According to relevant national standards, edible oil is generally divided into four grades, level 4 to level 1. The higher the grade, the higher the refining level.
The refining degree of first and second grade oil is relatively high. Through the vegetable oil refining process of degumming, deacidification, decolorization and deodorization, it has the characteristics of tasteless, light color, high smoke point, less cooking oil smoke, and difficult to solidify at low temperature. After vegetable oil refining, the contents of harmful components in the first and second oil are low, but at the same time many nutrients are lost. The refining degree of grade iii oil and grade iv oil is relatively low, only through simple degumming, deacidification and other procedures. Its colour and lustre is deeper, smoke point is inferior, oil smoke is big in cooking process. As a result of low refining, the content of impurities in the third and fourth grade cooking oil is higher, but at the same time, some nutrients are retained.
Next is the final Vegetable oil product's specification:
|1st grade||2nd grade||3rd grade||4th grade|
|Moisture & Volatile matter/ % Moisture & Volatile matter/ % ≤||0.05||0.05||0.1||0.2|
|Impurities / % ≤||0.05||0.05||0.05||0.05|
|Acid value(KOH)(mg/g) ≤||0.2||0.3||1||1|
|Peroxide value/(mmol/kg) ≤||5||5||7.5||7.5|
|Test tempeature (280°C)||_||_||No educt,Lovibond Tintometer: Yellow value not changed,red value increasing<0.4||Trace of educt,Lovibond Tintometer: Yellow value not changed,red value increasing<0.4 blue value<0.5|
|Saponified matter content / % ≤||_||_||0.03||0.03|
|Smoke point / °C ≥||215||205||_||_|
|Freezing test (0°C Storing 5.5hrs)||Transparent||_||_||_|
|Solvent residue/(mg/kg) ≤||Solvent extraction crude oil||None||None||50||50|
|Press crude oil||None||None||None||None|