Enzymatic extraction of polysaccharides from Laminaria Japonica and their free radical scavenging activity and antimicrobial activity evaluation

Complex enzymes, including cellulase, pectinase and neutral protease were used for extraction of laminaria polysaccharides, which have a broad range of applications in the food, pharmaceutical, agricultural and chemical industries. The enzymatic extraction conditions were optimized and the maximum polysaccharides yield was achieved with the addition of 2.5% of enzymes under a pH value of 5.0 and temperature of 55 degrees C for 210 min. Polysaccharides prepared under the above conditions were effective against some pathogenic and spoilage microorganisms, including Salmonella sp, Bacillus subtilis, Enterococcus faecalis, Proteus vulgaris, Staphylococcus aureus, Escherichia coli, Pseudomonas fluorescens, with a diameter range of 5.1 +/- 0.29-12.5 +/- 0.78 mm. In addition, antioxidant activity of laminaria polysaccharides against hydroxyl radicals was also investigated and it was observed that the polysaccharides displayed obvious scavenging activity on hydroxyl radicals in concentration-dependent manner. Overall, polysaccharides from Laminaria Japonica demonstrated potential applications in food safety and control.