They are all cold-pressed virgin oils and should be kept in the dark and refrigerated after opening to prevent them from becoming rancid.
Preservatives and antibacterials, added to many liquid products to keep them from becoming rancid or contaminated.
Lightly hydrogenated oils have very similar physical characteristics to regular soy oil, but are more resistant to becoming rancid.
Oxygen, light and heat all contribute to cooking oils becoming rancid.
The food however was very poor, including hardtack, rice and bully beef, some of which had become rancid and sickened many men.
Because of its high content of γ-tocopherol, the oil is very stable and is becoming rancid only slowly.
Most NOPs are still quite similar chemically to their parent vegetable oils and as such are prone to becoming rancid.
Keep them in the freezer to prevent them from becoming rancid before you use them.
Commercial pastes also contain food preservatives to keep them from becoming rancid.