Enhancement of Black Tea Aroma by Adding the β-Glucosidase Enzyme during Fermentation on Black Tea Processing

Table 2

The volatile compounds identified in black tea.

No.	Compound	CAS number	LRI	THK (ppb)	THE (ppb)	Odor description
Alcohols
1	2-Methylbutanol	137-32-6		6.97	21.29	Roasted wine, fruity
2	3-Hexenol	544-12-7		5.31	11.60	Green leafy
3	1-Octen-3-ol	3391-86-4	983	nd	1.35	Mushroom, earthy green
4	2-Ethylhexanol	104-76-7	1035	2.46	5.38	Citrus fresh, floral sweet
5	2-Butyloctanol	735273	1320	nd	3.05
6	7-Methoxy-1-naphthol	67247-13-6	1377	0.49	nd
Aromatic alcohol
7	Benzyl alcohol	100-51-6	1042	7.82	1.94	Floral rose
8	Phenylethyl alcohol	60-12-8	1119	12.97	18.40	Floral rose, dried rose flower
9	2-tert-Butylcyclohexanol	13491-79-7	1294	1.34	1.55	Pine camphor minty, patchouli
Terpenoid alcohol
10	Linalool oxide	5989-33-3	1075	6.73	15.32	Earthy, floral sweet, woody
11	trans-Linalool oxide	34995-77-2	1091	8.31	41.60	Floral
12	Linalool	78-70-6	1104	4.09	13.60	Citrus floral sweet, blueberry
13	cis-Linalool oxide	5989-33-3	1174	0.82	2.21	Earthy, floral sweet, woody
14	Epoxylinalool	14049-11-7	1179	4.62	11.98	Floral honey
15	cis-Geraniol	106-25-2	1232	nd	1.49	Sweet natural, neroli citrus
16	Geraniol	106-24-1	1260	2.49	4.52	Sweet floral, fruity, rose, citrus
17	Nerolidol	7212-44-4	1568	3.50	6.52	Floral green, citrus, woody
Ketones
18	2,3-Octanedione	585-25-1	988	0.43	6.83	Dill, asparagus, cilantro, herbal
19	2,5,5-Trimethylcyclohex-2-enone	42747-41-1	1301	2.42	2.91
20	2-Benzylcyclohexanone	946-33-8	1468	0.10	0.69
Aromatic ketone
21	Acetophenone	98-86-2	1062	1.76	0.78	Sweet pungent, almond, acacia
22	Camphenone, 6-	55659-42-2	1205	1.33	3.07
23	Geranyl acetone	3796-70-1	1455	0.62	1.32	Fresh green, fruity, rose, tropical
24	2,4,5-Trimethylacetophenone	2040-07-5	1486	1.79	4.52
25	Benzophenone	119-61-9	1634	1.12	1.05	Rose, powdery, geranium
26	4-Benzyloxyacetophenone	782-92-3	1693	0.27	nd
27	Hexahydrofarnesyl acetone	502-69-2	1847	nd	0.26	Jasmine, celery, woody
Ionone derivatives
28	β-Damascenone	23726-93-4	1386	0.86	0.80	Apple, rose, honey, tobacco, sweet
29	α-Ionone	127-41-3	1432	0.50	0.87	Sweet, woody, floral, tropical fruity
30	Dihydro-β-ionone	17283-81-7	1444	nd	0.15	Earthy, woody, dry amber
31	1-(4-tert-Butylphenyl)propan-2-one	81561-77-5	1453	0.42	nd
32	2,6-Di-tert-butylquinone	719-22-2	1471	1.59	2.56
33	α-Isomethyl ionone	127-51-5	1481	0.70	0.40	Sweet orris, powdery, floral, woody
34	trans-β-Ionone	79-77-6	1490	4.02	7.04	Dry powdery, floral, woody, orris
Esters
35	Methyl caprylate	111-11-5	1126	nd	3.38	Green, sweet orange
36	cis-3-Hexenyl-α-methylbutyrate	53398-85-9	1238	nd	0.62	Fresh, green apple, sweet, pear
37	Isobornyl acetate	125-12-2	1289	1.43	0.87	Herbal, woody, sweet
38	3-Hexenyl hexanoate	84434-19-5	1383	1.28	nd
39	Ethyl decanoate	110-38-3	1397	2.50	2.50	Sweet, fruity, apple, grape
