2. Moisture - it will cause and promote the deterioration of hydrophilic substances (such as phospholipids, enzymes, microorganisms, etc.), enhance the activity of enzymes, promote microbial reproduction, lead to hydrolysis and rancidity, increase the formation of lipid peroxides.

3. Light and radiation - light, especially ultraviolet light, can promote the oxidation of oil. This is due to photooxidation, and can decompose trace amounts of hydroperoxide in the oil, generate free radicals, and enter a chain reaction, which accelerates the oxidation of the oil. High-energy ray (β-, γ-ray) irradiated food can significantly improve the sensitivity of oxidative rancidity, which is usually interpreted as the radiant energy-induced free radical production.

4.Oxygen—The process of auto-oxidation and polymerization is a process in which oil and oxygen react with oxygen. The amount of oxygen absorbed during the automatic oxidation and polymerization process is gradually increased. In general, the greater the concentration of oxygen, the faster the oxidation rate. In the storage container, the greater the partial pressure of oxygen, the faster the oxidation proceeds.

5.Catalysts - oils and fats exist in the presence of many oxidizing substances, trace metals, especially valence metals have a significant impact, they are a strong catalyst for the automatic oxidation of oils and rancidity, due to their presence, greatly shorten the induction period of oil oxidation, speed up The rate of oxidation reaction. Therefore, when the oil is refined, it is necessary to avoid contact with these factors that affect the quality of the refined oil. Only in this way can the refining equipment exert a greater effect and produce high quality oil.