Production Of Volatile Organic Compounds Research Articles

211 Analysis of microbial communities from a commercial-size swine manure pit and their association with production of volatile organic compounds

Abstract Global pollution and emission concerns have been linked to concentrated animal feeding operations (CAFOs). Indeed, the U.S Environmental Protection Agency (US EPA) warns that there is a significant danger to human health, soil, and water quality from CAFOs. Volatile organic compounds (VOCs), which are amongst air contaminants that pose a serious risk, are abundantly produced in swine manure pits. While VOC emissions from swine manure have been well studied, the microbial species responsible for their production remain mostly uncharacterized. Thus, a deeper comprehension of the microorganisms responsible for VOC production in swine manure pits may help in the development of management approaches that target the microbiome in these environments. In this context, this study aimed to identify the major bacterial species populating the manure pit of a commercial-size swine wean-to-finish research facility. Manure collected from two sampling locations at different time points were analyzed using the 16S rRNA gene through PCR-amplification of the V1-V3 regions from microbial genomic DNA, followed by Illumina MiSeq 2X300 sequencing. An analysis of the most highly represented microorganisms identified 24 bacterial Operational Taxonomic Units (OTUs), with only four showing a species-level nucleotide sequence identity to currently known or valid species. As these results indicated that the majority of bacterial species from this manure pit were unknown, a metagenomics approach was used to assemble partial to full length genomes from the two most abundant OTUs: Pit_9-00239 [5.09% - 19.44%; Clostridium saccharoperbutylacetonicum (96.60%)] and Pit_ 7-00035 [5.58% - 17.30%; Bacteroides eggerthii (87.66%)]. From genome assembly analysis, 979 contigs were generated for a combined length of 12,367,510 bp, which together included 21,776 coding sequences. Predicted metabolic functions from these contig sets included pathways involved in carbohydrate utilization (glycolysis), vitamin synthesis (riboflavin), and butyrate production (volatile fatty acids). Notably, an enzyme responsible for the production of indole, a common VOC produced from swine manure pits, was also identified. Together, the results from this analysis provide insights on metabolic capabilities of abundant bacterial species from manure pits. These can in turn be used for the future development of management strategies or products that can reduce VOC emissions that result from swine CAFO manure storage.

The contributions of Pichia kudriavzevii EP1 to sourdough: Acid utilization, oligosaccharides and peptides production and aroma enhancement

Previous studies have demonstrated that co-fermenting Pichia kudriavzevii EP1 (EP) and Fructilactobacillus sanfranciscensis can enhance the aroma of sourdough bread. This research aimed to examine the fermentation mechanism of EP compared to Saccharomyces cerevisiae (N) in sourdough and investigate the pathways involved in aroma production. Gas chromatography was used to analyze volatile organic compounds (VOCs) and their correlative essential metabolites. Metabolomics and proteomics were utilized to track changes in metabolic pathways and protein expression during fermentation. The findings revealed that EP fermentation resulted in a significant decrease in VOCs like 2-phenylethanol and octanoic acid, while showing a notable increase (384%) in hexanol production. Essential metabolites revealed reduced utilization of sugars and amino acids, and decreased generation of organic acids like lactic and acetic acid. Specifically, EP fermentation led to decreased levels of glucose-6-phosphate dehydrogenase, pyruvate kinase, NAD+, and NADH, while ATP showed a significant increase. Metabolomics and proteomics analyses highlighted reduced utilization of sugars and amino acids for VOCs production. Consequently, sourdough fermented with EP was rich in oligosaccharides and small peptide molecules. EP utilized organic acids not only to reduce sourdough acidity but also to generate acetyl-CoA. Acetyl-CoA served as energy sources for metabolic activities, such as catalyzing transformations between asparagine, aspartate, glutamate, and glutamine, and played a role in producing higher alcohols like hexanol to enhance sourdough aroma. These findings suggest that EP prefers acid utilization over sugars and amino acids, offering a potential strategy for enhancing sourdough aroma through individual or combined fermentations with other microbiotas.

Inhibitory Effect and Potential Antagonistic Mechanism of Isolated Epiphytic Yeasts against Botrytis cinerea and Alternaria alternata in Postharvest Blueberry Fruits.

