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Considering the important influence of longtime (150 day) moromi fermentation and heat treatment on the aroma formation of traditional Chinese-type soy sauce (TCSS), volatile compounds in samples taken from different stages of moromi fermentation and heat treatment were analyzed by solid phase microextraction coupled with gas chromatography-mass spectrometry. Results showed that a total of 76 volatile compounds were identified in all the samples, and most of the volatile compounds were common. During 150 day of moromi fermentation, relative contents of acids, alcohols, aldehydes and ketones, esters, and furan(one)s along with all the sensory attributes of acidic, alcoholic, fruity, caramel-like, smoky, and malty changed greatly. Notably, relative contents of alcohols, aldehydes and ketones along with the sensory intensities of alcoholic, caramel-like, and smoky of heated sample (80°C/60 min) decreased markedly, whereas there were slight increases in relative contents of furan(one)s, phenols, and sulfur-containing compounds of it. Long-time moromi fermentation and heat treatment have significant influence on the formation and relative contents of volatile compounds in TCSS, whereas changes in volatile compounds and their relative contents of the samples were responsible for the differences in sensory attributes.

Fruit flavor is a result of a complex mixture of numerous compounds. The formation of these compounds is closely correlated with the metabolic changes occurring during fruit maturation. Here, we describe the use of DNA microarrays and appropriate statistical analyses to dissect a complex developmental process. In doing so, we have identified a novel strawberry alcohol acyltransferase (SAAT) gene that plays a crucial role in flavor biogenesis in ripening fruit. Volatile esters are quantitatively and qualitatively the most important compounds providing fruity odors. Biochemical evidence for involvement of the SAAT gene in formation of fruity esters is provided by characterizing the recombinant protein expressed in Escherichia coli. The SAAT enzyme showed maximum activity with aliphatic medium-chain alcohols, whose corresponding esters are major components of strawberry volatiles. The enzyme was capable of utilizing short- and medium-chain, branched, and aromatic acyl-CoA molecules as cosubstrates. The results suggest that the formation of volatile esters in fruit is subject to the availability of acyl-CoA molecules and alcohol substrates and is dictated by the temporal expression pattern of the SAAT gene(s) and substrate specificity of the SAAT enzyme(s).

The compound N-(17- hydroxylinolenoyl)-L-glutamine (named here volicitin) was isolated from oral secretions of beet armyworm caterpillars. When applied to damaged leaves of corn seedlings, volicitin induces the seedlings to emit volatile compounds that attract parasitic wasps, natural enemies of the caterpillars. Mechanical damage of the leaves, without application of this compound, did not trigger release of the same blend of volatiles. Volicitin is a key component in a chain of chemical signals and biochemical processes that regulate tritrophic interactions among plants, insect herbivores, and natural enemies of the herbivores

Wine aroma is one of the most important parameters responsible for its quality, and hence for consumer acceptance. In order to obtain an appropriate technique to study volatile aroma compounds in mulberry wines, headspace-solid phase microextraction (HS-SPME) comb 40°C for 30 min with a 50/30 μm divinylbenzenecarboxen-polydimethylsiloxane (DVB-CAR-PDMS) fiber. Approximately 80 volatile compounds have been quantified in the mulberry wine, pertaining at several chemical groups, mainly higher alcohols, fatty acids, esters, and some volatile phenols whose concentration range from few to 138.36 mg/L. This work describes a novel methodology for the analysis of mulberry wines by HS-SPME coupled to GC-MS. HS-SPME using a 50/30 μm DVB-CAR-PDMS fiber is provided the higher extraction efficiency (p<0.05) for the volatiles including the most esters, higher alcohols, and fatty acids than by the other fibers.

Volatile and non-volatile compounds, which contribute to flavor in raw fish, were compared in raw, cooked and recooked silver carp. In total, 20, 34 and 34 volatile compounds, including aldehydes, alcohols, ketones, hydrocarbons and heterocyclic compounds, were identified in raw, cooked and recooked samples, respectively. Cooking the samples resulted in a significant increase in volatile compounds and the formation of new aldehydes, alcohols, ketones, hydrocarbons and heterocyclic compounds. In addition, the content of free amino acids (FAA) decreased dramatically, and the amount of nucleotides and small peptides significantly changed. With recooking of the samples, the levels of most of the volatile compounds decreased significantly, and there was a substantial change in nucleotides and small peptides. However, the effect of recooking on FAA was not observable.

