Porphyran, porphyran oligosaccharides and porphyranase: Source, structure, preparation methods and applications

Seaweed has been increasingly researched in recent years and many of the active substances extracted from algae have been shown to have a wide range of biological activities and have found applications in agriculture, medicine and other fields. Red algae Porphyra is a rich and widely distributed species with high nutritional value. Porphyran extracted from Porphyra has been found to have good antioxidant, immune modulating, anti-aging and hypoglycaemic effects. The biological activity of oligo-porphyran, obtained by degradation of porphyran, is superior to that of its source porphyran. It is therefore important to find methods that can effectively degrade porphyran, and the main focus now is on finding suitable porphyranases to degrade porphyran to prepare oligo-porphyran. This paper described and summarized the biological activity and preparation of porphyran and oligo-porphyran, and highlights the progress of porphyranase research.