J. Agric. Food Chem. 1996, 44, 3913−3918
3913
Aroma Compounds from Aqueous Solution of Haze (Rhus succedanea) Honey Determined by Adsorptive Column Chromatography Mitsuya Shimoda,* Yin Wu, and Yutaka Osajima Department of Food Science and Technology, Faculty of Agriculture, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812, Japan
Aroma concentrate separated from an aqueous solution of Haze honey by adsorptive column chromatography had a stronger aroma intensity than that separated by a combination of a preliminary extraction with acetone and separation of volatile compounds from acetone extract by steam distillation extraction. A total of 130 compounds were identified, including 27 alcohols, 19 aldehydes, 9 ketones, 12 esters, 8 acids, 35 hydrocarbons, 10 furanoids or pyranoids, and 10 miscellaneous compounds. The sensory importance of the volatile compounds was investigated by sniffing the fractions separated by preparative gas chromatography. As a result, benzeneacetaldehyde, linalool, phenethyl alcohol, p-cresol, p-anisaldehyde, methyl-p-anisaldehydes, trimethoxybenzene, 5-hydroxy-2-methyl-4H-pyran-4-one, and lilac aldehydes seemed to contribute to Haze honey aroma. Keywords: Aroma compounds; flavor components; honey; column concentration Honey is a nutritious product with organoleptic importance and a distinctive aroma. Several studies on the volatile compounds of honey have been carried out since the work of Dorrscheidt and Friedrich (1962). For example, Merz (1963) dealt with the ether extract from honey and tried to correlate the quality of honey with amounts of 5-(hydroxymethyl)furfural (HMF) and of the higher boiling volatile components. Cremer and Reidmann (1964) extracted honey volatiles in a stream of hydrogen at 70-90 °C, and identified 80 volatiles. Graddon et al. (1979) extracted honey volatiles with dichloromethane from unifloral Austrian honeys and identified almost 100 components with varying degrees of certainty, including phenylacetaldehyde, benzyl alcohol, 2-phenylethanol, linalool oxide, and hexenyl butyrate. Aroma compounds and methylated compounds in extracts from many types of New Zealand unifloral honeys have been analyzed (Tan et al., 1988, 1989, 1990; Wilkins et al., 1993). Recently, organic extractives from Leatherwood honey were analyzed to investigate the effect of maturation of Leatherwood flowers and leaves on the volatile components (Rowland et al., 1995). There are several approaches to evaluate the potent aroma compounds of honey. The concentrations of aromatic acid, aldehydes, hydrocarbons, phenols, and N- or S-containing compounds in honey were compared with their odor threshold values (Steeg and Montag, 1987, 1988; Hausler and Montag, 1990a,b, 1991). Twenty-one compounds with high factors of dilution (FD) were designated as contributors to the aroma of linden honey (Blank et al., 1989) by aroma extract dilution analysis. It was reported that the aroma concentrate prepared by the SDE method coupled with acetone extrction had a stronger honey-like odor than those prepared by direct steam distillation extraction (SDE), by continuous extraction with Soxhlet apparatus, and by direct extraction with ethyl acetate (Bicchi et al., 1983). Recently, * Author to whom correspondence should be addressed. S0021-8561(96)00116-1 CCC: $12.00
Bouseta et al. (1995) optimized the method of Bicchi et al. (1983); that is, pre-extraction with dichloromethane under an inert atmosphere was followed by optimized SDE operation. We have applied a column extraction method to the separation of volatile compounds from infusions of green tea (Shimoda et al., 1995) and black tea (Shigematsu et al., 1994), wherein their aromas degrade during distillation even under reduced pressure, and from sake (Sakamoto et al., 1993), wherein ethyl alcohol (∼15 v/v%) disturbs a quantitative separation of volatile compounds. Separation of volatile compounds from the sugar matrix of honey is the most important procedure because it greatly influences the quality of the aroma concentrate. The aim of present paper was to use the column extraction method to separate the volatile compounds from honey and determine the contributors to the aroma of Haze (Rhus succedanea) honey, which are volatiles that have not yet been investigated. MATERIALS AND METHODS Materials. The Haze honey sample (1994 season) was purchased directly from a beekeeper in Nagasaki prefecture. Cyclohexanol, diethyl ether, and anhydrous sodium sulfate were from Nacalai Tesque, Inc. (Kyoto, Japan). Methanol was purchased from Wako Pure Chemical Industries Company, Ltd. (Osaka, Japan) and was purified by passing it twice through a column (50 × 3 cm i.d.) packed with activated charcoal (analytical grade). Porapak type Q (50-80 mesh) was from MIllipore Corp. (Milford, MA). 1-Phenyl-2-butanol and trimethoxybenzenes were from Aldrich Chemical Corp. (Milwaukee, WI). Isolation of Volatile Flavor Compounds. Column Extraction Method. The 100-g honey sample was dissolved in 500 mL of deionized water, and 10 µL of 1.0% cyclohexanol solution was added to the sample solution as an internal standard. The sample solution was passed through a column (2 cm i.d. × 10 cm) packed with porous polymer beads (Porapak Q), and then the column was washed with 50 mL of deionized water to remove water-soluble constituents. Adsorbed volatiles were eluted with 80 mL of diethyl ether, and the eluate was dried over anhydrous sodium sulfate and concentrated to ∼200 µL.
