Effects Of Amino Acids And Reducing Sugar On Thermal Decomposition Of Squid Trimethylamine Oxide At High Temperature And Its Control

China is a big country in the production and consumption of aquatic products with abundant aquatic resources.However,the safety of aquatic products has received much attention in recent years,and the safety of aquatic products has continued to appear,especially the excessive formaldehyde(FA)content in squid and other aquatic products has seriously affected the survival and development of other aquatic product processing industries,which have aroused widespread concern.Endogenous formaldehyde in aquatic products originates from the decomposition of Trimethylamine N-oxide(TMAO).TMAO can produce FA,Dimethylamine(DMA)and Trimethylamine(TMA)through enzymatic and non-enzymatic pathways.At present,the non-enzymatic pathway of TMAO high temperature thermal decomposition has been studied to some extent,and it is related to the generation of free radicals at high temperature,but the relationship between TMAO high temperature thermal decomposition and amino acids and reducing sugars is rarely reported.In view of this,the reaction characteristics of thermal decomposition of TMAO in squid supernatant to produce FA,DMA and TMA,as well as the changes of amino acids and reducing sugars in squid supernatant was studied.At the same time,a TMAO-Fe(II)in vitro simulation system was established to investigate the effect of lysine-galactose(Lys-Gal)on the thermal decomposition of TMAO.The effect of lysine-galactose on the thermal decomposition of TMAO to formaldehyde was studied by differential scanning calorimetry(DSC).The effects of dihydromyricetin on TMAO degradation and quality in grilled squid fillets were also studied.It was to provide theoretical basis for the control of endogenous formaldehyde in squid.The main findings are as follows:1.The thermal decomposition degree of trimethylamine oxide was the fastest when the heating temperature was 100? and the time was75 min,and the corresponding decomposition products formaldehyde,dimethylamine and trimethylamine are generated significantly(p<0.05).Peru squid is rich in protein and amino acids,and a small amount of reducing sugar.After heating,the amino acid and reducing sugar in the squid supernatant showed a downward trend,and the decrease of amino acids and reducing sugar was more obvious as the heating temperature and time increased.It was also found that heating temperature and time had a significant effect on the degree of browning,and the degree of browning increased significantly with increasing temperature.This showed that TMAO thermal decomposition was related to Maillard reactions of amino acids and reducing sugars.2.Lysine(Lys),galactose(Gal)and lysine-galactose(Lys-Gal)promoted TMAO degradation.Higher reaction temperature,longer reaction time and higher concentration Lys and Gal,Formaldehyde,dimethylamine,and trimethylamine increased significantly(p<0.05)by thermal decomposition of trimethylamine oxide.In addition,the DSC curve of TMAO thermal decomposition in Lys-Gal-TMAO-Fe(II)system significantly changed.The endothermic peak changes from 2 to 3.When the temperature was 67.68?,TMAO could decompose in the first stage Lower temperature,which could further promote the thermal decomposition of TMAO.Lysine-galactose promotes the thermal decomposition of TMAO in TMAO-Fe(II)solution,which was related to the fact that lysine-galactose can reduce the thermal decomposition temperature of TMAO.3.Dihydromyricetin could inhibit the degradation of TMAO,reduce the formation of FA,and effectively inhibit the loss of water in squid fillets,which could effectively delay the browning reaction of fried squid fillets,improve the color change of squid fillets.Dihydromyricetin could also reduce fat the degree of oxidation,increase the hardness and elasticity of the product,and the squid treated with dihydromyricetin showed odor changes on the 12 th and 20 th days,and the control group showed odor changes on the 4th,8th,and 16 th days,indicating that dihydromyricetin could delay the formation of undesirable volatile odors during the storage of the product process.Therefore dihydromyricetin could inhibit TMAO degradation and maintain the storage quality of fried squid fillets.