This study evaluated the biocontrol effect of isolated epiphytic yeasts (Papiliotrema terrestris, Hanseniaspora uvarum, and Rhodosporidium glutinis) against Botrytis cinerea and Alternaria alternata in blueberry fruits and its possible mechanisms. Our findings indicated that the three tested yeasts exerted a good biocontrol effect on postharvest diseases in blueberry, and that H. uvarum was the most effective. In addition, the three tested yeasts could improve the postharvest storage quality of blueberry fruits to some extent. H. uvarum demonstrated the strongest direct inhibitory effect on pathogens by suppressing spore germination, mycelial growth, and antifungal volatile organic compound (VOC) production. P. terrestris showed the highest extracellular lytic enzymes activities. It also had better adaptation to low temperature in fruit wounds at 4 °C. The biofilm formation capacity was suggested to be the main action mechanism of R. glutinis, which rapidly colonized fruit wounds at 20 °C. Several action mechanisms are employed by the superb biocontrol yeasts, while yeast strains possess distinctive characteristics and have substantially different action mechanisms.

Evaluation of Antifungal Activity of Endophytic Bacillus spp. and Identification of Secondary Metabolites Produced Against the Phytopathogenic Fungi.

Endophytic bacteria serve as a rich source of diverse antimicrobial compounds. Recently, there has been a growing interest in utilizing endophytic Bacillus spp. as biological agents against phytogenic fungi, owing to their potential to produce a wide range of antimicrobial substances. The objective of this research was to investigate the protective abilities of 15 endophytic Bacillus spp. isolated from previous study from wheat plant, against the phytopathogenic fungi, Fusarium graminearum and Macrophomina phaseolina. A dual culture plate assay was conducted as a preliminary analysis, revealing that 7 out of 15 endophytic Bacillus spp. demonstrated inhibition against one or both of the phytopathogenic fungi used in this study. All seven endophytes were further assessed for the presence of diffusible antifungal metabolites. The cultures were grown in potato dextrose broth for 120h, and the cell-free supernatant was extracted and analyzed using the cup plate method. The methanolic extract yielded similar results to the dual culture plate analysis, except for WL2-15. Additionally, deformities in the mycelial structure were examined under the light microscope upon exposure to methanolic extract. Furthermore, the analysis and identification of metabolites were carried out via gas chromatography-mass spectrometry of methanolic extract from selected seven endophytic Bacillus spp. The chromatogram revealed the presence of some major peaks such as tridecanoic acid, methyl ester, hydroperoxide, 1-methylbutyl, 9-octadecenamide, (z)-, hexane-1,3,4-triol, 3,5-dimethyl- tetradecanoic acid. To the best of our knowledge, this is the first report of these biocontrol agents in endophytic Bacillus spp. Interestingly, volatile organic compound production was also seen in all the isolates against the phytopathogenic fungi.

Rapid and non-destructive microbial quality prediction of fresh pork stored under modified atmospheres by using selected-ion flow-tube mass spectrometry and machine learning

Volatile organic compounds (VOCs) indicative of pork microbial spoilage can be quantified rapidly at trace levels using selected-ion flow-tube mass spectrometry (SIFT-MS). Packaging atmosphere is one of the factors influencing VOC production patterns during storage. On this basis, machine learning would help to process complex volatolomic data and predict pork microbial quality efficiently. This study focused on (1) investigating model generalizability based on different nested cross-validation settings, and (2) comparing the predictive power and feature importance of nine algorithms, including Artificial Neural Network (ANN), k-Nearest Neighbors, Support Vector Regression, Decision Tree, Partial Least Squares Regression, and four ensemble learning models. The datasets used contain 37 VOCs' concentrations (input) and total plate counts (TPC, output) of 350 pork samples with different storage times, including 225 pork loin samples stored under three high-O2 and three low-O2 conditions, and 125 commercially packaged products. An appropriate choice of cross-validation strategies resulted in trustworthy and relevant predictions. When trained on all possible selections of two high-O2 and two low-O2 conditions, ANNs produced satisfactory TPC predictions of unseen test scenarios (one high-O2 condition, one low-O2 condition, and the commercial products). ANN-based bagging outperformed other employed models, when TPC exceeded ca. 6 log CFU/g. VOCs including benzaldehyde, 3-methyl-1-butanol, ethanol and methyl mercaptan were identified with high feature importance. This elaborated case study illustrates great prospects of real-time detection techniques and machine learning in meat quality prediction. Further investigations on handling low VOC levels would enhance the model performance and decision making in commercial meat quality control.

