Characterization of Volatile Aroma Compounds from Red and Black

Characterization of Volatile Aroma Compounds from Red and Black Rice Bran Sukhontha Sukhonthara1,2, Chockchai Theerakulkait2 and Mitsuo Miyazawa1＊ 1 Department of Applied Chemistry, Faculty of Science and Engineering, Kinki University (Kowakae, Higashiosaka-shi, Osaka 577-8502, JAPAN) 2 Department of Food Science and Technology, Faculty of Agro-industry, Kasetsart University (Bangkok 10900, THAILAND)

Abstract: The volatile oils from red and black rice bran were obtained by hydrodistillation using diethyl ester and the components of that oil were analyzed by capillary GC-MS. The volatile components of essential oil from red and black rice bran were analyzed by GC and GC-MS. One hundred twenty-nine (129) of volatile compounds were identified in red and black rice bran. Myristic acid, nonanal, (E)-b- ocimene and 6, 10, 14-trimethyl-2-pentadecanone were main compounds in red rice bran, whereas myristic acid, nonanal, caproic acid, pentadecanal and pelargonic acid were main compounds in black rice bran. Guaiacol, presented at 0.81 mg/100 g in black rice bran, is responsible for the characteristic component in black rice.

Key words: red and black rice bran, volatile oil, hydrodistillation

1 INTRODUCTION papers, and antioxidant activity of purple black rice13). Red and Black rice, both found in Japan, are classified as Recently, the volatile aroma compounds of black rice have Oryza sativa L. The colored grains are cause by anto- been studied. Yang et al. studied volatile aroma compounds cyanins pigment giving the hulled rice a red and brownish in raw and cooked black rice found that 2-AP and guaiacol red appearance in red rice and dark purple color in black were major contributors to the unique character of black rice. Nowadays those two types of rice were gaining popu- rice14,15). However, the volatile components of red and black larity in Japan as functional food and often mixed with rice rice bran have not been reported. Therefore, the main to enhance the flavor, color, and nutritional value1). objective of this research was to identify and compare the Flavor in rice is considered of primary importance volatile components of red and black rice bran using gas affecting consumer preference. Several reports on the chromatography-mass spectrometry (GC-MS). volatile compounds of rice have been studied due to their typical flavor and odor. Rice bran, the outer brown layer that removed during the milling of brown rice, has been extensively studied, of which 4-vinylphenol was the main 2 METERIALS AND METHODS component having a characteristic unpleasant odor2-4). 2.1 Plant Many researchers have studied volatile compound in raw Red and black rice bran were cultivated in Shizuoka and and cooked rice, 2-acetyl-1-pyrroline (2-AP; popcorn aroma) Toyama prefecture of Japan, respectively. Both of them was reported as an important contributor to be the aroma were packed in polyethylene bags and stored at 5℃ until characteristic of rice5-9). Straw of rice also reported on used. volatile components, palmitic acid was the most abundant component, followed by hexahydrofarnesyl acetone and 2.2 Isolation of the volatile oil phytol10). Fifty grams of rice bran were hydrodistilled with a Reports on red and black rice are very few, studies only Likens-Nickerson-type apparatus using diethyl ether to the suppressive effect of the SOS-inducing activity11), obtain 17 mg (red rice bran) and 24 mg (black rice bran) of tyrosinase inhibitor of black rice bran12) in our previous yellowish green oil, which was dried over anhydrous sodi-

＊ Correspondence to: Mitsuo Miyazawa, Department of Applied Chemistry, Faculty of Science and Engineering, Kinki University, Kowakae, Higashiosaka-shi, Osaka 577-8502, JAPAN E-mail: [email protected] Accepted January 10, 2009 (received for review December 15, 2008) Journal of Oleo Science ISSN 1345-8957 print / ISSN 1347-3352 online http://www.jstage.jst.go.jp/browse/jos/

