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Initial results obtained by incorporation of an inductively coupled plasma (ICP) ion source with a Fourier transform ion cyclotron resonance (FTICR) mass spectrometer are reported, along with spectra which demonstrate submilligram-per-liter detection limits and high mass resolution (mass resolving power, m/[[Delta]m.sub.10%V] = 7000-10 000). Also shown is an ICP-FTICR spectrum with ultrahigh resolving power (m/[[Delta]m.sub.10%V] = 88 000). Both instrumental configurations used to conduct this work, one at the University of Florida, and the other at the National High Magnetic Field Laboratory, are described. Also included are concise results from a computer aided interference study designed to enumerate mass spectral interferences requiring mass resolving power in excess of 10 000.

Thresholds for flavour volatiles have been traditionally calculated in water or air but they may vary widely in more complex matrices such as milk, gels or fruit slurries. The data presented are part of a continuing study to provide the industry with threshold guidelines more adequate for the use of flavours in citrus juices. Thresholds of aroma compounds of orange juice (OJ) were determined in reconstituted pump-out (RPO), approaching a deodorized OJ matrix and served at 10-12 °C, the temperature at which OJ is consumed. The three-alternative forced choice (3-AFC) method was used (ASTM: E-679). Sixteen to twenty panelists were presented with RPO samples arranged in five rows of three samples corresponding to five spiking levels, each separated by a factor of 3, with a 3-AFC presentation at each level. For each compound, the test was repeated four times. Compounds tested were verified for purity by GC-MS and GC-O. Orthonasal and retronasal thresholds for esters were twice (methyl butanoate) to 30 times (ethyl propanoate) higher in the orange juice matrix than published values in water. The odour activity values (OAVs) of volatile compounds were calculated for two OJs; nine compounds had an orthonasal OAV < 1 when using thresholds determined in RPO, while in contrast, these compounds had an OAV > 1 when calculated with published thresholds determined in water. The relative OAV of some compounds had changed with respect to each other, indicating a different contribution of these compounds to OJ flavour when their OAV was calculated in RPO. These results show the importance of non-water-soluble compounds on odour and flavour perception. The threshold values provided herein are directly usable by the industry, in comparison with the current values published in water, and will help in developing models that would explain OJ flavour based on interactions with the matrix. Copyright © 2008 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Thresholds for flavour volatiles have been traditionally calculated in water or air, but they may vary widely in more complex matrices. Thresholds of key aroma compounds of orange juice (OJ) were determined in a deodorized OJ matrix. The three-alternative-forced-choice (3-AFC) method was used (ASTM: E-679). Untrained panelists, 33-58 in number, were presented with deodorized orange juice samples arranged in five rows of three samples, corresponding to five spiking levels, each separated by a factor of 3, with a 3-AFC presentation at each level. The test was repeated at least three times for experienced panelists. Odour thresholds in the orange juice matrix were 15 times (citral, hexanal) to over 200 times ( β-pinene, limonene) higher than published values in water. Retronasal odour thresholds were more consistent with published values, being higher only by 2-60-fold, except for octanal which was higher by 187-fold. These results will provide the industry with more realistic threshold guidelines for use in flavouring citrus juices. Copyright © 2004 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Apples [Malus sylvestris (L.) Mill var. domestica (Borkh.) Mansf. ('Gala', 'Delicious', 'Granny Smith' and 'Fuji')], pretreated or nontreated with 1-methylcyclopropene (1-MCP, 0.6 to 1.0 µL·L-1 for 18 hours at 20 °C), were stored in controlled atmosphere (CA, 1 to 1.5 kPa O2; 1 to 2 kPa CO2) or in regular atmosphere (RA) for up to 8 months at 1 °C. Firmness, titratable acidity (TA), soluble solids content (SSC), and volatile abundance were analyzed every month directly or after transfer to air at 20 °C for 1 week to determine effect of 1-MCP, storage atmosphere and storage time on apple quality immediately after cold storage and after simulated marketing conditions at 20 °C. The 1-MCP ± CA treatments delayed ripening and prolonged storage life as indicated by delayed loss of firmness and TA in all four cultivars during storage. The 1-MCP ± CA also slightly delayed loss of SSC for 'Gala' but had no effect on SSC levels for the other cultivars. There were differences among treatments for firmness and TA content [(1-MCP + RA) > CA] for 'Gala', 'Delicious', and 'Granny Smith' apples, but not for 'Fuji'. These differences were generally exacerbated after transfer of fruit to 20 °C for 1 week. A combination of 1-MCP + CA was generally best [(1-MCP + CA) > (1-MCP + RA) or CA] for maintaining 'Delicious' firmness and TA. However, the treatments that were most effective at retaining TA and firmness also retained the least volatiles. The results indicate that the efficacy of 1-MCP and CA in maintaining apple quality factors is cultivar dependent and that 1-MCP + RA may be a viable alternative to CA for optimal eating quality for some cultivars. [ABSTRACT FROM AUTHOR]

