Done a ice bucket once and extracted alot of anthocyanins, collected and stored to prevent their degradation. Anthocyanins are highly vulnerable to degradation by heat and oxygen. Cold storage at around 4°C significantly preserves their stability and functional quality, which is why samples are transported in a container with ice cubes immediately after collection.
Anthocyanins are a class of water-soluble pigments found in plant cells, specifically within the cell vacuole. They are not attached to cell membranes, which is why they are easily extracted by water and other polar solvents. Other plant pigments like chlorophyll and carotenoids are fat-soluble, changes how it works.
Gluck.