Changes Of Biogenic Amines And Volatile Compounds In North Pacific Squid During Storage

Biogenic amines are a group of nitrogen-containing organic compounds formed from the degradation of amino acids under the action of decarboxylase.Some representative biogenic amines are putrescine,cadaverine,histamine,spermine,tyramine,spermidine,etc.Biogenic amines are widely found in all kinds of foods,especially in foods with high levels of proteins or free amino acids as well as fermented food products,such as meat,poultry and fish products,dairy products,and various fermented products like wine and fermented pickles.A small amount of biogenic amines are active substances with physiological functions in human and other organisms,but excessive biogenic amines may affect the flavor of food,and even cause harm to human and other organisms.Therefore,understanding the amounts of biogenic amines and their formation pathways in aquatic products as well as their control methods have been a major research focus for the safety of aquatic food products.However,there is a lack of reported research on the changes of biogenic amines and volatile compounds in squid during storage.Therefore,the objective of this study is to apply high pressure liquid chromatography?HPLC?and gas chromatography-mass spectroscopy?GC-MS?to analyze the changes of biogenic amines and total volatile base nitrogen?TVB-N?values in Gonatopsis borealis stored at three different temperatures?0,4,25??.In addition,the amounts of biogenic amines and volatile compounds in Pacific squid as affected by 2%and 6%salt treatments were evaluated.The study was conducted in an attempt to provide theoretical support for the control technology of biogenic amines in squid and the guarantee of flavor quality.The major contents and results are as follows:1.The Gonatopsis borealis,which is widely used in China,was peeled and gutted,washed and dried,and then sealed in plastic bags and stored at different temperature?0?,4?:0-12 d;25?:0-24 h?.The levels of putrescine,cadaverine,histamine,spermidine,tyramine and spermine in the squid were analyzed by HPLC pre-column derivatization.The results showed that histamine?21.03-32.26 mg/kg?,spermine?10.84-7.94 mg/kg?and spermidine?3.67-11.20 mg/kg?were the main biogenic amines in the muscle of squid.The contents of six kinds of biogenic amines in squid muscle continuously increased during the storage.The formation of six biogenic amines in squid muscle were zero order reactions(0?,R²=0.834-0.979,k=0.0003-0.0006 mg/kg min^-1;4?,R²=0.705-0.994,k=0.0004-0.0006 mg/kg min^-1;25?,R²=0.454-0.931,k=0.0003-0.0512 mg/kg min^-1),indicating that the amount of biogenic amines in squid muscle has no effect on its formation rate.In addition,the concentration of biogenic amines was correlated with the TVB-N in squid muscle?R²=0.604-0.966?.This study revealed the changes and formation kinetics of six biogenic amines in squid during refrigerator and room temperature storage,which is helpful to improve the safety and quality of squid products.2.HPLC and GC-MS combined with headspace solid phase microextraction were used to monitor the changes of six biogenic amines and commonly seen volatile compounds in North Pacific squid during storage?4?:0-12 d?.In addition,as the change in p H value and TVB-N value of the squid were evaluated.The results showed that except for spermine and spermidine,the amounts of other four biogenic amines increased during the storage.The ranges of six biogenic amines during storage were 9.57-27.94 mg/kg?putrescine?,2.18-23.94 mg/kg?cadaverine?,4.29-22.47mg/kg?histamine?,28.10-135.78 mg/kg?tyramine?,10.40-12.80 mg/kg?spermidine?and 39.50-46.52 mg/kg?spermine?.During the storage,the type and the amounts of volatile components have changed significantly.Trimethylamine became the main volatile substance?22.48-35.36 ng/g?after 6 d,and hydrogen sulfide accumulated rapidly?26.12-30.24 ng/g?after 9 d.The TVB-N value,concentrations of biogenic amines?histamine,tyramine?and three typical volatile compounds?hexanal,trimethylamine,hydrogen sulfide?were significantly correlated with storage time?R²=0.546-0.986?.Meanwhile,the amounts of biogenic amines were highly correlated with the TVB-N value and the concentrations of volatile compounds.Therefore,the changes of volatile compounds could be used to reflect the freshness and the overall quality change of squid during the storage.3.The effects of salt treatment?2%w/w low salt and 6%w/w high salt?and storage time?4?,0-12 d?on the levels of two biogenic amines?histamine and tyramine?,TVB-N,p H value and volatile compounds of North Pacific squid were investigated.The results showed that salt treatment could effectively inhibit the formation of histamine and tyramine?P<0.05?.The total p H value first decreased and then increased during storage?6.49-7.13?.The p H value of the salt treatment group was slightly lower than that of the control group.The TVB-N value increased with time,and the salt had a significant inhibitory effect on the TVB-N value?P<0.05?.The main volatile components in this study are aliphatic hydrocarbons,alcohols,aldehydes,ketones,acids,esters,aromatic hydrocarbons,phenols,nitrogen compounds,sulfides and esters.Trimethylamine,butyric acid,hydrogen sulfide and other compounds can be used to assess the quality of aquatic products,and salt treatment can inhibit their formation.Overall,the addition of salt had a positive effect on increasing the shelf life of North Pacific squid and it is necessary to combine multiple quality indicators to determine the quality of North Pacific squid.The results from this study provide some theoretical foundation for further research on how to control the production of biogenic amines in squid and improve the quality and safety of aquatic products.