Fatty Aldehydes Research Articles

Characterizing and Decoding the Effects of Different Fermentation Levels on Key Aroma Substances of Congou Black Tea by Sensomics.

Fermentation is the key technology for black tea aroma formation. The key aroma substances of black tea at different fermentation stages (unfermented (WDY), underfermented (F1H), fully fermented (F4H), and overfermented (F8H)) were characterized by the methodology of Sensomics. Aroma extract dilution analysis was performed on volatile fractions extracted by using solvent-assisted flavor evaporation and solid-phase microextraction, yielding 93 odor-active areas. Internal standard method plus stable isotope dilution analysis was used for quantitative analysis. The omission experiment identified 23 aroma substances. Further reduction and addition experiments revealed phenylacetaldehyde, (E,E)-2,4-heptadienal, geraniol, linalool, β-damascenone, 2-methylbutyraldehyde, dimethyl sulfide, and isovaleraldehyde with odor activity values (OAV) > 100 as the characteristic aroma components of F4H and also as the main contributors to aroma differences between different fermentation degrees. The green odor of (E,E)-2,4-heptadienal was highlighted in WDY and F1H relative to that in F4H due to the lower contribution of phenylacetaldehyde and β-damascenone in the former two samples. Additionally, excessive OAV increase of fatty aldehydes in F8H masked its similar floral and fruity aroma.

Wild Mushrooms: A Hidden Treasure of Novel Bioactive Compounds.

Secondary metabolites are hidden gems in mushrooms. Understanding these secondary metabolites' biological and pharmacological effects can be aided by identifying them. The purpose of this work was to profile the mycochemical components of the extracts of Auricularia auricula judae, Microporus xanthopus, Termitomyces umkowaani, Trametes elegans, and Trametes versicolor to comprehend their biological and pharmacological capabilities. Mushroom samples were collected from Kenya's Arabuko-Sokoke and Kakamega National Reserved Forests and identified using morphological and molecular techniques. Chloroform, 70% ethanol, and hot water solvents were used to extract the mycochemical components. Gas chromatography mass spectrometry (GC-MS) was used to analyze the chloroform, 70% ethanol, and hot water extracts of all the species examined. A total of 51 compounds were isolated from all extracts and classified as carboxylic acids, esters, phenols, fatty acids, alcohol, epoxides, aldehydes, fatty aldehydes, isoprenoid lipids, and steroids. Tetracosamethyl-cyclododecasiloxane (18.90%), oleic acid (72.90%), phenol, 2, 6-bis (1, 1-dimethylethyl)-4-methyl-, and methylcarbamate (26.56%) were all found in high concentrations in A. auricular judae, M. xanthopus, T. umkowaani, T. elegans, and T. versicolor, respectively. Fatty acids make up the majority of the compounds isolated from the T. elegans chloroform extract and the T. umkowaani 70% ethanol extract, respectively. Particularly, these fatty acids play crucial roles in the anti-inflammatory, hypocholesterolemic, anticancer, and antibiofilm formation activities. These bioactive elements indicate that the extracts of five wild mushrooms may be reliable sources of secondary metabolites for therapeutic development. Therefore, additional research is required to comprehend the usefulness of these chemicals in many functional areas and to improve the present understanding of macrofungi.

Comparative analysis of the crystal morphology, chemical composition and key gene expression between two kumquat fruit cuticular waxes during postharvest cold storage

Waxes have an important protective role in the postharvest storage potential of fruit. However, there are few studies in which the waxes of fruit of kumquat cultivars have been analysed. In this work, the fruit of a kumquat mutant with a relatively thin skin ('Huapi' kumquat, HPK) was found to present lower fruit weight loss and decay during cold storage than the fruit of the control ('Rongan' kumquat, RAK) did. Scanning electron microscopy observations revealed the epicuticular wax crystals on the HPK fruit were more abundant and larger than those on the RAK fruit at harvest. Gas chromatography-mass spectrometry analysis showed the amounts of total wax, triterpenoids and most of the aliphatic wax fractions on the HPK fruit were much higher than those on the RAK fruit throughout the cold storage process. Correlation analysis showed that differences in amounts of fatty acids and aldehydes might be key factors responsible for the differences in the postharvest traits between the two kumquat cultivars. Additionally, the real-time quantitative RT-PCR analysis results indicated that 12 genes involved in wax synthesis, transport and transcription were considered to play important roles in regulating the wax formation of kumquat fruit during cold storage.