Interactions of Opuntia ficus-indica with Dactylopius coccus and D. opuntiae (Hemiptera: Dactylopiidae) through the Study of Their Volatile Compounds.

Opuntia ficus-indica has always interacted with many phytophagous insects; two of them are Dactylopius coccus and D. opuntiae. Fine cochineal (D. coccus) is produced to extract carminic acid, and D. opuntiae, or wild cochineal, is an invasive pest of O. ficus-indica in more than 20 countries around the world. Despite the economic and environmental relevance of this cactus, D. opuntiae, and D. coccus, there are few studies that have explored volatile organic compounds (VOCs) derived from the plant-insect interaction. The aim of this work was to determine the VOCs produced by D. coccus and D. opuntiae and to identify different VOCs in cladodes infested by each Dactylopius species. The VOCs (essential oils) were obtained by hydrodistillation and identified by GC-MS. A total of 66 VOCs from both Dactylopius species were identified, and 125 from the Esmeralda and Rojo Pelón cultivars infested by D. coccus and D. opuntiae, respectively, were determined. Differential VOC production due to infestation by each Dactylopius species was also found. Some changes in methyl salicylate, terpenes such as linalool, or the alcohol p-vinylguaiacol were related to Dactylopius feeding on the cladodes of their respective cultivars. Changes in these VOCs and their probable role in plant defense mechanisms should receive more attention because this knowledge could improve D. coccus rearing or its inclusion in breeding programs for D. opuntiae control in regions where it is a key pest of O. ficus-indica.

Characterization and sources of volatile organic compounds (VOCs) during 2022 summer ozone pollution control in Shanghai, China

An experimental study was conducted to evaluate the effectiveness of the measures for controlling ozone (O3) pollution in Jinshan District, Shanghai, China during the summer months of June 2022–August 2022. The study period was divided into a control period (CP) when measures were enforced and a non-control period (NCP) without interventions. The concentrations of volatile organic compounds (VOCs) were compared between the two periods, with the ranking of various types of identical VOCs, in which alkanes exhibited the highest (39.48%) concentrations, followed by aromatics (24.35%), halohydrocarbons (19.94%) and alkenes (16.23%). Compared to NCP, the mean levels of VOCs were 32.67% lower in CP, indicating the control measures significantly reduced the concentrations of VOCs during the months when control measures were in effect. The typical bimodal O3 pattern was eliminated during CP along with the absence of peak VOC levels between 10:00 Hrs and 16:00 Hrs, which surpassed the level of 40 μg/m3 during NCP. The analyses of O3 formation potential (OFP) and rate of loss of OH radicals (LOH) indicated that alkenes and aromatics were the most chemically active VOCs driving the production of O3. Following six types of sources were determined for VOCs using positive matrix factorization (PMF): (1) solvent use (8.2%); (2) fuel evaporation (25.1%); (3) petrochemical plant (17.3%); (4) LPG (20.1%); (5) industrial process (16.1%); (6) vehicular emissions (13.2%). Emissions from vehicles and solvent use declined by 19.21% and 15.43%, respectively, underscoring their importance as controllable VOC sources in Shanghai, China. Overall, the study demonstrated the effectiveness of regional control measures in improving air quality by reducing the production of O3 and related VOCs.

Antibacterial Properties of Bacterial Endophytes Isolated from the Medicinal Plant Origanum heracleoticum L.

