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- Camellia sinensis (2)
- 1-Phenylethanol (1)
- 2-Phenylethanol (1)
- 3,5-Dimethoxytoluene (1)
- Biosynthesis (1)
- Enantio-selective reduction (1)
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- Lemna paucicostata (1)
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- Pharbitis nil cv. Violet (1)
- Phenylpropanoids (1)
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- Rosa x level (1)
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- [N-15]Anthranilic acid (1)
- [N-15]Indole (1)
Institute
2-Phenylethanol (2PE) and 3,5-dimethoxytoluene (DMT) are characteristic scent compounds in specific roses such as Rosa x hybrida cv. 'Yves Piaget'. We analyzed the endogenous concentrations and emission of 2PE and DMT during the unfurling process in different floral organs, as well as changes in transcript levels of the two key genes, PAR and OOMT2.
The emission of both 2PE and DMT increased during floral development to reach peaks at the fully unfurled stage. The relative transcripts of PAR and OOMT2 also increased during floral development. Whereas the maximum for OOMT2 was found at the fully unfurled stage (stage 4), similar expression levels of PAR were detected at stage 4 and the senescence stage (stage 6). The results demonstrate a positive correlation between the expression levels of PAR and OOMT2 and the emission of 2PE and DMT. In addition, endogenous volatiles and relative transcripts showed tissue- and development-specific patterns. (C) 2014 Elsevier Masson SAS. All rights reserved.
We produced low temperature (15 degrees C) processed green tea (LTPGT) with higher aroma contents than normal green tea (Sencha). Normal temperature processed green tea (NTPGT), involved storing at 25 degrees C, and Sencha had no storing process. Sensory evaluation showed LTPGT had higher levels of floral and sweet odorants than NTPGT and Sencha. Aroma extract dilution analysis and gas chromatography-mass spectrometry-olfactometry indicated LTPGT had 12 aroma compounds with high factor dilution values (FD). Amongst LTPGT's 12 compounds, indole, jasmine lactone, cis-jasmone, coumarin, and methyl epijasmonate contributed to floral, fruity and sweet characters. In particular, indole increased initially, peaking at 16 h, then gradually decreased; Feeding experiments suggested [N-15]indole and [N-15]oxygenated indoles (OX-indoles) were produced from [N-15]anthranilic acid. We proposed the increase in indole was due to transformation of anthranilic acid during the 16 h storage and the subsequent decline in indole level was due to its conversion to OX-indoles.
Plant oxylipins are an important class of signaling molecules in plants. The cyclic adducts of epinephrine or norepinephrine with the naturally occurring oxylipin (12Z,15Z)-9-hydroxy-10-oxo-octadeca-12,15-dienoic acid (KODA, 1) or its synthetic analogues (2-6) have been reported to possess flower-inducing activity toward Lemna paucicostata. By in vivo and in vitro experiments with seedlings of Pharbitis nil cv. Violet carbonyl groups of the alpha-ketols (1 and 3) and the ketones (7 and 9) were enantio-selectively reduced to give their corresponding vicinal diols (2 and 4) and alcohols (8 and 10). The stereochemistry at the oxymethine carbon was determined based on the long range C H coupling constants and the modified Mosher's method. Orientation of the adjacent hydroxyl group in (1 and 3) did not affect the enantio-selectivity, whereas the conversion was slightly affected and higher yields were obtained with the R-enantiomers of the alpha-ketols.
This study is focused on the synthesis and characterization of hydroxy-apo-10'-carotenal/quantum dot (QD) conjugates aiming at the in vivo visualization of beta-ionone, a carotenoid-derived volatile compound known for its important contribution to the flavor and aroma of many fruits, vegetables, and plants. The synthesis of nanoparticles bound to plant volatile precursors was achieved via coupling reaction of the QD to C-27-aldehyde which was prepared from alpha-ionone via 12 steps in 2.4% overall yield. The formation of the QD-conjugate was confirmed by measuring its fluorescence spectrum to observe the occurrence of fluorescence resonance energy transfer.
Green algae are of great economic importance. Seaweed is consumed fresh or as seasoning in Japan. The commercial value is determined by quality, color, and flavor and is also strongly influenced by the production area. Our research, based on solid phase microextraction gas chromatography mass spectrometry (SPME-GC-MS), has revealed that volatile compounds differ intensely in the four varieties of commercial green algae. Accordingly, 41 major volatile compounds were identified. Heptadecene was the most abundant compound from Okayama (Ulva prolifera), Tokushima (Ulva prolifera), and Ehime prefecture (Ulva linza). Apocarotenoids, such as ionones, and their derivatives were prominent volatiles in algae from Okayama (Ulva prolifera) and Tokushima prefecture (Ulva prolifera). Volatile, short chained apocarotenoids are among the most potent flavor components and contribute to the flavor of fresh, processed algae, and algae-based products. Benzaldehyde was predominant in seaweed from Shizuoka prefecture (Monostroma nitidum). Multivariant statistical analysis (PCA) enabled simple discrimination of the samples based on their volatile profiles. This work shows the potential of SPME-GC-MS coupled with multivariant analysis to discriminate between samples of different geographical and botanical origins and form the basis for development of authentication methods of green algae products, including seasonings.
Tea aroma is one of the most important factors affecting the character and quality of tea. Recent advances in methods and instruments for separating and identifying volatile compounds have led to intensive investigations of volatile compounds in tea. These studies have resulted in a number of insightful and useful discoveries. Here we summarize the recent investigations into tea volatile compounds: the volatile compounds in tea products; the metabolic pathways of volatile formation in tea plants and the glycosidically-bound volatile compounds in tea; and the techniques used for studying such compounds. Finally, we discuss practical applications for the improvement of aroma and flavor quality in teas. (C) 2013 Elsevier Ltd. All rights reserved.
Camellia sinensis synthesizes and emits a large variety of volatile phenylpropanoids and benzenoids (VPB). To investigate the enzymes involved in the formation of these VPB compounds, a new C. sinensis short-chain dehydrogenase/reductase (CsSDR) was isolated, cloned, sequenced, and functionally characterized. The complete open reading frame of CsSDR contains 996 nucleotides with a calculated protein molecular mass of 34.5 kDa. The CsSDR recombinant protein produced in Escherichia coli exhibited dehydrogenase-reductase activity towards several major VPB compounds in C. sinensis flowers with a strong preference for NADP/NADPH co-factors, and showed affinity for (R)/(S)-1-phenylethanol (1PE), phenylacetaldehyde, benzaldehyde, and benzyl alcohol, and no affinity for acetophenone (AP) and 2-phenylethanol. CsSDR showed the highest catalytic efficiency towards (R)/(S)-1PE. Furthermore, the transient expression analysis in Nicotiana benthamiana plants validated that CsSDR could convert 1PE to AP in plants. CsSDR transcript level was not significantly affected by floral development and some jasmonic acid-related environmental stress, and CsSDR transcript accumulation was detected in most floral tissues such as receptacle and anther, which were main storage locations of VPB compounds. Our results indicate that CsSDR is expressed in C. sinensis flowers and is likely to contribute to a number of floral VPB compounds including the 1PE derivative AP.