Milk volatilome as affected by somatic cell count in Holstein cows

The aim of the current trial was to study the impact of a high somatic cell count (SCC) on milk volatilome of fresh raw milk, and its evolution during storage of processed fluid milk. Six Holstein cows were selected from our research dairy herd based on test-day SCC records. Three cows were used to produce low-SCC milk (20 × 103 cells/mL). The three other cows had one-quarter infected by Staphylococcus aureus. Infected and healthy udder halves were milked separately, and high-SCC milk was standardized to 400 × 103 cells/mL by mixing these two milks. The profile of milk volatile organic compounds (VOCs) was determined on raw milk and during the storage of processed milk. The processing included a standardization to 3.25% fat, followed by homogenization, and thermization (65 °C/30 min). This procedure was repeated four times over a period of 7 days. A total of 40 VOC were identified using the solid-phase microextraction technique followed by gas chromatography separation, mass spectrometry analysis, and database search. These VOC were grouped into seven different families, including alcohols (n = 4), free fatty acids (n = 5), sulfur compounds (n = 3), esters (n = 7), ketones (n = 7), aldehydes (n = 12), and aromatic hydrocarbons (n = 2). In raw milk, high SCC was associated with a tendency for lower concentrations of ethyl-hexanoate (P = 0.07), acetone (P = 0.06), and benzaldehyde (P = 0.07) and lower concentrations of trans-2 hexenal (P = 0.04). On the contrary, high SCC was associated with a tendency for greater concentrations of acetic acid (P = 0.09) and hexanoic acid (P = 0.07) and greater concentrations of 2-nonanone (P = 0.02) and pentanal (P = 0.01). Concentrations of most VOC increased during the storage of processed milk. Lower concentrations of butanoic acid (P = 0.09; tendency) and ethyl hexanoate (P = 0.04), and greater concentration of 1-ocen-3-ol (P < 0.01) were observed in high-SCC milk at all times of storage evaluated. Increases in concentrations over time were less pronounced for ethanol (P < 0.01), ethyl butanoate (P = 0.05), and propanal (P = 0.10) in high SCC as compared with low SCC milk. In conclusion, an increase in SCC has a limited effect on milk volatilome, when a SCC standard of 400 × 103 cells/mL for bulk milk is respected.

Fatty acid metabolism and C9 aldehyde biosynthesis are involved in ε-poly-l-lysine-induced citrus fruit resistance to Penicillium digitatum

Citrus fruit were easily infected by Penicillium digitatum, and caused green mold rapidly, resulting in enormous post-harvest losses. ε-poly-l-lysine (ε-PL) was generally regarded as a safe (GRAS) substance. Besides, it was proved to have a dual effect on harming fungi and triggering fruit defense responses. Fatty acid metabolism is closely related to fruit defense response. However, little is known about how ε-PL affected fatty acid metabolism in citrus fruit. Here, we found that ε-PL increased the expression of CsFATA, CsACSL, CsFAD2, CsFAD3, CsLOX2S, and CsHPL in fatty acid metabolism, decreasing oleic acid levels and enhancing linoleic and linolenic acid levels. Additionally, ε-PL enriched the activities of LOX and HPL during the oxidative decomposition of fatty acids, and activating C9 aldehyde biosynthesis. Interestingly, ε-PL combined with (2E,4E)-nonadienal (C9 aldehyde) would improve the inhibitory effect against Penicillium digitatum. And the combined bio-fungicide significantly delayed the citrus green mold compared to single concentrations of the individual components. These results suggested that ε-PL improved citrus fruit defense responses through fatty acid-mediated defense responses. Combined bio-fungicide consisting of ε-PL and (2E,4E)-nonadienal have an excellent prospect for controlling citrus green mold.

