Characteristics and chemical compositions of Pingwu Fuzhuan brick-tea, a distinctive post-fermentation tea in Sichuan province of China

Figures & data

Figure 1. Principal component analysis (PCA) model displaying separation related to origins based on 27 minerals. PWT, Pingwu Fuzhuan brick tea; HNT, Hunan Fuzhuan brick tea; SNT, Shaanxi Fuzhuan brick tea; GZT, Guizhou Fuzhuan brick tea. R2X^[1] refers to the fraction of explained variation in principal component 1 (t^[1]) and R2X^[2] the fraction of explains variation in PC2 (t^[2])

Table 1. Physicochemical properties of PWT, HNT, SNT and GZT

	PWT	HNT	SNT	GZT
Colour factors
L*	81.84 ± 0.00^c	70.62 ± 0.00^a	75.92 ± 0.01^b	83.60 ± 0.01^d
a*	6.55 ± 0.00^b	17.35 ± 0.01^d	12.21 ± 0.01^c	5.43 ± 0.01^a
b*	49.98 ± 0.01^a	60.01 ± 0.02^b	72.10 ± 0.02^d	61.07 ± 0.01^c
TCD	0	18.52	23.58	3.87
Chemical components (mg/g)
EGC	4.55 ± 0.36^b	2.47 ± 0.19^a	15.94 ± 0.90^c	9.17 ± 0.72^d
C	0.36 ± 0.06^a	0.21 ± 0.06^a	1.80 ± 0.14^c	0.56 ± 0.04^b
EGCG	1.13 ± 0.01^a	0.35 ± 0.03^a	23.23 ± 0.95^c	12.26 ± 0.63^b
EC	0.17 ± 0.00^a	0.11 ± 0.01^a	4.72 ± 0.18^c	2.13 ± 0.15^b
ECG	1.62 ± 0.12^b	0.63 ± 0.07^a	9.09 ± 0.86^d	3.89 ± 0.30^c
Total catechins	7.83 ± 0.61^b	4.55 ± 0.27^a	54.78 ± 1.93^d	28.02 ± 2.07^c
GA	1.90 ± 0.08^a	1.55 ± 0.07^a	4.25 ± 0.17^b	4.72 ± 0.47^c
Theobromine	0.15 ± 0.03^a	0.19 ± 0.01^a	0.51 ± 0.03^b	0.15 ± 0.02^a
Theophylline	0.12 ± 0.01^b	0.07 ± 0.01^a	0.42 ± 0.03^d	0.34 ± 0.03^c
Caffeine	12.58 ± 0.44^a	16.85 ± 0.65^b	23.36 ± 0.60^c	11.68 ± 0.75^a

Data are expressed as mean values ± standard deviation (n = 3).

^a-dMeans within each row with different letters are significantly different (p < 0.05).

L*, degree of brightness; a*, degree of redness-greenness; b*, degree of yellowness-blueness; TCD, total colour difference.

Table 2. Contents of amino acids in PWT, HNT, SNT and GZT (μg/g)

