Studies on antimicrobial and antioxidant properties of phosvitin hydrolysates produced by high hydrostatic pressure combined with enzymatic hydrolysis

  • Author / Creator
    Yoo, Hee Joo
  • Phosvitin (PV) is a metal binding protein in egg yolk with unique amino acid composition (more than 55% serine). Due to a high proportion of phosphorylated serine residues, PV shows metal chelating, antioxidant and antimicrobial activities. The use of PV, however, in nutra- or pharmaceutical application has been restricted mainly due to the formation of insoluble complexes with divalent metal ions in the gastrointestinal tract. The PV hydrolysates (PVH) that are hydrolyzed by proteases may solve the problem and increase their applications without compromising the PV’s functional properties. There are many attempts to produce the PVH. However, the yield of the PVH is low due to the PV’s negative charges causing the resistance to digestive enzymes. The present technology of the high hydrostatic pressure combined with enzymatic hydrolysis (HHP-EH) is a new method to increase the enzyme efficiency. The present study of the HHP-EH shows a higher degree of hydrolysis containing more peptides with Mw< 3 kDa compared to atmospheric pressure (AP). PV Hydrolysis with Alcalase (Alc) under HHP resulted in the highest degree of hydrolysis (31.3%). The PVH treated by Alc and Trypsin (Try) obtained from both HHP and AP treatments showed superior iron chelation capacity (69-73%). Alc-PVH produced by HHP-EH displayed significantly greater reducing power (3.5 μM Trolox equivalent/mg) than AP-PVH (1.3 μM Trolox equivalent/mg). In the second study, a combination of specific IgY (100 μg/mL) and PVH-Alc-HHP (1 mg/mL) as an anti-microbial agent was found to be the most efficient to control the foodborne Enterotoxigenic Escherichia coli (ETEC) K88 and K99 in vitro. The synergistic anti-microbial activities of IgY and PVH may support their potential application in feed supplementation to prevent microbial contamination and infectious diseases. In the third study, there is limited information available on the quantification of PV. The double antibody sandwich ELISA (DAS-ELISA) and biotinylated DAS-ELISA developed has a PV detection range of 5.6 – 90 µg/mL and 2.5 – 40 ng/mL, respectively. The biotinylated DAS-ELISA is a superior method for PV quantification regarding accuracy and sensitivity. This highly efficient PV detection method may recuperate the performance of the existing protein assay methods as well as facilitate future research on PV bioactivities and applications.

  • Subjects / Keywords
  • Graduation date
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.
  • Language
  • Institution
    University of Alberta
  • Degree level
  • Department
    • Faculty of Pharmacy and Pharmaceutical Sciences
  • Specialization
    • Pharmaceutical Sciences
  • Supervisor / co-supervisor and their department(s)
    • Sunwoo, Hoon (Pharmaceutical Science)/ Loebenberg, Raimar (Pharmaceutical Science)
  • Examining committee members and their departments
    • Siraki, Arno (Pharmaceutical Science)
    • Wu, Jianping (Agricultural)