Short-chain Aldehydes Research Articles

Inhibitory activity of some short-chain aliphatic aldehydes on pheromone and ammonium carbonate-mediated attraction in olive fruit fly, Bactrocera oleae.

The olive fruit fly (OFF), Bactrocera oleae (Rossi), is the main insect pest of olive trees worldwide. Legislation limits to the use of some synthetic larvicidal insecticides is leading to the development of new control options for preventive control of adult flies. In the present study, the biological activity of four short-chain aliphatic aldehydes, namely hexanal, (E)-2-hexenal, heptanal and (E)-2-heptenal, previously reported as repellents to the OFF adults was investigated. Electroantennography (EAG) recordings showed that antennae of OFF males and females are able to perceive the test compounds in a wide range of doses. In field trapping experiments, reservoir-type polypropylene (PP) membrane dispensers loaded with individual compounds did not elicit a significant attraction of OFF males and females. On the contrary, a significant reduction of male catches was noticed when sex pheromone dispensers and PP membrane dispensers, loaded with one of the test compounds, were applied on the same white sticky traps ≈20 cm apart. Likewise, male and female catches in yellow sticky traps baited with ammonium carbonate (AC) dispensers as food attractant were significantly reduced by the presence of PP membrane dispensers of individual aliphatic aldehydes on the same traps. In small plots control trials, solid formulations of the four aldehydes into a bentonite clay support induced a significant reduction of the OFF active infestation mainly when C6 and C7 aldehyde-activated bentonites were used. Short-chain aliphatic aldehydes showed inhibitory effects on sex pheromone and food attractant-mediated attraction of OFF. Results of field trials suggest potential of short-chain aliphatic aldehydes to develop new semiochemical-based OFF control options. © 2024 Society of Chemical Industry.

Dynamic and static collection followed by a GC–MS analysis of volatiles from Chagasic bugs’ feces: a case of short chain aldehydes

Dynamic and static collection followed by a GC–MS analysis of volatiles from Chagasic bugs’ feces: a case of short chain aldehydes

Physicochemical properties and flavor substances analyses of refined beef tallow with dry fractionation treatment

Dry fractionation represents a significant technique for separation of diverse fractions from beef tallow. The objective of this study was to undertake a systematic investigation of alterations in physicochemical properties, crystallization behavior, thermal properties, and flavor compounds that occur during the beef tallow dry fractionation process. The solid component yielded at 40, 30, and 15 °C were 44.88%, 33.72%, and 13.04% respectively, with an 8.36% liquid content at 15 °C, which was consistent with the characteristics of saturated fatty acids content. The β – β’ transformation in the dry fractionation process was clearly revealed by X-ray diffraction. Differential scanning calorimetry curves exhibited alterations in exothermic and endothermic peak, as well as enthalpy. Electronic nose identified short-chain compounds, aldehydes, ketones, and nitrogen-containing substances as flavor compounds. Volatile compounds were quantified using HS-SPME-GC–MS. Overall, dry fractionation produces beef tallow fractionated compounds with diverse physicochemical properties and aromatic-active substances, thereby expanding its potential utilization.

Comparative study of volatile organic compound profiles in aromatic and non-aromatic rice cultivars using HS-GC–IMS and their correlation with sensory evaluation

Analyzing of volatile organic compounds (VOCs) is important in rice quality control and breeding aromatic cultivars. This study utilized HS-GC–IMS, known for its simplicity, high sensitivity, and low cost, to analyze VOCs in 59 aromatic and 6 non-aromatic rice cultivars. The aromatic intensity of each rice cultivar was determined by artificial sensory evaluation, thus the correlation between sensory evaluation scores and VOC peak volumes was explored. A total of 77 VOCs were identified, with aromatic cultivars exhibiting prevalent short-chain aliphatic aldehydes, alcohols, and ketones, while non-aromatic samples contained higher concentrations of esters, furans, terpenes, and benzene derivatives. Principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) based on VOC data effectively distinguished the two rice types, and 35 VOCs were regarded as the marker VOCs contributing to the volatile variations. Furthermore, the correlation analysis between sensory evaluation and VOC markers revealed that most of these VOCs had a positive correlation with the sensory evaluation scores, with 1-pentanol, 2-acetyl-1-pyrroline (D), and 1-hexanol (M) exhibiting the highest correlation coefficients. Meanwhile, most VOC markers also exhibited positive correlations with other volatiles. The results confirm the suitability of HS-GC–IMS for VOC detection and rice category discrimination.

