Shipin Kexue (Nov 2024)
Effects of Catalase and/or Polyphenol Oxidase on the Aroma Quality of Instant Baiyaqilan Tea Powder
Abstract
In this study, headspace solid-phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS) and odor activity value (OAV) techniques were used to investigate the effects of catalase and/or polyphenol oxidase on the aroma components in instant Baiyaqilan tea powder. The results showed that all three enzymatic treatments led to significant changes in the types and contents of aroma components in Baiyaqilan instant tea powder. Catalase treatment resulted in the highest amount of aroma components and the highest increase in OAV, as well as the formation of new compounds such as trans-linalool oxide (furanose), cis-caproic acid-3-hexenyl ester and trans-β-farnesene, and it significantly increased the OAV of trans-2-nonenal, β-cyclocitral, trans-2-decenal and trans-geranylacetone when compared with untreated tea samples. Polyphenol oxidase treatment led to the formation of new compounds such as cis-3-hexenyl hexanoate, trans-β-farnesene, trans-β-ionone and β-epoxyviniferone, and significantly increased the OAVs of trans-2-nonenal, linalool and trans-β-ionone. The combined treatment group contained the greatest number of aroma components, including the newly formed compounds cis-3-hexen-1-ol, trans,trans-2,4-heptadienal, cis-β-ocimene, trans-2-octenal, trans,trans-3,5-octadien-2-one, nonanal, 5-ethyl-6-methyl-3-hepten-2-one, hexyl butyrate, Z-3-hexenyl valerate, hexyl 2-methylbutanoate, cis-hexanoic acid-3-hexenyl ester, hexyl hexanoate, trans-β-farnesene and trans-β-ionone, and showed a significant increase in the OAV of linalool. The mechanisms behind the changes in the aroma of instant Baiyaqilan tea powder induced by polyphenol oxidase and/or catalase treatments might be related to oxidative degradation of carotenoids, lipid peroxidation, and glycosidic bond rupture of terpene alcohol precursors. This study reveals a synergistic effect of combined treatment with catalase and polyphenol oxidase on the aroma of instant Baiyaqilan tea powder, which provides an important basis for improving the aroma quality of instant tea powder.
Keywords