
Chandrakanth E. answered 07/29/19
Associate Professor of Biology and an effective teacher for all
Water soluble polyphenols cause the bitter taste in olive fruits. That is why the separated oil (remember oil and water do not mix) does not taste bitter. The bitter taste however is specific to the taste receptors of animals that eat them. Birds that are involved in olive seed dispersal (the scientific term is "zoochory") do not taste the bitterness (just like chilli peppers do not "taste hot and spicy" to birds) , so seed dispersal by birds is unaffected.