Identification of volatile components and analysis of aroma characteristics of Jiangxi Congou black tea

Figures & data

Table 1. Descriptors and reference compounds of aroma of Jiangxi Congou black tea

Descriptors	Definition	Reference compounds
Sweet-smell	Suggestive of sugar, including caramel, honey, brown sugar, etc	7.80 µmol/L furaneol
Floral	Including rose, violet, magnolia, jasmine, narcissus and gardenia	0.65 µmol/L (R)-linalool
Fruity	It reminds people of fruits, including pineapple, apples, bananas, peaches, oranges, etc.	8.32 µmol/L phenylacetaldehyde
Roasted	Aroma related to baking, including pot, toast, coffee, etc	9.25 µmol/L 2,5-dimethyl pyrazine
Spicy	Including peppermint, holly, ginger, pepper, etc	0.66 µmol/L methyl salicylate
Fresh	The smell of cucumber just cut off
Green	The smell of fresh vegetables after being broken	µmol/L(E,E)-2,4-Hexadienal
Oil	Including butter, fat, grease, etc
Off-odor	It includes soap, medicine, fishy smell and earthy taste. Metallic, moldy, aged, smoked, burnt, bad fermentation, etc
Woody	Including rosin, hay, camphor, resin, etc	0.65 µmol/L (-)-alpha-terpineol
Smoky	The smell of wood burning
Overall-aroma	Integrated value of the whole aroma

Table 2. QDA results of Jiangxi Congou black tea

Sample	1	2	3	4	5	6	7	8	9	10	11	AS
Sweet-smell	10.5 ± 0.7a	9.5 ± 1.4ab	9.9 ± 2.7ab	7.2 ± 0.2ab	9.3 ± 0.7ab	9 ± 2.8ab	8.7 ± 0.4ab	7.0 ± 0.0b	10.0 ± 1.4ab	12.0 ± 1.4a	10.5 ± 2.1a	9.41
Floral	3.8 ± 0.4 f	4.2 ± 1.0 f	9.3 ± 0.6bc	10.4 ± 0.9b	7.9 ± 0.1 cd	6.4 ± 1.9de	6.3 ± 1.1de	5.5 ± 0.7ef	8.0 ± 0.0 cd	13.0 ± 0.0a	9.5 ± 0.7bc	7.64
Fruit	9.3 ± 0.4ab	8.5 ± 0.7bc	7.9 ± 0.1bc	6.1 ± 0.6df	7.1 ± 0.1 cd	8.3 ± 1.1bc	10.5 ± 0.7a	8.0 ± 0.0bc	5.5 ± 0.7dfg	4.0 ± 1.4 g	4.8 ± 1.1fg	7.26
Roasted	10.5 ± 0.7abc	11.8 ± 0.4ab	7.5 ± 0.7 fg	10.0 ± 2.1bcd	12.5 ± 0.7a	8.5 ± 0.7 cdf	5.4 ± 2.3 g	10.0 ± 0.0bcd	8.0 ± 0.0df	7.0 ± 0.0 fg	8.5 ± 0.7 cdf	9.06
Spicy	2.5 ± 0.7fg	3.3 ± 1.3 cdfg	4.3 ± 1.1cdfg	1.7 ± 0.9 g	4.9 ± 0.6cdf	5.8 ± 0.4bcd	5.8 ± 1.8bcd	3.0 ± 1.4dfg	8.5 ± 0.7ab	6.0 ± 2.8bc	10.5 ± 0.7a	5.10
Fresh	2.0 ± 1.4 cdf	3.5 ± 2.1abcdf	1.5 ± 0.7df	4.3 ± 0.4abcd	1.3 ± 0.4 f	6.3 ± 0.4a	5.5 ± 0.7ab	3.0 ± 0.0abcdf	3.8 ± 1.1abcdf	6.0 ± 2.8a	4.5 ± 0.7abc	3.77
Green	6.3 ± 0.4a	5 ± 1.3ab	1.3 ± 0.4 f	1.3 ± 0.4 f	3.4 ± 0.3bcd	1.0 ± 0.0 f	1.5 ± 0.7f	2.0 ± 1.4 cdf	1.8 ± 1.1df	1.0 ± 0.0f	3.5 ± 0.7bc	2.53
Oil	1.0 ± 0.0b	1.2 ± 0.2b	1.3 ± 0.4b	1.0 ± 0.0b	1.1 ± 0.1b	2.5 ± 0.7b	1.0 ± 0.0b	5.0 ± 0.0a	2.5 ± 2.1b	1.0 ± 0.0b	1.5 ± 0.7b	1.72
Off-odor	1.3 ± 0.4d	3.4 ± 0.6a	1.0 ± 0.0d	1.0 ± 0.0d	3.0 ±.00b	2.0 ± 0.0bcd	1.5 ± 0.7 cd	2.5 ± 0.7bc	1.5 ± 0.7 cd	1.5 ± 0.7 cd	1.5 ± 0.7 cd	1.83
Smoky	1.8 ± 1.1bcd	4.2 ± 0.3a	1.0 ± 0.0d	2.8 ± 0.4abcd	3.4 ± 0.9ab	2.3 ± 1.8bcd	1.3 ± 0.4cd	1.5 ± 0.7cd	2.0 ± 1.4bcd	1.0 ± 0.0d	3.0 ± 0.0abc	2.19
Woody	2.0 ± 1.4c	2.3 ± 1.8 c	10.2 ± 0.2a	8.8 ± 0.4ab	1.0 ± 0.0 c	1.0 ± 0.0 c	1.0 ± 0.0 c	2.5 ± 0.7c	1.0 ± 0.0 c	1.0 ± 0.0 c	8.0 ± 1.4b	3.51
Overall-aroma	12.1 ± 0.1b	6.9 ± 0.1i	12.0 ± 0.0bc	11.0 ± 0.7d	10.1 ± 0.0fg	11.2 ± 0.3cd	10.5 ± 0.7df	7.3 ± 0.3i	8.9 ± 0.6 h	14.1 ± 0.1a	9.5 ± 0.4gh	10.31

Note: sig≤0.05 level; AS:average strength

Figure 1. Distribution of samples on the first two principal components

Figure 2. PLS scatter diagram of volatile compounds and sensory properties of samples

Figure 3. VIP values of volatile compounds to the overall aroma sensory attributes