Ulvan and Ulva oligosaccharides: a systematic review of structure, preparation, biological activities and applications

Bioresources and Bioprocessing

Table 3 Different extraction methods of ulvan

Method	Advantages	Disadvantages
Hot water extraction	A. Low cost	A. It takes a lot of time
	B. Simple and easy to operate	B. Low product yield
	B. Simple and easy to operate	C. High temperatures may cause degradation of certain polysaccharides
Acid–Base extraction	A. Save time	A. May disrupt polysaccharide structure
Acid–Base extraction	A. Save time	B. Increased cost of waste liquid treatment
Physical-assisted extraction	A. Save time	A. May disrupt polysaccharide structure
	B. High extraction efficiency	B. Cannot improve polysaccharide yield and purity
	C. Maintain the structure and biological activity of polysaccharide	B. Cannot improve polysaccharide yield and purity
Enzyme-assisted extraction	A. Mild reaction conditions	A. High cost
Enzyme-assisted extraction	B. High extraction efficiency	A. High cost