Effect of Compressed Processing on the Aroma of Aged White Tea

In this study,after compressed processing,aroma components in different grades of white tea aged loose form and compressed form were compared,aiming to ascertain the effect of compressed processing on the aroma of aged white teas. The aroma components were analyzed using head space-solid phase microextraction(HS-SPME)and gas chromatography-mass spectrometry(GC-MS). Meanwhile,the national standard GB/T 23776-2018 was used for sensory evaluation of white tea. Results showed that,53 kinds of aromatic components were detected,including benzaldehyde,benzyl alcohol,linalool,linalool oxides,phenylethyl alcohol,α-terpene,geraniol,α-cedarene,β-cedarene,caryophyllene and cedrol. By comparing the aroma components of white tea aged from loose form and compressed form,it was found that many floral and fruity aroma components such as linalool and its oxides,methyl hexoate,β-ionone decreased,and the linalool and its oxides decreased significantly while cedrol,cedarene,bornyl acetate and α-copaene increased which had woody and medicinal aroma after compressed processing,and the cedrol and cedarene increased significantly. The compressed processing had a great influence on the types and contents of aroma components,which made the typical aged fragrance of white tea was more obvious after compressed processing,and the characteristic fragrance types such as jujube and medicinal fragrance were more prominent,while the aged loose tea kept more typical floral and fruity fragrance. The aroma of aged white tea of different grades was further analyzed,and for increasing the quality of aroma,White Mudan and Shoumei were more suitable for compressed processing,compared with White Silver Needle.