Novel Antioxidant Peptide Derived from the Ultrafiltrate of Ovomucin Hydrolysate

The techno-functional properties of ovomucin as a gel-forming agent and its biological properties are well-known. The aim of the present study was to investigate antioxidant activity in ovomucin hydrolysate using radical scavenging assays. Electrophoresis showed that ovomucin isolated from whole egg was well separated. Ovomucin hydrolysis was carried out using microbial protease according to different incubation times. These ovomucin hydrolysates exhibited 85% antioxidant activity as measured by the 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) assay after a 2 h incubation with protease and retained 90% activity until 24 h. At an incubation time of 4 h, the activity of ovomucin hydrolysates reached approximately 90%, corresponding to 115 μM gallic acid equivalent, regardless of the proteases used. The partially purified fraction of the hydrolysate by ultrafiltration and reverse-phase high-performance liquid chromatography was collected and then analyzed by liquid chromatography electrospray ionization mass spectrometry. Two peptides, LDEPDPL and NIQTDDFRT, in this fraction were identified. The antioxidant activities of these two synthesized peptides were measured to be 51.8 and 24.7% by the 2,2-diphenyl-1-picrylhydrazyl assay.