Cut off the tough root ends of the collard greens and discard. Wash greens thoroughly, rinsing several times. Coarsely chop leaves and stems. Fill a large stockpot about half full of water. In a food processor, blend about 1/2 cups of the collards and 1/2 cup of the water together, then add it to the pot. Add the ham hock, onion, corn syrup, salt, vinegar, Worcestershire, hot sauce, garlic powder, red pepper flakes and white and black pepper to the pot and bring to a boil. Add the chopped collards in batches, letting them cook down between additions so there is room to add more. When all the collards have been added, reduce heat and simmer for about 3 hours.