J. Agric. Food Chem. 2001, 49, 5883−5887
5883
Characterization of Volatiles in Strawberry Guava (Psidium cattleianum Sabine) Fruit Jorge A. Pino,*,† Rolando Marbot,‡ and Carlos Va´zquez§ Food Industry Research Institute, Carretera del Guatao km 3 1/2, La Habana 19200, Cuba; National Center for Scientific Research, La Habana, Cuba, and National Botanical Garden, La Habana, Cuba
Volatile compounds were isolated from strawberry guava fruit by simultaneous steam distillationsolvent extraction according to Likens-Nickerson. Compounds were identified by capillary GC-MS and sensorially characterized by sniffing GC. Two hundred and four compounds were identified in the aroma concentrate, of which ethanol, R-pinene, (Z)-3-hexenol, (E)-β-caryophyllene, and hexadecanoic acid were found to be the major constituents. The presence of many aliphatic esters and terpenic compounds is thought to contribute to the unique flavor of the strawberry guava fruit. Keywords: Volatiles; strawberry guava; aliphatic esters; terpenic compounds INTRODUCTION
Among the many attractive and desirable attributes that create demand for fruits from the tropics and subtropics, their characteristic flavor is the most noticeable to consumers. In addition, these fruits are often inexpensive, extremely rich in vitamins, and can be used in a wide range of food products. Probably native to, at least, the coastal scrubs and forests of eastern Brazil, strawberry guava (Psidium cattleianum Sabine) belongs in the same botanical family (Mytaceae) as guava and is often described as being more aromatic than that fruit. There are two known cultivars, the properly strawberry guava which is red and the yellow fruit (var. Lucidum Hort.). The chemical composition of strawberry fruit has been published elsewhere (1, 2), but there is little quantitative information about its volatile flavor constituents and their sensory significance (3, 4). This is the subject of the present study. EXPERIMENTAL PROCEDURES Materials. Fruits from the red cultivar were collected mature from the National Botanical Garden near Havana and immediately processed. Diethyl ether was purchased from Merck (Darmstadt, Germany). Sample Preparation. After addition of an internal standard (methyl undecanoate, 2 mng), pulp (200 g) was blended with distilled water (800 mL), adjusted to pH 7, and simultaneously distilled and extracted for 90 min in a LikensNickerson microapparatus with 25 mL of diethyl ether (previously redistilled and checked as to purity). The volatile concentrate was dried over anhydrous sulfate and concentrated to 0.6 mL in a Kuderna-Danish evaporator with a 12 cm Vigreux column and then to 0.2 mL with a gentle nitrogen stream. GC and GC-MS Analyses. A Konik 2000 GC 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. Injector and detector temperatures were both 250 °C. Oven temperature was held at 60 °C for 10 min and then †
Food Industry Research Institute. National Center for Scientific Research. § National Botanical Garden. ‡
