Degumming to remove impurities is mainly phospholipids and other quality.The molecular structure of these impurities are extremely complex, and content are few.They insolubles, soluble content or the presence of colloidal state.Of phospholipids was of poor thermal performance,palm oil processing plant temperature above 423.2 K begin to decompose step by step, can make the oil colour and lustre is gradually deepened.The phospholipid in plant oil is mainly lecithin and cephalin.They are classified as hydrated phosphatide and non hydrated phosphatide two types.
Degumming hydration method is commonly used.By water, in the oil soluble substances mainly phospholipids sol, precipitation, to go off and oil content.But hydration method can only be hydrated phosphatide, also can't meet the requirements of the preparation of physical refining oil.
Can be used to completely remove phospholipids, additive hydration method.Literatures, the degummed oil additive have been reported include sulfuric acid, hydrochloric acid, phosphoric acid, citric acid, cool drunk, oxalic acid, tartaric acid and so on.Alkali refining using caustic soda also has further the effect of dephosphorization.
After take off. Gum from hydrated oil, but also contains the carotenoid pigment, trace metals.Residual phospholipids and other impurities.To manufacture qualified salad oil, still need to make these impurities to allow level further, this mission is the decoloring.Decolorization adsorption method is the most commonly used method, namely by adsorbent adsorption ability to remove impurities.Adsorption process and equipment is simple, effective, adsorbent, cheap and no pollution problem.draught fan
Commonly used adsorbent activated clay, other sorbents such as activated carbon, zeolite, such as natural clay also has use.. The adsorption ability of activated clay as the origin, the original soil properties, activation method and the activation conditions vary.
(2) the decoloring time...