155 S. Sukhonthara, C. Theerakulkait and M. Miyazawa

um sulphate. bran. Hexanal has been reported as a volatile component of rice bran and probably cause an undesirable odor in enzy- 2.3 Gas chromatography (GC) matic hydrolyzed vegetable protein27,28). The absolute GC was carried out using a Hewlett Packard 5890 amounts of nonanal, octanal, 2-methylnaphtalene, (2E)- equipped with a flame ionization detector (FID) on two cap- decenal, benzaldehyde, 2-heptanone, 1-octen-3-ol, (2E)- illary columns, a J&W Scientific DB-5 (30 m×0.25 mm i.d., octenal, naphthalene, (2E)-nonenal, and (2E, 4Z)-decadienal film thickness 0.25 mm) and a GL Sciences TC-WAX (60 m of red rice bran was higher than black rice bran, whereas ×0.25 mm i.d., film thickness 0.25 mm). The column tem- the absolute amounts of n-pentanol of black rice bran was perature was programmed from 80 to 250℃ at a rate of 4℃ higher than red rice bran. Those compounds were consid- min–1 for 47 min. The injector and detector temperature ered the green and sweet odor-active compounds in white were 250 and 280℃, respectively. The flow rates of the car- and black rice14) and cooked black rice15). Therefore, the rier gas (He) were 1.00 mL min–1. Peak areas were quanti- green and sweet odor of red rice bran was stronger than ties with HP 3396B integrator on DB-5. one of black rice bran. Isovaleric acid, valeric acid, enantic acid and guaiacol were presented in black rice bran. Those 2.4 Gas chromatography-mass spectrometry (GC-MS) compound have been reported as odor threshold in water The GC-MS analysis was carried out with a Hewlett (OAVs) in the four cook rice cultivars; Aychade, Fidji, Packard 5972A. GC conditions were the same as previously Ruille, and Thai9). Guaiacol has been reported as the key described. The flow rates of the carrier gas (He) were also odorant in black rice; it also responsible for smoky or black the same. The detector interface temperature was set at rice-like aroma in cooked black rice and black rice14,15). 280℃, with the actual temperature in the MS source Therefore, the smoky odor of black rice bran was stronger reaching approximately 230℃ and the ionization voltage 70 than one of red rice bran. The relative proportion of aro- eV. matic hydrocarbon and heterocycle compounds of red rice bran was higher than black rice bran, whereas phenol com- 2.5 Identification and quantification of volatile component pounds of black rice bran was higher than red rice bran. In The components of the volatile oils were identified by aromatic rice, 2-acetyl-1-pyrroline (2-AP), a key aromatic direct comparison of their mass spectral pattern and reten- rice and cooked rice6,29), is the only volatile compound in tion index (RI) with those published in the literature16) and which the relationship between its concentration in rice by our previous work17-20). The quantitative composition of and sensory intensity has been established5). However, both oils was determined by GC (FID), by assuming the total of red and black rice bran were hardly found 2-AP. Yang et all the particular oil to be 100%. The quantitative analysis al.30) reported that removal of the bran, partial endosperm, was performed on the basis calibration curves for caproic and pigment quantitatively affected the volatile compounds acid25), (E)-b-ocimene39), guaiacol48), nonanal54), pelargonic formed in Ilpumbyeo (traditional white rice), Heugjinjubyeo acid75), pentadecanal111), myristic acid113), and 6,10,14- (black pigment), and Jeogjinjubyeo (red pigment) cooked trimethyl-2-pentadecanone117). These authentic samples rice, with certain volatiles higher in unmilled rice. The were used from our previous papers21-26). present of guaiacol, isovaleric acid, valeric acid, enantic acid, 2-nonenal, octanal, 2-methylnaphtalene, (2E)-decenal, benzaldehyde, 2-heptanone, 1-octen-3-ol, (2E)-octenal, naphthalene, (2E)-nonenal, (2E, 4Z)-decadienal, and n- 3 RESULTS AND DISCUSSION petanol may have been considered the odor-active com- The volatile oils collected by steam distillation from red pound in red and black rice bran. and black rice bran were obtained in yields of 0.034% and The quantification of the main compounds and charac- 0.048%, respectively. One hundred twenty-nine compo- teristic components from red and black rice bran was nents were determined by GC and GC-MS analysis (Table shown in Table 3. The main compounds of red rice bran 1), representing 95.01% (red rice bran) and 94.79% (black were myristic acid, nonanal, (E)-b-ocimene, and 6,10,14- rice bran) of total oil. The classification of rice bran sample trimethyl-2-pentadecanone, respectively, whereas black on the basis on the structure type is summarized in Table rice bran were myristic acid, nonanal, caproic acid, pen- 2. Acid compounds were the most abundant components of tadecanal, and pelargonic acid, respectively. The absolute volatile oil in red and black rice bran, following by aldehyde amounts of myristic acid and nonanal in black rice bran compounds. Marravel et al.9) reported that higher level of were higher than red rice bran. Nonanal was described as aliphatic aldehydes and acids in Thai (Asian scented sam- citrus and fatty odor in black rice14). Pentadecanal, slicky ple), attributed to lipid oxidation, and may be linked to odor of waxy and floral31), was found in black rice bran longer storage duration for market sample from Asia. The while 6, 10, 14- trimethyl-2-pentadecanone was found in level of hexanal in red rice bran was higher than black rice red rice bran. (E)-b-ocimene, presenting in red rice bran, bran, whereas linoleic acid hardly found in both of rice was responsible for wet, cloth and fruity odor32). Caproic