No.	AAs	PWT	HNT	SNT	GZT	Types
1	Thr	101.00 ± 4.58^c	5.00 ± 2.83^a	24.67 ± 1.15^b	4.67 ± 0.58^a	Essential AAs
2	Val	30.00 ± 1.00^a	–	36.33 ± 0.58^b	-
3	Ile	17.33 ± 1.53^b	3.33 ± 1.15^a	20.33 ± 0.58^c	4.33 ± 0.58^a
4	Leu	11.33 ± 0.58^c	4.33 ± 1.15^a	25.33 ± 0.58^d	6.33 ± 0.58^b
5	Phe	23.33 ± 2.52^b	–	42.00 ± 1.73^c	7.00 ± 1.73^a
6	Trp	28.00 ± 7.55^a	–	58.67 ± 6.43^b	-
7	Lys	6.33 ± 0.58^b	4.67 ± 0.58^a	26.33 ± 0.58^c	7.33 ± 0.58^b
	TEAAs	217.33 ± 12.58^b	17.33 ± 3.51^a	233.66 ± 4.51^c	29.66 ± 3.06^a
8	Asp	191.33 ± 8.02^c	53.67 ± 2.52^b	213.00 ± 3.00^d	37.67 ± 2.08^a	Non-essential AAs
9	Pro	23.33 ± 2.52^a	41.33 ± 2.52^b	138.00 ± 6.08^d	62.00 ± 12.12^c
10	Ser	31.33 ± 2.52^b	13.50 ± 0.71^a	52.00 ± 0.00^c	16.67 ± 1.53^a
11	Asn	68.67 ± 5.69^a	–	–	–
12	Glu	84.67 ± 10.97^c	18.33 ± 6.03^a	358.33 ± 4.16^d	55.33 ± 5.03^b
13	Gly	18.67 ± 2.08^b	7.00 ± 1.00^a	15.67 ± 2.89^b	8.33 ± 0.58^a
14	Ala	72.67 ± 3.79^b	15.33 ± 0.58^a	94.00 ± 6.24^c	15.33 ± 1.15^a
15	Tyr	30.67 ± 1.15^b	10.33 ± 2.08^a	47.33 ± 1.53^c	11.00 ± 2.65^a
16	Arg	37.67 ± 5.51^b	7.33 ± 0.58^a	74.00 ± 3.46^c	10.67 ± 1.15^a
17	His	–	–	8.67 ± 0.58^b	4.67 ± 0.58^a
	TNEAAs	559.01 ± 21.79^c	166.82 ± 3.25^a	1001.00 ± 9.54^d	221.67 ± 21.96^b
18	Thea	172.33 ± 3.51^c	7.67 ± 2.52^a	1169.00 ± 30.79^d	97.67 ± 8.50^b	Other AAs
19	GABA	531.67 ± 21.13^d	106.00 ± 1.73^b	222.33 ± 7.57^c	70.33 ± 4.51^a
	Total	1480.33 ± 56.31^c	297.82 ± 3.88^a	2625.99 ± 34.07^d	419.33 ± 34.65^b

All data were expressed as mean ± standard deviation (n = 3).

^a-d Means within each row with different letters are significantly different (p < 0.05).

PWT, HNT, SNT and GZT: Fu brick tea samples from Pingwu, Hunan, Shaanxi and Guizhou, respectively.

TEAAS, total essential amino acids.

TNEAAs, total non-essential amino acids.

-, not detected.

Figure 2. Volatile compositions in PWT, HNT, SNT and GZT. PWT, Pingwu Fuzhuan brick tea; HNT, Hunan Fuzhuan brick tea; SNT, Shaanxi Fuzhuan brick tea; GZT, Guizhou Fuzhuan brick tea

Figure 3. Heatmap of the contents of 23 chemicals in FBTs. The colour of box represents the value of (x – μ)/SD; x, the constituent level in individual tea samples; μ, the average level of constituents in four FBT samples; SD, the standard deviations of constituents in four types of FBT samples

Li, Q.; Huang, J.; Li, Y.; Zhang, Y.; Luo, Y.; Chen, Y.; Lin, H.; Wang, K.; Liu, Z. Fungal Community Succession and Major Components Change during Manufacturing Process of Fu Brick Tea. Sci. Rep. 2017, 7(1), 6947. DOI: 10.1038/s41598-017-07098-8.

 PubMedGoogle Scholar

Zheng, W.-J.; Wan, X.-C.; Bao, G.-H. Brick Dark Tea: A Review of the Manufacture, Chemical Constituents and Bioconversion of the Major Chemical Components during Fermentation. Phytochem. Rev. 2015, 14(3), 499–523. DOI: 10.1007/s11101-015-9402-8.

 Web of Science ®Google Scholar