Bacterial endophytic communities associated with medicinal plants synthesize a plethora of bioactive compounds with biological activities. Their easy isolation and growth procedures make bacterial endophytes an untapped source of novel drugs, which might help to face the problem of antimicrobial resistance. This study investigates the antagonistic potential of endophytic bacteria isolated from different compartments of the medicinal plant O. heracleoticum against human opportunistic pathogens. A panel of endophytes was employed in cross-streaking tests against multidrug-resistant human pathogens, followed by high-resolution chemical profiling using headspace-gas chromatography/mass spectrometry. Endophytic bacteria exhibited the ability to antagonize the growth of opportunistic pathogens belonging to the Burkholderia cepacia complex (Bcc). The different inhibition patterns observed were related to their taxonomic attribution at the genus level; most active strains belong to the Gram-positive genera Bacillus, Arthrobacter, and Pseudarthrobacter. Bcc strains of clinical origin were more sensitive than environmental strains. Cross-streaking tests against other 36 human multidrug-resistant pathogens revealed the highest antimicrobial activity towards the Coagulase-negative staphylococci and Klebsiella pneumoniae strains. Interestingly, strains of human origin were the most inhibited, in both groups. Concerning the production of volatile organic compounds (VOCs), the strain Arthrobacter sp. OHL24 was the best producer of such compounds, while two Priestia strains were good ketones producers and so could be considered for further biotechnological applications. Overall, this study highlights the diverse antagonistic activities of O. heracleoticum-associated endophytes against both Bcc and multidrug-resistant (MDR) human pathogens. These findings hold important implications for investigating bacterial endophytes of medicinal plants as new sources of antimicrobial compounds.

Functional analysis and comparative genomics of Rahnella perminowiae S11P1 and Variovorax sp. S12S4, two plant growth-promoting rhizobacteria isolated from Crocus sativus L. (saffron) rhizosphere.

Rahnella perminowiae S11P1 and Variovorax sp. S12S4 are two plant growth-promoting rhizobacteria that were previously isolated from the rhizosphere of Crocus sativus L. (saffron), and have demonstrated interesting PGP activities and promising results when used as inoculants in field trials. To further elucidate the molecular mechanisms underlying their beneficial effects on plant growth, comprehensive genome mining of S11P1 and S12S4 and comparative genomic analysis with closely related strains were conducted. Functional annotation of the two strains predicted a large number of genes involved in auxin and siderophore production, nitrogen fixation, sulfur metabolism, organic acid biosynthesis, pyrroloquinoline quinone production, 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity, volatile organic compounds production, and polyamine biosynthesis. In addition, numerous genes implicated in plant-bacteria interactions, such as those involved in chemotaxis and quorum sensing, were predicted. Moreover, the two strains carried genes involved in bacterial fitness under abiotic stress conditions. Comparative genomic analysis revealed an open pan-genomic structure for the two strains. COG annotation showed that higher fractions of core and accessory genes were involved in the metabolism and transport of carbohydrates and amino acids, suggesting the metabolic versatility of the two strains as effective rhizosphere colonizers. Furthermore, this study reports the first comparison of Multilocus sequence analysis (MLSA) and core-based phylogenies of the Rahnella and Variovorax genera. The present study unveils the molecular mechanisms underlying plant growth promotion and biocontrol activity of S11P1 and S12S4, and provides a basis for their further biotechnological application in agriculture.

Analysis of potential volatile organic compounds in Sitophilus zeamais (Coleoptera: Curculionidae)-infestedwheat based on lipid oxidation-a reference to early and rapid detection method.

The maize weevil, Sitophilus zeamais Motschulsky, is a hidden pest that presents serious risk to grain quality during postharvest storage. Lipid-derived volatile detection is considered a key reference for early prediction of S. zeamais infestation. However, the exact compositions of fatty acids and volatile organic compounds (VOCs) in S. zeamais-infested wheat are yet to be determined. In this study, we aimed to explore the effect of S. zeamais infestation on lipid metabolism in wheat infested with S. zeamais eggs (4 days), larvae (20 days), pupae (35 days), and adults (45 days). Compared to those in the control group, the activities of lipid oxidation enzymes, such as lipase, lipoxygenase, and alcohol dehydrogenase, increased by 82.73%, 105.12%, and 487.86%, respectively, during the storage period of 1 life cycle of S. zeamais. Additionally, the fatty acid composition of S. zeamais-infested wheat was significantly altered (palmitic acid [1.10-fold], oleic acid [1.07-fold], and linoleic acid [0.95-fold]). Furthermore, 91 VOCs were identified in all wheat samples; then, multivariate statistical analyses categorized these samples into 4 groups: uninfested, longer storage, lightly infested, and heavily infested. Moreover, 31, 26, and 45 potential VOCs were identified to distinguish uninfested wheat from those in the other 3 groups. These results demonstrated that S. zeamais infestation induces an elevation in lipid-related enzymatic activities, which potentially leads to a decrease in lipid content alongside the production of specific VOCs (undecan-4-olide, heptaldehyde, and 2-nonenal). These findings provide novel insights for rapidly identifying grains infested by hidden pests and effectively managing these pests during grain storage.