Colour and pigment in raw ground meat incorporated crushed garlic during the refrigerated storage: Their relationship to lipolytic and volatilomic changes.

The effects of freshly crushed garlic incorporated in raw ground meat at different rates 0% to 2% on colour, pigment forms, TBARS, peroxide, free fatty acids and volatilomic were investigated during 96h storage at 4°C. With advancing storage time and increasing garlic rate from 0% to 2%, the redness (a*), colour stability, oxymyoglobin and deoxymyoglobin decreased, but metmyoglobin, TBARS, peroxide, free fatty acids (C6, C15-C17), and aldehydes and alcohols, especially hexanal, hexanol, benzaldehyde, increased. Principal component analysis based on pigment, colour, lipolytic and volatilomic changes classified successfully the meat samples. Metmyoglobin was positively correlated with lipid oxidation products (TBARS, hexanal), but the other pigment forms and colour parameters (a* and b* values) were negatively correlated. Increased metmyoglobin proportion and decreased redness and colour stability may be used as reliable indicators of lipid oxidation. Also, the incorporation of fresh garlic into ground meat was not promising to increase oxidative stability.

Sjogren-Larsson syndrome brain volumetric reductions demonstrated with an automated software.

Sjogren-Larsson syndrome (SLS) is a neurocutaneous disease with an autosomal recessive inheritance, caused by mutations in the gene that encodes fatty aldehyde dehydrogenase (ALDH3A2), clinically characterized by ichthyosis, spastic diplegia, and cognitive impairment. Brain imaging plays an essential role in the diagnosis, demonstrating a nonspecific leukoencephalopathy. Data regarding brain atrophy and grey matter involvement is scarce and discordant. We performed a volumetric analysis of the brain of two siblings with SLS with the aim of detecting deep grey matter nuclei, cerebellar grey matter, and brainstem volume reduction in these patients. Volume data obtained from the brain magnetic resonance imaging (MRI) of the two patients using an automated segmentation software (Freesurfer) was compared with the volumes of a healthy control group. Statistically significant volume reduction was found in the cerebellum cortex, the brainstem, the thalamus, and the pallidum nuclei. Volume reduction in grey matter leads to the hypothesis that SLS is not a pure leukoencephalopathy. Grey matter structures affected in the present study suggest a dysfunction more prominent in the thalamic motor pathways.

Bioactive Compounds with Pesticide Activities Derived from Aged Cultures of Green Microalgae.

The excessive use of synthetic pesticides has caused environmental problems and human health risks and increased the development of resistance in several organisms. Allelochemicals, secondary metabolites produced as part of the defense mechanisms in plants and microorganisms, are an attractive alternative to replace synthetic pesticides to remediate these problems. Microalgae are natural producers of a wide range of allelochemicals. Thus, they provide new opportunities to identify secondary metabolites with pesticide activities and an alternative approach to discover new modes of action and circumvent resistance. We screened 10 green microalgae strains belonging to the Chlorophyta phylum for their potential to inhibit the growth of photosynthetic and nonphotosynthetic organisms. Bioassays were established to assess microalgae extracts' effectiveness in controlling the growth of Chlorella sorokiniana, Arabidopsis thaliana, Amaranthus palmeri, and the model nematode Caenorhabditis elegans. All tested strains exhibited herbicidal, nematocidal, or algicidal activities. Importantly, methanol extracts of a Chlamydomonas strain effectively controlled the germination and growth of a glyphosate-resistant A. palmeri biotype. Likewise, some microalgae extracts effectively killed C. elegans L1 larvae. Comprehensive metabolic profiling using LC-MS of extracts with pesticide activities showed that the metabolite composition of Chlamydomonas, Chlorella, and Chloroidium extracts is diverse. Molecules such as fatty acids, isoquinoline alkaloids, aldehydes, and cinnamic acids were more abundant, suggesting their participation in the pesticide activities.

