Quantitative And Rapid Detection Method For Umami Amino Acids In Brine And Its Application

Marinated meat products are the most representative traditional meat products in China,of which brine is an important source of contribution to product taste.The flavoring substances in brine mainly include sodium chloride,amino acids,nucleotides and peptides.According to the flavor characteristics,amino acids can be divided into four types: bitter,sweet,umami and astringent amino acids.In order to comprehensively evaluate the taste amino acids in brine,this paper takes the braised chicken brine as the research object,the high performance liquid chromatography was used to detect and analyze the overall taste amino acids in brine.At the same time,the previous research of the research found that N,N`-diphenylthiourea(DPTU)can be used as a umami-sensitive substance for electrochemical sensors to specifically detect umami amino acids,but it has not yet been standardized for the actual samples To carry out systematic research on the application,this research takes the brine as the research object,and uses the liquid chromatography detection result as the standard to study the suitable sensors for N,N`-diphenylthiourea film modification to quickly and accurately detect the best sample preparation method.The researches content were as follows:Firstly,determination of flavor amino acids in braised chicken brine.Taking braised chicken brine as the research object,the high-performance liquid chromatography was used to detect the flavor amino acid types and contents.The detections showed there are 15 kinds of amino acids in brine andthe total content is23.64 mmol/L.The proportion of bitter,sweet,umami and astringent amino acids in the total amino acids was 42.76%,29.31%,21.97% and 5.97%,respectively.The TAV values of Glu and Asp are 1.41 and 0.28,respectively,which are important umami amino acids in brine.Secondly,study on the sample processing method for detecting umami amino acid by electrochemical method.The composition of brine is complex and there are substance interference factors.Centrifugation is currently an effective method for removing interfering substances.Moreover,the brine has a high content of umami amino acids,and the detection sample exceeds the detection limit of the sensor,so it needs to be diluted to reach N,N `-Detylthiourea(DPTU)thin film sensor detection limit.Taking brine as the research object,the centrifugal force,centrifugation time and dilution factor were optimized as single factors,and the results of liquid chromatography were used as the standard.The optimal centrifugation conditions were: centrifugal force 13000 g,centrifugation time 20 min;The optimal dilution factor is 20 times.Under these conditions,the electrochemical detection result is the closest to that of liquid chromatography,and it can be used in actual production.Finally,standardization and stability study of brine based on umami amino acids.Ten pots of brine were randomly selected for testing and samples were taken every 10 d for measurement.The results showed that there was no significant difference in umami amino acids between different cooking pots(P>0.05),there was no significant difference in umami amino acids in different cooking batches of the same pot(P > 0.05),and the results of film modified sensorsdetection and liquid chromatographydetection are consistent.