Effect of lipids on soy protein isolate solubility

W. L. Boatright, N. S. Hettiarachchy

Research output: Contribution to journalArticlepeer-review

50 Scopus citations


Reduced-lipid soy protein isolate (SPI), prepared from soy flour treated so that most of the polar lipids have been removed, exhibited an increase in protein solubility of 50% over that of the control SPI prepared from hexane-defatted flour. Adding lipids from a commercial SPI during processing of reduced-lipid SPI decreased SPI solubility by 46%. The 19% decreased solubility caused by the lipids (primarily phospholipids) was largely recovered by treating the protein with a reducing agent (2-mercaptoethanol). The balance of protein insolubility, caused by the lipids, was attributed to a smaller lipid fraction (approximately 5% of the total lipids). Adding lipids during SPI processing contributed to both the formation of oxidized protein sulfhydryls, incapable of being reduced by 2-mercaptoethanol, and to oxidative deterioration of protein as determined by protein carbonyl contents.

Original languageEnglish
Pages (from-to)1439-1444
Number of pages6
JournalJournal of the American Oil Chemists' Society
Issue number12
StatePublished - Dec 1995


  • Lipid oxidation
  • lipids
  • phospholipids
  • protein oxidation
  • protein solubility
  • soy protein isolate
  • sulfhydryl

ASJC Scopus subject areas

  • General Chemical Engineering
  • Organic Chemistry


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