The volatilome reveals microcystin concentration, microbial composition, and oxidative stress in a critical Oregon freshwater lake.

Toxins produced by cyanobacterial blooms in freshwater lakes are a serious public health problem. The conditions leading to toxin production are unpredictable, thereby requiring expensive sampling and monitoring programs globally. We explored the potential of volatile organic compounds (VOCs) to indicate microcystin presence and concentration and microbial community composition in Upper Klamath Lake, Oregon. Elastic net regularization regression selected 24 of 229 detected m/z + 1 values (corresponding to unique VOCs) in models predicting microcystin contamination. These models outperformed regression models based only on environmental parameters, including chlorophyll, pH, and temperature. Several m/z + 1 values selected by elastic net were putatively identified as saturated fatty aldehydes, which defend cyanobacteria against oxidative stress. Elastic net also identified unique sets of m/z + 1 values that predicted the relative abundance of the dominant bacterial phyla, classes, and cyanobacterial genera. VOCs appear to reveal the physiological status of cyanobacteria during toxic blooms and may be a key component of lake monitoring strategies. IMPORTANCE Harmful algal blooms are among the most significant threats to drinking water safety. Blooms dominated by cyanobacteria can produce potentially harmful toxins and, despite intensive research, toxin production remains unpredictable. We measured gaseous molecules in Upper Klamath Lake, Oregon, over 2 years and used them to predict the presence and concentration of the cyanotoxin, microcystin, and microbial community composition. Subsets of gaseous compounds were identified that are associated with microcystin production during oxidative stress, pointing to ecosystem-level interactions leading to microcystin contamination. Our approach shows potential for gaseous molecules to be harnessed in monitoring critical waterways.

Effects of Stigmasterol on 3-Chloropropane-1,2-diol Fatty Acid Esters and Aldehydes Formation in Heated Soybean Oil.

In this study, we investigated the inhibitory effects of three soybean isoflavones and two soybean phytosterols on the formation of 3-chloropropane-1,2-diol fatty acid esters (3-MCPDE) and aldehydes in heated soybean oil model. 0.4 mM of genistin, genistein, daidzein, stigmasterol, and β-sitosterol significantly reduced 3-MCPDE formation by 25.7, 51.4, 21.4, 61.6, and 55.7%, and total aldehydes formation by 42.03, 43.94, 28.36, 54.74, and 39.23%, respectively. Further study showed that stigmasterol reduced the content of glycidyl esters (GEs) and glycidol, two key intermediates of 3-MCPDE, and prevented fatty acids degradation in the oils. Moreover, the effects of continuous frying time on the content of stigmasterol and the migration of stigmasterol were evaluated in the fried dough sticks model system. The content of stigmasterol in soybean oil was found to be significantly decreased with prolonged heating time. The concentrations of stigmasterol in fried dough sticks and the migration rates of stigmasterol from soybean oil to fried dough sticks decreased with repeated frying sessions. In addition, stigmasterol undergoes oxidative changes during heat treatment, and the oxidation products including 5,6α-epoxystigmasterol, 5,6β-epoxystigmasterol, 7α-hydroxystigmasterol, 7β-hydroxystigmasterol, stigmasterlol-3β,5α,6β-triol, and 7-ketostigmasterol were identified in the frying oils but not in the fried dough sticks. Overall, stigmasterol could be added to soybean oil to reduce 3-MCPDE and aldehydes formation, and reacting with GEs/glycidol and protection of lipid acids from oxidation may be the mechanism of action of stigmasterol.

