Characteristic Aroma Components of Rennet Casein

Yonca Karagül-Yüceer, Katrina N. Vlahovich, Mary Anne Drake, Keith R. Cadwallader

Research output: Contribution to journalArticlepeer-review


Rennet casein, produced by enzymatic (rennet) precipitation of casein from pasteurized skim milk, is used in both industrial (technical) and food applications. The flavor of rennet casein powder is an important quality parameter; however, the product often contains an odor described as like that of animal/wet dog. Two commercial rennet casein powders were evaluated to determine the compounds responsible for the typical odor. Aroma extracts were prepared by high-vacuum distillation of direct solvent (ether) extracts and analyzed by gas chromatography-olfactometry (GCO), aroma extract dilution analysis (AEDA), and GC-mass spectrometry (MS). Odorants detected by GCO were typical of those previously reported in skim milk powders and consisted mainly of short-chain volatile acids, phenolic compounds, lactones, and furanones. Results of AEDA indicated o-aminoacetophenone to be a potent odorant; however, sensory descriptive sensory analysis of model aroma systems revealed that the typical odor of rennet casein was principally caused by hexanoic acid, indole, guaiacol, and p-cresol.

Original languageEnglish (US)
Pages (from-to)6797-6801
Number of pages5
JournalJournal of Agricultural and Food Chemistry
Issue number23
StatePublished - Nov 6 2003


  • Aroma
  • Gas chromatography-olfactometry
  • Odor
  • Rennet casein
  • Volatile

ASJC Scopus subject areas

  • General Chemistry
  • General Agricultural and Biological Sciences


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