Green leaf volatiles (GLVs) are important secondary organic aerosol (SOA) precursors, while the SOA for mechanisms, especially the structural effects of GLV isomers, remain largely understudied. In this study, the ozonolysis of Z-3-hexenal (Z-3-H) and T-2-hexenal (T-2-H) in the presence of SO2 was investigated in a 30 m3 smog chamber. The experimental results showed that the SOA concentration produced by Z-3-H was far greater than that of T-2-H, indicating a significant influence of molecular structure on SOA formation. Through the mechanism study, a C3-carbonyl-RO2 radical (CHOC2H4O2) was regarded as a key intermediate playing a central role in the Z-3-H and T-2-H SOA formation. Due to the different double-bond positions, the ozonation of Z-3-H undergoes a relatively simpler pathway than T-2-H to produce this intermediate, which is considered one of the reasons for the higher SOA concentration of Z-3-H. Another key reason is that the average concentration of stable Criegee intermediate (sCI) in the Z-3-H/O3/SO2 system is much higher than that in the T-2-H/O3/SO2 system. The high level of sCI not only directly promotes a series of sCI-involved intramolecular and intermolecular reactions but also drives the rapid formation of H2SO4, which facilitates organosulfate production and acid-catalyzed aldol condensation reaction.

The Colletotrichum genus is one of the ten most relevant pathogenic fungi in the post-harvest sector owing to its high infection rate in tropical fruits; however, the search for alternatives to synthetic fungicides is crucial because of their adverse effects on health and the environment. This study evaluated the efficacy of chitosan (CH), citral (CT), and hexanal (HX) against Colletotrichum asianum, as well as the toxicological potential of these treatments. In in vitro tests, 1.0% CH, 0.03% CT, and 0.06% HX significantly inhibited fungal development in parameters of radial growth, sporulation, fungal biomass, and germination by 78–100% (p < 0.05). Furthermore, the toxicity index was low to moderate for most concentrations using cucumber and tomato seed germination as a study model. Toxicokinetic predictions suggest that CH, CT, and HX molecules do not pose a danger to human consumption, suggesting that they are promising alternatives to chemical fungicides for the control of phytopathogenic fungi.

Herein, DFT calculations were performed to investigate various properties of Al/Sn-decorated arsenene, including its electronic structure, magnetism, and hexanal sensing. Three main systems were examined: pristine arsenene (p-As), aluminum (Al)-decorated arsenene (Al-As), and tin (Sn)-decorated arsenene (Sn-As). Results showed that both decorated systems exhibit magnetism in the ground state. The introduction of Al/Sn atoms significantly alters the electronic structure of arsenene by inducing defect-level states within the band gap. Al-As showed metallic characteristics, and Sn-As exhibited a small band gap. The strength and nature of chemical bonding between the X (X = Al and Sn) and As atoms were evaluated using COHP and ELF analysis. It was found that the X-As bond exhibited a mixed covalent and ionic character. Finally, the adsorption of a volatile organic compound (VOC), hexanal (HL), was investigated. We found that HL was weakly adsorbed on p-As and Sn-As. However, chemisorption was observed on Al-As due to a significant charge transfer through p-p overlapping. Thus, Al-As can be considered a promising candidate for HL sensing.

Plants perceive volatile organic compounds (VOCs) released by mechanically- or herbivore-damaged neighboring plants and induce various defense responses. Such interplant communication protects plants from environmental threats. However, the spatiotemporal dynamics of VOC sensory transduction in plants remain largely unknown. Using a wide-field real-time imaging method, we visualize an increase in cytosolic Ca2+ concentration ([Ca2+]cyt) in Arabidopsis leaves following exposure to VOCs emitted by injured plants. We identify two green leaf volatiles (GLVs), (Z)-3-hexenal (Z-3-HAL) and (E)-2-hexenal (E-2-HAL), which increase [Ca2+]cyt in Arabidopsis. These volatiles trigger the expression of biotic and abiotic stress-responsive genes in a Ca2+-dependent manner. Tissue-specific high-resolution Ca2+ imaging and stomatal mutant analysis reveal that [Ca2+]cyt increases instantly in guard cells and subsequently in mesophyll cells upon Z-3-HAL exposure. These results suggest that GLVs in the atmosphere are rapidly taken up by the inner tissues via stomata, leading to [Ca2+]cyt increases and subsequent defense responses in Arabidopsis leaves.

