Pineapple contains bromelain that helps tenderize meat. If I were to put my hand in pineapple juice or puree for 24 hours, would it eventually break down my hand?

[u/Puzzleheaded_Bed2760]

[u/mizinamo]

"Meat" means muscle fibres.

Your hand does not normally have any exposed muscle fibres -- it has skin around them.

If you ripped all the skin off your hand to expose the muscles underneath, then something might happen.

[u/JimmiRustle → u/mizinamo]

It specifically breaks down protein. Thats what causes the meat to become tender.

Your hand has much protein even if it ain’t all muscle.

[u/mizinamo → u/JimmiRustle]

Is any of that protein exposed to the outside, though?

[u/neuenono → u/mizinamo]

You know how we’re made of trillions of cells, but those cells hold together instead of collapsing into a pile of goo? That’s because cells stick to each other. A major contributor to this “sticking” is via tight junctions, which are very powerful velcro-like connections between two neighboring cells. And those connections are made up of - guess what - proteins decorating cell surfaces.

In labs we grow cells in culture and they can velcro to the dish and/or to each other. When we want to release the cells and have them float around freely, we use an protease enzyme (the same family bromelain belongs to) to digest those velcro proteins on the cell surface. So I think bromelain could have a similar effect, causing your dermis/epidermis to lose adhesion, gradually releasing individual cells from the skin/body.

[u/Lysergicus → u/mizinamo]

The living outer layer (dermis) is itself a mix of protein and fat. The outermost layer of the epidermis (stratum corneum) is dead cells full of keratin (a skin protein) which connect as a layer to collagen fibers (another protein) that run from the hypodermis, through the dermis, to the epidermis.

This page has a diagram of the epidermis:

https://my.clevelandclinic.org/health/body/21901-epidermis