Odor-Active Compounds in Flexible Polyurethane Materials

Flexible polyurethane (PU) materials find extensive use in upholstery, mattresses, and automobiles, yet the molecular background of their odor is still inadequately understood. To address this gap, we aimed at identifying major odorants in fifteen samples representing eight common types of flexible PU materials. The volatiles isolated from the samples were subjected to activity-guided screening via gas chromatography-olfactometry. Structures were assigned by comparing odor, retention data, and mass spectra to those of authentic reference compounds. This approach led to the identification of 50 odorants, 39 of which had not previously been described in PU. The odorants belonged to a wide range of compound classes, including tertiary amines, fatty acid oxidation products, short-chain aldehydes, trioxocanes, pyrazines, aromatic hydrocarbons and heterocycles, chlorinated compounds, phenol derivatives, fragrance compounds, and nitriles. For some odorants, further insights were gained into their origins and release behavior. For example, the odorous 1,4-dimethylpiperazine had been used as a catalyst, and propanal was shown to be not only a PU odorant but also the precursor of an odor-active trioxocane. Additionally, the quantitation of acetaldehyde and propanal suggested their continuous regeneration from the samples. While the sources of other compounds still have to be clarified, the data obtained in this study could pave the way for odor reduction strategies in the production of PU materials, ultimately resulting in an improved odor and consumer experience.

Influence of dielectric barrier discharge plasma processing in the volatile compounds and aroma of cashew apple juice

Cashew apple juice is a popular beverage in several parts of the world due to its unique fruity aroma. However, the high styrene concentration contributes to an undesirable balsamic note. To address this issue, cold plasma technology was proposed to alter the juice's volatile compounds, thereby improving its flavor. This study has evaluated the effects of cold plasma on the volatile compounds and aroma of cashew apple juice. The research was conducted by applying dielectric barrier discharge plasma to the juice, varying the frequency (50–1000 Hz) and processing times (5–20 min) while keeping a constant voltage (18 kV). The plasma treatment induced noteworthy changes in the volatile compounds of the juice. Specifically, there was a significant decrease in volatile organic acids (73%) and an increase in aldehydes (52%), alcohols (67%), and short-chain esters (11%). Plasma induced the internal scission of fatty acids and esters, which resulted in the formation of short-chain esters and aldehydes. Further processing has oxidized the aldehydes, generating alcohols and isomerized short-chain esters, which generate branched esters. Cold plasma, however, did not significantly reduce the styrene concentration and could not mitigate the off-flavor caused by this compound.

Chemical symphony: Unraveling triatomine aggregation and attraction patterns for innovative pest control solutions

Aggregation is a spatial distribution pattern where individuals can be grouped through interaction with particular signals or cues [e.g., chemical substances]. Numerous triatomine species exhibit attraction and aggregation around both conspecific and heterospecific feces. It remains unclear whether compounds released by feces function as signals (pheromones or synomones) or cues. Employing a bioassay that mimics field conditions, we investigated the response of Triatoma pallidipennis bugs to volatiles present in its feces and blends of these compounds. Our findings indicate that short-chain aldehydes, namely nonanal, octanal, heptanal, and hexanal, attract fifth-instar nymphs. Furthermore, insects responded to individual compounds as well as secondary, ternary, and quaternary blends. The most attractive blend consisted of all four aldehydes. Additionally, quaternary blends at various compound ratios attracted fifth-instar nymphs of T. phyllosoma and T. longipennis. We discuss the potential roles of these compounds as signals or cues and explore their application as bait in control programs.

