Complex sentence: The low temperature of slow-cooking makes it almost impossible to burn even food that has been cooked too long; however, some meats and most vegetables become nearly tasteless or "raggy" if over-cooked.
Split into simpler sentences: The low temperature of slow-cooking makes it almost impossible to burn even food that has been cooked too long. However, some meats and most vegetables become nearly tasteless or "raggy" if over-cooked.