156 J. Oleo Sci. 58, (3) 155-161 (2009) Volatile Components of Red and Black Rice Bran

Table 1 Volatile Components from Red and Black Rice Bran. Rl1) Peak area (%)2) No Compound DB-5 TC-WAX Red rice bran Black rice bran 1 670 1149 n-butanol n.d. 0.06 2 767 1208 3-methyl-1-butanol n.d. 0.10 3 771 1305 n-pentanol 0.09 0.17 4 782 1083 2-hexanone 0.09 n.d. 5 790 1147 3-hexanol 0.18 0.06 6 795 1053 3-hexanone 0.06 n.d. 7 795 1216 2-hexanol 0.28 0.10 8 802 1103 hexanal 1.83 0.36 9 821 1213 2-methylpyridine＊＊ tr tr 10 827 1668 furfurylalcohol n.d. 0.25 11 836 1481 furfural n.d. 0.16 12 836 1687 isovaleric acid n.d. 0.48 13 855 1204 (2E)-hexenal＊＊ tr tr 14 858 1743 valericacid tr 0.33 15 871 1356 n-hexanol 0.65 1.72 16 892 1095 2-heptanone 0.19 0.08 17 902 1201 heptanal 0.39 0.23 18 936 1334 2-acetyl-1-pyrroline＊＊ tr tr 19 957 2008 phenol n.d. 0.08 20 960 1446 (2E)-heptenal 0.20 0.07 21 960 1508 benzaldehyde 0.34 n.d. 22 964 1570 5-methylfurfural n.d. 0.10 23 967 1456 n-heptanol 0.24 0.24 24 979 1396 1-octen-3-ol 0.34 0.32 25 984 1853 caproic acid 0.22 5.92 26 986 1321 2,3-octanedione 0.17 0.10 27 986 1348 6-methyl-5-hepten-2-one 0.19 0.21 28 991 1171 b-myrcene 0.21 n.d. 29 991 1281 2-octanone 0.06 n.d. 30 993 1243 2-pentyl-furan 2.11 0.36 31 999 1288 octanal 0.67 0.37 32 1001 1237 1,3,5-trimethylbenzene 0.08 n.d. 33 1014 1449 1,4-dichlorobenzene 0.43 0.35 34 1025 1287 p-cymene 0.24 n.d. 35 1027 1475 2-ethyl-1-hexanol 0.15 0.10 36 1029 1196 limonene 0.38 0.11 37 1037 1240 (Z)-b-ocimene 0.34 tr 38 1037 1408 3-octen-2-one 0.29 0.31 39 1050 1245 (E)-b-ocimene 3.30 0.30 40 1056 2012 o-cresol＊ tr tr 41 1060 1444 (2E)-octenal 0.74 0.32 42 1060 1960 2-acetylpyrrole n.d. 0.12 43 1068 1561 n-octanol 0.76 0.44 44 1073 1453 (Z)-linalool oxide 0.21 0.21 45 1076 1958 enantic acid tr 1.34 46 1076 2089 p-cresol＊ tr tr 47 1087 1490 (E)-linalool oxide 0.11 0.16 48 1089 1863 guaiacol n.d. 1.69 49 1090 1398 2-nonanone 0.08 0.06 50 1091 1534 3,5-octadien-2-one 0.22 0.15