Investigation on dynamic VOC production from industrial, high solids content emulsion polymerizations

Volatile Organic Compounds (VOC) pose a serious threat to human health and the environment. Unfortunately, many processes from fine chemistry involve VOCs as reagents, solvents, products or by-products. International standards and market requirements keep asking for lower VOC content in commercial goods, with the final aim of VOC-free products. Accomplishing such a task is a challenge because VOCs, due to their high vapour pressure, are hard to remove with traditional industrial methods, such as vacuum stripping or absorption. For this reason, it is important to know and understand how VOCs evolve throughout a chemical reaction. In this field, adhesives, which are usually developed exploiting polymerizations, represent an interesting subject, due to the complexity of their industrial synthesis: VOCs appear as reagents (monomers), conversion enhancers (post-polymerization), and by-products (hydrolysis and small chains). In this work, a study on the evolution and content of VOCs of an industrial recipe involving emulsion polymerizations is carried out. The industrial recipe is characterized by high solids content (about 70% w/w) and is mainly composed of 2-ethylhexyl acrylate (up to 50% w/w), anionic and nonionic surfactants. The evolution of the main VOCs found under different working conditions is discussed. The main VOCs found are acetaldehyde, acetone, t-butanol, vinyl acetate, butanol, methyl-methacrylate, butyl acrylate, 2-ethyl-exyl-alcohol, 2-ethyl-exyl-acetate and 2-ethyl-exyl-acrylate.

Volatile compound dynamics during blueberry fermentation by lactic acid bacteria and its potential associations with bacterial metabolism

Lactic acid bacteria (LAB) fermentation offers a promising strategy to address blueberry perishability, while also imparting its distinctive flavor and enhancing its health benefits. In this study, three strains of LAB (Lactobacillus plantarum NCU116, Lactobacillus casei NCU215, and Lactobacillus acidophilus NCU402) were meticulously selected to partake in the fermentation of blueberry juice. To evaluate their application prospects, this study scrutinized alterations in nutrients, flavor compounds, and color that transpire during the fermentation process. Throughout the fermentation of three LAB species, the glucose content and six main amino acids underwent a substantial decrease. There was a substantial augmentation in the concentrations of organic acids, particularly lactic acid. A noteworthy observation emerged as the blueberry juice subjected to L. plantarum NCU116 fermentation initiated the utilization of sucrose at 36 h, a phenomenon distinct from the fermentation dynamics observed in L. casei NCU215 and L. acidophilus NCU402. The fermentation process also led to a significant increase in the total content of identified volatile organic compounds (VOCs) in all blueberry juice samples, with L. plantarum NCU116 fermentation showing a remarkable increase among the three strains of LAB. This phenomenon is hypothesized to be related to the higher glycolysis and tricarboxylic acid cycling capacity exhibited by L. plantarum NCU116. In conclusion, these LAB strains, especially L. plantarum NCU116, can effectively utilize both glucose and amino acids as sources of carbon and nitrogen, fostering their growth, and facilitating the production of VOCs, especially terpene.

The inhibitory action of lactocin 63 on deterioration of seabass (Lateolabrax japonicus) during chilled storage.

