5880
J. Agric. Food Chem. 2001, 49, 5880−5882
Volatile Flavor Constituents of Acerola (Malpighia emarginata DC.) Fruit Jorge A. Pino*,† and Rolando Marbot‡ Food Industry Research Institute, Carretera del Guatao km 31/2, C. Habana 19200, Cuba, and National Center for Scientific Research, C. Habana, Cuba
Volatile components were isolated from acerola fruit by simultaneous steam distillation-solvent extraction according to the Likens-Nickerson method and analyzed by GC and GC-MS methods. One hundred fifty constituents were identified in the aroma concentrate, from which furfural, hexadecanoic acid, 3-methyl-3-butenol, and limonene were found to be the major constituents. The amounts of esters, 3-methyl-3-butenol, and their various esters were thought to contribute to the unique flavor of the acerola fruit. Keywords: Acerola; vitamin C; flavor; fruit; red; tree; vitamin INTRODUCTION
The flavor of tropical fruits is of increasing interest to consumers worldwide. This is true for fruits with a high market potential around the globe, such as mango and guava, but many fruits which are so far only regionally important are also catching the attention of flavor researchers, due to their unusual sensory properties. The acerola fruit comes from the acerola tree (Malpighia emarginata DC., syn. Malpighia punicifolia L.), which is native to the Caribbean islands, Central America, and the Amazonian region. The red fruit itself is oval in form, and is commonly named the acerola or Barbados cherry. This fruit is very appreciated for its flavor and color, but its most important characteristic is the high vitamin C content. Because of these aspects, the cultivation and consumption of this fruit represents an attractive source of income. The chemical composition of acerola fruit has been published elsewhere (1-3), but there is little information about the composition of its volatile flavor constituents (4, 5). Therefore, in the study presented here, we investigated the volatile flavor constituents of this fruit cultivated in Cuba. EXPERIMENTAL SECTION Materials. Mature fruits were collected from a commercial plantation near Havana and immediately processed. Pure reference standards of acetaldehyde, ethyl formate, 2-methylfuran, ethyl acetate, 3-methylbutanal, 2-ethylfuran, ethyl propanoate, 2-pentanone, methyl butanoate, isobutyl acetate, 2-butanol, 2-methyl-3-buten-2-ol, ethyl butanoate, 3-hexanone, ethyl 3-methylbutanoate, butyl acetate, hexanal, methyl pentanoate, 2-methyl-2-butenal, β-pinene, ethylbenzene, ethyl pentanoate, butanol, m-xylene, myrcene, R-terpinene, methyl hexanoate, 3-methylbutanol, 1,8-cineole, (E)-2-hexenal, ethyl hexanoate, 3-methyl-3-butenol, γ-terpinene, p-cymene, hexyl acetate, acetoin, 2-octanone, cyclohexanone, octanal, 2,6dimethylpyrazine, 2,5-dimethylpyrazine, ethyl heptanoate, hexanal, (Z)-3-hexenol, 3-octanol, nonanal, cyclohexanol, (Z)† ‡
Food Industry Research Institute. National Center for Scientific Research.
2-hexenol, butyl hexanoate, ethyl octanoate, 1-octen-3-ol, heptanol, menthone, furfural, 2-ethylhexanol, decanal, 2-acetylfuran, benzaldehyde, linalool, octanol, menthyl acetate, isophorone, methyl benzoate, phenylacetaldehyde, acetophenone, furfuryl alcohol, ethyl benzoate, salicylic aldehyde, neral, R-terpineol, carvone, geranial, methyl salicylate, 2-tridecanone, trans-carveol, hexanoic acid, geranylacetone, cis-carveol, benzyl butanoate, safrole, (E)-β-ionone, γ-nonalactone, (E)-nerolidol, octanoic acid, ethyl (E)-cinnamate, γ-decalactone, nonanoic acid, tetradecanol, ethyl hexadecanoate, decanoic acid, (E,E)farnesol, hexadecanol, dodecanoic acid, ethyl linoleate, ethyl linolenate, (E)-phytol, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, and