Volatile Organic Compounds Profiles Research Articles

Antibacterial activity of <i>Arthrobacter</i> strains isolated from Great Gobi A Strictly Protected Area, Mongolia

<abstract> <p>Desert soil hosts many microorganisms, whose activities are essential from an ecological viewpoint. Moreover, they are of great anthropic interest. The knowledge of extreme environments microbiomes may be beneficial for agriculture, technology, and human health. In this study, 11 <italic>Arthrobacter</italic> strains from topsoil samples collected from the Great Gobi A Strictly Protected Area in the Gobi Desert, were characterized by a combination of different techniques. The phylogenetic analysis, performed using their 16S rDNA sequences and the most similar <italic>Arthrobacter</italic> sequences found in databases, revealed that most of them were close to <italic>A. crystallopoietes</italic>, while others joined a sister group to the clade formed by <italic>A. humicola, A. pascens</italic>, and <italic>A. oryzae</italic>. The resistance of each strain to different antibiotics, heavy-metals, and NaCl was also tested as well as the inhibitory potential against human pathogens (i.e., <italic>Burkholderia</italic> ssp., <italic>Klebsiella pneumoniae, Pseudomonas aeruginosa</italic>, and <italic>Staphylococcus</italic> ssp.) via cross-streaking, to check the production of metabolites with antimicrobial activity. Data obtained revealed that all strains were resistant to heavy metals and were able to strongly interfere with the growth of many of the human pathogens tested. The volatile organic compounds (VOCs) profile of the 11 <italic>Arthrobacter</italic> strains was also analyzed. A total of 16 different metabolites were found, some of which were already known for having an inhibitory action against different Gram-positive and Gram-negative bacteria. Isolate MS-3A13, producing the highest quantity of VOCs, is the most efficient against <italic>Burkholderia cepacia</italic> complex (Bcc), <italic>K. pneumoniae</italic>, and coagulase-negative Staphylococci (CoNS) strains. This work highlights the importance of understanding microbial populations' phenotypical characteristics and dynamics in extreme environments to uncover the antimicrobial potential of new species and strains.</p> </abstract>

Gut microbiota functional profiling in autism spectrum disorders: bacterial VOCs and related metabolic pathways acting as disease biomarkers and predictors.

Autism spectrum disorder (ASD) is a multifactorial neurodevelopmental disorder. Major interplays between the gastrointestinal (GI) tract and the central nervous system (CNS) seem to be driven by gut microbiota (GM). Herein, we provide a GM functional characterization, based on GM metabolomics, mapping of bacterial biochemical pathways, and anamnestic, clinical, and nutritional patient metadata. Fecal samples collected from children with ASD and neurotypical children were analyzed by gas-chromatography mass spectrometry coupled with solid phase microextraction (GC-MS/SPME) to determine volatile organic compounds (VOCs) associated with the metataxonomic approach by 16S rRNA gene sequencing. Multivariate and univariate statistical analyses assessed differential VOC profiles and relationships with ASD anamnestic and clinical features for biomarker discovery. Multiple web-based and machine learning (ML) models identified metabolic predictors of disease and network analyses correlated GM ecological and metabolic patterns. The GM core volatilome for all ASD patients was characterized by a high concentration of 1-pentanol, 1-butanol, phenyl ethyl alcohol; benzeneacetaldehyde, octadecanal, tetradecanal; methyl isobutyl ketone, 2-hexanone, acetone; acetic, propanoic, 3-methyl-butanoic and 2-methyl-propanoic acids; indole and skatole; and o-cymene. Patients were stratified based on age, GI symptoms, and ASD severity symptoms. Disease risk prediction allowed us to associate butanoic acid with subjects older than 5 years, indole with the absence of GI symptoms and low disease severity, propanoic acid with the ASD risk group, and p-cymene with ASD symptoms, all based on the predictive CBCL-EXT scale. The HistGradientBoostingClassifier model classified ASD patients vs. CTRLs by an accuracy of 89%, based on methyl isobutyl ketone, benzeneacetaldehyde, phenyl ethyl alcohol, ethanol, butanoic acid, octadecane, acetic acid, skatole, and tetradecanal features. LogisticRegression models corroborated methyl isobutyl ketone, benzeneacetaldehyde, phenyl ethyl alcohol, skatole, and acetic acid as ASD predictors. Our results will aid the development of advanced clinical decision support systems (CDSSs), assisted by ML models, for advanced ASD-personalized medicine, based on omics data integrated into electronic health/medical records. Furthermore, new ASD screening strategies based on GM-related predictors could be used to improve ASD risk assessment by uncovering novel ASD onset and risk predictors.