Supplementing branched-chain volatile fatty acids in dual-flow cultures varying in dietary forage and corn oil concentrations. II: Biohydrogenation and incorporation into bacterial lipids

To maintain membrane homeostasis, ruminal bacteria synthesize branched-chain fatty acids (BCFA) or their derivatives (vinyl ethers) that are recovered during methylation procedures as branched-chain aldehydes (BCALD). Many strains of cellulolytic bacteria require 1 or more branched-chain volatile fatty acid (BCVFA). Therefore, the objective of this study was to investigate BCVFA incorporation into bacterial lipids under different dietary conditions. The study was an incomplete block design with 8 continuous culture fermenters used in 4 periods with treatments (n = 4) arranged as a 2 × 2 × 2 factorial. The factors were high (HF) or low forage (LF, 67 or 33% forage, 33:67 alfalfa:orchardgrass), without or with supplemental corn oil (CO; 3% dry matter, 1.5% linoleic fatty acid), and without or with 2.15 mmol/d (5 mg/d 13C each of isovalerate, isobutyrate, and 2-methylbutyrate). After methylation of bacterial pellets collected from each fermenter's effluent, fatty acids and fatty aldehydes were separated before analysis by gas chromatography and isotope ratio mass spectrometry. Supplementation of BCVFA did not influence biohydrogenation extent. Label was only recovered in branched-chain lipids. Lower forage inclusion decreased BCFA in bacterial fatty acid profile from 9.45% with HF to 7.06% with LF and decreased BCALD in bacterial aldehyde profile from 55.4% with HF to 51.4% with LF. Supplemental CO tended to decrease iso even-chain BCFA and decreased iso even-chain BCALD in their bacterial lipid profiles. The main 18:1 isomer was cis-9 18:1, which increased (P < 0.01) by 25% from CO (data not shown). Dose recovery in bacterial lipids was 43.3% lower with LF than HF. Supplemental CO decreased recovery in the HF diet but increased recovery with LF (diet × CO interaction). Recovery from anteiso odd-chain BCFA and BCALD was the greatest; therefore, 2-methylbutyrate was the BCVFA primer most used for branched-chain lipid synthesis. Recovery in iso odd-chain fatty acids (isovalerate as primer) was greater than label recovery in iso even-chain fatty acids (isobutyrate as primer). Fatty aldehydes were less than 6% of total bacterial lipids, but 26.0% of 13C recovered in lipids were recovered in BCALD because greater than 50% of aldehydes were branched-chain. Because BCFA and BCALD are important in the function and growth of bacteria, especially cellulolytics, BCVFA supplementation can support the rumen microbial consortium, increasing fiber degradation and efficiency of microbial protein synthesis.

Quality control, ontogenetic variability and sensory profiling of ‘cilantro-mimic’ spiny coriander (Eryngium foetidum L.): A flavour perspective

Spiny coriander (Eryngium foetidum L.) is a cilantro-flavoured aromatic oil-bearing herb and traditional food flavouring agent. In this study, a gas chromatography-mass spectrometry technique was developed in conjunction with cluster analysis for its quality control and chemotaxonomic differentiation with common coriander. Spiny coriander was distinguished by a high ratio of fatty aldehydes versus fatty alcohols (378.5:1.0) and trans-alkenals versus alkanals (16.3:1.0) in the essential oil. A systematic investigation on its ontogenetic variability recommended the harvest of whole aerial part at full maturity to maximize the oil yield (24.6 mg/plant). Various sensory analyses established the uniqueness in its odour with more pungency (but less sweet and earthy) compared to common coriander. Volatile chemo-profiling revealed high abundance of fatty aldehydes (98.36%) over alcohols (not detected) as the chemical origin of its sensorial distinguishability. trans-2-Dodecenal, major oil constituent was found to be the key odorant and odour-mimic to this herb. The preference test demonstrated the potential of its essential oil (0.005–0.01% v/v) as a unique and readymade natural flavour in soup. Thus, the current study described an authentication technique, ontogenetic variability and sensorial profile of spiny coriander oil in reference to common coriander that may encourage its inclusion in food industries.

The flavour of grape colour: anthocyanin content tunes aroma precursor composition by altering the berry microenvironment.

