Comparative Study Of Comprehensive Quality To Four Different Aging Pu'er Tea Made From Ancient Tea Garden

In the past two decades,the Pu'er tea industry has developed rapidly.Due to its characteristics of “Increased aroma after storage” and the unique flavor and health function of the old-quality Pu'er tea,it is more and more popular among consumers at home and abroad.Pu'er tea's collection investment has flourished and has become an important investment industry.However,the quality changes in the ancient tea garden Pu'er tea storage in recent years are related to its quality optimization and value-added investment functions.The study on the transformation of ancient Pu'er tea aging quality has difficulty in obtaining controllable and comparable samples,and the time span is long.Therefore,there is little reliable research on the quality change of Pu'er tea in the storage of ancient Pu'er tea.There is no systematic comparative study on the quality transformation of Pu'er tea in ancient tea garden.This experiment uses the same variety,the same ancient tea garden raw materials,the same factory production,the same processing technology,and under the same packaging and storage conditions,2015,2016,2017,2018 raw tea,ancient tree tea garden tea samples,simultaneously with the platform A comparative study of sensory quality,main biochemical components,and volatile aroma components was conducted to investigate the variation of the aging of Pu'er tea produced in ancient tea gardens.The results of this experiment are as follows: 1.According to the evaluation method of national standard Pu'er teas national standard,the sensory comparison of color,aroma and taste in four ancient tea samples was carried out.With the increase of storage year,the color of the soup changes from yellow-green to greenish yellow;the aroma changes from the more floating blue-and-white fruit scent to the more stable alder and honey-scent;the taste increases with the year,the bitterness and freshness are weakened,and the sweetness It has enhanced lingering and throat sensation,enhanced alcohol and degree and coordination,improved palatability and reduced irritation.The results of analysis of the main biochemical components of the four ancient tea samples showed that:(1)there was no significant difference in the water content of the four tea samples;the content of caffeine and theobromine alkaloids decreased significantly after one year of storage.,but then more stable,basically no major changes;(2)water extract content,tea polyphenol content,total catechin content,water extract content,tea polyphenol content,total catechin content,free amino acids The total content decreased after storage,and the total content of tea polyphenols and free amino acids was negatively correlated with storage time.(3)The content of soluble sugar,flavonoids,thearubigin and theaflavin in the four tea samples increased with the increase of storage time.The content of soluble sugar,flavonoids and thearubigin was significantly positively correlated with storage time.3.By analyzing and comparing the bitterness and astringency index(CBTI)of the four tealike catechins,it was found that the catechins and tastes of the ancient Pu'er tea were reduced with the prolongation of storage time.4.A total of 80 volatile aroma components were detected in 4 tea samples by the combination of HS-SPME and GC-MS.It was found that the alcohol compounds showed a decreasing trend with the increase of storage time,and the content ratio of alkane and olefinic compounds,aldehydes,nitrogen compounds and aromatic hydrocarbons was significantly positively correlated with storage time.The relative content of the floral components decreased with storage time,while the components with woody and musk gradually increased.5.The free amino acid components and their contents were determined by automatic amino acid analyzer.A total of 28 free amino acid components were detected and analyzed by principal component analysis.The original data was mainly divided into three main components.The main component 1 can represent the freshness,the main component 2 can represent the richness of the amino acid taste,and the main component 3 can represent the richness of the aromatic amino acid.In 2015,the tea scored the highest in the main component 3,and the lowest score in the main component 1;the scores of the main components in 2016 were not high;the 2017 tea scored the highest in the main component 1 and the principal component 2;2018 The annual tea scores in the main component 1 and the main component 3 are also relatively high.6.Using the principal component analysis method to analyze the volatile aroma components,which are divided into three main components,the main component 1 represents the flower wood fragrance,the main component 2 represents the woody and musk,and the main component 3 represents the fruity fragrance.Sweet and fragrant.In 2015,the tea ingredient 2 scored the highest,and in 2016,the tea ingredient 1 scored the highest.In 2017,the tea ingredient 3 scored the highest.