. 2021 Jul 13;26(14):4255. doi: 10.3390/molecules26144255

Table 2.

Effect of Fe²⁺ on the transformation of catechins in green tea infusion with heat treatment.

Concentrations (μg/mL)	Untreated	Heat Treatment	2 μM FeCl₂ + Heat Treatment	4 μM FeCl₂ + Heat Treatment
GA	4.41 ± 0.19 ^a	12.6 ± 0.8 ^b	13.0 ± 0.8 ^b	13.4 ± 1.1 ^b
GC	18.6 ± 0.1 ^a	41.6 ± 1.3 ^b	38.3 ± 0.6 ^c	37.3 ± 0.1 ^d
EGC	53.9 ± 3.6 ^a	52.6 ± 2.7 ^a	50.6 ± 3.3 ^a	49.5 ± 2.0 ^a
C	5.14 ± 0.18 ^a	12.0 ± 0.8 ^b	11.2 ± 0.1 ^b	11.5 ± 0.2 ^b
EGCG	818 ± 9 ^a	582 ± 5 ^b	568 ± 22 ^bc	561 ± 5 ^c
EC	45.5 ± 1.8 ^a	33.2 ± 0.5 ^b	33.0 ± 1.5 ^b	32.9 ± 0.6 ^b
GCG	5.07 ± 0.25 ^a	219 ± 4 ^b	200 ± 10 ^c	197 ± 10 ^c
ECG	93.3 ± 0.2 ^a	95.7 ± 2.1 ^a	93.7 ± 1.0 ^a	92.9 ± 3.0 ^a
CG	6.10 ± 0.11 ^a	16.9 ± 0.2 ^b	15.6 ± 1.0 ^bc	15.5 ± 0.9 ^c
Total catechins	(1.05 ± 0.02) ×10^{3 a}	(1.05 ± 0.01) ×10^{3 a}	(1.01 ± 0.02) × 10^{3 b}	998 ± 6 ^b
Non-gallated catechins	123 ± 5 ^a	139 ± 5 ^b	133 ± 6 ^ab	131 ± 3 ^a
Gallated catechins	923 ± 9 ^a	914 ± 7 ^a	877 ± 10 ^b	867 ± 9 ^b
Non-epi-catechins	35.0 ± 0.2 ^a	290 ± 6 ^b	265 ± 11 ^c	262 ± 11 ^c
Epi-catechins	(1.01 ± 0.01) ×10^{3 a}	763 ± 6 ^b	745 ± 26 ^bc	737 ± 5 ^c

Non-gallated catechins referred to GC, EGC, C, and EC, while gallated catechins referred to GCG, EGCG, CG, and ECG. Non-epi-catechins referred to GC, C, GCG, and CG, while epi-catechins referred to EGC, EC, EGCG, and ECG. The experiments were carried out in triplicate. The same letter within each row indicates no significant difference (p > 0.05).