Refining Vegetable Oils: Chemical and Physical Refining

Table 1

Undesirable constituents in oil removed during refining.

Component	Origin	Effect
Free fatty acids	Hydrolysis of triglycerides	(i) Taste, smoke if heating
		(ii) Hydrolysis
Phosphatides (phospholipids)	Natural compounds	(i) Cloudy aspect
		(ii) Deposit a residue in the oil flavors
		(iii) Dark color if heating
Oxidation products	Oxidation of unsaturated fatty acids	(i) Undesirable flavors
		(ii) Stability
		(iii) Color—nutrition
Flavors	Natural compounds of seeds, autooxidation	(i) Odorous components
		(ii) Flavors
Waxes and pigments	Natural components of seeds	(i) Odorous components
		(ii) Flavors
Metals (iron and copper)	Technological pollution; Pollution during storage transport and processing	(i) Oxidation catalysts
		(ii) Stability
Chemical pollutants		(i) Safety toxicity
Heavy metals
Pesticides
PAHs (B[a]P)
Mycotoxins
Dioxins