raised to 280 °C at 2 °C/min and held for 40 min. Carrier gas (hydrogen) flow rate was I mL/min. These conditions were used for quantitative analysis, by the internal standard method. The recovery of the method was determined by the standard addition technique applied to a sample. The analytes (Rpinene, limonene, ethyl hexanoate, 1- hexanol, (Z)-3-hexenol, ethyl octanoate, (E)-β-caryophyllene and R-terpineol) were added at two different concentrations. The average recoveries were about 89-102% and their relative standard-deviations were lower than 10%. GC-MS analyses were performed on a Hewlett-Packard model 5890 series II or model 6890 series IIGC 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). Temperature programming was as follows: from 60 °C (10 min) to 280 °C at 3 °C/min and held for 60 min in the apolar column and from 65 °C (10 min) to 250 °C at 2 °C/min and held for 60 min in the polar column; injector temperature was 250 °C; transfer line temperature, 250 °C and carrier gas (helium) flow rate, 1 mL/min. Mass spectra were obtained at 70 eV. Linear retention indices were calculated against those of n-paraffins (5). Components identification was carried out by comparing the relative retention indices and mass spectra of 3 reference compounds in both columns. Mass spectra of published data were also compared (6, 7). GC Sniffing Analysis. Odor assessments were carried out using a Hewlett-Packard model 5890 series II GC equipped with a thermal conductivity detector (TCD). Separations were done with a methyl siloxane HP-1 fused silica column (30 cm × 0.53 mm, 2.65 µm film thickness). An injector temperature of 250 °C, a detector temperature of 280 °C, and an oven temperature program of 60 °C to 280 °C at 3 °C/min were used. Sample size for each injection was approximately 0.5-1 µL.. RESULTS AND DISCUSSION
The volatile constituents of strawberry guava fruit were obtained by simultaneous steam distillationsolvent extraction and analyzed by GC and GC-MS using fused silica capillary columns. Table 1 shows the identified compounds and the sensory description of the corresponding peaks at the sniffing port of the GC. Two hundred and four compounds were identified in the aroma concentrate. Shiota et al. (3) identified 35 compounds in the fruits of red
10.1021/jf010414r CCC: $20.00 © 2001 American Chemical Society Published on Web 11/30/2001
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Table 1: Volatile Compounds of Strawberry Guava compound acetaldehyde methyl acetatec butanalc ethyl acetate ethanol isopentanalc ethyl propanoatec ethyl isobutanoate propyl acetatec 2-pentanone pentanalc methyl butanoatec 4-methyl-3-penten-2-onec isobutyl acetatec R-pinene ethyl butanoate 3-hexanonec R-fenchenec camphenec butyl acetatec hexanal isobutanol ethyl carbonatec 2-pinenec 2-pentanolc isoamyl acetate p-xylene ethyl pentanoatec 1-butanol m-xylene δ-3-carenec 1-penten-3-olc myrcene R-phellandrenec 1(7),8-p-menthenec 1-pentyl acetatec R-terpinene 2-heptanone o-xylene methyl hexanoatec limonene isopentanol 1,8-cineolec β-phellandrenec cis-anhydro linalool oxidec 2-methylbutanolc (E)-2-hexenal ethyl hexanoate (Z)-β-ocimene trans-anhydro linalool oxidec γ-terpinene (E)-β-ocimene styrenec 2-heptyl acetatec isopentyl butanoatec p-cymene hexyl acetate acetoin terpinolene octanalc isopentyl pentanoatec ethyl (E)-3-hexenoatec ethyl (Z)-3-hexenoatec (E)-3-hexenyl acetate 2-heptanolc (Z)-2-pentenolc (Z)-3-hexenyl acetate (E)-2-heptenalc (Z)-2-hexenyl acetate 2-methyl-2-hepten-6-onec ethyl lactatec 1-hexanol isobutyl hexanoatec (E)-3-hexenol isoprenyl pentanoatec (E,E)-alloocimenec