Correlation between microbial communities and volatile organic compounds in an urban soil provides clues on soil quality towards sustainability of city flowerbeds

Soil functionality is critical to the biosphere as it provides ecosystem services relevant for a healthy planet. The soil microbial composition is significantly impacted by anthropogenic activities, including urbanization. In this context, the study of soil microorganisms associated to urban green spaces has started to be crucial toward sustainable city development. Microbes living in the soil produce and degrade volatile organic compounds (VOCs). The VOC profiles may be used to distinguish between soils with various characteristics and management practices, reflecting variations in the activity of soil microbes that use a variety of metabolic pathways. Here, a combined approach based on DNA metabarcoding and GC-MS analysis was used to evaluate the soil quality from urban flowerbeds in Prato (Tuscany, Italy) in terms of microbial biodiversity and VOC emission profiles, with the final aim of evaluating the possible correlation between composition of microbial community and VOC patterns. Results showed that VOCs in the considered soil originated from anthropic and biological activity, and significant correlations between specific microbial taxa and VOCs were detected. Overall, the study demonstrated the feasibility of the use of microbe-VOC correlation as a proxy for soil quality assessment in urban soils.

Screening and characterization of biocontrol bacteria isolated from Ageratum conyzoides against Collectotrichum fructicola causing Chinese plum (Prunus salicina Lindl.) anthracnose.

Chinese plum (Prunus salicina Lindl.) is a nutritionally and economically important stone fruit widely grown around the world. Anthracnose, caused by Collectotrichum spp., is one of the primary biotic stress factors limiting plum production. Medicinal plants may harbor rhizospheric or endophytic microorganisms that produce bioactive metabolites that can be used as anthracnose biocontrol agents. Here, 27 bacterial isolates from the medicinal plant A. conyzoides with diverse antagonistic activities against C. fructicola were screened. Based on morphological, physiological, biochemical, and molecular characterization, 25 of these isolates belong to different species of genus Bacillus, one to Pseudomonas monsensis, and one more to Microbacterium phyllosphaerae. Eight representative strains showed high biocontrol efficacy against plum anthracnose in a pot experiment. In addition, several Bacillus isolates showed a broad spectrum of inhibitory activity against a variety of fungal phytopathogens. Analysis of the volatile organic compound profile of these eight representative strains revealed a total of 47 compounds, most of which were ketones, while the others included alkanes, alkenes, alcohols, pyrazines, and phenols. Overall, this study confirmed the potential value of eight bacterial isolates for development as anthracnose biocontrol agents.

Identification, semi-quantification, and dynamics of volatile organic compounds during spontaneous fermentation of two cocoa varieties from northern Peru, using HS-SPME/GC-MS techniques

During spontaneous fermentation, an important process through which cocoa beans pass, volatile organic compounds (VOCs) and non-VOCs are generated and act as precursors of aromas and flavors that influence the chocolate. In the north of Peru, cocoas of different varieties and qualities are grown, and one of the most valued is the fine aroma native cocoa (Cacao Fino de Aroma (CFA)) compared with the Castro Naranjal 51 Collection (CCN-51) variety. In this investigation, the VOCs generated during the spontaneous fermentation of CFA and CCN-51 varieties, from the department of Amazonas, Peru, were analyzed. For the extraction of VOCs, the headspace (HS) and solid-phase microextraction (SPME) techniques were used, while gas chromatography coupled to a mass spectrophotometer (GC-MS) was employed for their subsequent separation and identification. The spontaneous fermentation process lasted for 156 h, and a total of 122 VOCs were identified in 2 varieties. The dynamics of 20 VOCs were assessed, and the principal component analysis of 22 VOCs was performed to compare the profiles of VOC of the 2 cocoa varieties. In conclusion, the CFA variety presented higher concentrations of floral, fruity, and sweet aromatic VOCs that positively influence the quality of the chocolate.