oleic acid were purchased from Aldrich (Steinheim, Germany). Diacetyl, 3-methylbutanal, limonene, (E)-β-caryophyllene, R-humulene, 2-phenylethanol, and octadecanol were obtained from Sigma (Steinhem, Germany), and isobutanal, (Z)-linalool oxide, and terpinen-4-ol were purchased from Fluka (Buchs, Switzerland). Diethyl ether was purchased from Merck (Darmstadt, Germany). Sample Preparation. After addition of an internal standard (methyl undecanoate, 2 mg), pulp (200 g) was blended with distilled water (800 mL) and simultaneously distilled and extracted for 90 min in a Likens-Nickerson microapparatus with 25 mL of diethyl ether (previously redistilled and checked with regard to purity). The volatile concentrate was dried over anhydrous sulfate and concentrated to 0.6 mL on a KudernaDanish evaporator and, then, to 0.2 mL with a gentle nitrogen stream. GC and GC-MS Analyses. A Konik 2000 gas chromatograph equipped with a 30 m × 0.25 mm (0.25 µm film thickness) DB-1 fused silica capillary column and a flame ionization detector (FID) was used. The injector and detector temperatures were 250 °C. The oven temperature was held at 60 °C for 10 min and then increased to 280 °C at a rate of 2 °C/min and held for 40 min. The carrier gas (hydrogen) flow rate was 1 mL/min. GC-MS analyses were carried out on a Hewlett-Packard model 5890 series II or model 6890 series II gas chromatograph coupled to an HP 5972 or HP 5973 mass spectrometer. They were fitted with a CP-SIL-5CB Chrompack fused silica column (50 m × 0.32 mm, 0.4 µm film thickness) or an AT-WAX Alltech fused silica column (60 m × 0.32 mm, 0.25 µm film thickness). The temperature was increased from 60 (10 min) to 280 °C at a rate of 3 °C/min and held for 60 min in the apolar column and from 65 (10 min) to 250 °C at a rate of 2 °C/min and held for 60 min in the polar column. The injector temperature was 250 °C; the transfer line temperature was 250 °C, and the carrier gas (helium) flow rate was 1 mL/min.
10.1021/jf010270g CCC: $20.00 © 2001 American Chemical Society Published on Web 11/10/2001
Volatile Flavor Constituents of Acerola Fruit
J. Agric. Food Chem., Vol. 49, No. 12, 2001 5881
Table 1. Volatile Constituents of Acerola compound
RI1a
RI2a
IDc
acetaldehydeb ethyl formateb 2-methylfuranb ethyl acetate isobutanalb 3-methylbutanalb ethanolb 2-ethylfuranb ethyl propanoateb 2-pentanone diacetylb methyl butanoate methyl 2-methylbutanoateb isobutyl acetateb 2-butanolb R-thujeneb 2-methyl-3-buten-2-olb ethyl butanoate ethyl 2-methylbutanoateb 3-hexanoneb ethyl 3-methylbutanoateb butyl acetateb hexanal methyl pentanoate 2-methyl-2-butenalb β-pineneb ethylbenzeneb ethyl pentanoate butanolb m-xyleneb myrceneb R-phellandreneb R-terpineneb methyl hexanoate 3-methyl-3-butenyl acetate limonene 3-methylbutanol 1,8-cineoleb β-phellandreneb (E)-2-hexenal ethyl hexanoate 3-methyl-3-butenol γ-terpineneb 3-methyl-3-butenyl propanoate p-cymene hexyl acetateb acetoin terpinoleneb 2-octanoneb cyclohexanoneb octanalb ethyl (Z)-3-hexenoateb (Z)-3-hexenyl acetate 2,6-dimethylpyrazineb 2,5-dimethylpyrazineb ethyl heptanoate 2-methyl-2-hepten-6-oneb 3-methyl-3-butenyl butanoate (Z)-3-hexenyl (E)-2-hexenoateb hexanol allyl hexanoateb (Z)-3-hexenol (Z)-3-hexenyl propanoateb 3-octanol nonanalb cyclohexanolb (Z)-2-hexenol butyl hexanoateb hexyl butanoate ethyl octanoate (Z)-linalool oxyde (furanoid)b 1,4,4,7a-tetramethyl-4,5-dihydroindeneb 1-octen-3-ol heptanolb menthoneb furfuralb
669 728 815 828 830 867 873 928 943 951 958 989 989 994 1019 1021 1024 1040 1040 1054 1056 1067 1075 1093 1094 1124 1128 1131 1154 1154 1167 1173 1182 1187 1187 1192 1195 1206 1224 1244 1244 1252 1258 1264 1272 1274 1294 1275 1279 1290 1306 1306 1311 1324 1326 1330 1331 1337 1358 1367 1370 1380 1382 1386 1389 1402 1405 1424 1424 1432 1437 1443 1448 1452