157 J. Oleo Sci. 58, (3) 155-161 (2009) S. Sukhonthara, C. Theerakulkait and M. Miyazawa

Table 1 (Continued.) Rl1) Peak area (%)2) No Compound DB-5 TC-WAX Red rice bran Black rice bran 51 1097 1552 linalool 0.08 0.08 52 1100 1100 n-undecane tr 0.04 53 1101 1345 6-methyl-3,5-heptadien-2-one 0.18 0.33 54 1101 1410 nonanal 10.41 9.44 55 1114 1867 phenethyl alcohol n.d. 0.05 56 1132 1-(3-methylphenyl)-ethanone 0.39 0.27 57 1145 1250 3,5-xylenol＊ tr tr 58 1152 p-menthan-3-one＊＊ tr tr 59 1161 2471 benzoic acid＊ tr tr 60 1162 1537 (2E)-nonenal 1.60 0.68 61 1169 1659 n-nonanol 0.25 0.21 62 1172 2060 caprylic acid＊ 0.37 2.25 63 1175 1572 4-terpineol 0.40 n.d. 64 1180 2417 4-vinylphenol＊ tr tr 65 1181 1757 naphthalene 0.47 0.28 66 1189 1704 a-terpineol 0.42 0.12 67 1192 1609 2-decanone 0.15 0.10 68 1199 2-hydroxy-6-methylbenzaldehyde tr 2.05 69 1200 1200 n-dodecane 0.15 0.26 70 1202 1511 decanal 1.51 0.50 71 1212 1719 (2E,4E)-nonadienal＊＊ tr tr 72 1213 1944 benzothiazole 0.18 0.16 73 1225 1590 b-cyclocitral 0.19 0.21 74 1264 1656 (2E)-decenal 1.87 0.44 75 1271 2164 pelargonic acid 1.53 3.31 76 1291 1859 2-methylnaphthalene 0.19 n.d. 77 1293 1780 (2E,4Z)-decadienal 0.54 0.20 78 1300 1300 n-tridecane 0.16 0.52 79 1307 1613 n-undecanal 0.27 0.24 80 1307 1893 1-methylnaphthalene 0.25 0.10 81 1315 2198 4-vinylguaiacol＊ tr tr 82 1317 1827 (2E,4E)-decadienal 2.56 0.91 83 1318 1692 (Z)-citral n.d. 0.08 84 1341 1737 (E)-citral n.d. 0.14 85 1360 1752 (2E)-undecenal 1.60 0.28 86 1361 2046 4-nonanolide 0.68 0.65 87 1370 2288 capric acid＊ tr tr 88 1377 1966 biphenyl 0.06 0.06 89 1400 1400 n-tetradecane 0.73 1.62 90 1400 2045 1,3-dimethylnaphthalene 0.14 0.11 91 1402 1661 6,10-dimethyl-2-undecanone 0.29 0.36 92 1408 1577 longifolene n.d. 0.18 93 1409 1716 dodecanal 0.06 0.13 94 1455 1868 geranylacetone 2.16 1.63 95 1489 1953 b-ionone 0.24 0.32 96 1496 1769 cadina-1,4-diene 0.26 n.d. 97 1500 1500 n-pentadecane tr 0.88 98 1500 1705 a-muurolene 0.40 0.28 99 1510 1824 tridecanal 0.11 0.37 100 1523 1747 d-cadinene 0.84 0.44

