epigallocatechin
compound / compound-egc
エピガロカテキン / epigallocatechin (EGC)
Epigallocatechin is a non-galloylated tea catechin. Compared to galloylated catechins (such as EGCG), it is described as having weaker astringency and bitterness.
On this page (8 sections)
Reading the bitterness
Epigallocatechin (EGC) is a type of tea catechin classified as non-galloylated. A 2018 chemical analysis of matcha, summarizing previous research, explicitly contrasts EGC as 「苦渋味の弱い」 (in translation: "weaker in astringency and bitterness") catechin with galloylated epigallocatechin gallate (EGCG) as 「苦渋味の強い」 (in translation: "stronger in astringency and bitterness") catechin. However, quantitative thresholds or ratios supporting this contrast are not provided.
A 2022 study evaluated the intensity of Huigan (the sensation of sweetness remaining in the mouth) 10 seconds after swallowing in an aqueous solution of epicatechin (EC, 400 ppm) and EGC (100 ppm) mixed at a 4:1 ratio, using an 11-point scale. In a group of subjects described as sensitive to Huigan, scores for this mixture were oral stage 5.2±1.3, oral-pharyngeal stage 5.2±1.0, and were significantly higher compared to other samples (p<0.05). However, EC and EGC were always tested as a mixture, and the individual contribution of EGC cannot be separated from this study. Huigan itself is a sensation distinct from bitterness, and it is important to note that this result does not directly measure EGC's bitterness itself.
In tencha production, while EGC (epigallocatechin) content increases as new shoots mature, shade-growing suppresses this increase. In raw tea of 'Yabukita' first flush, EGC content on a dry matter basis is targeted to remain at approximately 2% or less.
Sources for this overview
抹茶の点て方に関する化学的考察 (Chemical research on the preparation of matcha)
Checked for this overview: The description of astringency and bitterness contrast between EGC and EGCG was adopted.
Tea compound-saliva interactions and their correlations with sweet aftertaste
Checked for this overview: Huigan score data for the EC/EGC mixture was adopted.
Checked for this overview: EGC content suppression by shade-growing and the target value for raw tea.
Other names: EGC (en)
Follow the connections
epigallocatechin →is correlated with→ sweet aftertaste
tea shading cultivation →reduces→ epigallocatechin
Structured claims — open a section to read each claim's confidence, evidence and limits
Sensory (2)
Scope: Catechins derived from tea (Camellia sinensis)
Show data
compound-egc —has_sensory_attribute→ "Bitterness and astringency (described as weaker compared to EGCG, a galloylated catechin)"Scope: An aqueous solution of EC 400 ppm and EGC 100 ppm (4:1 ratio). Compared to L-theanine 200 ppm, trilobatin 30 ppm, and distilled water controls. Scores in the Huigan-sensitive group were oral stage 5.2±1.3, oral-pharyngeal stage 5.2±1.0 (with significant difference from other samples at p<0.05)
Show data
compound-egc —is_correlated_with→ concept-huiganHow processing and cooking change it (1)
Scope: Layer: Food. Tencha (matcha raw material), raw tea of 'Yabukita' variety first flush. EGC content is analyzed using analytical instruments such as HPLC.
Note: The description indicates the direction that EGC content increases with new shoot maturity, while shade covering suppresses this increase. Specific measured differences before and after covering (percentage points) are not shown in the relevant section of this material.
Show data
process-tea-shading-cultivation —reduces→ compound-egc