged drains :slight_smile:

They added the enzyme-active part later for New and Improved! Fab. I remember the shorter version, too, though.

I seem to remember from Freshman Chem that there are enzymes in most common detergents (laundry and dish) called surfactants.

These may not technically be enzymes because I don’t know if they are organic or not, but they are catalysts for cleaning. I think there are others too, but surfactants are almost ubiquitous.

Enzymes and surfectants are two different things:

Surfectants reduce the surface tension of water, allowing the water to get into places better than it would otherwise.

Enzymes break down proteins, so they are only effective on protein based stains. Most non-chlorine bleaches are basically enzyme solutions. Note that silk and wool are protein based fibers - you will want to use the enzymes with caution if cleaning these.

There are also detergents, which dissolve the grease but dissolve in water.

Chlorine bleaches strip oxygen atoms from all molecules, therefore breaking the molecules down.
As to the OP, enzymes aren’t used in dish detergent because the proteins don’t bind to dishware materials (ceramic, plastic and metal) as easily as they bind to cloth.

For more information: “It All Comes Out in the Wash” Smithsonian, Sept 1997

The washing powders we use in my lab do not include enzymes of any sort. Generally strong acid, strong base, detergents, phosphates, or a combination of the above, and some elbow grease to boot, will get anything off the glass and plastic items we use.

LL

I thought non-chlorine bleaches were oxygen bleaches.

er, because the enzymes might start eating your hand. okay maybe not but it would be bad for your hands to expose them to it all the time.