158 J. Oleo Sci. 58, (3) 155-161 (2009) Volatile Components of Red and Black Rice Bran

Table 1 (Continued.) Rl1) Peak area (%)2) No Compound DB-5 TC-WAX Red rice bran Black rice bran 101 1529 2259 dihydroactinidiolide n.d. 0.21 102 1540 1840 (Z)-calamenene 0.30 0.31 103 1567 2487 lauric acid＊ tr tr 104 1600 1600 n-hexadecane tr 0.63 105 1613 1932 tetradecanal tr 0.97 106 1642 2170 epi-a-muurolol 0.53 0.10 107 1654 2219 a-cadinol n.d. 0.17 108 1665 2617 tridecylic acid＊ tr tr 109 1689 1998 2-pentadecanone 0.13 0.15 110 1700 1700 n-heptadecane tr 0.41 111 1710 2030 pentadecanal 0.46 5.90 112 1724 2032 methyl tetradecanoate n.d. 0.12 113 1757 2698 myristic acid 39.65 31.07 114 1796 2261 ethyl tetradecanoate n.d. 0.14 115 1800 1800 n-octadecane 0.07 0.22 116 1814 2640 n-hexadecanal tr 0.49 117 1845 2126 6,10,14-trimethyl-2-pentadecanone 3.06 1.64 118 1858 2798 pentadecylic acid＊ tr tr 119 1890 2196 2-heptadecanone n.d. 0.38 120 1900 1900 n-nonadecane tr 0.13 121 1922 2220 methyl hexadecanoate 0.15 1.74 122 1962 2859 palmitic acid tr 1.32 123 1993 2256 ethyl hexadecanoate n.d. 0.96 124 2094 2506 methyl linoleate 0.69 n.d. 125 2102 2457 methyl oleate 2.47 n.d. 126 2120 3095 linoleic acid＊ tr tr 127 2122 3110 linolenic acid＊ tr tr 128 2147 3042 oleic acid tr tr 129 2170 3011 stearic acid＊ tr tr

1)RI: Retention indices on DB-5 and TC-WAX capillary column 2)Peak area (%): Peak area was detected by GC-FID on DB-5 ＊: volatile compounds from rice bran (ref. No 3) ＊＊: Volatile compounds from black rice (ref. No 14) n.d.: not detacted; tr = trace (<0.01%)

acid and pelargonic acid, presenting in black rice bran, reported as the key odorant in black rice and responsible were responsible for sweaty, animal and cheese odor4,9). for smoky or black rice-aroma. The main compounds in red Gaiacol, presented at 0.81 mg/100 g in black rice bran, was rice bran were myristic acid, nonanal, (E)-b-ocimene and 6, contributed a characteristic component due to a unique 10, 14-trimethyl-2-pentadecanone, whereas the main com- odor in black rice bran since it associated a smoky odor. pounds in black rice bran were myristic acid, nonanal, caproic acid, pentadecanal and pelargonic acid.

4 CONCLUSION Many volatile oils were identified from red and black rice References bran and the results indicated that acids were the most 1. Itani, T.; Ogawa, M. History and recent trends of red abundant components in red and black rice bran, following rice in Japan. Jpn. J. Crop. Sci. 73, 137-147 (2004). by aldehydes compounds. Those compounds contributed to 2. Mitsuda, H.; Yasumoto, K.; Iwami, K. Analysis of unpleasant odor. The difference between red and black rice volatile components in rice bran. Agric. Biol. Chem. bran was due to the difference of the content of guaiacol, 32, 453-458 (1968).

