Study On The Purine Content Of Aquatic Products And Purine Removing Method

Purine compounds are natural substances exist in all human cells and most foods,and are mostly present in foods as combined form.The final product of purine metabolism in the human body is uric acid,which causes hyperuricemia or even gout when the purine intake exceeds the body's metabolic capacity.With the economic development and changes in people's dietary structure,the prevalence of hyperuricemia and gout in the population has increased year by year.Uric acid can be used as an antioxidant to protect against active oxygen in the human body.The supply of uric acid is very important to protect the blood vessels of the human body.However,frequent and high intake of foods containing high purine content will increase serum uric acid concentration then increase the risk of hyperuricemia and gout,so purine is closely related to gout.Studies have found that limiting the intake of purine rich food can prevent gout.Therefore,it is of great significance to study the method of reducing the content of purine in food and studying the content of purine in food.In this paper,the reversed-phase high performance liquid chromatography(HPLC)method for the determination of purine content in aquatic products was established.The purine content of representative aquatic products in China was tested.The effect of purine removal method and cooking method on purine content was also explored.The main conclusions are as follows:1.Using reversed-phase high performance liquid chromatography conditions:column Waters Atlantis T3(4.6×250 mm,5?m),mobile phase potassium dihydrogen phosphate buffer(0.02 mol/L,pH=3.6),flow rate at 1.0 mL/min,injection volume is 10?L,the column temperature is30°C and the DAD detection wavelength is 254 nm.According to the methodological verification,the method can separate 4 kinds of purine,and the linear relationship between the four purines in the range of 1-400mg/L is good(R~2?0.999).The detection limits of adenine,guanine,hypoxanthine and xanthine are 0.1,0.02,0.04,0.02 mg/L respectively.The precision of the method was tested by 32 mg/L standard solution.The RSD of all four purines was less than 3%,and the method reproducibility was good.Four kinds of purine recovery rates were detected by taking the fish samples.The mean recoveries of Adenine,Guanine,Xanthine and Hypoxanthine are 102.7%,99.3%,103.8%,101%respectively.2.The purine content of 24 common aquatic products was tested based on established detection methods.Marine fish have the highest purine content with sardines and tuna total purine content as high as2401.5 mg/kg and 2262.4 mg/kg.The purine content of the samples tested was sardine>tuna>Litopenaeus Vannamei>other marine fish>Oysters>shellfish>freshwater fish.The purine content of marine fish sardines and tuna is higher than 2000 mg/kg,and the total content of freshwater fish carp is lower,but the presence of xanthine is detected.3.The effect of ultrasonic technology on the removal of purines in sardines is better than that in Trichiurus haumela,on the contrary,the effect of microwave on the purine content of Trichiurus haumela is obvious.Microwave technology reduced the content of purine by 80%in Trichiurus haumela for 5 min,and the purine content in sardines decreased by 40%in 10 min.4.After different cooking treatments,the purine content of Trichiurus haumela and sardines was decreased.The change of total purine content was mainly caused by the decrease of hypoxanthine and adenine.The content of xanthine and guanine also decreased to varying degrees,among which boiled heat treatment extraction is beneficial to the dissolution of the purine compound in the Trichiurus haumela.In general,the content of purine tends to balance as the cooking time is slowly decreased.The boiled cooking methods for two fishes are more effective than other methods for reducing the purine content.