Development of an Innovative Optoelectronic Nose for Detecting Adulteration in Quince Seed Oil.

In this study, an innovative odor imaging system capable of detecting adulteration in quince seed edible oils mixed with sunflower oil and sesame oil based on their volatile organic compound (VOC) profiles was developed. The system comprises a colorimetric sensor array (CSA), a data acquisition unit, and a machine learning algorithm for identifying adulterants. The CSA was created using a method that involves applying a mixture of six different pH indicators (methyl violet, chlorophenol red, Nile blue, methyl orange, alizarin, cresol red) onto a Thin Layer Chromatography (TLC) silica gel plate. Subsequently, difference maps were generated by subtracting the "initial" image from the "final" image, with the resulting color changes being converted into digital data, which were then further analyzed using Principal Component Analysis (PCA). Following this, a Support Vector Machine was employed to scrutinize quince seed oil that had been adulterated with varying proportions of sunflower oil and sesame oil. The classifier was progressively supplied with an increasing number of principal components (PCs), starting from one and incrementally increasing up to five. Each time, the classifier was optimized to determine the hyperparameters utilizing a random search algorithm. With one to five PCs, the classification error accounted for a range of 37.18% to 1.29%. According to the results, this novel system is simple, cost-effective, and has potential applications in food quality control and consumer protection.

Tailor-made fermentation of sourdough reduces the acrylamide content in rye crispbread and improves its sensory and nutritional characteristics

Thirty strains of lactic acid bacteria (LAB) and Saccharomyces cerevisiae E8.9 (wild type) were used to formulate fifteen combinations of starters by mixing two or three LAB with the yeast (ratio LAB: yeast, 10: 1). Such combinations were used to prepare rye sourdough and their performance in term of acidification and biochemical characteristics during fermentation at two temperatures (30 and 37 °C) and duration (4 and 8 h) were screened. The best thirteen sourdough formulations were selected and used for rye crispbread making. The analysis of acrylamide concentration demonstrated that 11 out 13 formulations resulted in significant decreases of concentration compared to the baker's yeast (control), with reductions up to 79.6 %. The rye sourdough crispbreads showed also higher amount of volatile organic compounds (VOCs) compared to the baker's yeast control. Two rye sourdough crispbreads, selected to represent the opposite extremes within the thirteen formulations in term of VOC profiles and fermentation performances, demonstrated better sensory and nutritional features, such as phytic acid reduction (up to 47.3 %), and enhanced total free amino acid compared to the control. These evidences suggest the potential of tailored sourdough fermentations as alternative and suitable biotechnological strategy for lowering acrylamide levels in rye crispbread.

Compositional Characteristics, Fatty Acid Profile, Phenolic Content and Volatile Organic Compounds (VOCs) of Feta Cheese Made in Mountainous Grasslands and Plains of Greece

The study aimed to compare the physicochemical composition, fatty acid profile, phenolic content and volatile organic compounds (VOCs) of feta cheese produced in two regions in Greece (mountainous grasslands and plains). The VOC profiles of forage in the mountainous grasslands were also investigated in order to detect any relationship between the two profiles. Forbs were found to be the major functional group in the mountainous area and the most abundant VOCs were aldehydes, alcohols, and terpenes. Significant variations were observed between the main compositional features of the two types of cheeses, with the cheese produced from the milk of ewes and goats grazing in the mountainous region having a higher moisture content, lower fat content, and higher protein content. A total of 34 VOCs were identified and the most abundant groups in the cheese samples were esters, hydrocarbons, and alcohols. The fatty acid profile, phenolic content, and terpene profile of the cheese were also affected by the type of pasture. The cheese produced from the milk of ewes and goats grazing in the mountainous region also had a higher content of conjugated linoleic acid (CLA) and a lower content of saturated fatty acids (SFAs). These findings suggest that the grasslands grazed by ewes and goats in the mountainous region have a positive impact on the nutritional quality of feta cheese.

The Influence of the Vacuum Impregnation, Beetroot Juice, and Various Drying Methods on Selected Properties of Courgette and Broccoli Snacks.

