45C-29 |
Volatile compounds and their corresponding sensory aromas in baked and boiled sweet potatoes |
A. E. BOND1, Z. Xu1, W. Prinyawiwatkul1, and F. Malekian2. (1) Dept. of Food Science, Louisiana State Univ. Agricultural Center, 111 Food Science Bldg., Baton Rouge, LA 70803-4200, (2) Pennington Biomedical Research Center, Louisiana State Univ., 6400 Perkins Rd., Baton Rouge, LA 70808-4124 Sweet potato is an important agricultural commodity in Louisiana and around the world. Its flavor/aroma attributes are critical to product acceptance. Not much research has been conducted to understand the effects of cooking methods on the formation of flavor compounds in sweet potatoes. This study was conducted to identify volatile compounds and their corresponding sensory aromas formed in sweet potatoes during baking and boiling. Sweet potatoes were baked for 1.5 hours at 350 F. The chopped sweet potato pieces (1-inch cubes) were boiled in distilled water for 25 minutes. The homogenized sample (20 g) from each cooking method was mixed with 1.0 mL of 4-methyl-2-pentanone (an internal standard) and incubated at 80 C for 45 minutes. The solid-phase microextration (SPME) PDMS fiber was used to collect the headspace volatile compounds, which were subsequently injected into the GC systems. The GC-MS system was used to identify volatile compounds, while the GC-Olfactory system was used to determine sensory aromas corresponding to the detected volatile compounds. Major identified volatile compounds (sensory aroma descriptors) included methyl-cyclopentane (roasted/popcorn), benzeneacetaldehyde/toluene (meaty), 3,7-dimethyl-1, 6-ocatadien-3-ol (mint/peppermint), and O-(2-methlypropyl)-hydroxylamine (nutty/sweet). Comparing the two cooking methods, the boiled sweet potatoes had lower concentrations of the same volatile compounds than the baked ones during the first 30 minutes of elution. However, after 30 minutes, the major compounds were different. The sensory aromas were described as mild roasted, melted plastic, pleasant sweet/caramel, and bean-like for the boiled sweet potatoes. All of these compounds were tentatively identified as the derivatives of cyclic compounds that may have been produced by the reactions involving amino acids hydrolyzed from proteins and sugars during boiling. This study indicated that the method of cooking (baking or boiling) affects the formation of volatile compounds in sweet potatoes. This information is useful for the conception of new sweet potato products.
Session 45C, Food Chemistry: Flavor and aroma chemistry
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