The Preliminary Research On Flavor Fingerprint Of Main Freshwater Cultured Fish In China

In China,more than 3000 kinds of fish are consumed every year,making them a valuable food with large market.Compared with marine fish,there are relatively more fish bones in freshwater fish,its low price and similar nutritional value make it win the favor of most consumers in Asia.Researchs on the flavor of freshwater fish was single in China,and there were no systematic researchs on freshwater fish,and secondly,few innovations in the methods and evaluation methods of flavor research had been found.Through the fingerprints,this paper systematically explored the odor compounds of common freshwater fish in China,and developed several new research methods,which may provide new possibilities for later research directions.Fingerprint technology is a technique that can reflect the characteristics of a sample by using a certain analytical method to obtain a chromatogram,a spectrogram or other map data that can characterize the sample after proper processing.In this paper,18 kinds of freshwater cultured fish and three puffer fish soups in China were analyzed by fingerprint techniques,including odor fingerprints and mass spectrometry fingerprints.The results were as follows:(1)Fingerprints were established by electronic nose,sensory evaluation and solid phase microextraction-gas chromatography-mass spectrometry(SPME-GC-MS)for the volatile compounds of 18 kinds of raw and cooked common freshwater fish in China.The raw Ctenopharyngodon idellus(No.050)and raw catfish(No.120)had similar aldehydes and alcohols that provided fishy odor.The odor composition was close,and the fishy,soil odor were relatively heavy;the odor of raw Carassius auratus(060)was different from other fish,and it may due to five substances,including 4-methyl-5-nonanol,(Z)-3-decen-1-ol,aminodithioformic acid-diethyl methyl ester,3-hydroxy-2-butanone and dimethyl ether;cooked Lateolabrax japonicus(031),cooked Ctenopharyngodon idellus(051),and cooked Ophiocephalus argus Cantor(091)were relatively abundant in aldehydes and alcohols,and their odor composition were similar;The aldehydes and alcohols in the cooked Monopterus albus(071)and cooked Misgurnus anguillicaudatus(081)were relatively poor,and there were many hydrocarbons,mainly based on unpleasant odor.The esters which provide fruity and floral for raw fish meat were reduced after heating,and the hydrocarbons in cooked fish meat were increased.It may be that the esters were thermally decomposed into some hydrocarbons.(2)A new method for the development of gas chromatography-ion mobility spectroscopy(GC-IMS)and ultra-fast gas chromatography electronic nose was used to establish fingerprints of volatile compounds in four kinds of raw and cooked fish.The results show that both technologies can quickly distinguish between different samples and established fingerprints.Gas chromatography-ion mobility spectrometry(GC-IMS)and ultra-fast gas chromatography electronic nose have the advantages of fast response,high sensitivity and qualitative accuracy.(3)A new mass spectrometry fingerprint database was developed to establish a mass spectrometric fingerprint of three puffer fish soups based on metabolomics.The results showed that the matrix-assisted laser desorption ionization-time-of-flight-mass spectrometry(MALDI-TOF-MS)experiment of the fish soups could be completed in a short time,and then the multivariate statistical analysis of the samples identification were carried out.The compounds in the puffer fish soups were further identified by high performance liquid chromatography-tandem mass spectrometry(HPLC-MS)based on the information of the unique MS signals indicated by the principal components analysis(PCA)and Partial Least Squares Discriminant Analysis(PLS-DA)models.It is expected that the developed method will be applied to the construction of fingerprints of food to prevent detection of authenticity.