Odor-scavenging capabilities of pre-formed “empty” V-type starches for beany off-flavor compounds

Green leaf volatiles (GLVs), the common constituents of herbivore-infested plant volatiles (HIPVs), play an important role in plant defense and function as chemical cues to communicate with other individuals in nature. Reportedly, in addition to endogenous GLVs, the absorbance of airborne GLVs emitted by infested neighboring plants also play a major role in plant defense. For example, the exclusive accumulation of (Z)-3-hexenyl vicianoside in the HIPV-exposed tomato plants occurs by the glycosylation of airborne (Z)-3-hexenol (Z3HOL); however, it is unclear how plants process the other absorbed GLVs. This study demonstrates that tomato plants dominantly accumulated GLV–glycosides after exposure to green leaf alcohols [Z3HOL, (E)-2-hexenol, and n-hexanol] using non-targeted LC–MS analysis. Three types of green leaf alcohols were independently glycosylated without isomerization or saturation/desaturation. Airborne green leaf aldehydes and esters were also glycosylated, probably through converting aldehydes and esters into alcohols. Further, we validated these findings in Arabidopsis mutants- (Z)-3-hexenal (Z3HAL) reductase (chr) mutant that inhibits the conversion of Z3HAL to Z3HOL and the acetyl-CoA:(Z)-3-hexen-1-ol acetyltransferase (chat) mutant that impairs the conversion of Z3HOL to (Z)-3-hexenyl acetate. Exposure of the chr and chat mutants to Z3HAL accumulated lower and higher amounts of glycosides than their corresponding wild types (Col-0 and Ler), respectively. These findings suggest that plants process the exogenous GLVs by the reductase(s) and the esterase(s), and a part of the processed GLVs contribute to glycoside accumulation. Overall, the study provides insights into the understanding of the communication of the plants within their ecosystem, which could help develop strategies to protect the crops and maintain a balanced ecosystem.

This study investigated lipid oxidation and aldehyde formation in roasted scallop during in vitro gastrointestinal digestion, and the effects of co-digestion of antioxidant of bamboo leaves (AOB) on this process. The results showed that the contents of lipid hydroperoxides (LOOH), conjugated dienes (CD), and Schiff bases (SB) were increased during gastrointestinal digestion. Besides, malondialdehyde (MDA) levels and total aldehyde formation decreased initially at the gastric stage but increased at the intestinal stage. The results of HPLC-ESI-MS/MS analysis showed that the contents of hexanal (HEX), trans, trans-2,4-octadienal (ODE), trans, trans-2,4-decadienal (DDE), 4-hydroxyhexenal (HHE) and 4-hydroxynonenal (HNE) in the digestive juices were all initially decreased and then increased during gastrointestinal digestion. Meanwhile, the content of acrolein, propanal, and trans-2-pentenal at the end of intestinal digestion was lower than that in the initial stage of gastric digestion. Additionally, the digestion of roasted scallop caused significant oxidation of polyunsaturated fatty acids (PUFAs) and release of free fatty acids (FFA) in the intestinal phase, which were positively related to aldehyde production. However, co-digestion of AOB significantly reduced lipid oxidation and formation of lipid oxidation products (LOOH, CD, SB, and aldehyde) during gastrointestinal digestion, indicating that the addition of AOB was effective in reducing gastrointestinal lipid oxidation.

Continuous aldehydes monitoring in primary schools in France: Evaluation of emission sources and ventilation practices over 5 weeks

This research aimed to investigate the effect of different extraction methods and chemical composition of the essential oil (EO) and solid-phase microextraction (SPME) from Campanula latifolia L. sub-sp. latifolia which is native to Turkey, with different medicinal properties. Phenolic components, antioxidant and enzyme inhibitory effects of essential oil (EO), n-hexane, acetonitrile, methanol and water extracts of C. latifolia subsp. latifolia were also studied. The volatile components of the EO, SPME and SPME of n-hexane extracts, obtained from the Campanula latifolia L. subsp. latifolia, were analyzed by GC-FID/MS. A total of 32, 31 and 36 compounds were identified comprising 99.8 %, 99.9 % and 94.4 % of the SPME, SPME of n-hexane extract and EO of C. latifolia subsp. latifolia, respectively. The major compounds identified in the SPME and SPME of n-hexane extract were limonene (44.0 %) and 1,2,3-trimethyl benzene (27.4 %), respectively. Whereas the EO of Campanula latifolia subsp. latifolia was rich with capro aldehyde (23.1 %), nonanal (9.3 %), 2(E)-hexenal (6.8 %), benzene acetaldehyde (6.8 %), E-β-caryophyllene (4.4 %) and E-β-ionone (3.3 %). The phenolic content of extracts was analyzed by RP-HPLC. Results revealed the sinapic, benzoic, syringic and p-coumaric acids as major constituents. Antioxidant activities (DPPH, PRAP and FRAP) and enzyme inhibitory (tyrosinase, acetylcholinesterase (AChE) and α-glucosidase) effects of the EO, n-hexane, acetonitrile, methanol and water extracts obtained from C. latifolia subsp. latifolia were investigated. The acetonitrile extract, among the other extracts of C. latifolia subsp. latifolia, was found to have the highest antioxidant activity and inhibitory effect for all tested enzymes due to its high phenolic content.

