Effect Of Storage Year On The Quality And Health Function Of Jingyang Fuzhuan Brick Tea

Fuzhuan brick tea is a kind of dark tea,originated from the“Silk Road”starting point of Jingyang,Shaanxi Province,has many health effects on the human body,deeply loved by consumers.“Golden flower”and“arohid flavour”are produced with“fungal fermentation”stage,and they are the unique quality characteristics of Fuzhuan brick tea.For a long time,Jingyang Fuzhuan brick tea has been adhering to the tradition of“processing new tea and selling storage tea”.However,there is no report on the changes in the quality and health function of Jingyang Fuzhuan brick tea after being stored locally in Jingyang.In this study,Jingyang Fuzhuan bricks with storage 1 to 5 years were selected as materials and their sensory quality,physical and chemical composition,aroma components,antioxidant activity and effects onα-amylase and pancreatic lipase were analyzed.This study aimed to provide a theoretical reference for the aging of Jingyang Fuzhuan brick tea.The results were as follows:1.The content of water extract,amino acids,tea polyphenols,catechins,caffeine,tea polysaccharide and theabrownine varied from 29.98%³5.71%、0.85%².05%、8.41%¹7.11%、3.93%⁸.40%、2.85%³.10%、1.90%².62%and 1.88%².28%.The content of water extract,amino acids,tea polyphenols and catechins exhibited a decreasing tend and the content of tea polysaccharide and theabrownine presented an increasing trend with the extension of storage time,whereas caffeine content was relatively stable.With the prolonged aging time,the color of dry tea was mainly black and brown,with no obvious change.The liquor color changes from“orange-red and bright”to“red and bright”,and then to“darkness”,the taste changed from“a litter bitter”to“pure and mild”.Jingyang Fuzhuan brick tea had the highest sensory scores and the best quality when it stored for 4 years.2.Using HS-SPME-GC-MS to analyze the aroma components of Jingyang Fuzhuan brick tea stored for 1 to 5 years,it indicated that 2-Hexenal,Safranal,Hexanal,Geranyl acetone,β-Ionone,Hexadecanoic acid,ethyl ester,Dihydroactinidiolide,Tetradecanoic acid,ethyl ester and 1-Octen-3-ol were the key components of the aroma in Jingyang Fuzhuan brick tea.The relative content of alcohols decreased with the prolonged aging time,while the ketones and esters increased.2-Hexenal,（E,E）-2,4-Heptadienal,Methylhptenone,（E,E）-3,5-Octadien-2-one and Geranyl acetone,which were play an important role in the“arohid flavor”.It was found that these substances had the highest relative content in the Jingyang Fuzhuan tea stored for 4 years.3.Jingyang Fuzhuan brick tea stored for 1-5 years had strong DPPH free radical scavenging ability,hydroxyl free radical scavenging ability and Fe³⁺reducing ability.IC₅₀ranged from 0.116 to 0.140 mg/mL,5.250 to 9.269 mg/mL,and 0.478 to 0.839 mg/mL,respectively.With the extension of storage year,the antioxidant ability of Jingyang Fuzhuan brick tea was decreased,but there was a small rebound when it stored for 4 years.4.Jingyang Fuzhuan brick tea stored for 1-5 years showed significant inhibition ability on the activities ofα-amylase and pancreatic lipase.IC₅₀ ranged from 5.712 to 11.447 mg/mL and 7.563 to 8.651 mg/mL,respectively.With the extension of storage year,the inhibitory ability of Jingyang Fuzhuan brick tea onα-amylase was weakened,while the inhibitory ability on pancreatic lipase was increasing.Under the same concentration conditions,the inhibition rate of Jingyang Fuzhuan brick tea onα-amylase and pancreatic lipase reached a stable state when it stored for 4 years.5.After a comprehensive consideration of sensory review,physicochemical analysis,aroma analysis and function study,it was found that Jingyang Fuzhuan brick tea stored for 4years,which had a moderate proportion of its contents,contained the highest relative content of alkenals and ketene compounds,the inhibition rate onα-amylase and pancreatic lipase reached a stable state under the same concentration conditions.Therefore,Jingyang Fuzhuan brick tea stored for 4 years had the best quality and weight loss effect during the storage period of 1-5 years.