derivatives, benzenoids/phenylpropanoids, terpenoids, and nitrogen-containing compounds ( Table 1 ). Two monoterpenes, linalool and ( E )-β-ocimene, were predominant in floral volatiles for both species. Their emission rates were 11.2 and 4.0 μg·h −1 ·g −1
Yifan Jiang, Xinlu Chen, Hong Lin, Fei Wang, and Feng Chen
Kil Sun Yoo, Leonard M. Pike, and Brian K. Hamilton
A simple and fast method for measuring low boiling point (LBP) volatile terpenoids in carrots (Daucus carota L.) was developed by using a direct headspace sampling technique. Seven LBP terpenoid compounds were separated with high sensitivity and consistency via gas chromatography. High boiling point terpenoids above terpinolene were not well characterizable. Standard compounds showed highly linear responses up to 10 μg.g-1, with a detection limit of 0.01 μg.g-1. We confirmed that high α- and β-pinene and/or total terpenoids contributed to harsh or oily flavors. Up to 40 samples can be analyzed in an 8-h day using this method, compared to 10 samples using previous methods.
Maarten Benschop and A. A. De Hertogh
Cell-free extracts which incorporated mevalonate-2-14C (MVA) into terpenes were obtained from shoot tissue of Tulipa gesneriana L. cv. Golden Melody. Maximal incorporation occurred at pH 6.5 in 0.1 M KH2 PO4-K2HPO4 buffer with an incubation temperature of 35°C. Total incorporation was linear up to 5 mg protein/assay and it could be enhanced by increasing MVA concentration up to 8 × 10-8 M. After differential centrifugation, all enzymatic activity was located in the 100,000 × g supernatant. In combination Mg++ and Mn++, ATP stimulated incorporation more than CTP, GTP, and UTP. Using ATP as the energy source, Mn++ was highly stimulatory at 1 and 5 × 10-3 M. Mg++ alone or in combination with Mn++ was less effective than Mn++.
The radioactivity from MVA was recovered in 2 fractions: the “neutral” fraction isolated by extraction with benzene, and the “acid hydrolyzable” fraction extracted with benzene after acid hydrolysis of the residual aqueous “neutral” fraction. For subsequent identification of the neutral terpene products, the optimal conditions are either high protein concentration (18 mg/assay) after a 15,000 × g centrifugation and a 4-hr incubation period or high protein concentration without centrifugation and a 1-hr incubation period. The optimal conditions for identification of the acid hydrolyzable products are low protein concentration (5 mg/assay) and 1-hr incubation.
P.W. Simon, C.E. Peterson, and W.H. Gabelman
Ying Jia, Dianren Xia, and E.S. Louzada
A cDNA coding for a putative terpene synthase (Grtps) was isolated from `Rio Red' grapefruit (Citrus paradisi Macf.) mature fruit by differential display RT-PCR and the corresponding full-length cDNA and genomic clone were subsequently obtained. The isolated cDNA clone was 1644 bp in length encoding a protein of 548 amino acids with a predicted molecular mass of 64 kDa and of pI 5.38. The genomic clone was 3203 bp in length with 6 introns and 7 exons. This Grtps appears to be a sesquiterpene synthase based on molecular weight, genomic organization, and similarity with the other terpene synthases. Both RT-PCR and Northern blot expression analysis indicated that Grtps is not expressed in immature fruits, roots, or leaves, but only in mature fruits. Southern blot analysis of genomic DNA demonstrated that Grtps is one of the members in the family of terpene synthases.
Dong Sik Yang, Ki-Cheol Son, and Stanley J. Kays
acids in tomato play an important role in characterizing tomato flavor ( Goff and Klee, 2006 ). Several terpenoid compounds [e.g., camphene, p -cymene, δ -3-carene, α -humulene, limonene, linalool, ( E )- β -ocimene, α -pinene, β -thujone
John C. Beaulieu, Rebecca E. Stein-Chisholm, and Deborah L. Boykin
-Aldrich Fine Chemicals, Flavors and Fragrances Products [St. Louis, MO]}, according to Table 1 . Compound classes were defined and comprised of aldehydes (ALD), alcohols (OLS), esters (EST), ketones (ONE), furans (FUR), terpenoids (OID), and aromatics (ARO
Dedang Feng, Hongying Jian, Hao Zhang, Xianqin Qiu, Zhenzhen Wang, Wenwen Du, Limei Xie, Qigang Wang, Ningning Zhou, Huichun Wang, Kaixue Tang, and Huijun Yan
sect. Bracteatae ( Fig. 1A ). A total of 47 floral volatile compounds were detected by HS-SPME–GC/MS, including 27 terpenoids, 15 aromatic hydrocarbons, and five fatty acid derivatives, which accounted for more than 95% of the total compounds detected
Shea A. Keene, Timothy S. Johnson, Cindy L. Sigler, Terah N. Kalk, Paul Genho, and Thomas A. Colquhoun
composed of mixtures of volatile organic compounds (VOCs or volatiles) that are mostly lipophilic liquids with high vapor pressures at ambient temperatures ( Pichersky et al., 2006 ). Floral volatiles typically fit in the families of terpenoids
Solveig J. Hanson and Irwin L. Goldman
flavor: geosmin, sucrose, oxalate, and saponins. Earthy aroma, conferred by the volatile terpenoid geosmin ( Gerber, 1967 ), is identified as the signature flavor of table beet ( Goldman and Navazio, 2003 ) but can be unpalatable in excess ( Tyler et al