The bacteriocins, particularly derived from lactic acid bacteria, currently exhibit potential as a promising food preservative owing to their low toxicity and potent antimicrobial activity. This study aimed to evaluate the efficacy of lactocin 63, produced by Lactobacillus coryniformis, in inhibiting the deterioration of Lateolabrax japonicas during chilled storage, while also investigating its underlying inhibitory mechanism. The measurement of total viable count, biogenic amines, and volatile organic compounds were conducted, along with high-throughput sequencing and sensory evaluation. The findings demonstrated that treatment with lactocin 63 resulted in a notable retardation of bacterial growth in L. japonicas fish fillet during refrigerated storage compared with the water-treated and nisin-treated groups. Moreover, lactocin 63 effectively maintained the microbial flora balance in the fish fillet and inhibited the proliferation and metabolic activity of specific spoilage microorganisms, particularly Shewanella, Pseudomonas, and Acinetobacter. Furthermore, the production of unacceptable volatile organic compounds (e.g. 1-octen-3-ol, hexanal, nonanal), as well as the biogenic amines derived from the bacterial metabolism, could be hindered, thus preventing the degradation in the quality of fish fillets and sustaining relatively high sensory quality. The results of this study provide valuable theoretical support for the development and application of lactocin 63, or other bacteriocins derived from lactic acid bacteria, as potential bio-preservatives in aquatic food. © 2024 Society of Chemical Industry.

Volatile organic compounds as potential biomarkers of Cadophora luteo‐olivacea presence on kiwifruits

AbstractCadophora luteo‐olivacea is the causal agent of the skin‐pitting disease of kiwifruit, a syndrome that appears after 4–5 months of cold storage. However, it is assumed that the infection takes place in the field during fruit development. The present work takes into consideration the production of volatile organic compounds (VOCs) of Actinidia deliciosa ‘Hayward’ at different phenological phases as potential C. luteo‐olivacea infection biomarkers. In vitro assays were conducted to gain knowledge on the effect of kiwifruit VOCs on pathogen conidial germination and mycelial growth. VOCs produced by kiwifruit either inoculated or not with C. luteo‐olivacea were analysed at different phenological phases by SPME/GC–MS analysis. In particular, ethanol, o‐xylene, d‐limonene and acetic acid showed a significant increase in the presence of fungal inoculation. Ethanol and d‐limonene were also detected as volatile metabolites of the pathogen. The effect of each compound (ethanol, o‐xylene, d‐limonene and acetic acid) was tested on the fungal conidial germination at different concentrations, showing a growth stimulation at lower amounts. These results show how the production of some VOCs can contribute to the knowledge of fruit–pathogen interaction in the field with the aim of developing future tools for early disease detection and consequent effective control.

Volatile organic compounds of the soil bacterium Bacillus halotolerans suppress pathogens and elicit defense-responsive genes in plants

Volatile organic compounds (VOCs) produced by bacteria play an important, yet relatively unexplored role in interactions between plants and phytopathogens. In this study, the soil bacterium Bacillus halotolerans NYG5 was identified as a potent biocontrol agent against several phytopathogenic fungi (Macrophomina phaseolina, Rhizoctonia solani, Pythium aphanidermatum, and Sclerotinia sclerotiorum) through the production of VOCs. NYG5-emitted VOCs also inhibited the growth of bacterial pathogens (Agrobacterium tumefaciens, Xanthomonas campestris, Clavibacter michiganensis, and Pseudomonas syringae). When cultured in various growth media, NYG5 produced a variety of VOCs. Five distinct VOCs (2-methylbutanoic acid, 5-methyl-2-hexanone, 2,3-hexanedione, 2-ethyl-1-hexanol, and 6-methyl-2-heptanone) were identified using headspace GC-MS. 2,3-Hexanedione exhibited potent lethal effects on the tested phytopathogens and nematicidal activity against Meloidogyne javanica at a concentration of 50 ppm. In addition, 0.05 ppm 2,3-hexanedione stimulated the expression of pathogenesis-related genes 1 and 2 in Arabidopsis thaliana. Interestingly, 2,3-hexanedione is used as a food additive at higher concentrations than those tested in this study. Hence, 2,3-hexanedione is a promising biologically active compound that might serve as a sustainable alternative to common chemical pesticides and an elicitor of plant defense.

