olive oil for preservation
Canning with oil is an old method of preserving food. There are three ways to preserve with oil. Once you can put the vegetables raw or cooked floating in oil. Another option is to chop the vegetables and other ingredients and then mix them with oil (basil pesto) or pickle dried vegetables in oil (dried tomatoes in oil).
Spices can also be preserved in oil to flavor the oil (garlic and chilli oil).