The global distribution of 22 potentially harmful organochlorine compounds was investigated in more than 200 tree bark samples from 90 sites worldwide. High concentrations of organochlorines were found not only in some developing countries but also in industrialized countries, which continue to be highly contaminated even though the use of many of these compounds is restricted. The distribution of relatively volatile organochlorine compounds (such as hexachlorobenzene) is dependent on latitude and demonstrates the global distillation effect, whereas less volatile organochlorine compounds (such as endosulfan) are not as effectively distilled and tend to remain in the region of use

Parasitic and predatory arthropods often prevent plants from being severely damaged by killing herbivores as they feed on the plants. Recent studies show that a variety of plants, when injured by herbivores, emit chemical signals that guide natural enemies to the herbivores. It is unlikely that herbivore-damaged plants initiate the production of chemicals solely to attract parasitoids and predators. The signaling role probably evolved secondarily from plant responses that produce toxins and deterrents against herbivores and antibiotics against pathogens. To effectively function as signals for natural enemies, the emitted volatiles should be clearly distinguishable from background odors, specific for prey or host species that feed on the plant, and emitted at times when the natural enemies forage. Our studies on the phenomena of herbivore-induced emissions of volatiles in corn and cotton plants and studies conducted by others indicate that (i) the clarity of the volatile signals is high, as they are unique for herbivore damage, produced in relatively large amounts, and easily distinguishable from background odors; (ii) specificity is limited when different herbivores feed on the same plant species but high as far as odors emitted by different plant species and genotypes are concerned; (iii) the signals are timed so that they are mainly released during the daytime, when natural enemies tend to forage, and they wane slowly after herbivory stops.

In response to insect feeding on the leaves, cotton (Gossypium hirsutum L.) plants release elevated levels of volatiles, which can serve as a chemical signal that attracts natural enemies of the herbivore to the damaged plant. Pulse-labeling experiments with [13C]CO2 demonstrated that many of the volatiles released, including the acyclic terpenes (E,E)-alpha-farnesene, (E)-beta-farnesene, (E)-beta-ocimene, linalool,(E)-4,8-dimethyl-1,3,7-nonatriene, and (E,E)-4,8,12-trimethyl-1,3,7,11-tridecatetrane, as well as the shikimate pathway product indole, are biosynthesized de novo following insect damage. However, other volatile constituents, including several cyclic terpenes, butyrates, and green leaf volatiles of the lipoxygenase pathway are released from storage or synthesized from stored intermediates. Analysis of volatiles from artificially damaged plants, with and without beet armyworm (Spodoptera exigua Hubner) oral secretions exogenously applied to the leaves, as well as volatiles from beet armyworm-damaged and -undamaged control plants, demonstrated that the application of caterpillar oral secretions increased both the production and release of several volatiles that are synthesized de novo in response to insect feeding. These results establish that the plant plays an active and dynamic role in mediating the interaction between herbivores and natural enemies of herbivores

Atmospheric concentrations of ozone and other air pollutants, in some regions, are sensitive to surface fluxes of volatile organic compounds (VOCs). Plant foliage is the source of at least half of all VOC emissions in the United States and more than two-thirds of global VOC emissions. Observed spatial and seasonal variations in foliar VOC emissions range over several orders of magnitude. Land characteristics data are an important component of the modeling techniques used to estimate VOC emission rate variations due to seasonal and spatial changes in species composition, foliar density, and other factors. Model techniques and land characteristics databases are compared and evaluated in this paper. Significant differences in VOC fluxes are predicted depending on spatial resolution, procedures used to develop land characteristics databases, and foliar density models. Satellite and ground observations can be combined to generate the accurate estimates of the species composition and foliar density required for natural VOC emission models.