© 1996 American Chemical Society
3914 J. Agric. Food Chem., Vol. 44, No. 12, 1996
Shimoda et al.
Table 1. Volatile Compounds Separated by Column Extraction Method from Haze Honey threshold value peak
KIa
compound
concentration (ppb)
1 2 3 4 5 6 7 8 9 10 11 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75
882 889 921 975 985 992 1000 1007 1020 1022 1036 1040 1048 1072 1081 1089 1100 1106 1136 1140 1142 1147 1160 1176 1183 1186 1187 1200 1207 1212 1226 1228 1234 1246 1259 1265 1272 1285 1289 1291 1300 1322 1341 1345 1356 1361 1366 1371 1388 1397 1400 1404 1410 1448 1451 1461 1467 1477 1495 1500 1514 1522 1534 1541 1547 1556 1560 1564 1571 1573 1576 1588 1600 1613
ethyl acetat ?-methyloctane 2-propanol 2-pentanone methyl butyrate 1,2-dimethoxyethanec,d n-decane methyl 2-methylbutyrate trichloromethane 2-butanol n-decene toluene 3-methyldecane butyl acetate n-hexanal unknown n-undecane 3,7-octadien-2-onec,d 1,4-dimethylbenzene 3-methyl-2(3H)-furanone 1,3-dimethylbenzene 4-methylundecanec 2-methylcyclopentyl acetatec,d 1,2,3-trimethylbenzene 2-heptanone n-heptanal 1,2-dimethylbenzene n-dodecane 2-methylbutanol n-propylbenzene 1-ethyl-4-methylbenzene 1-ethyl-3-methylbenzene ethyl 2-oxopropanoate 3,4-dimethyl-1-decenec ethenylbenzene 1-methylethylbenzene 4-penten-2-old 1,2,4-trimethylbenzene 3-hydroxy-2-butanone n-octanal n-tridecane 2-octanol 1-ethyl-2-methylbenzene 2,3-butanediol tetrahydro-3,7-dimethyl-2H-pyran-2-onec,d 1,3-bis(1-methylethyl)benzenec,d 3-methyltridecane 4-ethyl-1,2-dimethylbenzene (Z)-3-hexenold n-nonanal n-tetradecane 1,4-bis(1-methylethyl)benzenec,d cyclohexanol (internal standard) linalool oxide (trans-furanoid) acetic acid octyl acetate furfural linalool oxide (cis-furanoid) 2-ethylhexanolc,d n-pentadecane acetylfuran trans-decahydronaphthalene benzaldehyde 2,3-butanediol linalool lilac aldehydec unknown lilac aldehydec 2-methylpropanoic acid 5-methyl-2-furfural 1,3-butanediol lilac aldehydec n-hexadecane 2,6-dimethyl-1,3,7-octatrien-6-ol
269 21 253 28 61 trf 11 74 35 34 84 54 44 27 28 55 72 37 19 30 15 6 61 11 22 10 8 48 55 12 7 17 5 6 3 7 6 21 19 tr 281 3 9 9 21 8 6 2 21 95 71 4 1000 2461 358 tr 18 1967 10 71 9 8 136 633 113 31 10 28 76 tr 29 30 37 113
in airb (ppb,v/v) 263
1500 4.68
in water (ppb) 5000l
43m
32 1700 1550 195 13.8
66n 4.5o
490 324
4.79 851 229 115
140p 2q
155 1.35
0.7r
5.62
2.24
70o 1s
7000t 145 776
12u 3000p 6000t
245 10000p 41.7
3r
53.7
6v
19.5
J. Agric. Food Chem., Vol. 44, No. 12, 1996 3915
Aroma Compounds from Honey Table 1 (Continued)
threshold value peak
KIa
compound
76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149