The drying process is used in the food industry to extend the shelf life of fruits and vegetables without the use of preservatives. As quality, visual, and aroma characteristics are important determinants of consumer interest, they play a key role in the development of new foods. In the present study, vacuum impregnation (VI) was used prior to vacuum drying (VD) and freeze drying (FD) of courgette and broccoli. Organic beet juice was used to produce the novel snacks. The study showed that the use of vacuum impregnation significantly affected the VOCs profile (volatile organic compounds profile), in which the following compounds were found: viz: 2-(E)-hexen-1-ol, 2-(Z)-hexen-1-ol and aceto-phenone. VI caused a decrease in volumetric gel index (VGI), drying shrinkage (S), water activity (AW), decreased color saturation (∆C), and increased dry matter content (DM). All these properties testify to the positive effect of the pretreatment used. The drying methods used had a significant effect on the properties of the dried vegetables. The dries obtained by the FD method showed higher density and water activity, as well as better preserved color (lower ∆E) and higher VOCs, so it is considered that freeze drying is a suitable method for obtaining novel courgette and broccoli snacks.

Detection of volatile organic compounds in headspace of Klebsiella pneumoniae and Klebsiella oxytoca colonies

IntroductionEarly diagnosis of infections and sepsis is essential as adequate therapy improves the outcome. Unfortunately, current diagnostics are invasive and time-consuming, making diagnosis difficult, especially in neonatology. Novel non-invasive analytical methods might be suitable to detect an infection at an early stage and might even allow identification of the pathogen. Our aim is to identify specific profiles of volatile organic compounds (VOCs) of bacterial species.MethodsUsing multicapillary column-coupled ion mobility spectrometry (MCC/IMS), we performed headspace measurements of bacterial cultures from skin and anal swabs of premature infants obtained during weekly screening for bacterial colonization according to KRINKO. We analyzed 25 Klebsiella pneumoniae (KP) cultures on MacConkey (MC) agar plates, 25 Klebsiella oxytoca (KO) cultures on MC agar and 25 bare MC agar plates as a control group.ResultsUsing MCC/IMS, we identified a total of 159 VOC peaks. 85 peaks allowed discriminating KP and bare MC agar plates, and 51 peaks comparing KO and bare MC agar plates and 6 peaks between KP and KO (significance level of p < 0.05 after Bonferroni post hoc analysis), respectively. Peaks P51 (n-Decane) and P158 (Phenylethyl Alcohol), showed the best sensitivity/specificity/ positive predictive value/negative predictive value of 99.9% each (p < 0.001) for KP. P158 showed the best sensitivity/specificity/positive predictive value/negative predictive value of 99.9% each (p < 0.001) for KO. Comparing KP and KO, best differentiation was enabled using peaks P72, P97 and P16 with sensitivity/specificity/positive predictive value/negative predictive value of 76.0%, 84.0%, 82.6%, 77.8%, respectively (p < 0.05).DiscussionWe developed a method for the analysis of VOC profiles of bacteria. Using MCC/IMS, we demonstrated that VOCs derived from bacteria are clearly distinguishable from a bare agar plate. Characteristic peaks obtained by MCC/IMS are particularly suitable for the species-specific identification and differentiation of KP and KO. Thus, MCC/IMS might be a useful tool for in vitro diagnostics. Future studies must clarify whether similar patterns of VOCs can be detected in vivo in patients that are colonized or infected with KP or KO to enable rapid and accurate diagnosis of bacterial colonization.

Changes in Composition of Some Bioactive Molecules upon Inclusion of Lacticaseibacillus paracasei Probiotic Strains into a Standard Yogurt Starter Culture.

Incorporation of probiotic Lacticaseibacillus paracasei into a standard yogurt starter culture can drastically improve its health promoting properties. However, besides being an advantage in itself, the incorporation of a new probiotic strain can significantly affect the overall composition of fermented milk. In this article, the effect of incorporation of the L. paracasei probiotic strains (KF1 and MA3) into several standard yogurt starter cultures (consisting of the following strains: Streptococcus thermophilus 16t and either Lactobacillus delbrueckii Lb100 or L. delbrueckii Lb200) was investigated. Such parameters as the degree of proteolysis, antioxidant activity, ACE-inhibitory activity, content of organic acids, profile of FAs and profile of volatile organic compounds were measured, and the influence of the starter culture composition on these parameters was described. It was demonstrated that, at least in the case of the studied strains, yogurt with L. paracasei had an advantage over the standard yogurt in terms of the content of acetoin, acetic acid, butyric acid and conjugated linoleic acid. Moreover, the incorporation of L. paracasei KF1 significantly improved the hypotensive properties of the resulting yogurt. Thus, the presented study provides insight into the bioactive molecules of probiotic yogurt and may be useful for both academia and industry in the development of new dairy-based functional products.

