Web Release Date: October 3,
Characteristic Aroma Components of Rennet Casein
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Canakkale Onsekiz Mart Universitesi, Canakkale, Turkey, Department of Food Science, Cornell University, 116 Stocking Hall, Ithaca, New York 14853, Department of Food Science, North Carolina State University, Southeast Dairy Foods Research Center, Box 7624, Raleigh, North Carolina 27695, and Department of Food Science & Human Nutrition, University of Illinois, 1302 West Pennsylvania Avenue, Urbana, Illinois 61801
Received for review June 2, 2003. Revised manuscript received August 25, 2003. Accepted August 31, 2003.
Abstract:
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.
Keywords: Rennet casein; odor; aroma; volatile; gas chromatography-olfactometry
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