Microwave heating of tea residue yields polysaccharides, polyphenols, and plant biopolyester

J Agric Food Chem. 2008 Dec 10;56(23):11293-9. doi: 10.1021/jf802253s.


Microwave heating was used to produce aqueous-soluble components from green, oolong, and black tea residues. Heating at 200-230 degrees C for 2 min extracted 40-50% of polysaccharides and 60-70% of the polyphenols. Solubilization of arabinose and galactose by autohydrolysis occurred with heating above 170 degrees C, whereas heating above 200 degrees C was necessary to solubilize xylose. Catechins were soluble in water by heating at low temperature (110 degrees C); however, new polyphenols having strong antioxidant activity were produced above 200 degrees C. The amount of solubilized materials and antioxidant activity increased with increased fermentation of harvested tea leaves (green tea < oolong tea < black tea). Cutin, a plant biopolyester, remained in the residue after heating as did cellulose and lignin/tannin. The predominant cutin monomer that was recovered was 9,10-epoxy-18-hydroxyoctadecanoic acid, followed by dihydroxyhexadecanoic acid and 9,10,18-trihydroxyoctadecanoic acid.

MeSH terms

  • Antioxidants
  • Flavonoids / chemistry*
  • Microwaves*
  • Phenols / chemistry*
  • Plant Extracts / chemistry
  • Polyesters / chemistry*
  • Polyphenols
  • Polysaccharides / chemistry*
  • Solubility
  • Tea / chemistry*


  • Antioxidants
  • Flavonoids
  • Phenols
  • Plant Extracts
  • Polyesters
  • Polyphenols
  • Polysaccharides
  • Tea