Why Do Avocados Turn Brown?

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© Compound Interest

The Chemistry of Avocados

Anyone who’s ever purchased an avocado will testify that, after taking several days to reach the point of perfect ripeness, they remain at that point for an incredibly short amount of time before morphing into a brown, sludgy mess. As if to confound this problem, if you do catch them at the optimum ripeness, they turn brown incredibly quickly after being cut open if not eaten straight away. As always, there are chemical processes at work that are to blame for this occurrence.

The flesh of avocados is made up of mainly fatty acids, such as oleic acid and linoleic acid. They contain very little sugar or starch. Avocados don’t start to ripen until they are picked from the tree, and if you put them into the fridge whilst still unripe, it can prevent them from ripening at all. Putting into the fridge once they have reached the point of ripeness, however, can prolong the time at which they stay at this point for several days.