159 J. Oleo Sci. 58, (3) 155-161 (2009) S. Sukhonthara, C. Theerakulkait and M. Miyazawa

Table 2 Classification of the Volatile Oil Composition frou Red and Black Rice Bran. Peak area (%) Compound Red rice bran Black rice bran Aliphatic Hydrocarbons 7.14 6.33 Alcohols 4.69 4.34 Aldehydes 24.99 22.32 Ketones 7.95 6.28 Acids 41.76 46.02 Esters 3.32 2.96 Aromatic Hydrocarbons 1.43 0.54 Phenols 0.00 1.77 Heterocycles 2.97 1.79 Miscellaneous 0.77 2.45 Unknown 4.99 5.21

Table 3 Absolute Quantification of Main Compounds and Aroma Active Compounds of the Volatile Oil. mg/100 g Rice bran1) No Compound Red rice bran Black rice bran 25 caproic acid 2.84 39 (E)-b-ocimene 1.12 48 guaiacol 0.81 54 nonanal 3.54 4.53 75 pelargonic acid 1.59 111 pentadecanal 2.83 113 myristic acid 13.48 14.91 117 6,10,14-trimethyl-2-pentadecanone 1.04

1) Quantitaitve analysis was performed by means of internal standard addition metho and authentic samples were used from previous papers.

3. Fujimaki, M.; Tsugita, T.; Kurata, T. Fractionation and rice. J. Agric. Food Chem. 49, 773-779 (2001). identification of volatile acids and phenols in the steam 7. Tava, A.; Bocchi, S. Aroma of cooked rice (Oryza sati- distillate of rice bran. Agric. Biol. Chem. 41, 1721-1725 va): comparison between commercial basmati and ital- (1977). ian line B5-3. Cereal Chem. 76, 526-529 (1999). 4. Jarunrattanasri, A.; Theerakulkait, C.; Cadwallader, 8. Zeng, Z.; Zhang, H.; Chen, J. Y.; Zhang, T.; Matsunaga, K.R. Aroma components of acid-hydrolyzed vegetable R. Flavor volatiles of rice during cooking analyzed by protein made by partial hydrolysis of rice bran protein. modified headspace SPME/GC-MS. Cereal Chem. 85, J. Agric. Food Chem. 55, 3044-3050 (2007). 140-145 (2008). 5. Champagne, E.T. Rice aroma and flavor: A literature 9. Maraval, I.; Mestres, C.; Pernin, K.; Ribeyre, F.; review. Cereal Chem. 85, 445-454 (2008). Boulanger, R.; Guichard, E.; Gunata, Z. Odor-active 6. Mahatheeranont , S.; Keawsa-ard, S.; Dumri, K. Quan- compounds in cooked rice cultivars from camargue tification of the rice aroma compound, 2-acetyl-1- (France) analyzed by GC-O and GC-mS. J. Agric. Food pyrroline, in uncooked Khao Dawk Mali 105 brown Chem. 56, 5291-5298 (2008).

