Study On Rapid Determination Of Amino Acid Taste Substances In Red Sour Soup Based On Near Infrared Spectrometry

As the most representative fermented condiment in Guizhou,red sour soup is deeply loved by people in Guizhou because it has a unique and charming taste and a sweet and sour aftertaste.Free amino acids are important taste substances in food,and amino acids can be divided into four categories:bitter,sweet,fresh and astringent according to the main taste of amino acids.In order to comprehensively evaluate the amino acid flavor substances in the sour soup and their flavor characteristics,this study collected 135 representative sour soup samples of different brands,different varieties and different production batches,determined the amino acid content according to high performance liquid chromatography,analyzed their organoleptic characteristics,and collected near-infrared transmission spectra to construct a quantitative analysis model of four types of amino acid flavor substances.The content and results of this study are as follows:1.Establishment of a High Performance Liquid Chromatography(HPLC)method for the determination of 16 free amino acids in Sour Decoction.The extraction conditions of free amino acids in Hongsuan Decoction were investigated,and the extraction method,ultrasonic time and solid-liquid ratio were investigated;the chromatographic conditions were optimized,and the HPLC method was established for the determination of free amino acids in sour decoction,and the methodology was carried out.Research expedition.Experiments showed that the extraction efficiency of free amino acids was the best when the extraction conditions were ultrasonic for 20min and the ratio of solid to liquid was 1:25.The established HPLC detection method has good instrument precision,repeatability and stability.The 16 free amino acids have a good linear relationship within the linear range(R~2?0.999),and the average recovery rate of the 16 free amino acids is between 95.66%and 99.49%.(RSD<2%,n=9),the established method can be used for the quality evaluation of free amino acids in sour soup.2.Determination of amino acid taste substances in sour soup.Taking 9 kinds of red sour decoction as the research object,the content of 135 sour decoctions was determined by HPLC.Experiments showed that 16 kinds of free amino acids were detected in Hongsuan Decoction,the content of which was 1.9352 mg/g?24.1185mg/g,and the proportions of fresh,sweet,bitter and astringent amino acids were78.79%,9.75%,11.27%and 0.18%,of which the Taste active value(TAV)of glutamic acid and alanine is greater than 1,which is the amino acid that contributes more to the taste in sour soup.3.To establish the quantitative analysis of multi-components by singer-marker(QAMS)to simultaneous determination of 6 components in Zanthoxylum bungeanum Maxim of Red sour soup excipients.GC method was adopted.Using limonene as the internal reference,establish its relative correction factor with the other five volatile components.Simultaneously,the internal standard method(ISM)and QAMS are used to determine the content of the 6 components and compare them to verify the accuracy and feasibility of the multi-evaluation method in the quality evaluation of Zanthoxylum bungeanum Maxim.The results shows,The method has good instruments'precision,repeatability and stability,the volatile components are within the linear range(R~2?0.999),and there is a good linear relationship.The average recovery rate of the 6 volatile components is between 98.60%and 102.12%(RSD<2%,n=6),and QAMS compared with ISM,there is no significant difference(p>0.05).The established QAMS is simple to operate and has good repeatability,which can provide a reference for the quality evaluation of Zanthoxylum bungeanum Maxim.4.Established near-infrared spectroscopy for the analysis and identification of red sour soup with different freshness.According to the different umami amino acid contents measured in the samples,the red sour soup samples were divided into three categories:freshness 1,freshness 2,and freshness 3,and a near-infrared qualitative analysis model was established for them to predict the freshness of unknown samples.The results show that the database is suitable for the rapid identification of red acid soup with freshness grades of 1 and 3,and the prediction is not accurate enough when the freshness level of red acid soup is 2.5.A rapid method for the determination of four amino acid flavor substances in sour soup by near-infrared spectroscopy was established.The influence of different near-infrared scanning parameters on the diffuse reflectance spectrum and the prediction results of the quantitative model were discussed.Through the optimal selection of spectral preprocessing and the correction by regression method,the quantitative model of four amino acid taste substances of bitter,sweet,umami and astringent was established.The final results show that the optimal processing method and scanning parameters are 8 cm^-1 resolution and 64 scans,respectively.The RMSECV and RMV-r of the near-infrared quantitative model of bitter,sweet,umami and astringent amino acids were 0.9504?0.353;0.903?0.9561;1.44?0.572;0.914?0.9538,respectively.It shows that the four quantitative models can be well applied to the content prediction of unknown samples.The results of this study show that it is feasible to use NIR spectroscopy to detect amino acid flavor substances in sour soup,which provides an effective,rapid and reliable quality detection method for four types of amino acids with different flavors in sour soup.