Table 1.
List of abundant identified VOCs (>0.1% at least at one time point). The experimental and literature retention indices (RIs) are presented along with the compound category, the range of % peak area percentages, references whether it impacts flavor and references of previous occurrence in strawberries.
| No | RIexp | RIlit | Compound | Compound Category | Flavor Impact | Range of Peak Area Percentages | Ref. |
|---|---|---|---|---|---|---|---|
| 1 | 777 | 785 | 2-Methylpropanoic acid (isobutyric acid) |
Acids | a: rancid, butter, cheese | 0.08–0.94 | b, c, d |
| 2 | 799 | 802 | 2,3-Butanediol | Alcohols | a: fruit, onion; f: creamy | <0.31 | e, f |
| 3 | 803 | 802 | Ethyl butanoate | Esters | a: apple; b: estery, fruity, sweet; g | <0.33 | b, c, d, g |
| 4 | 805 | 790 | Butanoic acid (butyric acid) |
Acids | a: rancid, cheese, sweat; b: cheesy, fruity; g | tr.<4.23 | b, c, d, g |
| 5 | 831 | 811b | Methyl 2-hydroxybutanoate (methyl 2-hydroxy butyrate) | Esters | <0.21 | b | |
| 6 | 834 | 830/832/839 | Furfural | Furans | a: bread, almond, sweet | <0.22 | b, c, d |
| 7 | 856 | 827 (Kovat’s index) | Maleic anhydridestd (cis-butenedioic anhydride; 2,5-furandione) |
Furans/Anhydrides | 0.59–8.83 | ||
| 8 | 871 | 846/886 | 2-Methylbutanoic acid | Acids | b: cheesy, stinky; g | 0.03–4.86 | b, c, d, g |
| 9 | 890 | 890 | Styrene (vinylbenzene) |
Aromatic compounds | a: balsamic, gasoline | <1.44 | b |
| 10 | 915 | 915/916/922 | Butyrolactone [dihydrofuran-2(3H)-one] |
Furans/Lactones | a: caramel-sweet | 0.12–0.66 | c |
| 11 | 925 | 924 | Methyl n-hexanoate (methyl caproate) |
Esters | a: fruit, fresh, sweet | <0.12 | b, c, d, g |
| 12 | 947 | 949 (ZB-5) | Citraconic anhydride (3-methyl-2,5-furandione) |
Furans/Anhydrides | 0.73–9.00 | b | |
| 13 | 979 | 977 (VF-5MS) | 3-Hydroxybutanoic acid | Acids | <6.49 | ||
| 14 | 990 | 981 | Phenol | Aromatic compounds | a: phenol | <0.51 | b,f |
| 15 | 1001 | 996 | Ethyl hexanoate (ethyl caproate) |
Esters | a: apple, peel, fruit; b: fruity, sweet; g | <0.15 | b, c, d, g |
| 16 | 992 | 996/1001/1003/1005/1006 | α-Phellandrene * | Terpenes | a: dill | <0.17 * | d |
| 17 | 992 | 987/994/970/988/992/998/990/993 | 2-Pentylfuran * | Furans | a: green bean, butter | b, d | |
| 18 | 1006 | 977/981 | Hexanoic acid (n-caproic acid) |
Acids | b: sour, cheesy | 0.44–12.84 | b, c, d, g |
| 19 | 1016 | 995/1008/1013-1018 | Terpilene (α-terpinene) |
Terpenes | a: lemon | <0.11 | b, d |
| 20 | 1026 | 1022 (non-polar) | Succinic anhydride std (dihydro-2,5-furandione) |
Furans/Anhydrides | 0.59–3.15 | e | |
| 21 | 1028 | 1007/1020/1022/1025–1033 | Limonene | Terpenes | a: citrus, mint | <0.30 | b, c, d |
| 22 | 1038 | 1020/1033–1036/1042 | Benzyl Alcohol | Aromatic compounds | a: sweet, flower; g | 0.43–1.39 | b, c, d, g |