Influence of culinary practices on protein and lipid oxidation of chicken meat burgers during cooking and in vitro gastrointestinal digestion

Four different corn oil samples including stripped (SCO, Control), refined (RCO), stripped corn oil enriched with rosemary extract (SCO+ROS) and ascorbyl palmitate (SCO+AP) were exposed to microwave (MWH) and conventional heating (CVH). For both heating methods, peroxide value (PV) and conjugated dienes increased at up to 230 °C, at which temperature hexanal (HEX) and conjugated trienes started to increase instead. Kinetic analysis revealed that PV and HEX formation were first ordered and the reaction rate among the samples was as follows: Control > SCO+ROS > RCO > SCO + AP for PV and SCO + ROS > RCO > SCO+AP > Control for HEX. The unsaturated fatty acid contents of CVH and MWH treated samples showed 9.5 and 12.9% reduction in SCO, while they were 2.9 and 7.7% in RCO, 3.6 and 6.1% in SCO + ROS, and finally 4.0 and 4.8% in SCO + AP. It was concluded that MWH led to a more severe deterioration and that the antioxidant activity of ROS was superior to that of AP for both heating methods.

Green leaf volatiles (GLVs), which have mostly been described as providers of protection against insect herbivory and necrotrophic pathogen infections, were recently shown to provide significant fortification against cold stress damage. It was further demonstrated that cold-damaged maize seedlings released a significant amount of GLVs, in particular, Z-3-hexenal (Z-3-HAL). Here, we report that the in-cold treatment of maize seedlings with Z-3-HAL significantly improved cold stress resistance. The transcripts for cold-protective genes were also significantly increased in the Z-3-HAL treated maize seedlings over those found in only cold stressed plants. Consequently, the maize seedlings treated with HAL during cold showed a significantly increased structural integrity, significantly less damage, and increased growth after cold stress, relative to the non-HAL treated maize seedlings. Together, these results demonstrate the protective effect of in-cold treatment with HAL against cold damage, and suggest that the perception of these compounds during cold episodes significantly improves resistance against this abiotic stress.

Rice fragrance is one of the most important and determining factors in rice quality. Aromatic rice is a special group considered to be of the best quality. It is important to know the physiological behavior and genetic source of aromatic rice in order to improve breeding programs. In this research, thirteen rice cultivars were used for molecular and biochemical evaluations. The research population included three aromatic cultivars and ten cultivars from Khuzestan province in Iran. Thirteen SSR and four MAS markers related to grain aroma were used for genotyping the rice cultivars. The highest PIC for SSR markers was 0.75. Cluster analysis using the UPGMA method classified all cultivars into three groups. The results of MAS for EAP and INSP primers showed a molecular band of 355 bp in the non-aromatic rice cultivars. In this study, four non-aromatic cultivars (Hamar (Sorkheh), Danial, Garde Ramhormoz, and Hoveizeh) were detected. The results of IFAP and ESP primers further revealed a band of 257 bp, identified in Tarom, Domsiah, Basmati, Anbarbo Najafi, Anbarbo Red, Anbarbo Yellow, Kadoos, Champa, and Shafagh, all aromatic cultivars. Moreover, the volatile components of rice seed samples were extracted and identified using the sensitive and efficient solid phase extraction method, GC-MS. Eight compounds (aldehyde, pentane, hexanal, heptane, tetradecane, ketone, acetic acid, and 2-acetyl-1-pyrroline) were identified from the studied cultivars as the most important chemical compositions of aroma in rice. The 2-AP compound was recognized in Tarom, Domsiah, and Anbarbo Najafi cultivars. Finally, four MAS primers identified all aromatic rice cultivars as well as thirteen SSR markers related to rice fragrance.

