一、Storage characteristics of peanut oil
Under the general storage conditions of peanut oil manufacturers,the process of automatic oxidation rancidity will occur,and its changes are as follows:Automatic oxidation process is associated with season,if start storage in winter,low temperature can effectively alleviate the style of lipase and oxygen,as the season changes,the rise of temperature,the temperature in the 15 to 30 ℃,on the one hand,due to the solution of lipase,make fat hydrolysis,higher acid value,on the other hand immersion of oxygen in air,prompts the grease form hydrogen peroxide oxidation.
In summer,the temperature of room temperature and storage tank temperature exceeds 30℃.If stored in open oil tank or open storage yard,it will be exposed to sunlight every day.In this case,environmental factors will promote the oxidation process of oil to accelerate.Especially in sunlight under the action of ultraviolet rays or metal catalysts,when the radiation temperature exceeds 50℃,peroxides and hydroperoxides,will be further decomposed and reprocessed:molecules rearranged into aldehydes,ketones,so that the stored oil rancy.
二、Storage measures of peanut oil
(1) Temperature the peanut oil in the temperature below 15℃,full container sealed storage,otherwise lipase and oxygen will play a role in the oil,the result is the acid value and peroxide value increased,to meet this oil storage conditions;The storage depot should be built underground.Because the ground temperature is below 4 meters,it is below 20℃ all year round.
(2) For peanut oil stored for a long time,0.2% citric acid or ascorbic acid can be added to destroy the catalytic effect of metal ions and prolong the storage period.These substances are added to oil exported from abroad,and some of them also add antioxidants (such as BHA, BHT, PG, etc.).