retention RI1 669 724 813 825 854 864 925 930 941 944 950 955 970 986 1012 1025 1037 1045 1052 1052 1062 1064 1083 1091 1094 1107 1117 1125 1126 1132 1138 1141 1155 1157 1158 1161 1167 1172 1174 1175 1187 1187 1193 1196 1199 1204 1206 1225 1228 1233 1236 1244 1245 1255 1255 1259 1265 1273 274 1276 1288 1291 1295 1298 1301 1302 1307 1326 1327 1330 1333 1343 1346 1364 1365 1366
indexa RI2 381 511 600 581 377 617 681 726 686 653 657 696 741 925 781 756 937 940 791 772 592 747 965 664 855 852 881 619 847 1001 981 993 993 893 1006 859 863 904 1016 700 1022 1016 979 708 817 981 1026 993 1046 1037 871 1022 1041 1007 993 667 1076 981 1090 981 982 983 887 734 984 930 993 962 787 849 1137 823 1113 -
concentration (ppm)
odor description
tb 0.03 0.09 2.91 9.70 t 0.03 t t 0.39 t 0.02 t 0.03 6.44 0.98 t 0.03 0.04 0.04 0.66 0.14 0.03 0.36 0.19 0.19 t t 0.18 0.05 0.08 0.09 4.01 t 0.02 t t 0.37 0.05 0.07 2.06 0.67 0.47 0.10 t t 0.27 2.63 3.45 t 0.73 1.36 t t 0.05 0.24 0.58 0.48 1.77 t t 0.11 0.01 0.03 t t 0.91 t 0.02 0.01 0.34 3.58 t 0.13 t 0.08
overripe, somewhat fruity estery, fruity
fruity ethereal-fruity ethereal-fruity
fruity pine-like fruity
ethereal-fruity fatty-green sweet woody winy-ethereal banana, fruity ethereal-fruity chemical
sweet-balsamic
fruity-spicy citrus fruity-winey camphoraceous
fruity, green fruity-winey floral, herbaceous herbaceous-citrus floral, herbaceous
citrus sweet fruity buttery pine-like pineapple, fruity fruity fruity, green fruity, green
ethereal-buttery fatty, fruity grassy, green
Volatiles in Strawberry Guava Fruit
J. Agric. Food Chem., Vol. 49, No. 12, 2001 5885
Table 1 (Continued) compound
retention RI1
indexa RI2
concentration (ppm)
(Z)-3-hexenol 2-nonanone methyl octanoatec nonanal (E,E)-2,4-hexadienal (Z)-2-hexenol butyl hexanoatec hexyl butanoate ethyl octanoate 1,3,8-p-menthatrienec 1-heptanolc acetic acid isopentyl hexanoatec (Z)-3-hexenyl butanoate furfural cis-linalool oxide (furanoid) (Z)-3-hexenyl 2-methylbutanoatec 1-octyl acetatec R-ylangenec R-copaene ethyl (E)-3-octenoatec 2-acetylfuran ethyl sorbatec ethyl 3-hydroxybutanoatec 2-nonanol benzaldehyde (E)-2-nonenaIc R-gurjunenec 4-undecanonec linalool 1-octanol linalyl acetate isobutanoic acidc cis-2-p-menthene-1-olc β-longipinenec bomyl acetatec endo-fenchol terpinen-4-ol cisR-bergamotenec (E)-β-caryophyllene aromadendrenec 1-hexyl hexanoate phenylacetaldehyde isopentanoic acidc ethyl decanoate δ-patchoulenec (E)-2-decenalc (Z)-3-hexenyl hexanoate γ-patchoulenec R-humulene allo-9-aromadendrenec 4,11-selinadienec limonene-4-olc R-terpenyl acetatec γ-muurolenec R-terpineol borneolc germacrene-Dc eremophilenec R-selinenec R-muurolenec β-bisabolenec cadinenec δ-cadinenec β-maalienec (Z)-3-hexenyl heptanoatec 3,7(1 1)-selinadienec cubenenec R-cadinenec trans-chrysanthenyl acetatec 2-tridecanone phenylethyl acetate 5-decenyl acetatec trans-calamenenec ethyl dodecanoatec hexanoic acid
1368 1379 1381 1381 1400 1402 1404 1406 1425 1429 1443 1443 1447 1448 1448 1449 1462 1464 1467 1476 1483 1488 1490 1501 1505 1508 1509 1516 1518 1530 1544 1545 1556 1560 1561 1562 1565 1571 1573 1576 1589 1597 1612 1642 1625 1627 1637 1642 1648 1651 1653 1656 1664 1673 1673 1679 1680 1684 1697 1699 1704 1716 1727 1741 1750 1755 1760 1761 1766 1785 1791 1795 1805 1812 1824 1825
