Physicochemical properties and anti-oxidation activities of ulvan from Ulva pertusa Kjellm

The present study investigated the effect of extraction conditions (including hot water-HW, ultrasonic assistedUA, enzyme assisted-EA and ultrasonic-enzyme assisted-UEA) on the yields, chemical composition, rheological properties and antioxidant activities of ulvan. The yields obtained by the above four extraction methods ranged from 17.88% to 26.77%. The use of enzymes helped to improve the yields of extraction, and through ultrasonicenzyme treatment, the maximum yield was obtained (26.7%). It was found that ulvan primarily consisted of sugar (41.9%?51.3%), uronic acid (14.1%?19.7%), protein (2.4%?3.3%) and ash (21.2%?24.9%), and the neutral sugars largely comprised rhamnose (22.4%?29.5%), xylose (10.0%?13.3%), glucose (5.0%?8.2%) and galactose (0.3%?0.5%). The results of the rheological measurements revealed that ulvan (4%, w/w) extracted by enzyme-assisted, ultrasonic-enzyme-assisted, ultrasonic-assisted and hot water treatment exhibited the stable shear viscosities of 24.5, 29.2, 56.7 and 95.2 mPa?s, respectively. Furthermore, ulvan extracted by enzymeassisted and ultrasonic-enzyme-assisted treatment showed visible DPPH radical scavenging ability over that extracted by hot water extraction and ultrasonic-assisted treatment, especially that extracted by enzyme-assisted treatment (SC50 6.52 mg/mL). Overall, the physicochemical properties of ulvan could be significantly affected by extraction methods. Polysaccharide from Ulva pertusa Kjellm, for its anti-oxidation activities, has high application implication in the field of healthcare, and subsequent researches should discuss its bioactive functions.

Automated summary

The study investigated the effects of different extraction conditions on the yields, chemical composition, rheological properties, and antioxidant activities of ulvan. Enzyme and ultrasonic treatment improved extraction yields and affected the composition of ulvan, with enzyme-assisted extraction showing the highest DPPH radical scavenging ability. The physicochemical properties of ulvan were significantly influenced by extraction methods, highlighting potential applications in healthcare due to its antioxidative properties.