Characterization of Italian honeys: integrating volatile and physico-chemical data

This article focuses on the comprehensive characterization of Italian honeys using various physico-chemical analyses and their volatile organic compounds (VOCs) fingerprint obtained through the PTR-ToF-MS technology. Honey characteristics, including pH, electrical conductivity, moisture content, hydroxymethylfurfural (HMF), and sugar content, were analyzed to assess their quality and origin. Honey samples from different flowers, including acacia, chestnut, citrus, linden, and multifloral, were collected and investigated. Furthermore, a few aged honeys were collected and analyzed and compared with the fresh ones. Physico-chemical analysis revealed that chestnut honey is characterized by high pH and EC values. Acacia honey has a higher fructose content, while aging appears to influence HMF levels, a vital indicator of honey quality, with aged samples exhibiting significant increases in HMF content. The VOC profiles have been found to vary among different honey types, suggesting that VOCs could be used as indicators of honey origin. Multivariate statistical analyses, such as partial least squares discriminant analysis (PLS-DA), have been applied to the VOCs data to differentiate honey types based on their volatile profiles. Acacia honey exhibited different physicochemical parameters but on the contrary, in the VOCs analysis, it displayed similarities with the linden honey due to their shared low emissions of volatile compounds. Citrus honey had similar chemical parameters to linden and multifloral honeys, but its distinctive VOCs emission allowed for a more accurate identification. In conclusion, the analysis performed with the PTR-ToF-MS was successful in obtaining specific volatile fingerprints of those samples and was effective for improving the characterization of honeys.

Protection against oxygen in the vinification of the red grape Nerello Mascalese affects volatile organic compounds profile

We hypothesised that the protection against oxygen (PAO) of must and wine during vinification by avoiding contact with air can preserve the primary volatile organic compounds (VOCs) of Nerello Mascalese. PAO was performed in two seasons (2020 and 2021) using carbon dioxide pellets (CO2,s) and gas (CO2,g), inactivated yeasts and ascorbic acid during fermentation; the control wine was made via traditional vinification without adding the aforementioned components. During fermentation, the two winemaking processes mainly differed in terms of the application of aeration during maceration/fermentation in the pump-over and délestage activities, and the care taken to avoid contact with oxygen during racking. In both years, higher concentrations of polyphenols and total anthocyanins were found in the PAO wine (about 16 % and 20 % respectively). The concentrations of nerol, citronellol and geraniol were significantly higher in the PAO wine in both seasons, albeit with small differences which affected the sensory evaluation. The free/bound terpenes ratio was 0.35 (PAO) and 0.55 (Control). Bound C13-norisoprenoids contents were higher than the free ones; in the PAO wine, free 3-oxo-α-ionol and bound vomifoliol concentrations were slightly higher than in the control wine. Thiols were measured in Nerello for the first time. In 2020 in particular, sulfanylhexan-1-ol was present in larger amounts in the PAO wine. Applying PAO in the production of Nerello Mascalese modified certain VOCs, as well as the overall free/bound ratio due to the increase in bound VOCs, thus influencing the aroma of the wine.

Butter from Different Species: Composition and Quality Parameters of Products Commercialized in the South of Spain.

Butter is an important product for the dairy industry due to its particular sensory attributes and nutritional value, while the variability of the composition of the fatty acids in the milk can alter the nutritional and physical properties of butter and its acceptance by consumers. Butter is highly appreciated for its distinctive flavor and aroma; however, one of its main drawbacks lies in the difficulty in spreading it at low temperatures. Several types of butter that are present in the market were used in this study. We assessed the variability in the composition of the samples regarding their texture, color properties, and volatile organic compound profiles. We analyzed samples commercially produced from sheep's milk (SB), goat's milk (GB), and cow's milk (CB); samples from the latter species with (CSB) and without salt (CB); and the low-fat (CLB) version. All the physicochemical composition parameters were significantly affected by the effect of the type of butter, although only 29 out of the 45 fatty acids examined were identified in the butter samples analyzed. The textural properties of the butters were influenced by both their solid fat content and the fatty acid profile. In addition, the origin of the milk not only affected the texture parameters but also the color of the butters and the compounds associated with traits such as odor and flavor. Through the multivariate data analysis of butter fatty acids and volatile compound percentages, we observed a clear differentiation of the samples based on the species of origin.

