I would like to get the large data set of polyphenols content and antioxidant activity in olive fruits, oil and pomace. Ideally from different countries. Is anyone aware if such data is available?
Have you looked into the USDA Food Composition Database (https://ndb.nal.usda.gov/) and The Canadian Nutrient File (http://www.hc-sc.gc.ca/fn-an/nutrition/fiche-nutri-data/index-eng.php)? Both contain nutrient data about many foods, and it's likely that the ones you are looking for are represented there in some form.