Evaluation of Distillery Fractions in Direct Methanol Fuel Cells and Screening of Reaction Products

Fuel cells represent an appealing avenue for harnessing eco-friendly energy. While their fuel supply traditionally stems from water electrolysis, an environmentally conscious approach also involves utilizing low-weight alcohols like methanol and ethanol. These alcohols, concentrated from sustainable sources within the enological by-product distillation process, offer a noteworthy contribution to the circular economy. This study delved into evaluating the efficacy of distillery fractions in powering methanol fuel cells. Beyond their energy-generation potential, the performed GC-MS analysis unveiled appreciable quantities of acetic acid resulting from the partial oxidation of ethanol. This revelation opens the door to intriguing possibilities, including the recovery and repurposing of novel compounds such as short-chain fatty acids (predominantly acetic acid), ketones, and aldehydes—establishing a link between sustainable energy production and the emergence of valuable by-product applications.

Associational Effects of Desmodium Intercropping on Maize Resistance and Secondary Metabolism.

Intercropping is drawing increasing attention as a strategy to increase crop yields and manage pest pressure, however the mechanisms of associational resistance in diversified cropping systems remain controversial. We conducted a controlled experiment to assess the impact of co-planting with silverleaf Desmodium (Desmodium uncinatum) on maize secondary metabolism and resistance to herbivory by the spotted stemborer (Chilo partellus). Maize plants were grown either in the same pot with a Desmodium plant or adjacent to it in a separate pot. Our findings indicate that co-planting with Desmodium influences maize secondary metabolism and herbivore resistance through both above and below-ground mechanisms. Maize growing in the same pot with a Desmodium neighbor was less attractive for oviposition by spotted stemborer adults. However, maize exposed only to above-ground Desmodium cues generally showed increased susceptibility to spotted stemborer herbivory (through both increased oviposition and larval consumption). VOC emissions and tissue secondary metabolite titers were also altered in maize plants exposed to Desmodium cues, with stronger effects being observed when maize and Desmodium shared the same pot. Specifically, benzoxazinoids were strongly suppressed in maize roots by direct contact with a Desmodium neighbor while headspace emissions of short-chain aldehydes and alkylbenzenes were increased. These results imply that direct root contact or soil-borne cues play an important role in mediating associational effects on plant resistance in this system.

Lessons to be popular: the chemical basis of aggregation in Trypanosoma cruzi-infected and non-infected Chagasic bugs.

Aggregation is one of the most remarkable behaviours in the animal kingdom-a process that is usually governed by pheromones. Triatomines are blood-sucking bugs that act as vectors of Trypanosoma cruzi, the etiological agent of Chagas disease in mammals, including humans. Triatomines usually gather in roosting refuges by using aggregation pheromones of unknown chemical structure. In terms of vector control, one option to reduce triatomine-human contact is via capturing the insects into traps baited with lures based on such aggregation pheromones. As a first step towards this aim, we elucidated the aggregation pheromone in the triatomine Triatoma pallidipennis, using T. cruzi-infected and non-infected bugs. We used different extraction techniques and gas chromatography coupled to mass spectrometry for the identification. Also, two different bioassays were implemented for evaluating the attractant and arrestant activity of the pheromone. We found that T. pallidipennis produced short-chain aldehydes as attractants, and nitrogen-derived compounds as arrestants. We detected differences in the production and perception of these compounds according to whether animals were infected or not. These findings show that T. cruzi may influence triatomine chemical ecology and are promising tools for triatomine control.

Aldehyde-containing clays: a sustainable approach against the olive tree pest, Bactrocera oleae.

A set of organic/inorganic layered materials was obtained by functionalizing a montmorillonite-containing bentonite natural clay with linear aliphatic C6 or C7 aldehydes through a cost-effective and technologically simple incipient-wetness deposition method. The solids were investigated by means of a multi-technique approach (X-ray powder diffraction, XRPD, scanning electron microscopy, SEM, Fourier-transform infrared spectroscopy, FT-IR, thermogravimetric analysis, TGA, elemental analysis and solid-state nuclear magnetic resonance, ssNMR) to clarify the nature of the deposited organic species and the mode of interaction between the aldehyde and the clay. Since both natural clays and short-chain linear aldehydes find application as alternative strategies in the control of the olive fruit fly, Bactrocera oleae, the hybrid layered materials were tested under real-life conditions and their insect-inhibiting capability was evaluated in open-field trials on olive tree orchards in Tuscany, Central Italy. Specific tests were conducted to evaluate the resistance of the solids to weathering and their capability to provide a constant and long-lasting release of the bioactive ingredient. Aldehyde-containing bentonite clays have shown promising performance in controlling B. oleae infestation (with up to 86-95% reduction of affected olive fruits) in open-field trials across two years in two locations with different pedological and meteo-climatic characteristics.

