FOOD SCIENCE ›› 2012, Vol. 33 ›› Issue (20): 113-118.

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Extraction and Antioxidant Activity of Proteins from Porphyra yezoensis

YAO Xing-cun,Liu-Quan SHU, ,   

  • Received:2011-08-11 Revised:2012-09-19 Online:2012-10-25 Published:2012-11-09
  • Contact: YAO Xing-cun E-mail:yaoxingcun@126.com

Abstract: Response surface methodology was employed to optimize the extraction of proteins from Porphyra yezoensis. The extraction efficiency of proteins was investigated with respect to ultrasonic treatment time, temperature and solid/solvent ratio. The optimum conditions for the extraction of proteins from Porphyra yezoensis were determined as 10 min, 50 ℃ and 10:1 (mg/mL). Under these conditions, the actual extraction efficiency of proteins was 37.6%. The resulting extract was separated by Superdex 200 column chromatography into four fractions and their molecular weights were measured. A pooled sample of fractions 1, 2 and 3, all of which were proteins with a molecular weight larger than 10 ku and obvious free scavenging activity, was analyzed by SDS-PAGE and evaluated for scavenging activities against hydroxyl and DPPH free radicals. The molecular weights of fractions 1, 2 and 3 were 55, 22 ku and 17 ku as measured by SDS-PAGE. Pooled fractions 1, 2 and 3 possessed a marked free radical scavenging activity in a dose-dependent manner. The IC50 values against hydroxyl and DPPH free radicals were 1.481 mg/mL and 0.452 mg/mL, respectively.

Key words: Porphyra yezoensis, protein, extraction, separation and purification, antioxidant activity

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