The volatilome signatures of Plasmodium falciparum parasites during the intraerythrocytic development cycle in vitro under exposure to artemisinin drug

Volatile organic compounds (VOCs) comprise a diverse range of metabolites with high vapour pressure and low boiling points. Although they have received attention, they are a largely unexplored part of the metabolome. Previous studies have shown that malaria infections produce characteristic, definitive, and detectable volatile signatures. Many transcriptional and metabolic differences are observed at different stages of the parasite Intraerythrocytic Developmental Cycle (IDC) as well as when artemisinin-resistant parasites are put under drug pressure. This prompted our research to characterize whether these responses are reflected at a volatile level in malaria during the IDC stages using gas chromatography-mass spectrometry. We investigated whether the resistant P. falciparum parasites would produce their own characteristic volatilome profile compared to near-isogenic wild-type parasite in vitro; firstly at three different stages of the IDC and secondly in the presence or absence of artemisinin drug treatment. Finally, we explored the VOC profiles from two media environments (Human serum and Albumax) of recently lab-adapted field parasite isolates, from Southeast Asia and West/East Africa, compared to long-term lab-adapted parasites. Recognizable differences were observed between IDC stages, with schizonts having the largest difference between wild type and resistant parasites, and with cyclohexanol and 2,5,5-trimethylheptane only present for resistant schizonts. Artemisinin treatment had little effect on the resistant parasite VOC profile, whilst for the wild type parasites compounds ethylbenzene and nonanal were greatly affected. Lastly, differing culturing conditions had an observable impact on parasite VOC profile and clustering patterns of parasites were specific to geographic origin. The results presented here provide the foundation for future studies on VOC based characterization of P. falciparum strains differing in abilities to tolerate artemisinin.

Desorption Kinetics Profiling of Volatile Organic Compounds in Nanoporous Anodic Alumina Photonic Crystal Optical Microcavities

Desorption Kinetics Profiling of Volatile Organic Compounds in Nanoporous Anodic Alumina Photonic Crystal Optical Microcavities

Effects of Isochoric Freezing on the Quality Characteristics of Raw Bovine Milk.

This study investigated the effects of isochoric freezing (IF) on the shelf-life and quality of raw bovine milk over a 5-week period. The results were compared with conventional refrigeration (RF) and refrigeration after pasteurization (HTST). The IF treatment process entailed storing liquid raw milk in isochoric chambers in thermodynamic equilibrium at -5 °C/77 MPa and -10 °C/96 MPa. Several parameters were analyzed, including microbiology count, physicochemical properties, indigenous enzyme activity, protein content, volatile organic compounds profile, and lipid degradation. Both raw and pasteurized milk experienced increases in the microbial level past the acceptable threshold (≥5.5 log CFU/mL) after 2 weeks and 5 weeks, respectively, leading to the deterioration of other parameters during storage. In comparison, microbiology count decreased significantly during storage for both IF treatment conditions but was more pronounced for the higher pressure (96 MPa) treatment, leading to undetectable levels of microorganism after 5 weeks. IF treatment maintained stable pH, titratable acidity, viscosity, lipid oxidation, volatile profiles, total protein content, and lactoperoxidase activity throughout the storage period. Color was preserved during IF treatment at -5 °C/77 MPa; however, color was impacted during IF treatment at -10 °C/96 MPa. Protein structures were also modified during pressurized storage in both IF treatments. Overall, the study demonstrated that isochoric freezing could significantly increase the shelf-life of milk by reducing microbiology activity, whilst maintaining its nutritional content. These results underscore the potential role of isochoric freezing as a valuable tool in eliminating pathogens while maintaining quality characteristics similar to raw milk over long storage periods.

