14A-5 |
Character impact aroma compounds in whole milk powder |
M. E. CARUNCHIA WHETSTINE1, Y. Karagul-Yuceer, J. D. Parker, and M. A. Drake4. (1) Dept. Food Science, North Carolina State University, Raleigh, NC 27695, (2) Dept. of Food Science, North Carolina State Univ., Schaub Hall, Box 7624, Raleigh, NC 27695-7624 Whole milk powder (WMP) is an important dairy ingredient, and is utilized in a wide array of food products. Because of the high fat content of these powders, off-flavors may develop during storage. By characterizing flavor compounds in WMP, the flavor and flavor stability of WMP will be more greatly understood. The objectives of this research were to characterize and quantify the aroma-active compounds that contribute to flavors in whole milk powder, both by instrumental and sensory analysis. Six whole milk powders of varying ages were collected and stored at -20C until analysis. Descriptive sensory analysis was conducted on the reconstituted powders using a trained panel with a previously established sensory language. Duplicate samples (300g) with internal standards were extracted with diethyl ether, followed by isolation of volatile material by high vacuum distillation. Volatile extracts were separated into neutral/basic and acidic fractions and analyzed by gas chromatography-olfactometry (GC-O). Compounds were identified by comparison of retention indices, odor properties and GC-MS data against reference standards. Selected compounds were quantified by standard additions. Fresh WMP were characterized by cooked, caramelized and milkfat flavors. WMP more than 6 months old exhibited grassy, painty, fatty, and fishy flavors. GC-O analysis revealed that important neutral/basic character impact compounds found in fresh WMP included 2-3 butanedione (buttery), 3-methyl thiophene (rubbery), 2-acetyl-1-pyrroline (popcorn), 2-acetyl-2-thiazoline (roasted), -decalactone (sweet), and 3-methylindole (mothball). WMP older than 6 months were characterized by hexanal (grassy), (Z)-4-heptanal (fatty), (E,E)-2-4-nonadienal, (E, E)-2,4-decadienal (fatty), and guaiacol (tobacco). Important acidic compounds for fresh and stored WMP included acetic acid (vinegar), isobutyric acid (sweaty), hexanoic acid (sweaty), and maltol (caramelized). Intensities of benzoic acid (sweet/urine), 2,5-dimethyl-4-hydroxy-3-(2H) furanone (caramelized), and sotolon (cotton candy) were increased in stored WMP. Determining the character impact compounds in whole milk powders will be beneficial to understanding whole milk powder flavor.
Session 14A, Dairy Foods: General developments in dairy technology I
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