Characterization of the aromatic profile in commercial guava essence and fresh fruit puree by GC-MS yielded a total of 51 components quantified. Commercial essence was characterized to present a volatile profile rich in components with low molecular weight, especially alcohols, esters, and aldehydes, whereas in the fresh fruit puree terpenic hydrocarbons and 3-hydroxy-2-butanone were the most abundant components. In the olfactometric analyses totals of 43 and 48 aroma active components were detected by the panelists in commercial essence and fruit puree, respectively. New components were described for the first time as active aromatic constituents in pink guava fruit (3-penten-2-ol and 2-butenyl acetate). Principal differences between the aroma of the commercial guava essence and the fresh fruit puree could be related to acetic acid, 3-hydroxy-2-butanone, 3-methyl-1-butanol, 2,3-butanediol, 3-methylbutanoic acid, (Z)-3-hexen-1-ol, 6-methyl-5-hepten-2-one, limonene, octanol, ethyl octanoate, 3-phenylpropanol, cinnamyl alcohol, alpha-copaene, and an unknown component. (E)-2-Hexenal seems to be more significant to the aroma of the commercial essence than of the fresh fruit puree.

Gas chromatography-mass spectrometry (GC-MS) and multidimensional gas chromatography olfactometry (GC/GC-O) were utilized to study the aroma profile and the aroma active components of commercial kiwi essence and the initial fresh fruit puree. Totals of 29 and 33 components were identified and quantified in the essence and the puree, respectively. Ten components were quantified for the first time as constituents of the kiwi fruit including 3-penten-2-ol, 3-hydroxy-2-butanone, 3-methyl-2-butenal, 2-hexanol, nonanal, 3-methyl-1-butanol, 2-methyl-1-butanol, 3-methyl-2-butanone, 3-methyl 3-buten-2-one, and octane. Analysis of these samples by multidimensional gas chromatography-olfactometry (GC-O) allowed for the identification of >80% of the aroma active components present at level traces in this fruit. A total of 35 components appear to contribute to the aroma of kiwi fresh puree and its aqueous essence. Components described for the first time as constituents of the aroma profile in this fruit were 2-ethylfuran, 3-methyl-1-butanol, 2-cyclohexen-1-one, (E,E)-2,6-nonadienal, diethyl succinate, and hexyl hexanoate.

Chemical characterization by gas chromatography-mass spectometry (GC-MS) of the aromatic profile of yellow passion fruit essence and the juice of the fruit yielded a total of 62 and 34 components, respectively. Four new components have been identified and quantified for the first time in this fruit: 3-methyl-2-butanone; ethyl lactate (quantified only in the fruit juice); diethyl malonate (quantified only in the essence); and 3-penten-2-ol (quantified in both samples). Analysis of these samples by gas chromatography/olfactometry (GC/O) yielded a total of 66 components which appear to contribute to the aroma of passion fruit juice and its aqueous essence. Of these, four could not be quantified by GC-MS: acetic acid, ethyl propionate, ethyl 3-oxobutyrate, and propyl hexanoate. New components were described for the first time as constituents of the aromatic profile in this fruit including acetal, 1,3-dimethyl benzene, and 2-methylbutyl hexanoate. Aroma extract dilution analysis (AEDA) allowed for the detection of the most potent odorants in the commercial essence (2-methylbutyl hexanoate and hexyl hexanoate) and in the fresh juice (1,3-dimethyl benzene and 2-methylbutyl hexanoate). 2-Methylbutyl hexanoate, considered as one of the most potent odorants in this fruit, has been described for the first time as an aromatic constituent of yellow passion fruit.