China's soybean oil grading is very unscientific, giving people a "quality" grading feeling, in fact, this is a category of differentiation. First-class soybean oil is after the "five off" process, in addition to colloidal substances, pigments, odor (deodorization), etc., so that the color of soybean oil becomes lighter, there is no soybean smell, mainly used for cold, etc., foreign countries called "salad oil". Secondary oil is mainly soybean oil-based blending oil, tertiary oil is not decolorized soybean oil. Tertiary oil does not mean that the quality of oil is inferior to the first level of oil, at present, our consumers are still mainly tertiary oil.