160 J. Oleo Sci. 58, (3) 155-161 (2009) Volatile Components of Red and Black Rice Bran

10. Miyazawa, M.; Nagai, S.; Oshima, T. Volatile compo- littoralis. Flavour Fragr. J. 16, 215-218 (2001). nents of the straw of Oryza sativa L. J. Oleo Sci. 57, 22. Miyazawa, M.; Maehara, T.; Kurose, K. Composition of 139-143 (2008). the essential oil from the leaves of Eruca sativa. 11. Miyazawa, M.; Oshima, T.; Tokura, M.; Hisama, M. Flavour Fragr. J. 17, 187-190 (2002). Suppression of chemical mutagens-induced SOS 23. Miyazawa, M.; Yamafuji, C.; Kurose, K.;Ishikawa, Y. response by phenolic acids from black rice bran usind Volatile components of the rhizomes of Cirsium japon- Salmonella typhimurium TA1535/pSK1002 umu test. icum DC. Flavour Fragr. J. 18, 15-17 (2003). J. Oleo Sci. 52, 471-481 (2003). 24. Miyazawa, M.; Teranishi, A.; Ishikawa, Y. Components 12. Miyazawa, M.; Oshima, T.; Koshio, K.; Itsuzaki, Y.; of the essential oil from Petasites japonicus. Flavour Anzai, J. Tyrosinase inhibitor from black rice bran. J. Fragr. J. 18, 231-233 (2003). Agric. Food Chem. 51, 6935-6956 (2003). 25. Miyazawa, M.; Nishiguchi, T.; Yamafuji, C. Volatile 13. Ichikawa, H.; Ichiyanagi, T.; Xu, B.; Yushii, Y.; Nakaji- components of the leaves of Brassica rapa L. var. per- ma, M.; Konishi, T. Antioxidant activity of anthocyanin viridis Bailey. Flavour Fragr. J. 20, 158-160 (2005). extract from purple black rice. J. Med. Food. 4, 211-218 26. Kawata, J., Kameda, M.; Miyazawa, M. Constituents of (2001). essential oil from the dried fruits and stems of Akebia 14. Yang, D.S.; Shewfelt, R.L.; Lee, K.S.; Kays, S.J. Com- quinata (Thunb.) Decne. J. Oleo Sci. 56, 59-63 (2007). parison of odor-active compounds from six distinctly 27. Juliano, B.O. Rice bran in Rice: Chemistry and Tech- different rice flavor types. J. Agric. Food Chem. 56, nology (Juliano, B.O. ed.). The American Association of 2780-2787 (2008). Cereal Chemists Inc. St. Paul, Minnesota. 647-688 15. Yang, D.S.; Lee, K.S.; Jeong, O.Y.; Kim, L.J.; Kays, S.J. (1985). Characterization of volatile aroma compounds in 28. Aaslyng, M.D.; Martens, M.; Poll, L.; Nielsen, P.M.; cooked black rice. J. Agric. Food Chem. 56, 235-240 Flyge, H.; Larsen, L.M. Chemical and sensory charac- (2008). terization of hydrolyzed vegetable protein, a savory fla- 16. Adams, R.P. Identification of Essential Oil Compo- voring. J. Agric. Food Chem. 46, 481-489 (1998). nents by Gas Chromatography/Quadrupole Mass 29. Jezussek, M.; Juliano, B.O.; Schieberle, P. Comparison Spectroscopy. Academic Press. New York (2001). of key aroma compounds in cooked brown rice vari- 17. Miyazawa, M.; Kawata, J. Identification of the key eties based on aroma extract dilution analyses. J. aroma compounds in dried roots of Rubia cordifolia. Agric. Food Chem. 50, 1101-1105 (2002). J. Oleo Sci. 55, 37-39 (2006). 30. Yang, D.S.; Lee, K.S.; Kim, K.J.; Kays, S.J. Site of origin 18. Miyazawa, M.; Kawata, J. Composition of the essential of volatile compounds in cooked rice. Cereal Chem. 85, oil of rootstock from Cimicifuga simplex. Nat. Prod. 591-598 (2008). Res. 20, 542-547 (2006). 31. Chisholm, M.G.; Wilson, M.A.; Gaskey, G.M. Character- 19. Miyazawa, M.; Horiuchi, E.; Kawata, J. Components of ization of aroma volatiles in key lime essential oils (Cit- essential oil from Matteuccia struthiopteris. J. Oleo rus aurantifolia Swingle). Flavour Frag. J. 18, 106- Sci. 56, 457-461 (2007). 115 (2003). 20. Kawata, J.; Kameda, M; Miyazawa, M. Constituents of 32. Jordan, M.J.; Margaria, C.A.; Shaw, P.E.; Googner, K.L. essential oil from dried fruits and stems of Akebia Volatile components and aroma active compounds in quinata (Thunb.) Decne. J. Oleo Sci. 56, 59-63 (2007). aqueous essence and fresh pink guava fruit puree 21. Miyazawa, M.; Kurose, K.; Itoh, A.; Hiraoka, N; Kameo- (Psidium guajava L.) by GC-MS and multidimensional ka, H. Components of the essential oil from Glehnia GC/GC-O. J. Agric. Food Chem. 51, 1421-1426 (2003).

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