What chemicals does lime juice contain that slows the browning?

Citric acid: Citric acid is a weak organic acid that is found in citrus fruits, including limes. It is a natural preservative that can help to slow down the browning of fruits and vegetables by inhibiting the activity of enzymes that cause browning.

Vitamin C: Vitamin C is an antioxidant that can help to slow down the browning of fruits and vegetables by preventing the oxidation of phenolic compounds. Phenolic compounds are responsible for the colour of fruits and vegetables, and when they are oxidised, they turn brown.