Anthocyanin-less (white) instead of black/red (coloured) fruits develop in grapevine cultivars without functional VviMYBA1 and VviMYBA2 genes, which conditions the colour of wines that can be produced. To evaluate whether this genetic variation has additional consequences on fruit ripening and composition, we performed microenvironment, transcriptomics and metabolomics comparisons of developing grapes between near-isogenic white- and black-berried somatic variants of Garnacha and Tempranillo cultivars. Berry temperature was up to 3.5ºC lower in white- compared to black-berried Tempranillo. An RNA-seq study combined with targeted and untargeted metabolomics revealed that ripening fruits of white-berried variants were characterized by the upregulation of photosynthesis and other light-responsive genes and their higher accumulation of specific terpene aroma precursors, fatty acid-derived aldehyde volatiles and phenylpropanoid precursor amino acids. MYBA1-MYBA2 function proved essential for flavonol trihydroxylation in black-berried somatic variants, which were also characterized by enhanced pathogen defence gene expression in berry skin and increased accumulation of C6-derived alcohol and ester volatiles and GABA. Collectively, our results indicate that anthocyanin depletion entails side effects on grape composition by altering the berry internal microenvironment and the partition of the phenylpropanoid pathway. These findings show how fruit colour can condition other fruit features, such as flavour potential and stress homeostasis.

Possibility for detecting 14 typical odorants occurring in drinking water by employing human odor-binding protein OBP2a

Odor issues occurring in drinking water have been a big challenge to face for water suppliers globally, which highly commend to develop quick or on-site odor detection tools for the management of odor problems. Olfactory sensors based on odor-binding proteins (OBPs) have been utilized to analyze pollutants in food and air samples, while their application for the detection of typical odor-causing compounds in drinking water is rarely reported, partly due to the lack of knowledge about the binding properties of odorants. In this study, the binding affinity and mechanism of human odor-binding protein OBP2a to 14 typical odorants in water were first assessed using fluorescent competitive binding assays and molecular docking techniques. The 14 odorants include 7 aldehydes, 2 terpenes, 2 thioethers, bis(2-chloro-1-methylethyl) ether (DCIP), 2-ethyl-4-methyl-1,3-dioxolane (2E4MDL), and 2-isobutyl-3-methoxypyrazine (IBMP). The results showed that OBP2a could bind to 9 odorants (Ki = 29.91 μmol/L–48.36 μmol/L), including IBMP, 2-MIB, and six aldehydes (hexanal, heptanal, benzaldehyde, 2-octenal, decanal, and β-cyclocitral), among which stronger binding affinity for aldehydes is observed (Ki = 29.91 μmol/L–43.87 μmol/L). Molecular docking confirmed that Lys112 and Phe97 are major amino acid residues involved in the binding of the most target odorants. To be specific, IBMP and aldehydes can form hydrogen bonds with Lys112; aromatic ring-containing odorants such as IBMP and benzaldehyde can also form pi–pi stacking with Phe97. The binding affinity of OBP2a to fatty aldehydes including hexanal, heptanal, 2-octenal, decanal, and β-cyclocitral increased with the increase of hydrophobicity of aldehydes. The valuable information to the binding of OBP2a to typical odorants in this study would provide a theoretical foundation for the development of OBP-based odor detection biosensors to achieve quick detection in drinking water, further helping the improvement of water treatment processes in the water industry.Graphical

Sunflower Oil Winterization Using the Cellulose-Based Filtration Aid-Investigation of Oil Quality during Industrial Filtration Probe.