Identification, characterization, and expression of lipoxygenase genes in sweet cherry (Prunus avium L.) cv. Regina and their relationship with the development of an herbaceous off-flavor during fruit ripening

Flavor is an essential characteristic of fruit quality and is significant for consumers. Off-flavors have been reported in several fruits, including sweet cherry. This fruit has been reported to show an herbaceous/grassy-like flavor. The herbaceous off-flavor in sweet cherries detected in cultivar Regina has been related to the differential development of aroma compounds such as short-chain aldehydes and esters. One of the main biosynthesis pathways for these compounds is the fatty acid oxidation mediated by lipoxygenases (LOX). In order to have a better understanding of the biological basis of the differences in the volatile profile, the LOX gene expression profile was characterized during fruit development with and without herbaceous off-flavor. A genome-wide analysis of LOX in sweet cherry was carried out and compared to other species such as Arabidopsis, tomato, apple, prunus and strawberry. The structural features of 9-LOX and 13-LOX genes, encoded protein domains and their synteny were examined. Moreover, we analyzed the LOX expression at four developmental stages along ripening by RT-qPCR. Thirteen LOX gene candidates (six 9-LOX and seven 13-LOX) were identified. The 13-LOXs, PaLOX10, PaLOX11, and PaLOX12 were differentially expressed in herbaceous sweet cherries. Furthermore, their expression profile positively correlated with key volatile compounds linked to the herbaceous off-flavor. Overall, this study involves the genome-wide characterization of the LOX family in Prunus avium cv. Regina and provides information that can aid in studying LOX-related fruit deterioration in sweet cherries and associated species.

Analysis of Anti-Inflammatory Properties of Plant Oxylipins Produced in the Hydroperoxide Lyase Branch

Short-chain and medium-chain aldehydes and their derivatives, yielded by the enzymes hydroperoxide lyases from fatty acids, are present in many products of plant origin. They are often used as supplements to food to postpone its expiration date and to add a flavor of freshness. Since these compounds can be absorbed by the intestine cells and pass into systemic circulation, it is important to be aware of their influence on human health. In the present study, the potential biological activity of aldehydes and alcohols with chains containing six to nine carbon atoms were assessed. Their proinflammatory activities were tested in the experimental system based on donors’ whole blood. It was found that nine-carbon oxylipins stimulated the synthesis of the proinflammatory TNF-α cytokine (tumor necrosis factor alpha), and the stimulation by the aldehydes was weaker than that caused by the alcohols. The oxylipins containing six or eight carbons did not manifest proinflammatory activity. The obtained data may be of help to work out nutritional recommendations for patients suffering from inflammatory diseases.

Wastewater from natural gas Cansolv desulfurization process: Comprehensive characterization and effective removal of organic compounds

The wastewater generated by the solvent amine desulfurization process in natural gas purification plants is characterized by its recalcitrant organic compounds and high salinity. Without effective treatment, it has the potential to inflict severe environmental harm. The composition of organic matter, however, exerts a profound influence on the outcomes of oxidation processes. To rectify the limitations associated with indiscriminate oxidation that yields suboptimal results, this investigation meticulously performed a molecular-level analysis of organic matter. Based on the organic matter composition in the influent, this study compared the treatment efficacy of three oxidation processes and determined O3/H2O2-Fenton as the optimal joint approach. After O3/H2O2 oxidation, long-chain unsaturated organic compounds (C > 40,DBE > 20) underwent degradation into short-chain aldehydes and low-molecular-weight fatty acids, with priority given to reactions involving CC, CO, and OH over CH reactions. Subsequent Fenton oxidation effectively removed the refractory organics (CHOS, CHONS) and significantly reduced the diversity of organic matter (from 7730 to 4237). The carboxylation, demethylation, and dehydrogenation reactions further facilitated the removal of recalcitrant organic compounds. In light of these findings, this study substantiates that the conversion of extended-chain unsaturated compounds into abbreviated-chain saturated compounds within the system through O3/H2O2 oxidation significantly enhances the subsequent efficacy of Fenton oxidation in organic matter removal. These insights offer valuable perspectives for the efficient remediation of analogous high-salinity organic wastewater scenarios.

