Under normal storage conditions, peanut oil will undergo an auto-oxidation and rancidity process, and its changes are as follows: the auto-oxidation process is related to the season. If it is stored in winter, low temperature can effectively delay the reaction of lipase and oxygen. With the change of seasons and the rise of temperature, when the temperature is between 15-30℃, on the one hand, due to the action of lipase, the oil is hydrolyzed and the acid value increases. On the other hand, the infiltration of oxygen in the air will promote the oxidation of oil to form hydroperoxides.
In summer, the room temperature and the tank temperature exceed 30℃. If it is stored in an open-air oil tank or an open-air yard, it will be exposed to sunlight every day. In this case, environmental factors will accelerate the oxidation process of oil. Especially in the sunlight, under the action of ultraviolet rays or metal catalysts, when the radiation temperature exceeds 50℃, peroxides and hydroperoxides will further decompose and then rearrange molecules into aldehydes and ketones, making the stored oil rancid.