828 1077 1109 1089 877 847 1176 1173 1181 949 547 1238 1166 795 1068 1217 1189 1371 1374 1177 892 694 907 1084 923 1135 1405 1083 1054 1243 732 1104 1274 1094 1157 1414 1410 1437 1371 1009 816 1382 1452 1242 1364 1483 1443 1490 1410 1157 1335 1171 1151 1476 1486 1491 1491 1505 1508 1511 1462 1530 1531 1527 1480 1221 1515 1581 988
6.55 0.14 0.07 0.14 t 0.04 0.04 0.12 1.38 0.05 t 0.11 0.03 0.11 0.09 0.11 t t 0.14 0.60 t 0.05 t 0.10 0.05 0.05 t t 0.03 0.92 0.03 0.03 t t 0.07 0.09 0.09 0.27 t 10.25 0.07 0.33 t 0.04 1.04 t t 0.38 0.30 1.72 t 0.21 0.34 0.17 0.45 2.48 0.09 0.43 0.71 0.38 0.17 0.09 0.30 1.21 0.23 0.08 0.98 0.09 0.04 0.04 0.79 0.23 0.06 0.03 0.23 0.74
odor description grassy, green fruity-floral fatty-floral grassy fruity fruity-winey, sweet acid sweet-green burnt floral-woody
woody
tarry
floral floral buttery
spicy woody-spicy fruity-grassy sweet, oily
fruity-green woody woody woody herbaceous, sweet woody floral, sweet dry-woody woody woody woody dry-woody, spicy dry-woody, spicy woody woody
spicy, herbaceous rosy-fruity fatty-fruity acrid-acid
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Table 1 (Continued) compound β-vetivenec (Z)-3-hexenyl octanoatec R-calacorene 2-phenylethanol β-calacorenec 2-tridecanol 3-phenylpropyl acetate β-caryophyllene epoxide 1,4,9-cadalatrienec 3-hydroxy-2-pyranonec R-humulene epoxide Ic 2-pentadecanone R-humulene epoxide IIc (E)-nerolidol β-caryophyllene hydratec cubenol epi-cubenolc viridiflorolc (Z)-methyl isoeugenol (E)-methylisoeugenol cubebolc 2-pentadecanolc ethyl (E)-cinnamate γ-eudesmolc T-cadinol T-muurololc δ-cadinolc R-eudesmolc methyl hexadecanoatec β-eudesmol R-cadinol 2-hexadecanonec R-11-selinene-4-olc ar-himachalenec ethyl hexadecanoatec decanoic acidc 2-hexadecanol caryophyllenolc (E)-isoeugenol undecanoic acidc methyl octadecanoatec 2-octadecanonec ethyl stearatec dodecanoic acidc ethyl linoleatec ethyl linolenatec phytol benzyl benzoate tetradecanoic acidc pentadecanoic acidc hexadecanoic acidc oleic acidc
retention RI1
indexa RI2
concentration (ppm)
1833 1837 1887 1888 1893 1899 1917 1954 1962 1967 1986 1997 2009 2015 2021 2030 2035 2053 2059 2062 2063 2097 2103 2136 2139 2154 2167 2186 2191 2195 2198 2202 2216 2220 2224 2242 2295 2299 2309 2346
1546 1561 1531 1081 1550 1490 1345 1578 1601 1578 1682 1549 1553 1618 1621 1587 1420 1460 1500 1690 1443 1620 1633 1622 1631 1613 1590 1628 1632 1563 1981 1360 1794 1614 1460
2402 2424 2448 2491 2555 2571 2579 2624 2756 2862 2933
2181 1561 2141 2145 2066 1743 1844 1952 1930
0.13 0.14 0.87 0.23 0.16 0.92 0.03 1.16 0.05 0.17 0.08 0.55 0.27 0.25 0.70 0.15 0.62 0.09 0.05 0.05 0.15 0.53 0.10 0.19 0.60 0.86 1.07 0.42 0.11 0.29 1.04 0.09 0.55 1.34 0.19 0.14 0.08 0.95 t 0.05 t t t 0.32 0.19 0.11 0.02 0.02 1.22 0.12 8.25 0.12
odor description fruity-green dry-woody floral sweet-fruity spicy
spicy, herbaceous spicy sweet-woody
floral balsamic sweet-woody woody spicy spicy sweet-woody sweet-woody spicy woody woody
spicy
waxy
waxy
a RI and RI ) retention indices on AT-WAX and CP-SIL-5CB capillary column. b t ) trace (
