Identification Of American Silver Carp And Characterization Of Key Odor Compounds

Silver carp is a kind of migratory fish,which feeds on zooplankton and phytoplankton.In the seriously polluted lakes,the cultivation of silver carp is regarded as a way to improve the water quality.In one case,the phenomenon of water bloom was alleviated by long-term stocking of silver carp in Qiandao Lake.Therefore,in the 1970 s,the United States also introduced Asian carp(Black carp,Grass carp,Silver carp,Bighead carp,crucian and carp)from China to improve water quality.Its numbers increased and natural enemies decreased in the 21 st century,resulting in large populations of this rarely eaten fish.Now we are actively exploring solutions to explore the potential of their consumption.In contrast,the invading Indian Ganges catfish,which has a less fishy odor,is very popular among the local people.The odor of food,including odor characteristics and concentrations,greatly affects consumer acceptance.This study mainly focused on the nutritional value of silver carp and key odor compounds characterization.Its main results were listed as follows:1.There was no significant difference in water and ash content between American and Chinese silver carp.The content of crude protein American silver carp was slightly lower than 9.11%,which is 18.12g/100 g.The content of crude fat is lower than 38.23%,which is 1.01g/100 g.The American silver carp has the characteristics of high protein and low fat.There was no significant difference in mineral content,among which arsenic,mercury,lead,chromium and other heavy metals were not found to exceed the standard.The content of fatty acids in American silver carp is generally lower than that in Chinese silver carp.The content of ?-3 / ?-6 in Chinese silver carp is 2.19,that in American silver carp is 1.99.DHA and EPA accounted for 23% of fatty acids in American silver carp and 18% in Chinese silver carp,respectively.2.Three Mono Trap RCC18 adsorbents were used to extract 15 g samples at 50? for 50 min.Volatile components were analyzed by gas phase-olfaction-mass spectrometry.The main odor-active substances were identified by aroma extraction dilution analysis.The overall odor profile was analyzed by electronic nose.Overall sensory evaluation showed that metallic and grassy in Chinese carp were heavier than those in American.Trimethylamine,ketones,aldehydes and alcohols were the main odor components in the two species.Flavor dilution factors indicated hexanal(grassy),1-octen-3-ol(mushroom-like),and 2,3-pentanedione(milky)were important.Trimethylamine,1-pentene-3-ol,2,3-pentanedione,pentanal,3-methyl-1-butanol,hexanal,1-Hexanol,heptanal,1-heptanol,1-octen-3-ol,octanal,2,3-pentanedione.D-limonene,nonanal,decanal,and naphthalene were the main flavor substances.The contents and intensities of volatile substances are generally higher in American than in Chinese silver carp.3.Headspace solid-phase microextraction combined with GC?×?GC-TOFMS was used to detect the volatile substances in the samples.Through the mass spectrometry library and comparison of retention index,142 kinds of effective volatile compounds were detected,including 33 aldehydes,25 ketones,42 alcohols,10 esters,5 furans,7 pyridines,9 acids,3 sulfides,5 aromatics,1 ether and 2 others.According to ROAV analysis,the substances that contribute to the overall flavor include propanal,butanal,pentanal,(E)-2-butenal,hexanal,heptanal,(z)-4-heptanal,octanal,nonanal,cis-4-decanal,2,3-butanedione,methanethiol,1-hexanol,1-octen-3-ol,benzene.These compounds interact to form the flavor characteristics of silver carp.