The Study Of Flavored Amino Acid Detection Method Of Beef Based On Membrane Sensor Array

The flavored attribute of beef is a decisive factor for consumers when choosing beef.The main method for assessing flavor attribute in the traditional meat industry is sensory evaluation.However,the process of beef sample preparation in the sensory evaluation is tedious and susceptible to the subjective factors of the evaluators,with a large deviation.Therefore,how to quickly detect the flavor attribute of beef online becomes a research hotspot for researchers.Based on the reasonable and effective grading standards and system of beef attribute.The search for reliable beef flavored amino acid testing methods has become an urgent task to guide the development direction of the beef market.The main research contents and conclusions are as follows:(1)Pyrrole modified platinum plate electrode.Changing the morphology of polypyrrole on the working electrode surface by changing the electrochemical polymerization method and parameters.To determine a polymerization method to make the electrode surface polypyrrole membrane uniform,small roughness and good electrochemical properties of the electrode.The best way of polypyrrole is to use cyclic voltammetry scanning with a scan interval of-0.15 to 0.7V,the starting scan potential was set at 0.7V,the initial scan was positive,the scan rate was 40mV/s,and the sampling interval was 0.001 s.(2)Study on fixing method of polyvinyl chloride(PVC)membrane and construction of PVC base membrane.There are four poly membrane methods used in this study: dip coating,drop coating,spin coating,and membrane-forming adhesion coating.Separately measure the open circuit potential(OCP)value of the membrane obtained by each poly membrane method.The conclusion is that the OCP value of the membrane-forming adhesive coating method is the largest.Blending of plasticizers,coupling agents,stabilizers,and tougheners.As a result,the OCP value of the base membrane formed by adding 0.4mL of dibutyl phthalate,0.25 mL of lauryl ether phosphate,3.6mg of magnesium stearate,and 6mg of thermoplastic polyurethane elastomer rubber to the PVC membrane was the largest.Characterize the original and base membrane: The response of the electrode to the beef potential,the physical properties of the PVC membrane texture analyzer,the electrode immersion study,the PVC membrane scanning electron microscope detection,the electrode impedance data detection and the PVC membrane life analysis.The result obtained by the above experiment is that the optimal base membrane has better physical and chemical properties than the original membrane.(3)Ammonia-sensitive material selection and sensor array construction.To select 14 substances that can react with the amino acid specific structure of beef in mild conditions.After modification to the electrode surface,electrode stability detection,single factor variance analysis and cluster analysis were performed.Finally,a sensor array was constructed using N-bromosuccinimide,ferrocene,furfuryl alcohol,1,2-cyclohexanedione,ethyleneimine,and diazobenzenesulfonic acid.The accuracy of sensor array was detected by Fisher discriminant modeling.The accuracy of the predicted beef sample grade was 94.4% for the sensor array constructed by the modified electrode.(4)Sensor array characterizes beef flavored amino acid under different thawing methods.Air thawing,water thawing,ultrasonic thawing and microwave thawing beef were studied respectively.Choosing the best beef thawing method based on juice loss rate,cooking loss rate and pH value: The microwave thawing was stopped for 10 seconds every working 35 s,until the frozen beef surface was softened,thawed at 15? air to a center temperature of-8?,and finally ultrasonic wave thawing at 220 W to a beef center temperature of 0?.The optimal combined thawing beef was graded using a well-established sensor array and the result was 1 grade.The result of using ion electrode is consistent with that of ammonia modified sensor array.It is proved that the ammonia-sensitive material modified sensor array has good accuracy,and the joint thawed beef has high flavor attribute.