Bradley pointed out that antioxidants, especially phenolic compounds, are highest when the avocado is perfectly ripe, before enzymes start breaking them down. Other vitamins and minerals, like potassium, magnesium and folate, stay steady, while fats become fully available.
Article source: https://www.huffingtonpost.co.uk/entry/avocado-ripeness-health-benefits_uk_697227d6e4b0e15d54cc1dd4