Influence of Glow Discharge Plasma Treatment on Cashew Apple Juice’s Aroma Profile and Volatile Compounds

Cashew apple juice has a distinctive fruity aroma but contains an undesired balsamic/chemical note caused by the high concentration of styrene and other aromatic hydrocarbons. Cold plasma technology can induce chemical changes to fruit juices’ volatile compounds, improving the aroma of fruit juices. This study is aimed at evaluating the chemical effects of cold plasma on the volatile compounds and aroma of cashew apple juice, which is characterized by a complex mixture of compounds. Glow discharge plasma was applied to cashew apple juice, varying the plasma flow rate (10 to 30 mL/min) and processing time (10 to 20 min) at a constant voltage (80 kV). Plasma treatment induced several changes in the juice’s volatile compound composition, with a significant decrease in fatty acids and fatty acid esters (92%) and an increase in aldehydes (50%), alcohols (86%), and short-chain esters (21%). The primary reaction observed during plasma treatment was the internal scission of fatty acid and fatty acid esters, which formed short-chain esters and aldehydes. Further hydrogenation of aldehydes produced alcohols. The chemical changes induced by plasma treatment intensified cashew apple juice’s aroma by 28% while maintaining its aroma profile.

Addition of olivetol to crackers decreases malondialdehyde content and produces malondialdehyde-olivetol adducts

This study was undertaken to investigate the malondialdehyde-trapping ability by m-diphenols and the consequent decrease of malondialdehyde in foods. Olivetol was added to crackers, which were prepared with wheat flour and either oxidized or fresh sunflower, linseed, and camelina oils. When crackers were prepared with oxidized oils, olivetol-containing crackers contained less malondialdehyde (∼30%) than control crackers. This decrease of malondialdehyde content was parallel to the formation of malondialdehyde-olivetol adducts (250–1300 ng/g). When fresh oils were employed, storage produced more malondialdehyde (300–700%) in control than in olivetol-containing crackers. This decrease of malondialdehyde content was also parallel to the formation of malondialdehyde-olivetol adducts (10–90 ng/g). In both cases, the formation of adducts required the contribution of either formaldehyde or acetaldehyde. Obtained results suggest that olivetol not only removed malondialdehyde, but also short chain aldehydes, therefore contributing to the decrease of the content of these toxic aldehydes in phenolic-enriched crackers.

Amino-Acid-Derived Oxazolidin-5-Ones as Chemical Markers for Schiff Base Formation in Glycation Reactions

Imine or Schiff base formation is considered as a key event in the catalytic mechanisms of many enzymes and in certain biological transformations, including glycation. In this process, less stable amino-acid-derived Schiff bases rearrange into more stable ketoamines or Amadori products. Schiff bases are also stipulated to be stabilized through complexation with metal ions, or through intramolecular cyclization to form more stable and reversible cyclic isomers, such as oxazolidin-5-ones. These intermediates can be easily detected relative to Schiff bases due to their higher stability. In this study, high-resolution mass spectrometry and isotope labeling techniques were used to identify labile imines as their oxazolidin-5-one derivatives in heated reaction systems of glucose/alanine/FeCl2, including their 13C-labeled counterparts. The reaction mixtures were heated for 2h at 110 °C and were analyzed by high resolution qTOF/MS for the presence of masses corresponding to Schiff bases of α-alanine with short chain aldehydes that can be generated from glucose degradation and also for the incorporation of 13C-labeled atoms from 13C-3 alanine and 13C-U glucose. Analysis of the data has indicated that Schiff bases can indeed be detected in the form of oxazolidin-3-ones, when methanol is used as the solvent. Furthermore, it was discovered that metal-ion-stabilized Schiff bases, in addition to forming oxazolidin-3-ones, can also undergo aldol addition with short chain sugars and initiate oligomerization reactions, leading to the formation of dimeric or trimeric oxazolidin-3-one oligomers, as demonstrated by their characteristic MS/MS fragmentations.