381 481 710 581 500 629 443 676 681 653 538 696 754 741 565 918 582 781 829 756 824 791 780 804 704 965 856 881 619 847 981 993 1006 904 856 1016 700 1022 1016 817 981 705 1046 958 1007 993 667 1076 974 1096 981 984 984 880 888 1081 962 1047 847 1062 827 1079 981 1089 856 837 1165 1177 1181 1068 1199 964 949 1131 795
A A A A A A A C A A A A B A A B A A A A A A A A A A A A A A A B A A A A A A B A A A A C A A A B A A A A A A A A C C C A C A B A A A A A B A A C A A A A
concn (ppm) 0.01 td t 0.04 t t 0.09 t t t t 0.02 t t t t 0.01 0.02 t t t t 0.02 t t t t t 0.02 0.02 0.01 0.01 0.01 0.36 0.12 0.68 t t 0.01 0.04 0.23 0.72 t t 0.01 t 0.01 t t t 0.01 t 0.03 t t 0.01 0.01 0.16 t 0.05 t 0.07 t 0.01 0.01 t 0.01 0.01 0.02 0.01 0.01 0.02 0.08 t 0.02 2.19
compound
RI1a
RI2a
IDc
2-ethylhexanolb decanal 2-acetylfuranb benzaldehyde 3-methyl-3-butenyl hexanoate 3-methyl-3-butenyl tiglateb linaloolb octanol menthyl acetateb isophoroneb 3-methyl-2-butenyl hexanoateb (E)-β-caryophylleneb terpinen-4-olb hexyl hexanoate β-cyclocitralb methyl benzoateb edulan IIb 2,5-epoxy-6,8-megastigmadieneb phenylacetaldehyde acetophenone methyl 3-hydroxyhexanoate (Z)-3-hexenyl hexanoateb furfuryl alcohol ethyl benzoate R-humuleneb (E)-2-hexenyl hexanoateb salicylic aldehydeb neralb limonene-4-olb R-terpineolb 1,5-p-menthadien-8-olb carvoneb geranialb (E,E)-R-farneseneb methyl salicylateb cuminaldehydeb 2-tridecanoneb hexyl octanoateb (E)-β-damascenone trans-carveolb ethyl (E,Z)-2,4-decadienoateb hexanoic acid geranylacetoneb (Z)-3-hexenyl octanoateb cis-carveolb benzyl butanoateb safroleb 2-phenylethanol (E)-β-ionone unknown 1e 3-hydroxy-2-pyranone γ-nonalactoneb (E)-nerolidolb octanoic acid unknown 2f ethyl (E)-cinnamateb γ-decalactone nonanoic acid tetradecanolb 4-vinylguaiacol isopropyl hexadecanoateb ethyl hexadecanoateb (E)-dihydrofarnesolb decanoic acidb (E,E)-farnesolb γ-dodecalactoneb hexadecanol dodecanoic acid ethyl linoleateb ethyl linolenateb octadecanolb (E)-phytolb tetradecanoic acid pentadecanoic acid hexadecanoic acid oleic acidb
1474 1488 1489 1508 1522 1528 1530 1551 1551 1571 1572 1576 1585 1597 1604 1607 1605 1620 1625 1643 1643 1645 1650 1651 1651 1654 1658 1663 1664 1679 1709 1711 1711 1732 1739 1747 1796 1796 1798 1818 1818 1825 1828 1837 1848 1849 1865 1888 1892 1903 1997 2003 2008 2032 2092 2112 2116 2135 2144 2166 2210 2224 2239 2252 2308 2333 2342 2444 2488 2542 2546 2557 2632 2791 2861 3095
1019 1186 878 923 1213 1083 1281 1281 1090 1244 1410 1157 1371 1196 1066 1328 1322 1009 1031 1026 1364 819 1141 1443 1370 1011 1215 1151 1171 1131 1211 1245 1501 1162 1211 1480 1571 1362 1196 1446 956 1434 1561 1208 1312 1265 1081 1470 1318 959 1325 1549 1151 1628 1430 1431 1260 1664 1280 2012 1981 1677 1360 1701 1640 1864 1561 2141 2145 2070 2101 1743 1844 1941 -
A A A A C C A A A A C A A B C A C C A A B B A A A C A A C A C A A C A C A B C A C A A C A A A A A C A A A A A A A C C A C A A B A A A A A A A A A A
concn (ppm) t 0.01 0.02 0.02 0.24 0.01 0.03 0.02 0.01 0.03 0.01 0.08 0.02 0.04 0.01 0.01 t 0.04 0.02 t 0.01 0.03 t t t t t 0.01 t 0.06 0.04 0.03 0.01 0.10 0.01 t t t 0.04 t 0.18 t t t t t t t t 0.16 0.22 0.04 0.03 0.01 0.09 0.01 0.01 t t t 0.05 t t t 0.07 0.01 0.09 0.03 t t 0.02 0.02 0.16 0.01 0.58 0.05
a RI and RI are retention indices on AT-WAX and CP-SIL-5CB capillary columns, respectively. b Reported for the first time. c The 1 2 reliability of the identification proposal is indicated by the following: A, mass spectrum and Kovats index agreed with standards; B, mass spectrum and Kovats index agreed with literature data; C, mass spectrum agreed with mass spectral database. d t means trace (