Recruiting grape‐isolated antagonistic yeasts for the sustainable bio‐management of Botrytis cinerea on grapes

AbstractBotrytis cinerea is the causative agent of grey mould disease in grapes, which was linked to significant postharvest losses. This study examined three grape‐isolated yeasts (Metschnikowia aff. fructicola, Metschnikowia pulcherrima, and Hansenispora uvarum) through in vitro and in vivo tests on detached grape berries against grey mould, as well as the elucidation of their possible mechanisms of action. The antifungal mechanism of action of yeasts was determined by the lytic enzyme activity, inhibition of spore germination, biofilm activity, iron depletion, diffusible metabolites, wound‐site colonisation, mycocin, and volatile organic compounds (VOCs) production. The highest in vitro efficacy (83.13%) was observed on M. aff. fructicola, followed by M. pulcherrima (82.10%) and H. uvarum (71.66%). Metschnikowia yeasts exhibited comparable enzyme activities, including protease, β‐1,3 glucanase, gelatinase chitinase, and cellulase, while H. uvarum had a poor enzymatic activity with chitinase and gelatinase. M. aff. fructicola showed relatively higher iron depletion activity than M. pulcherrima, while M. pulcherrima outperformed via diffusible metabolites. All yeast cultures significantly reduced spore germination by at least 86%. Overall, M. aff. fructicola exhibited the highest biocontrol activity with its iron depletion, inhibition of conidial germination, biofilm formation, VOCs, and well colonisation on grape berries. M. aff. fructicola 1‐UDM outperformed all other yeasts by significantly reducing disease incidence and lesion diameter values (93.4% and 94.3%, respectively). Remarkably, H. uvarum VOCs demonstrated potential as a biofumigant for suppressing grey mould. All yeasts are well adapted to their ecological niche to bio‐protect grapes from grey mould disease.

PYROLYSIS OF SOYBEAN WASTE: A ROUTE TO BIOCARBON FOR PESTICIDES CAPTURE

Background: This study explores the potential use of biomass residues from soybean pressing via static pyrolysis to produce carbonaceous materials for pesticide adsorption. It emphasizes concerns regarding the environmental impact of agroindustrial waste and the persistent nature of pesticides in soil and water systems. Aims: To investigate the efficacy of biochar obtained from soybean waste in adsorbing pesticides. Specifically, to analyze the gas products generated during pyrolysis and characterize the obtained carbonaceous material for its adsorption capabilities. Methods: Soybean residue underwent static pyrolysis at various temperatures and durations. Gas analysis utilizing FTIR spectroscopy identified the gaseous products generated during the pyrolysis process. The obtained biochar underwent successive washes and characterization through FTIR spectra comparison with commercial activated carbon. Through absorption assays, using UV-VIS spectroscopy, investigations were conducted on the solid biocarbon fractions to evaluate their capacity for absorbing pesticides. Results: Gas Analysis: The study revealed the production of volatile organic compounds (VOCs) and highlighted the prevalence of mono-carbon compounds with increased temperature and pyrolysis time. The analysis demonstrated consistent carbon mass percentages across different reaction conditions. Characterization of Biochar: Comparison with activated carbon indicated structural similarities with heightened intensity in certain bands, suggesting the presence of incomplete cellulose cracking in the obtained biochar. Regarding the Chlorothalonil, Atrazine and DIcamba remotion, notably, the concentration of Chlorothalonil in a 7:3 water: acetonitrile solution decreases by 77 % through adsorption on the carbons. Discussion: The investigation examined the adsorption efficiency of the biochar for Chlorothalonil, Atrazine, and Dicamba from aqueous solutions. Chlorothalonil exhibited substantial retention by the biochar, while Atrazine showed comparatively lower adsorption effectiveness. Remarkably, Dicamba did not demonstrate retention by either the biochar or activated carbon. Conclusion: The study underscores the potential of pyrolyzed soybean waste for pesticide adsorption, particularly highlighting Chlorothalonil's strong affinity with the carbonaceous structure. Further research is needed to optimize adsorption properties and explores potential enhancements of these materials through additional treatment methods, offering promising avenues for environmental remediation.