| 23 | 1040 | 967 (DB-1) | Itaconic anhydride * (dihydro-3-methylene-2,5-furandione) |
Furans/Anhydrides | 0.90–2.75 * | e | |
| 24 | 1040 | 1014b | Pantolactone * [dihydro-3-hydroxy-4,4-dimethyl-2(3H)-furanone; 2-hydroxy-3,3-dimethyl-γ-butyrolactone] |
Furans/Lactones | a: cotton candy | b | |
| 25 | 1049 | 1017/1020/1029/1033/1037–1040 |
cis-Ocimene (cis-3,7-dimethyl-1,3,6-octatriene) |
Terpenes | a: citrus, herb, flower | <0.16 | b |
| 26 | 1057 | 1056 | γ-Hexalactone [γ-ethyl-γ-butyrolactone, dihydro-5-ethyl-2(3H)-furanone, γ-caprolactone] |
Furans/Lactones | <0.27 | b, c, d | |
| 27 | 1063 | 1065 | Mesifurane [2,5-dimethyl-4-methoxy-3(2H)-furanone; DMMF] |
Furans | b: toffee, sugary, sweet; g | 0.24–1.29 | b, c, d, g |
| 28 | 1076 | 1055/1072/1097 | Furaneol [2,5-dimethyl-4-hydroxy-3(2H)-furanone; DMHF] |
Furans | a: caramel; b: sweet, candy, caramellic; g | 0.42–4.55 | b, c, d, g |
| 29 | 1088 | 1067/1071/1076/1080/1085–1089 | Terpinolene [p-mentha-1,4(8)-diene] |
Terpenes | <0.16 | b, d | |
| 30 | 1089 | 1065/1069/1087–1088/1091 |
trans-Linalool oxide (furanoid) [trans-5-ethenyltetrahydro-α,α,5-trimethyl-2-furanmethanol] |
Terpenes | a: flower | <0.18 | b, c |
| 31 | 1098 | 1084 (DB-5) | δ-Hexalactone (tetrahydro-6-methyl-2H-pyran-2-one; δ-caprolactone) |
Lactones | <0.26 | b, c, d | |
| 32 | 1102 | 1079/1082/1092/1094/1097–1105 | Linalool (3,7-dimethyl-1,6-octadien-3-ol) |
Terpenes | a: flower, lavender; b: floral | 0.06–0.63 | b, c, d |
| 33 | 1115 | - | Levoglucosenone * | Ketones | 0.20–1.03 * | h | |
| 34 | 1115 | 1109/1114–1119/1139 | 2-Phenylethyl Alcohol * (benzeneethanol) |
Aromatic compounds | a: honey, spice, rose, lilac | b, c, d | |
| 35 | 1173 | 1163 (DB-5MS) | 4-Ethylphenol | Aromatic compounds | a: must | 0.14–0.87 | |
| 36 | 1180 | 1159/1178 | Benzoic Acid | Aromatic compounds | a: urine | 0.09–0.45 | b, c, d |
| 37 | 1192 | 1187/1192 | 1-Dodecene | Alkenes | <0.20 | ||
| 38 | 1216 | 1197 (DB-5) | 1,2-Benzenediol (pyrocatechol; 2-hydroxyphenol; catechol) |
Aromatic compounds | <0.52 | i | |
| 39 | 1228 | 1223–1224 (SPB-5) | Coumaran (2,3-dihydrobenzofuran) |
Aromatic compounds | e: green tea | 1.35–5.62 | e |
| 40 | 1319 | 1326 (VF-5MS) | Salicylic acid std * (o-hydroxybenzoic acid; phenol-2-carboxylic acid) |
Aromatic compounds | 0.13–1.30 * | c, d | |
| 41 | 1319 | 1314–1318 | 2-Methoxy-4-vinylphenol * | Aromatic compounds | b, c, d | ||
| 42 | 1386 | 1343b |
cis-Cinnamic acid [(Z)-3-phenyl-2-propenoic acid) |
Aromatic compounds/Phenylpropanoids | 0.07–0.47 | b, d, i | |
| 43 | 1442 | 1432 | Tyrosol (4-hydroxyphenylethyl alcohol) |
Aromatic compounds | <0.88 | b, c, i | |
| 44 | 1471 | 1450/1462 (DB-1) |
trans-Cinnamic acid std [(E)-3-phenyl-2-propenoic acid] |
