| Matcha,as a high-end tea product,has both nutrition and health.It retains a variety of nutrients in tea.It "eats tea" and makes its nutritional value higher than the water extract of tea.At the same time,it has a variety of nutrients of vegetables,which is especially easy to be digested and absorbed by intestines and stomach.It can not only drink directly,but also is widely used in dairy products,drinks,cold food,baked food,health products.Medicine,cosmetics and other industries,in line with the light trend of leisure food and tea drink consumption.At present,the market of matcha in China is intermingled with each other,and the price of matcha is quite different,in addition to the enterprises that produce matcha in China.Many,different scale,the quality of matcha production is also uneven,the cost is less than 1/3 of matcha,which is not conducive to the development of matcha in the domestic market.The detection standards of matcha are not perfect,and the detection of matcha and the research of aroma components of matcha are vacant in China.In this study,different kinds of matcha were used as samples,and the aroma substances in matcha were extracted,detected and analyzed by means of electronic nose and gas chromatography-mass spectrometry.The main characteristic aroma components in matcha were screened out,the typical aroma substances were obtained,and a rapid detection and identification method was established,and provide a reference for the quality and later quality control of matcha processing.1.Optimizing the influence factors of the electronic nose in analyzing the aroma of matcha,establishing the analysis system of the aroma of the electronic nose matcha,verifying the feasibility of the analysis method with the fingerprint radar map of the sensor,analyzing the composition and difference of the aroma components of different kinds of matcha,quickly and efficiently detecting the aroma of matcha,providing scientific support and technical reference for the identification and quality control of matcha.2.Sensory evaluation and routine physical and chemical index determination of matcha were carried out to determine the specific content range of nutritional components in matcha.According to the results,the differences and correlation among different matcha samples were analyzed.The water content(3%～5.4%),water extract content(29.2%～40.7%),free amino acid content(1.1%～3.7%),caffeine content(4.0%～6.6%),tea polyphenols content(14.6%～23.7%),catechin content(9.14%～11.02%),crude fiber content(1.1%～6.3%),chlorophyll content(3.47%～7.32).3.According to the aroma extraction method of tea,the best aroma extraction method was selected as SPME..When the extraction conditions of SPME were optimized,such as tea / water ratio,extraction head type,extraction temperature,extraction time and rotating speed,the extraction conditions were determined as follows: 100 μ m PDMS extraction head,tea water ratio 1:7,extraction temperature 60 ℃ and extraction time 60 min,rotation speed 400 r,the highest aroma components and contents were obtained.4.The aroma components in matcha were qualitatively and quantitatively analyzed by GC/MS/MS,and the main aroma components in matcha were identified.Combined with the analysis of aroma components in matcha by electronic nose,the results showed that the contents of alcohols,ketones,aldehydes and esters in matcha were the same as those of alcohols,ketones,aldehydes and esters,and the contents of aroma substances in matcha were the same as those of alcohols,ketones,aldehydes and esters.It is alcohol content >ester compound content > aldehyde compound content > ketone compound content >terpene content > nitrogen content > alkane content.The main aroma components are linalool,benzyl alcohol,octyl acetate,Maersk ketone,Delta-pentalactone,2-nonyl alcohol,vanillin,nonaldehyde,trans-2-hexenyl acetate,(S)-(-)limonene,4-methyl nonane,laurene,methyl salicylate,eucalyptus oil,α-ionone,β-ionone,L(-camphor,cis-3-hexenal,BETA-cyclic citral,etc.,through qualitative and quantitative... |
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