17B-18 |
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T. K. SINGH1, M. A. Drake2, and K. R. Cadwallader1. (1) Dept. of Food Science & Human Nutrition, Univ. of Illinois, Urbana-Champaign, 1302 W. Pennsylvania Ave., Agriculture Bioprocess Lab., Urbana, IL 61801, (2) Dept. of Food Science, North Carolina State Univ., Schaub Hall, Box 7624, Raleigh, NC 27695-7624 In addition to the characteristic desirable flavors, certain specific flavor notes or defects are frequently identified in cheeses. While desirable flavor has been difficult to define in chemical and sensory terms, since consumers vary in preference and definition of Cheddar flavor, the specific cause(s) of many of these specific flavors or off-flavors (e.g., fecal, malty, fruity, floral, nutty) have been established more or less definitively. The objective of this study was to characterize compound(s) responsible for brothy flavor in Cheddar cheese. Commercial Cheddar cheeses identified with brothy flavor (12 samples) and control cheeses (not brothy, 2 samples) were selected using descriptive sensory analysis. In duplicate, each cheese plus internal standards (2-ethyl butyric acid and 2-methyl-3-heptanone) was extracted with diethyl ether, followed by isolation of volatiles by solvent assisted flavor evaporation (SAFE). Volatiles were separated into acidic and neutral/basic fractions and analyzed by gas chromatography-olfactometry (GCO) and aroma extract dilution analysis (AEDA). For the dynamic headspace dilution analysis (DHDA), headspace volatiles were purged on to Tenax using nitrogen for varying times (25, 5, 1 min at flow rate 50 mL/min) then thermally desorbed and cryo-focused before injection for GCO and GCMS analysis. Compounds were identified by comparison of GC/MS data, retention indices and odor properties. There was remarkable similarity in the overall GCO-AEDA and DHDA aroma compounds profiles of brothy and control Cheddar cheeses. The brothy Cheddar cheeses had higher flavor dilution factors for 3-(methylthio)-propanal, 4-hydroxy-2,5-dimethyl-3(2H)-furanone and 2-ethyl-4-hydroxy-5-methyl-3(2H)-furanone than control cheeses. 2-Methyl-3-furanthiol and its dimerized form were also identified in brothy cheeses. Contribution of these compounds to brothy flavor in Cheddar was confirmed by sensory analysis of cheese models, prepared from Cheddar cheeses free of brothy flavor. This study identified compounds responsible for brothy flavor in Cheddar cheese which will help in better understanding of cheese flavor chemistry.
Session 17B, Dairy Foods: General
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