Dynamic controlled atmosphere monitored by respiratory quotient as a new method to store pears: Effect on the volatile compounds profile and general quality

Pears (Pyrus communis) are climacteric fruit that require storage under appropriate conditions to extend availability and delay ripening. This study evaluated the production of volatile organic compounds (VOCs) and the physicochemical quality of ‘Santa Maria’ and ‘Rocha’ pears after storage in a controlled atmosphere (CA) or dynamic controlled atmosphere (DCA), monitored by respiratory quotient (RQ). The pears, harvested from an orchard in São Joaquim (Santa Catarina State), were stored at − 0.5 °C in CA (2.0 kPa O2) and DCA with RQ levels of 1.1, 1.2, 1.3, and 1.4, all under 1.0 kPa CO2. ‘Santa Maria’ pears were stored for four months, and ‘Rocha’ pears for six months, followed by seven days at 20 °C before quality analysis. Storage of ‘Santa Maria’ pears in CA resulted in fruit with a more yellow skin color, lower flesh firmness, and higher ethylene production, while ‘Rocha’ pears in CA retained higher flesh firmness and produced less ethylene at 4 and 7 days at 20 °C compared to DCA conditions. Storage conditions did not significantly affect soluble solids and acidity. In ‘Rocha’ pears, DCA, regardless of RQ, suppressed the production of butyl acetate, hexyl acetate, pentyl acetate, methyl acetate, and propyl acetate, while in ‘Santa Maria’ pears, esters such as butyl acetate and hexyl acetate were less affected. In conclusion, no significant differences were found between the DCA-RQ levels evaluated in this research in maintaining physicochemical quality and VOCs production. However, DCA suppressed VOCs production in both ‘Santa Maria’ and ‘Rocha’ pears compared with CA storage.

Effect of dietary administration of red orange and lemon extract on volatile compounds: profile and sensory parameters of lamb meat

The aim of this work was to study the effects of red orange and lemon extract (RLE) inclusion on volatile organic compounds (VOCs) and sensory profile of lamb meat aged seven days. A total of 44 Merino lambs were randomly divided into two experimental groups: one that received the RLE (n = 22) and the control group (CON; n = 22). The RLE extract was orally and individually administered (90 mg/kg of live weight) to each lamb every day from colostrum assumption until slaughter (40 ± 1 days). Longissimus lumborum muscle was sampled and dry aged at 4 °C for seven days. The VOC and sensorial analyses were carried out at 1, 3 and 7 days. A total of 65 VOCs were detected. Aldehyde family was the most abundant, followed by ketones and alcohols in both groups. Extending ageing period, content of aldehydes and thiols increased only in control group (p < 0.01), but no differences were observed 24 h after slaughtering (p > 0.05). Regardless of dietary treatment, sensory evaluation, tenderness and juiciness showed a similar trend in both groups. Along ageing days, a significant improvement in these patterns was observed (p < 0.05). Our results showed that RLE inclusion did not have effects on both volatile compounds and sensory profile after slaughtering; ageing improves some sensory characteristics of lamb meat and the inclusion of RLE also seems to have a positive effect on the production of VOCs and on sensory properties such as meaty odour and overall liking.

Changes in properties of human milk under different conditions of frozen storage

Human milk is the best source of nutrition for infants. Lower freezing temperatures and faster freezing rates allow for better preservation of human milk. However, research on the freezing conditions of human milk is limited. This study investigated the effectiveness of quick freezing and suitable freezing conditions for home preservation. Human milk was stored under different freezing conditions (−18 °C, −18 °C quick freezing, −30 °C, −40 °C, −60 °C, and − 80 °C) for 30, 60, and 90 days and then evaluated for changes in the microbial counts, bioactive protein, and lipid. The results showed that the total aerobic bacterial and Bifidobacteria counts in human milk after storage at freezing temperatures of − 30 °C and lower were closer to those of fresh human milk compared to − 18 °C. Furthermore, the lysozyme loss, lipid hydrolysis degree, and volatile organic compound production were lower. However, −18 °C quick freezing storage was not markedly different from −18 °C in maintaining human milk quality. Based on the results, for household and environmental reasons, the recommended temperature for storing human milk is suggested as −30 °C.