Volatile aldehydes sensing in headspace using a room temperature ionic liquid-modified electrochemical microprobe

Effects of commercial aldehydes from green leaf volatiles (green odour) on rumen microbial population and fermentation profile in an artificial rumen (Rusitec)

Researchers in nanocomposite processing may inhale a variety of chemical agents, including nanoparticles. This study investigated airway oxidative stress status in the exhaled breath condensate (EBC). Nineteen employees (42.4 ± 11.4 y/o), working in nanocomposites research for 18.0 ± 10.3 years were examined pre-shift and post-shift on a random workday, together with nineteen controls (45.5 ± 11.7 y/o). Panels of oxidative stress biomarkers derived from lipids, nucleic acids, and proteins were analyzed in the EBC. Aerosol exposures were monitored during three major nanoparticle generation operations: smelting and welding (workshop 1) and nanocomposite machining (workshop 2) using a suite of real-time and integrated instruments. Mass concentrations during these operations were 0.120, 1.840, and 0.804 mg/m3, respectively. Median particle number concentrations were 4.8 × 104, 1.3 × 105, and 5.4 × 105 particles/cm3, respectively. Nanoparticles accounted for 95, 40, and 61%, respectively, with prevailing Fe and Mn. All markers of nucleic acid and protein oxidation, malondialdehyde, and aldehydes C6–C13 were elevated, already in the pre-shift samples relative to controls in both workshops. Significant post-shift elevations were documented in lipid oxidation markers. Significant associations were found between working in nanocomposite synthesis and EBC biomarkers. More research is needed to understand the contribution of nanoparticles from nanocomposite processing in inducing oxidative stress, relative to other co-exposures generated during welding, smelting, and secondary oxidation processes, in these workshops.

Retention and release kinetics of aroma compounds from white sauces made with native waxy maize and potato starches: Effects of storage time and composition

White-nose syndrome (WNS) is caused by Pseudogymnoascus destructans, a psychrophilic fungus that infects hibernating bats and has caused a serious decline in some species. Natural aroma compounds have been used to control growth of fungal food storage pathogens, so we hypothesized that a similar strategy could work for control of P. destructans. The effectiveness of exposure to low concentrations of the vapor phase of four of these compounds was tested on mycelial plugs and conidiospores at temperatures of 5, 10 and 15 °C. Here we report the efficacy of vapor phase mushroom alcohol (1-octen-3-ol) for inhibiting mycelial and conidiospore growth of P. destructans at 0.4 and 0.8 µmol/mL and demonstrate that the R enantiomer of this compound is more effective than the S enantiomer, supporting the finding that biological systems can be sensitive to stereochemistry. Further, we report that vapor phase leaf aldehyde (trans-2-hexenal), a common aroma compound associated with cut grass odors and also the major volatile compound in extra virgin olive oil, is more effective than mushroom alcohol. At 0.05 µmol/mL, trans-2-hexenal is fungicidal to both conidiospores and mycelia of P. destructans.

E-2-hexenal is a volatile compound that is commonly emitted by wounded or stressed plants. It belongs to the group of so-called green leaf volatiles (GLVs), which play an important role in transferring information to plants and insects. While most biosynthetic enzymes upstream of E-2-hexenal have been studied extensively, much less is known about the enzyme responsible for the conversion from Z-3- to E-2-hexenal. In this study we have identified two (3Z):(2E)-hexenal isomerases (HIs) from cucumber fruits by classical biochemical fractionation techniques and we were able to confirm their activity by heterologous expression. Recombinant protein of the HIs did not only convert the leaf aldehyde Z-3-hexenal to E-2-hexenal, but also (Z,Z)-3,6-nonadienal to (E,Z)-2,6-nonadienal, these last two representing major flavor volatiles of cucumber fruits. Transient expression of the cucumber HIs in Nicotiana benthamiana leaves drastically changed the GLV bouquet of damaged plants from a Z-3- to an E-2-enriched GLV profile. Furthermore, transcriptional analysis revealed that the two HIs showed distinct expression patterns. While HI-1 was specifically expressed in the flesh of cucumber fruits HI-2 was expressed in leaves as well. Interestingly, wounding of cucumber leaves caused only a slight increase in HI-2 transcript levels. These results demonstrate that cucumber HIs are responsible for the rearrangement of Z-3-aldehydes in both leaves and fruits. Future research will reveal the physiological importance of an increased conversion to E-2-aldehydes for plants and insects.

Researches regarding the assessment of heritability and phenotypic, genotypic and environmental correlations in some traits of a laying hen line