Comparison of Nutritional Quality and Volatile Flavor Compounds of Duck Leg Meat Roasted by Electric Oven with Two Roasting Methods

The present work was to compare quality differences of the duck leg roasted with or without tinfoil paper wrapping using electric oven. The sensory characteristics, cooking loss, fatty acids, amino acids, and volatile flavor composition in the meat of the two roasted duck leg samples were analyzed. In comparison, the duck leg roasted without tinfoil paper wrapping had greater roasted aroma and cooking loss, while that with paper wrapping was more tender and had lower cooking loss. No matter with or without tinfoil paper wrapping, both fatty acid contents and amino acid contents in the meat were increased after roasting. The sample roasted without tinfoil paper wrapping had higher values in polyunsaturated fatty acids content to saturated fatty acids content (PUFA/SFA) and essential amino acid content to total amino acid content (EAA/TAA). Head-space solid phase microextraction and gas chromatography-mass spectrometry (HS-SPME/GC-MS) analysis identified in total 44 volatile compounds in the two samples while those like aldehydes, alcohols, ketones, etc. had greater amounts in the sample roasted without tinfoil paper wrapping. Orthogonal partial least squares discriminant analysis (OPLS-DA) suggested that hexadecanal, octanal, tetradecanal, (E,E)-2,4-decadienal, pentanal, hexanal, etc. (VIP>1) could be markers to differentiate volatile flavor composition of the two samples. Moreover, gas chromatography-olfactometry of aroma extract dilution analysis (AEDA/GC-O) identified 22 odor-active compounds (i.e. odorants) in the two samples with aldehydes being the highest number followed by sulfur-containing compounds and pyrazines. Overall, the odor-active compounds found by GC-O were similar in the two samples whereas they had different flavor dilution factors. Then aroma profile of the two samples was compared by radar charts based on the compounds of higher dilution factors representing the roasted duck leg odors. It suggested harmonious and more prominent roasted and fatty aromas pertaining to the sample without tinfoil paper wrapping, which agreed with the sensory analysis results.