Volatile Composition and Enantioselective Analysis of Chiral Terpenoids of Nine Fruit and Vegetable Fibres Resulting from Juice Industry By-Products

Table 2

Average relative percentage of volatile compounds present and their distribution ranges in different production batches (in parenthesis) of apple, pear, peach, and carrot fibres, as determined by HS-SPME-GC-MS analysis.

	LRI (exp.)	LRI (ref.)	Apple fibre	Pear fibre	Peach fibre	Carrot fibre
			Mean	Mean	Mean	Mean
Hydrocarbons
2,4-Dimethyl-1-heptene			2.1 (0.9–4.4)	0.1 (traces–0.3)
4-Methyl octane			0.5 (traces–1.3)			3.0
Subtotal			2.6	0.1	0.0	3.0
Aldehydes
Hexanal			19.7 (9.2–27.7)	7.4 (5.2–9.0)	17.4 (10.6–21.3)	20.3
Furfural			2.6 (1.8–3.4)	15.2 (9.0–21.1)	43.2 (38.8–43.3)	1.6
Heptanal	902	905	1.3 (1.0–1.7)	0.7 (0.5–0.9)	1.4 (0.5–1.7)	2.6
(E)-2-heptenal	959	957	14.9 (12.1–20.2)	3.9 (1.5–6.4)	2.6 (1.8–4.1)	3.6
Benzaldehyde	963	961	15.6 (11.6–22.4)	3.6 (0.9–6.3)	2.5 (traces–3.6)	1.3
Pentylfuran	993	996	Traces
Octanal	1004	1001	1.7 (1.0–3.3)	2.0 (1.34–2.41)
Nonanal	1106	1103	1.7 (1.2–2.2)		2.6 (traces–4.1)	3.0
Decanal	1207	1205				0.4
Subtotal			57.5	32.8	69.7	32.8
Ketones
1-Octen-3-one	980	980	6.3 (3.9–9.2)	3.1 (0.9–4.4)	1.7 (1.0–3.0)	4.7
2-Methyl-3-octanone	986	985			0.7 (traces–1.8)
6-Methyl-5-hepten-2-one	989	985	5.3 (2.7–7.7)	2.7 (1.9–3.7)	3.7 (2.50–4.8)	3.0
2,2,6-Trimethylcyclohexanone	1037	1036				6.5
3,4,4-Trimethylcyclohexen-1-one	1082					1.9
Subtotal			11.6	5.8	6.1	16.1
Ethers
Butyl ether			0.7 (0.4–1.0)	1.0 (0.4–1.4)	1.6 (traces–2.2)	1.8
Esters
Butyl acetate				3.8 (2.9–6.0)
Pentyl acetate	917	916		1.1 (0.9–1.2)
Butyl isobutyrate	956	954	12.1 (9.5–16.6)			0.9
Hexyl acetate	1017	1016	1.5 (0.5–2.7)	49.1 (40.4–61.2)
Hexyl 2-methylbutanoate	1244	1239	0.6 (0.2–1.1)
Butyl benzoate	1378	1376	1.3 (1.1–2.0)			4.2
Hexyl hexanoate	1391	1386	0.8 (0.3–2.7)
Subtotal			16.3	54.0	Traces	5.1
Alcohols
1-Hexanol				1.2 (0.8–1.7)
(E)-2-Cyclohexen-1-ol	1097	1097				0.9
2,6-Dimethyl cyclohexanol	1110	1114				0.4
Subtotal			Traces	1.2	Traces	1.3
Terpenoids
α-Pinene	937	939	0.2 (traces–0.5)		0.2 (traces–0.6)	1.2
β-Pinene	978	980		1.2 (0.6–2.3)
Myrcene	996	991				0.6
α-Phellandrene	1005	1005			3.2 (1.8–6.1)
p-Cymene	1027	1026			1.1 (0.3–2.0)	2.7
Limonene	1031	1031	3.1 (0.9–3.2)		6.1 (1.9–17.8)
γ-Terpinene	1062	1062	5.6 (4.0–8.9)		2.2 (0.4–3.4)
α-Terpinolene	1086	1088				1.3
Linalool	1100	1098			0.9 (0.5–2.0)
cis-β-Terpineol	1147	1144	0.2 (0.1–0.3)
4-Terpineol	1178	1177			0.4 (traces–1.3)
α-Terpineol	1191	1189	1.5 (0.8–2.0)	1.5 (1.0–1.9)	6.6 (4.1–9.5)	1.0
β-Cyclocitral	1223	1222				3.5
Neryl acetate	1371	1368			1.1 (0.6–1.5)
(E)-β-Caryophyllene	1420	1418				1.9
α-Ionone	1428	1426				8.1
Geranyl acetone	1454	1455				2.5
β-Ionone	1488	1485				9.8
Valencene	1493	1491	0.4 (0.1–0.5)		0.2 (traces–0.5)
-Farnesene	1511	1508	0.4 (0.2–0.8)	0.2 (0.2–0.3)
7-epi-α-Selinene	1516	1517			0.4 (traces–2.1)
γ-Bisabolene	1534	1533				2.7
Total (%)			11.4	2.9	22.4	35.3
Total normalised area						5.6

The term “traces” indicates area percentage < 0.05%.