Study On Changes Of Texture And Flavor Compounds In Grass Carp During Low Temperature Storage

Grass carp is one of four freshwater fish species, nutritious and delicious, but the fish hard to keep fresh.now cold storage is the general way to extend its shelf life, for texture and flavor of the fish after cryopreservation were worse than fresh fish, the topic study on changes of texture characteristics and flavor compounds in grass carp during low temperature storage. using texture analyzer,automatic amino acid analyzer,high performance liquid chromatography and solid phase micro extraction-GC-MS to detect textural properties of carp muscle,free amino acids, flavor nucleotides and volatile flavor compounds in grass carp stored at4℃and-20℃,combined with the T-VBN and sensory evaluation.the results showed that:1)grass carp storaged at4℃reach six days,storaged at-20℃within eight months;the sensory evaluation and texture parameters were decreased during cold storage,decrease of hardness, springiness and chewiness related to sensory evaluation reduction.compared with storaged at4℃,textural characteristics changing faster and more significant than storaged at-20℃, destruction of fish meat texture quality was more obvious.although freezing storage beneficial to fresh fish than cold storage, but it has drawbacks.2)13kinds of free amino acids were detected in fresh grass fish,include serine, glutamic, proline,glycine,alanine,valine,methionine,isoleucine,leucine,Phenylalanine,lysine,histidine and arginine,which histidine content were significantly higher.all kinds of free amino acids essential to reduce the increasing trend after the first after cryopreservation, but later were increased slightly, and the storage temperature the more lower the free amino acids changed more slowly,so that the lower temperature to storage the better to maintain the flavor of the fish.3)ATP content is273.17mg/kg, ADP content95.22mg/kg, IMP content504.34mg/kg, AMP content62.38mg/kg, HxR content51.76mg/kg, Hx content8.62mg/kg in fresh grass fish. ATP can only be detected in fresh fish,IMP accumulation time is shorter during storage,ADP and AMP were relatively stable,HxR and Hx levels increased significantly, the lower the temperature the change trend more slowly.4)Fresh grass fish were identified51kinds of volatile flavor compounds,known by the relative percentage,esters and hydrocarbons are the main components of volatile flavor compounds in fresh fish,high levels of self and1-octen-3-alcohol flavor characteristics detected after cryopreservation, but the types of volatile flavor compounds were significantly reduced after4℃and-20℃storage.