Influence of heating temperature on the development of volatile compounds in bigeye tuna meat (Thunnus obesus) as assessed by E-nose and SPME-GC/MS

To explore the relationship between the composition of volatile compounds in bigeye tuna (Thunnus obesus) and different processing temperatures, we employed electronic nose (E-nose) and gas chromatography coupled with mass spectrometer (GC/MS) using headspace solid-phase micro-extraction (SPME) for sample preparation. This methodology detected the tuna meat’s composition of volatile compounds before and after exposure to temperatures ranging from 70°C to 150°C. E-nose data were subjected to principal component analysis (PCA) and linear discriminant analysis (LDA). These results clustered samples into three distinct groups, untreated, 70-120°C and 150°C heat treated. First, E-nose was used to evaluate tuna meats treated with different heating temperatures. Based on the analysis of the E-nose, the untreated samples and samples heated to 100°C and 150°C were further analyzed using SPME-GC/MS. Different volatile compounds were detected in these selected samples. Compounds that contribute the fresh flavor of bigeye tuna meats were found in the untreated sample group. However, as heating temperature increased, the relative amount of aldehydes, ketones, alcohols decreased rapidly and hydrocarbons, heterocyclic compounds increased. This was also detectable with E-nose. In this study, using an E-nose and SPME-GC/MS combined analysis approach a more complete profile of volatiles in bigeye tuna meat has been created.