Mentha suaveolens as Allelopathic Biomass for Weed Control: Phenolics, Organic Acids, and Volatile Organic Compounds Profiles

The need to find alternatives to synthetic herbicides has led to the evaluation of the use of allelopathic biomass from different agroforestry species as soil amendments for weed control. Mentha suaveolens Ehrh. (apple mint) could be a suitable candidate as an ecoherbicide due to its availability in the agroecosystem, well-studied biological activities, and known chemical composition. For the present study, two greenhouse pot experiments were conducted by incorporating flowering aerial biomass of apple mint into the soil. In the first one, the potential phytotoxic effects of M. suaveolens at doses 1 and 2% were evaluated on the germination and growth of maize and its accompanying weeds. In a second temporary assay, the duration of phytotoxicity and the effects of apple mint (0.5% dose) on the physicochemical properties of the soil were elucidated. The soluble (phenolics and organic acids) and volatile compounds potentially releasable from the allelopathic biomass were identified. The apple mint exerted adverse effects on the germination and growth of dicotyledonous weed species, especially Amaranthus retroflexus and Solanum nigrum, with almost 100% inhibition, as well as on the growth of monocotyledonous weeds such as Digitaria sanguinalis, with a reduction of more than 95%. On the contrary, maize yield and soil properties pH, CECe, organic matter, and exchangeable cations were improved by the ecoherbicide. Chemical analyses of apple mint aerial biomass revealed the presence of 7 phenolic compounds, 9 organic acids, and 32 volatiles. For this study, the effects of incorporating M. suaveolens aerial biomass into soil were evaluated for the first time, and it was demonstrated that it has potential as an eco-friendly plant-based tool for Integrated Weed Management.

Genotypes of Eruca vesicaria subsp. sativa grown in contrasting field environments differ on transcriptomic and metabolomic levels, significantly impacting nutritional quality.

Rocket (Eruca vesicaria subsp. sativa) is a source of sulfur-containing glucosinolates (GSLs). GSLs and their breakdown hydrolysis products (GHPs) are responsible for health-related benefits, such as anti-cancer and anti-neurodegenerative properties. Understanding how phytochemical composition changes between cultivation environments is key to developing cultivars with improved nutritional quality. Two consecutive harvests (first and second regrowth) of crops, grown in both Italy and the UK, were used to determine the phytochemical and transcriptomic differences between six lines of Eruca. Samples were taken upon delivery from field sites (D0) and after five days of cold storage (D5) for each location. Leaves were analysed for sulfur content, volatile organic compounds (VOCs), GSLs, GHPs, and sugars. Transcriptome data were associated with metabolite profiles to identify differentially expressed genes between plants grown in the two environments. VOC compounds (carbon disulfide, methyl thiocyanate) were associated with growth environment and with differences in sulfur metabolism gene expression (APR2, LSU2, LSU3, SDI1, SiR), GSL biosynthesis (MYB28, FMOGS-OX2) and GHP formation (ESM1, TGG1, TGG2). The concentrations of sugars were an order of magnitude greater in UK grown samples (up to 29.9 mg g-1 dry weight; dw). Sulfur content was significantly higher in the Italy plant samples (11.4 - 20.1 mg g-1 dw), which was in turn associated with higher concentrations of GSLs (pentyl GSL, up to 15.8 μmol g-1 dw; sinigrin, up to 0.005 μmol g-1 dw; glucoraphanin, up to 5.1 μmol g-1 dw; glucorucolamine, up to 23.6 μmol g-1 dw; neoglucobrassicin, up to 5.3 μmol g-1 dw) and hydrolysis products (sativin, up to 13.5 μmol g-1 dw; erucin, up to 1 μmol g-1 dw; sulforaphane, up to 34.7 μmol g-1 dw). VOC profiles of plants cultivated in the UK were distinct from Italy grown plants, with higher relative abundances of alkanes and esters in second cut and shelf-life (D5) samples. The data indicate a significant interaction of cultivar response with environment, highlighting the difficulty of producing Eruca crops with consistent phytochemical and postharvest traits. Genes with differential expression between plants grown in Italy and the UK could be used as markers of phytochemical quality and composition.

70. The volatile organic compound profile in commercial post-weaning diets differ from gestating or lactating diets potentially contributing to neophobic feeding behaviours in piglets

70. The volatile organic compound profile in commercial post-weaning diets differ from gestating or lactating diets potentially contributing to neophobic feeding behaviours in piglets