40	Methyl laurate	111-82-0	1529	nd	1.96	Creamy, coconut, mushroom
41	cis-3-Hexenyl benzoate	25152-85-6	1576	0.42	1.06	Fresh green, leafy, floral, orchid
42	Methyl palmitate	112-39-0	1928	0.24	1.01	Waxy, fatty orris
Aldehydes
43	2-Methylpropanal	78-84-2		22.51	31.52	Floral green
44	2-Methylbutanal	96-17-3		17.70	44.94	Musty, cocoa, coffee, nutty
45	Hexanal	66-25-1		3.54	4.85	Fresh green, grass leafy, sweaty
46	2-Hexenal, (E)-	6728-26-3		2.15	4.63	Green banana, fatty, cheesy
47	Heptanal	111-71-7	902	5.75	4.19	Fresh green, herbal, wine-lee ozone
48	2,4-Heptadienal, (E,E)-	4313-03-05	1012	nd	1.25	Fatty green oily, cake cinnamon
49	Nonanal	124-19-6	1106	20.61	39.88	Rose, fresh orris, orange peel
50	Decanal	112-31-2	1207	0.82	0.74	Sweet, orange peel, citrus floral
Aromatic aldehyde
51	Benzaldehyde	100-52-7	962	4.08	6.61	Sweet, almond, cherry
52	Benzeneacetaldehyde	122-78-1	1046	16.00	37.18	Floral, sweet, clover, honey, cocoa
53	2-Butenal, 2-phenyl	4411-89-6	1276	0.38	0.50	Beany, honey cocoa, nutty radish
54	4-Indanecarbaldehyde	51932-70-8	1306	1.09	1.68
55	2-Hexylcinnamaldehyde	101-86-0	1753	0.33	nd	Fresh, floral green, jasmine, herbal
Terpenoid aldehyde
56	β-Cyclocitral	432-25-7	1223	3.22	5.22	Sweet, fruity, tropical, saffron, rose
57	(R)-(+)-Citronellal	2385-77-5	1242	nd	0.31	Fresh herbal, citrus
58	Citral	5392-40-5	1274	0.39	0.29	Sharp lemon sweet
Hydrocarbons
59	4-Methyldecane	2847-72-5	1023	1.44	1.19
60	3,6-Dimethyldecane	17312-53-7	1058	1.93	2.05
61	4-Methylundecane	2980-69-0	1059	2.39	1.65
62	3,8-Dimethyldecane	17312-55-9	1150	1.05	0.87
63	3-Methylundecane	1002-43-3	1171	1.99	1.85
64	Cyclododecane	294-62-2	1192	1.44	1.27
65	Dodecane	112-40-3	1201	30.48	31.71
66	2-Undecene, 5-methyl-	56851-34-4	1215	1.98	1.42
67	2-Methyldodecane	1560-97-0	1264	4.26	2.35
68	5-Ethyl-2-methyloctane	62016-18-6	1280	4.39	2.50
69	3,5-Dimethyldodecane	107770-99-0	1340	0.69	0.63
70	2,3,7-Trimethyldecane	62238-13-5	1343	nd	0.24
71	4-Ethyldecane	1636-44-8	1347	1.08	1.40
72	3-Dodecene, (Z)-	7239-23-8	1365	nd	0.75
73	3-Methyltridecane	6418-41-3	1371	2.48	2.39
74	Cyclopentane, nonyl-	2882-98-6	1386	0.87	nd
75	1-Tetradecene	1120-36-1	1392	1.82	1.66
76	Tetradecane	629-59-4	1401	15.52	13.89	Mild waxy
77	Cyclotetradecane	295-17-0	1449	0.52	0.62
78	4,8-Dimethyltridecane	55030-62-1	1463	1.47	1.03
79	Pentadecane	629-62-9	1500	0.71	26.58	Waxy
80	Hexadecane	544-76-3	1541	0.69	0.87
81	Heptadecane	629-78-7	1600	2.33	3.38
Aromatic hydrocarbon
82	Naphthalene	91-20-3	1186	12.06	12.22	Pungent, dry tarry
83	Eicosane	112-95-8	1710	0.24	0.44	Waxy
84	Cadinene	5951-61-1	1336	1.88	1.67
85	Ionene	475-03-6	1360	nd	0.23
86	2,6-Dimethylnaphthalene	581-42-0	1426	nd	0.54	Grass
87	1,3-Diisopropylnaphthalene	1000374-05-2	1682	0.48	nd
88	Cadalene	483-78-3	1686	0.76	1.21
89	1,4-Diisopropylnaphthalene	1000374-05-7	1727	0.29	0.82
