Effect of Yeast Extract on Deodorization of Crude Oil from Snakehead Fish Viscera

This study investigated the effect of yeast extract on the removal of fishy odor and flavor components in the refining process of crude fish oil from snakehead fish viscera. Crude fish oil was obtained through aqueous extraction and subsequently subjected to deodorization optimization via single-factor analysis. The yeast extract addition amount, temperature, and time were optimized using the sensory evaluation score and color change of fish oil as the indicators. The changes in fatty acids and smell in fish oil before and after deodorization were compared. Finally, volatile flavor compounds in fish oil before and after deodorization were analyzed using headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS). The results showed that the optimal deodorization process for crude fish oil was achieved by adding 1.5% yeast extract in a 35 ℃ water bath for 60 min, and the sensory score of the deodorized fish oil was the highest and the total color value (∆E^*) was low. A total of 20 fatty acids were detected in snakehead fish crude fish oil and yeast extract deodorized fish oil, among which C18:1n9c, C18:2n6c, and C16:0 were the main ones, and the types of fatty acids remained unchanged. A total of 54 volatile flavor substances were detected in snakehead fish crude fish oil and yeast extract defishy fish oil. The yeast extract mainly removed the volatile compounds such as 1-octen-3-ol, trans-2-decenal, and trans,trans-2,4-heptadienal in snakehead fish visceral fish oil. This study can provide theoretical basis and technical support for the deodorization process of freshwater fish visceral fish oil by yeast extract.