Aromatic compounds/Phenylpropanoids | a: honey | 19.41–37.28 | b, c, d, i |
| 45 | 1472 | 1470 | γ-Decalactone [5-hexyldihydro-2(3H)-furanone] |
Furans/Lactones | a: peach, fat; b: sweet, peach, lactonic; g | <2.49 | b, c, d, g |
| 46 | 1553 | 1491 (LM-5) | Levoglucosan * (1,6-anhydro-β-D-glucopyranose) |
Others | 0.30–7.88 * | ||
| 47 | 1553 | 1538 (VF-5MS) |
p-Salicylic acid * std (4-hydroxybenzoic acid; paraben-acid; 4-carboxyphenol ) |
Aromatic compounds | |||
| 48 | 1566 | 1544/1561–1563/1568/1569 |
trans-Nerolidol [(E)-3,7,11-trimethyldodeca-1,6,10-trien-3-ol] |
Terpenes | a: wax; g | <0.57 | b, c, d, g |
| 49 | 1571 | 1559/1566/−1568/1570/1573/1576 | Dodecanoic acid (lauric acid) |
Acids/Fatty acids | <0.23 | b, c, d | |
| 50 | 1659 | 1659 | Homovanilic acid * (4-hydroxy-3-methoxybenzeneacetic acid; vanilacetic acid) |
Aromatic compounds | 1.08–2.69 * | j | |
| 51 | 1659 | 1658 | Bisabolol oxide II * | Terpenes | |||
| 52 | 1683 | 1675 | γ-Dodecalactone [dihydro-5-octyl-2(3H)-furanone] |
Furans/Lactones | a: sweet, flower, fruit; g | <0.24 | b, c, d, g |
| 53 | 1765 | 1759/1767/1769/1770/1777/1780/1787/1790 | Tetradecanoic acid (myristic acid) |
Acids/Fatty acids | <0.53 | b, c, d | |
| 54 | 1864 | 1869/1878 | Pentadecanoic acid | Acids/Fatty acids | <0.44 | c | |
| 55 | 1881 | 1871/1879/1882 | 1-Hexadecanol (cetyl alcohol) |
Alcohols | a: flower, wax | <0.33 | |
| 56 | 1888 | 1881 (DB-1) | Ferulic acid [(E)-4-hydroxy-3-methoxycinnamic acid] |
Aromatic compounds/Phenylpropanoids | <0.31 | j, l | |
| 57 | 1944 | 1953 (HP-5) | Z-11-Hexadecenoic acid | Acids/Fatty acids | <0.89 | ||
| 58 | 1968 | 1962/1963/1969/1971/1972/1975/1977/1978/1991/1995/2003 |
n-Hexadecanoic acid (palmitic acid) |
Acids/Fatty acids | g | 0.66–3.70 | b, c, d, g |
| 59 | 2086 (HP-5) | Heptadecanoic acid (margaric acid) |
Acids/Fatty acids | <0.11 | c, d | ||
| 60 | 2095/2104/2130/2140/2144/2170 | Linoleic acid [(9Z,12Z)-octadeca-9,12-dienoic acid] |
Acids/Fatty acids | <0.32 | b, c, d | ||
| 61 | 2102/2141/2152/2175 | Oleic Acid [(Z)-octadec-9-enoic acid] |
Acids/Fatty acids | a: fat | <1.65 | b, c, d | |
| 62 | 2172/2178/2180/2188 | Stearic acid (Octadecanoic acid) |
Acids/Fatty acids | 0.16–1.60 | c |
The literature RI (RIlit) has been retrieved from the NIST database [35] based on van Dool and Kratz calculation [36] on a HP-5MS column, unless otherwise stated. The superscript std in the third column denotes that an external standard compound has been used for the identification. Asterisks in two adjacent rows denote that those compounds co-elute and thus the percentage is given in the first row. Small letters indicate the references: a: [37]; b: [8]; c: [7]; d: [38]; e: [39]; f: [40]; g: [6]; h: [41]; i: [42]; j: [43]; k: [44]; l: [45].