Atlantic salmon (Salmo salar) is one of the most widely consumed seafood products in the United States, with flavor being a critical factor in consumer preference and acceptance. The volatile compounds present in salmon play a significant role in shaping its flavor profile and are often indicators of product quality. Salmon is a fatty fish so it is more susceptible to spoilage and has a short shelf life. The spoilage is due to physical, microbiological and chemical processes such as lipid oxidation and proteolysis. These chemical processes affect salmon due to either its protein and high-fat content, causing off-flavors, rancidity, and loss of nutritional quality, making the fish unmarketable which results in food waste and economic loss. The purpose of this study is to investigate the effect of rearing temperatures, gender, presence of skin, fillet location, freezing and storage on the volatile profile of Atlantic salmon.
Fish reared at different temperatures (13oC and 23oC) were killed by a blow to the head, bled and filleted. Fillets were frozen at -80oC until analysis. Samples were thawed on ice for 1 hour before analysis. Raw and frozen samples of skin-on, skin-off and skin alone from the same location on the fillets from each fish were compared. The head, centre and tail of fillet was tested for variation of volatiles in fillet. Storage was compared from 0, 3, 5, 7 and 12 days in refrigerator at 4oC. 2g samples cut into small pieces (1mm) mixed in 20ml of 0.5% ethanol were processed for analysis. The samples were homogenized and held at 42oC in a shaking water bath for 30 minutes. Six replicates were conducted. Measurements were done using SIFT-MS Headspace method. Statistical analysis was conducted using 3-way ANOVA with Fisher’s least significance difference posthoc analysis (p value < 0.05).
The fish reared at 23oC had higher concentrations of 38 volatiles as compared to the fish reared at 13oC. The higher concentration is probably due to greater growth rate and metabolism. The fish at 23oC were 328 ± 23.9g and fish at 13oC were 184 ± 9.62g in weight and the fish at 23oC were 30.9 ± 0.17cm and fish at 13oC were 27.3 ± 1.04cm. Female salmon had higher concentrations of 20 volatiles suggesting that male and female fish produce distinct volatile profiles at the same growth temperature. Muscle and skin individually showed higher concentrations of all the volatiles than Skin on muscle. The Head of the fillet showed the highest concentration of volatiles followed by centre and then tail. Freezing fillets at -80oC maintained the volatile concentration at the same level as it was in the fresh salmon. The volatile concentration increased as the time of storage increased when stored at 4oC. This research establish how the factors like rearing temperature, gender, skin on vs off, fillet location and freezing influence volatile profile of salmon and also identify the volatiles that results in off-odors.