1620 1623 1631 1646 1662 1669 1673 1694 1797 1700 1705 1706 1711 1721 1724 1731 1734 1745 1769 1779 1782 1786 1796 1800 1808 1821 1823 1836 1843 1853 1856 1866 1870 1876 1886 1894 1903 1920 1923 1942 1951 1955 1960 1976 1982 1989 1993 1998 2001 2016 2020 2030 2037 2044 2048 2060 2073 2076 2082 2090 2099 2128 2139 2179 2184 2191 2200 2206 2216 2226 2318 2347 2354 2380
1-p-menthen-9-al borneol butanoic acid benzeneacetaldehyde furfuryl alcohol 5-ethenyl-5-methyl-2(3H)-furanonec,d 3-methylbutanoic acid (Z)-2-hexenyl acetate γ-octalactoned n-heptadecane R-terpineol azulened 4-ethylbenzaldehyded isomer of linalool oxide 1,2,3,4-tetrahydro-2,7-dimethylnaphthalene 4-(1-methylethyl)benzaldehydec unknowng linalool oxide (trans-pyranoid) linalool oxide (cis-pyranoid) methyl salicylate 2,2,6-trimethyl-1,4-cyclohexanedioned unknowng 2,3-butanedione monooximec,d n-octadecane N,N-dibutylacetamidec,d methyl 2,4-dimethylbenzoatec,d tetrahydro-2-furanmethyl acetated 1-(3,4-dimethylphenyl)ethanoned 2-methyl-1-propenylbenzenec,d 2,5-hexanediolc,d hexanoic acid p-guaiacol exo-2-hydroxycineolec,d 1-(2,4-dimethylphenyl)ethanoned benzenemethanol unknown unknown 2,6-bis(1,1-dimethylethyl)-4-methylphenole phenethyl alcohol a sesquiterpene (E)-3-hexenyl hexanoated unknown unknownh unknowni unknown unknowni unknownh unknownj furyl hydroxymethyl ketonec,d p-anisaldehyde unknownj 5-hydroxy-2-methyl-4H-pyran-4-oned unknownk unknownk octanoic acid trimethoxybenzene 1,5-bis(1,1-dimethylethyl)-3,3-dimethyl-bicyclo[3.1.0]hexan-2-onec,d 2-hydroxybenzaldehyde unknownh 2,6-dimethyl-?,?-octadiene-?,?-diol unknownh nonanoic acid unknown unknown 2,6-dimethyl-?,?-octadiene-?,?-diol 4-methoxybenzenemethanold n-docosane 3,5-dihydroxy-2-methyl-4H-pyran-4-oned 2,6-dimethyl-?,?-octadiene-?,?-diol trans-p-menth-8-ene-1,2-diolc 3-hydroxybenzeneethanolc,d unknownl unknownl 1-phenyl-2-butanold
concentration (ppb) in airb (ppb,v/v) in water (ppb) 2 tr 40 49 98 140 210 tr 79 35 tr 23 31 25 5 21 tr 3407 3665 65 tr 62 6 29 47 tr 72 326 24 5 39 17 18 174 3932 484 83 4077 820 11 804 57 790 257 116 58 481 61 208 560 642 42 203 273 127 25 201 18 615 611 1964 396 240 3561 796 961 592 404 1834 49 40898 3928 656 9667
38.9
2.45
200w 4l 1900p 750w
7 46
3600t 5400t 43.7
12.6 1
3v 20000v
17
33.1
3.98
7.41
1000o
3916 J. Agric. Food Chem., Vol. 44, No. 12, 1996
Shimoda et al.
Table 1 (Continued) threshold value peak
KIa
compound
concentration (ppb)
150 151 152 153
2410 2436 2442 2490
5-(hydroxymethyl)-2-furfural 1-phenyl-1-pentanolc,d cis-p-menth-8-ene-1,2-diolc benzeneacetic acid
2769 19754 563 2717
in airb (ppb,v/v)
in water (ppb)
a Modified Kovats indices calculated for DB-wax capillary column on the GC system. b Devos et al., 1990. c Tentatively identified by mass spectrum. d Reported as honey constituents for the first time. e Antioxidant/stabilizer in ethyl ether. f tr represents concentration of