Waxes, phospholipids, free fatty acids, peroxides, aldehydes, soap, trace metals and moisture present in crude sunflower oil have a negative effect on the oil quality and are, therefore, removed during the refining process. Waxes crystallizing at low temperatures are removed during winterization by cooling and filtration. Waxes have poor filtration characteristics and an industrial filtration process must be enhanced by the use of filtration aids, which improve filter cake structure and properties, and consequently prolong the filtration cycle. Today, traditional filtration aids (diatomite, perlite, etc.) being used in the industry are frequently replaced by cellulose-based aids. The aim of this study is to examine the effect of oil filtration assisted by two cellulose-based filtration aids on the chemical parameters (wax, moisture, phospholipids, soaps, and fatty acids), oil transparency, carotenoids, and Fe and Cu content of sunflower oil obtained in an industrial horizontal pressure leaf filter. In order to investigate the mentioned parameters, the following techniques were used: gravimetric (waxes and moisture content), spectrophotometric (phospholipids and carotenoid content and oil transparency), volumetric (soaps and free fatty acids content) as well as inductively coupled plasma mass spectrometry (ICP-MS) for Fe and Cu content. An artificial neural network model (ANN) was employed for the prediction of removal efficiency based on the chemical quality, oil transparency, Fe and Cu content in oils before filtration, as well as filtration aid quantity and filtration time. Cellulose-based filtration aids had multiple beneficial effects; on average, 99.20% of waxes, 74.88% of phospholipids, 100% of soap, 7.99% of carotenoids, 16.39% of Fe and 18.33% of Cu were removed.

Ultra-high performance liquid chromatography high-resolution mass spectrometry for metabolomic analysis of dental calculus from Duke Alessandro Farnese and Maria D’Aviz

Dental calculus is a valuable resource for the reconstruction of dietary habits and oral microbiome of past populations. In 2020 the remains of Duke Alessandro Farnese and his wife Maria D’Aviz were exhumed to get novel insights into the causes of death. This study aimed to investigate the dental calculus metabolome of the noble couple by untargeted metabolomics. The pulverized samples were decalcified in a water-formic acid mixture, extracted using methanol/acetonitrile and analyzed by ultra-high performance liquid chromatography coupled to high-resolution mass spectrometry (UHPLC-HRMS) using a reversed-phase separation followed by electrospray ionization and full scan in positive and negative ion mode. Waters Synapt-G2-Si High-Definition hybrid quadrupole time-of-flight mass spectrometer was used. Significant features were then identified using MSE acquisition mode, recording information on exact mass precursor and fragment ions within the same run. This approach, together with data pre-treatment and multivariate statistical analysis allowed for the identification of compounds able to differentiate between the investigated samples. More than 200 metabolites were identified, being fatty acids, alcohols, aldehydes, phosphatidylcholines, phosphatidylglycerols, ceramides and phosphatidylserines the most abundant classes. Metabolites deriving from food, bacteria and fungi were also determined, providing information on the habits and oral health status of the couple.

Untargeted Metabolomic Analysis of Sjögren-Larsson Syndrome Reveals a Distinctive Pattern of Multiple Disrupted Biochemical Pathways.

Sjögren-Larsson syndrome (SLS) is a rare inherited neurocutaneous disease characterized by ichthyosis, spastic diplegia or tetraplegia, intellectual disability and a distinctive retinopathy. SLS is caused by bi-allelic mutations in ALDH3A2, which codes for fatty aldehyde dehydrogenase (FALDH) and results in abnormal lipid metabolism. The biochemical abnormalities in SLS are not completely known, and the pathogenic mechanisms leading to symptoms are still unclear. To search for pathways that are perturbed in SLS, we performed untargeted metabolomic screening in 20 SLS subjects along with age- and sex-matched controls. Of 823 identified metabolites in plasma, 121 (14.7%) quantitatively differed in the overall SLS cohort from controls; 77 metabolites were decreased and 44 increased. Pathway analysis pointed to disrupted metabolism of sphingolipids, sterols, bile acids, glycogen, purines and certain amino acids such as tryptophan, aspartate and phenylalanine. Random forest analysis identified a unique metabolomic profile that had a predictive accuracy of 100% for discriminating SLS from controls. These results provide new insight into the abnormal biochemical pathways that likely contribute to disease in SLS and may constitute a biomarker panel for diagnosis and future therapeutic studies.

Biocatalytic Production of Odor-Active Fatty Aldehydes from Fungal Lipids.

