The main component of the ink in octopus is water, and the reason why it is black is because the ink contains black particles invisible to the naked eye. So ink is actually a viscous suspension. Each milliliter contains 200mg of particles, which are spherical, and most of them are120 ~180 nm in diameter. Particles have a two-layer structure, a high-density inner core and a low-density outer shell.

The core is called ink melanin. The chemical composition of ink is a complex of melanin and proteoglycan. Melanin is a polymer of indoloquinone, which is bound to or not bound to protein.

Treatment of octopus eating;

1. Add proper amount of vinegar and alkaline noodles to the water, then add the octopus, and rub it by hand until the mucus on the octopus surface is cleaned.

2. Then find out the octopus's teeth and dig them out.

3. Then open the octopus's head, squeeze out all its internal organs and clean the ink.

4. As shown in the picture, the viscera of the removed octopus are all thrown away.

5. Then peel the octopus and tear it down from the head. Finally, rinse the octopus again, and the clear water means clean.

6. Clean octopus.