TABLE 6.

ALA enrichment methods.

	Advantages	Disadvantages
Solvent Extraction	Simple operation	Low purity
Silver Ion Complexation	Good separation effect.	Expensive. Heavy metal pollution.
	High product purity
Molecular Distillation	No foreign substances’ introduction.	Need high vacuum.
	Temperature is far below the boiling point.	High energy consumption.
	Short heating time.	Low purity of the product.
	Fit for continuous production.	Not ideal for the separation of fatty acids with similar molecular weights.
Low-temperature Crystallization	Cheap equipment, easy to operate, and can effectively protect active ingredients	A large amount of organic solvent needs to be recovered, and the separation efficiency is not high.
Urea Complexation	Simple process, low cost, and the active ingredients protective.	Difficulty separating fatty acids with similar degrees of unsaturation.