title: Investigation of the protein-protein aggregation of egg white proteins under pulsed electric fields.
abstract: Egg whites were exposed to pulsed electric fields (PEFs) to investigate the protein-protein aggregation. No insoluble protein aggregate was found when egg whites were exposed to PEFs at 25, 30, and 35 kV/cm for 400 micros. However, atomic force microscopy showed that the sizes of the protein particles increased. Native polyacrylamide gel electrophoresis (PAGE) demonstrated the existence of aggregates under PEFs at 35 kV/cm for 400 micros. Sodium dodecyl sulfate (SDS)-PAGE in the presence and absence of 2-mercaptoethanol further indicated that sulfhydryl-disulfide interchange reactions occurred under PEFs. Differential scanning calorimetry scans showed 400 micros of PEF treatment at 35 kV/cm denatured 16.5% proteins. Insoluble egg white protein aggregates were induced by PEF (35 kV/cm, 800 micros) and heat (60 degrees C, 3.5 min) treatments. Disulfide bonds were the dominant binding forces in the formation of protein aggregates. However, the weakly noncovalent bonds play a much more important role in the protein aggregation forming in heat treatment (60 degrees C, 3.5 min) than that in PEF treatment (35 kV/cm, 800 micros).
authors.affiliation: State Key Laboratory of Food Science and Technology, Jiangnan University, No. 1800 Lihu Road, Wuxi 214122, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhao
authors.forename: Ruijin
authors.initials: R
authors.lastname: Yang
authors.forename: Yali
authors.initials: Y
authors.lastname: Tang
authors.forename: Wenbin
authors.initials: W
authors.lastname: Zhang
authors.forename: Xiao
authors.initials: X
authors.lastname: Hua
mesh_terms: D000818:Animals; D002152:Calorimetry, Differential Scanning; D055598:Chemical Phenomena; D002645:Chickens; D004220:Disulfides / Q000737:chemistry; D004527:Egg Proteins / Q000737:chemistry*; D015387:Egg Proteins, Dietary; D004529:Egg White / Q000737:chemistry; D004560:Electricity; D004591:Electrophoresis, Polyacrylamide Gel; D005519:Food Preservation / Q000379:methods*; D006358:Hot Temperature; D008623:Mercaptoethanol; D018625:Microscopy, Atomic Force; D010316:Particle Size; D011485:Protein Binding
chemical_list: D004220:Disulfides; D004527:Egg Proteins; D015387:Egg Proteins, Dietary; D008623:Mercaptoethanol