Odor-active fatty aldehydes are important compounds for the flavor and fragrance industry. By a coupled enzymatic reaction using an α-dioxygenase (α-DOX) and an aldehyde dehydrogenase (FALDH), scarcely available aldehydes from the biotransformation of margaroleic acid [17:1(9Z)] were characterized and have shown highly interesting odor profiles, including citrus-like, soapy, herbaceous, and savory notes. In particular, (Z)-8-hexadecenal and (Z)-7-pentadecenal exhibited notable meaty odor characteristics. Submerged cultivation of Mortierella hyalina revealed the accumulation of the above-mentioned, naturally uncommon fatty acid 17:1(9Z). Its production was significantly increased by the modulation of culture conditions, whereas the highest accumulation was observed after 4 days at 24 °C and l-isoleucine supplementation. The lipase-, α-DOX-, and FALDH-mediated biotransformation of M. hyalina lipid extract resulted in a complex aldehyde mixture with a high aldehyde yield of ∼50%. The odor qualities of the formed aldehydes were assessed by means of gas chromatography-olfactometry, and several of the obtained fatty aldehydes have been sensorially described for the first time. To assess the aldehyde mixture's potential as a flavor ingredient, a sensory evaluation was conducted. The obtained product exhibited intense citrus-like, green, and soapy odor impressions.

Aging behavior of polyphosphoric acid/styrene-butadiene-styrene-modified bio-mixed asphalt based on high-temperature rheological properties and microscopic mechanism

This study investigates the performance of polyphosphoric acid/styrene–butadienestyrene (PPA/SBS)-modified bio-mixed asphalt after thermo-oxidative and ultraviolet (UV) aging, based on its high-temperature rheological properties and microscopic characteristics. The temperature sweep test results revealed that long-term thermo-oxidative aging significantly increased the dynamic shear moduli of the composite-modified asphalts, where the maximum increment in composite-modified asphalts reached to 425 %. However, the dynamic shear modulus of the composite-modified asphalt decreased owing to the degradation of aromatic aldehydes to fatty aldehydes after ultraviolet aging, leading to softer composite-modified asphalts. In addition, the multiple-stress creep recovery (MSCR) test revealed that the maximum increment in the recovery rate of composite modified asphalt reached to 37.4 %. Moreover, the increasing rate of Jnr was significantly lower than that of the control asphalt after long-term aging, particularly at a stress level of 3.2 kPa. Finally, the microstructures of each asphalt sample before and after aging were observed using atomic force microscopy. The surface morphology of the composite modified asphalt after aging was relatively smoother, indicating that the molecular homogeneity of the aging residue of the composite-modified asphalt sample was better than that of the control asphalt sample.

Ether lipids and a peroxisomal riddle in sperm.

Sperm are terminally differentiated cells that lack most of the membranous organelles, resulting in a high abundance of ether glycerolipids found across different species. Ether lipids include plasmalogens, platelet activating factor, GPI-anchors and seminolipid. These lipids play important roles in sperm function and performance, and thus are of special interest as potential fertility markers and therapeutic targets. In the present article, we first review the existing knowledge on the relevance of the different types of ether lipids for sperm production, maturation and function. To further understand ether-lipid metabolism in sperm, we then query available proteomic data from highly purified sperm, and produce a map of metabolic steps retained in these cells. Our analysis pinpoints the presence of a truncated ether lipid biosynthetic pathway that would be competent for the production of precursors through the initial peroxisomal core steps, but devoid of subsequent microsomal enzymes responsible for the final synthesis of all complex ether-lipids. Despite the widely accepted notion that sperm lack peroxisomes, the thorough analysis of published data conducted herein identifies nearly 70% of all known peroxisomal resident proteins as part of the sperm proteome. In view of this, we highlight open questions related to lipid metabolism and possible peroxisomal functions in sperm. We propose a repurposed role for the truncated peroxisomal ether-lipid pathway in detoxification of products from oxidative stress, which is known to critically influence sperm function. The likely presence of a peroxisomal-derived remnant compartment that could act as a sink for toxic fatty alcohols and fatty aldehydes generated by mitochondrial activity is discussed. With this perspective, our review provides a comprehensive metabolic map associated with ether-lipids and peroxisomal-related functions in sperm and offers new insights into potentially relevant antioxidant mechanisms that warrant further research.