Volatile Short-Chain Aliphatic Aldehydes Act as Taste Modulators through the Orally Expressed Calcium-Sensing Receptor CaSR.

Aldehydes are natural volatile aroma compounds generated by the Maillard reaction of sugars and amino acids in food and affect the flavor of food. They have been reported to exert taste-modifying effects, such as increases in taste intensity at concentrations below the odor detection threshold. The present study examined the taste-enhancing effects of short-chain aliphatic aldehydes, such as isovaleraldehyde (IVAH) and 2-methylbutyraldehyde, thus attempting to identify the taste receptors involved. The results obtained revealed that IVAH enhanced the taste intensity of taste solutions even under the condition of olfactory deprivation by a noseclip. Furthermore, IVAH activated the calcium-sensing receptor CaSR in vitro. Receptor assays on aldehyde analogues showed that C3-C6 aliphatic aldehydes and methional, a C4 sulfur aldehyde, activated CaSR. These aldehydes functioned as a positive allosteric modulator for CaSR. The relationship between the activation of CaSR and taste-modifying effects was investigated by a sensory evaluation. Taste-modifying effects were found to be dependent on the activation state of CaSR. Collectively, these results suggest that short-chain aliphatic aldehydes function as taste modulators that modify sensations by activating orally expressed CaSR. We propose that volatile aroma aldehydes may also partially contribute to the taste-modifying effect via the same molecular mechanism as kokumi substances.

Salivary Volatile Organic Compound Analysis: An Optimised Methodology and Longitudinal Assessment Using Direct Injection Mass Spectrometry

Analysis of salivary volatile organic compounds (VOCs) may offer a novel noninvasive modality for disease detection. This study aims to optimise saliva headspace VOC analysis and assess longitudinal variation of salivary VOCs. Whole saliva from healthy participants was acquired in order to assess four methodological parameters: saliva collection, volume, dilution, and acidification. Saliva VOCs were analysed using untargeted proton transfer reaction time-of-flight mass spectrometry. Using the optimised method, five saliva samples collected over 3 weeks assessed the longitudinal VOC variability and reproducibility with targeted selected ion flow tube-mass spectrometry analysis. The method of saliva collection influenced VOC detection and was a source of contamination. An amount of 500 µL of whole saliva by passive drool yielded optimal VOCs. Longitudinal variation was negligible with target short chain fatty acids and aldehydes. However, certain compounds showed variability suggesting the influence of potential exogenous factors. Overall, there was an acceptable range of inter- and intraindividual VOC variability. Standardisation with morning sampling after a 6 h fast is recommended demonstrating minimal intersubject variability. Future studies should seek to establish salivary VOC levels in healthy and diseased populations.

Development of an analytical chip for colorimetric detection of medium-chain aldehydes by reaction with pararosaniline in porous glass

Medium-chain aldehydes are common human biogases that can be detected in the breath of patients with lung diseases. As such, the measurement of medium-chain aldehyde gases in human breath can provide significant, noninvasive, and diagnostic information related to the potential presence of such diseases. In this study, an analytical chip is developed for the detection of medium-chain aldehydes without interference from short-chain aldehydes. This analytical chip is composed of porous glass impregnated with pararosaniline and an acid (i.e., acetic acid with small amount of phosphoric acid). After exposure to medium-chain aldehydes, the red analytical chip became violet in color, and an absorption peak was observed at 620 nm. It was found that a non-reversible reaction occurred in the porous glass, therefore, the analytical chip functions in a cumulative manner. A linear relationship was determined between the absorbance change of the analytical chip at 620 nm and the nonanal exposure concentration. Importantly, the developed analytical chip successfully detected nonanal at concentrations of 8–270 ppb as calculated from the absorbance change at 620 nm after a 24 h exposure time. In addition, nonanal concentration was estimated using the change in the R value of the analytical chip photograph. This method is suitable for point-of-care breath analysis. Finally, the analytical chip was also found to be active toward octanal and decanal with a relative sensitivity of 0.7 compared to that of nonanal; it was not active toward short-chain aldehydes.