90	2,6-Diisopropylnaphthalene	24157-81-1	1730	3.60	2.26
91	Copaene	3856-25-5	1379	1.16	1.06	Woody spicy honey
92	Modephene	68269-87-4	1383	nd	0.77
93	Cyclosativene	22469-52-9	1374	nd	0.84
94	Berkheyaradulene	1000373-94-1	1391	nd	1.09
95	Caryophyllene	87-44-5	1424	2.34	2.87	Sweet, woody spice clove dry
96	Alloaromadendrene	25246-27-9	1505	0.58	0.76	Woody
97	Butylhydroxytoluene	128-37-0	1518	2.69	4.60	Mild camphor
Terpenoid hydrocarbon
98	o-Xylene	95-47-6		7.75	9.18	Geranium
99	D-Limonene	5989-27-5	1028	0.26	0.57	Citrus orange, fresh sweet
100	α-Cubebene	17699-14-8	1354	0.90	0.77	Herbal waxy
101	α-Longifolene	475-20-7	1409	1.25	1.31	Sweet woody, rose, medical, fir
102	ε-Muurolene	30021-46-6	1415	1.32	2.41
103	β-Cubebene	13744-15-5	1436	nd	0.26	Citrus, fruity, radish
104	trans-α-Bergamotene	13474-59-4	1438	nd	0.14	Woody, warm tea
105	β-Guaiene	88-84-6	1442	nd	0.27	Sweet woody, spicy, powdery
106	β-Bisabolene	495-61-4	1459	0.61	0.80	Balsamic, woody
107	γ-Gurjunene	22567-17-5	1478	nd	0.95	Musty
108	α-Farnesene	502-61-4	1511	1.45	3.07	Citrus, lavender, bergamot, green
109	γ-Cadinene	39029-41-9	1521	nd	3.26	Herbal, woody
110	α-Cedrene	469-61-4	1654	nd	0.36	Woody, cedar, sweet fresh
111	α-Longipinene	5989-0805	1658	nd	0.35
112	Dehydro-ar-ionene	30364-38-6	1358	0.54	0.32	Licorice
Phenolic compounds
113	o-Cresol	95-48-7	1165	1.85	1.15	Musty, plastic, medicinal, leathery
114	Eugenol	97-53-0	1364	1.44	0.31	Sweet spicy, clove woody
115	Methyl salicylate	119-36-8	1199	5.60	35.19	Wintergreen, mint
116	2,4-Di-tert-butylphenol	96-76-4	1524	2.05	2.52
117	4-(1-Hydroxyallyl)-2-methoxyphenol	112465-50-6	1531	2.28	0.51
118	2,4,6-Tri-tert-butylphenol	732-26-3	1910	nd	nd
Furanoid
119	Furan, 2-pentyl-	3777-69-3	992	2.00	5.06	Fruity, green
120	Furan, 3-phenyl-	13679-41-9	1226	nd	1.73	Floral
Nitrogenous compounds
121	5-Methylthiazole	3581-89-3	1246	1.55	2.44
122	Dihydroactinidiolide	17092-92-1	1538	0.62	nd
123	2-Methylphenothiazine	5828-51-3	1648	nd	0.92
124	Caffeine	58-08-2	1858	1.76	3.35	Odorless
Acids
125	2-Ethylhexanoic acid	149-57-5	1139	4.47	1.46
126	n-Decanoic acid	334-48-5	1283	0.56	0.44	Unpleasant, rancid, sour fatty
Sulfur compound
127	2-Ethyl-5,7-dimethyl-1-benzothiophene	18428-05-2	1422	0.57	nd
Others
128	1-Oxaspiro[4.5]dec-6-ene,2,6,10,10-tetramethyl-1-oxaspiro[4.5]dec-6-ene	36431-72-8	1315	nd	0.76	Tea, herbal, green, wet tobacco leaf, woody, spicy
129	Diphenyl ether	101-84-8	1405	0.90	0.78	Geranium leaf, green
130	Cyclopropane, nonyl-	74663-85-7	1474	0.35	0.27
131	Biphenyl-, 2,2,5,5-tetramethyl-	3075-84-1	1716	0.34	0.58

Note: THK: black tea from PGL 15 controls; THE: black tea treated with β-glucosidase; THP: black tea from the Pagilaran factory. Ethyl decanoate was used as an internal standard. References based on http://www.thegoodscentscompany.com/. nd: not detected.