Deciphering the Influence of Reheating Methods on Flavor of Ginger Duck through Instrumental Analysis Coupled with Multivariate Statistics

The study investigated the effects of three reheating methods (water bath, stir-frying, and microwave) on the flavor of ginger duck, a traditional Chinese dish, using solid-phase microextraction (SPME) combined with gas chromatography-mass spectrometry (GC-MS), high performance liquid chromatography (HPLC), electronic nose (E-nose), electronic tongue (E-tongue), and multivariate statistical analysis. The results showed that while the number of aroma compounds increased after reheating, their total content decreased. Stir-frying and microwave reheating produced the highest number of aroma compounds (77), whereas water bath reheating resulted in the lowest aroma loss and the highest content of volatile compounds. Principal component analysis of the E-nose data revealed that the aroma characteristics of water bath-reheated samples closely resembled those of fresh samples and were significantly different from those of stir-fried and microwaved samples. Partial least squares-discriminant analysis (PLS-DA) combined with odor activity values (OAVs) identified 11 key aroma compounds as differential markers. Taste analysis indicated a decrease in free amino acid contents and an increase in bitter nucleotide contents after reheating, while umami and sweet nucleotide contents remained largely unchanged. Glutamic acid, 5’-guanylic acid, 5’-inosinic acid, and 5’-adenylic acid contributed significantly to the taste, but PLS-DA showed no significant differences in their levels among reheating methods, resulting in similar taste profiles. These findings provide a scientific basis for quality control and reheating method selection in the industrial production of ginger duck.