2. Academic Validation
  3. Tannase-catalysed gallic acid release for clean-label inhibition of green tea auto-oxidative browning

Tannase-catalysed gallic acid release for clean-label inhibition of green tea auto-oxidative browning

  • Food Chem. 2025 Dec 26:503:147775. doi: 10.1016/j.foodchem.2025.147775.
Junfeng Tan 1,  Mark G Sanders 2,  Janniek H Ritsema 2,  Bram van de Put 2,  Jean-Paul Vincken 2,  Zhi Lin 3,  Wouter J C de Bruijn 4
Affiliations

Affiliations

  • 1 Laboratory of Food Chemistry, Wageningen University, P.O. Box 17, 6700 AA Wageningen, The Netherlands; Tea Research Institute, Chinese Academy of Agricultural Sciences, 9 Meiling South Road, Hangzhou 310008, Zhejiang, People's Republic of China.
  • 2 Laboratory of Food Chemistry, Wageningen University, P.O. Box 17, 6700 AA Wageningen, The Netherlands.
  • 3 Tea Research Institute, Chinese Academy of Agricultural Sciences, 9 Meiling South Road, Hangzhou 310008, Zhejiang, People's Republic of China. Electronic address: [email protected].
  • 4 Laboratory of Food Chemistry, Wageningen University, P.O. Box 17, 6700 AA Wageningen, The Netherlands. Electronic address: [email protected].
PMID: 41475257 DOI: 10.1016/j.foodchem.2025.147775
Abstract

Ready-to-drink (RTD) green tea is rich in flavan-3-ols, which readily undergo auto-oxidation, causing browning. Conventional browning inhibitors can induce undesirable ingredient interactions, flavour changes, and health concerns. Here, we explored a clean-label strategy to inhibit RTD green tea browning by releasing gallic acid from naturally present galloylated compounds using the enzyme tannase (from Aspergillus ficuum). In-depth analysis of green tea by a combination of UHPLC-HRMS, NMR, and enzymatic hydrolysis led to the (tentative) identification of 75 galloylated compounds with four scaffold types. Hydrolysis of these galloylated compounds by tannase was affected by the scaffold type, scaffold stereo configuration, position of gallate attachment, and number of gallate moieties. Tannase treatment resulted in a substantial reduction in auto-oxidative browning of green tea. These results demonstrate that tannase treatment has the potential to decrease reliance on additives for maintaining the colour of RTD green tea and Other phenolic-rich beverages.

Keywords

Catechins; Colour preservation; Degalloylation; Discolouration; Tannin acylhydrolase.

Figures
Products