Mechanical Properties and Water Vapor Permeability of Edible Films from Whey Protein Isolate and N-Ethylmaleimide or Cysteine

Peter Fairley, Frank J. Monahan, J. Bruce German, John M. Krochta

Research output: Contribution to journalArticle

27 Scopus citations


The role of sulfhydryl/disulfide interchange in determining the water vapor permeability (WVP) and mechanical properties of edible films from whey protein isolate (WPI) was investigated. Nearly total inhibition of sulfhydryl/disulfide interchange by the sulfhydryl blocking agent N-ethylmaleimide (NEM) reduced protein solubility by 50%, but had no effect on WVP, Young's modulus, yield stress, or breaking stress. Breaking strain was reduced significantly at high levels of added NEM. Reduction of disulfide bonds with cysteine had no effect on WVP. The effects of hydrogen bonding far outweigh those of disulfide bonding in WPI films.

Original languageEnglish (US)
Pages (from-to)3789-3792
Number of pages4
JournalJournal of Agricultural and Food Chemistry
Issue number12
StatePublished - Dec 1996



  • Biodegradable films
  • Edible films
  • Elastic modulus
  • Sulfhydryl / disulfide interchanpge
  • Tensile stress
  • Thiol / disulfide interchange

ASJC Scopus subject areas

  • Agricultural and Biological Sciences (miscellaneous)
  • Food Science
  • Chemistry (miscellaneous)

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