Why does pineapple juice thicken after two days in the fridge?

PineApple Juice thickens after a couple of days in the fridge due to the enzymatic activity of bromelain, an enzyme found in pineApples. Bromelain breaks down proteins, which can lead to the formation of a gel-like consistency as the juice's components interact over time. Additionally, the natural sugars in the juice can also contribute to a thicker texture as they may concentrate or ferment slightly.