Exploring volatile compounds and microbial dynamics: Kluyveromyces marxianus and Hanseniaspora opuntiae reduce Forastero cocoa fermentation time.

Traditional cocoa bean fermentation is a spontaneous process and can result in heterogeneous sensory quality. For this reason, yeast-integrated starter cultures may be an option for creating consistent organoleptic profiles. This study proposes the mixture of Hanseniaspora opuntiae and Kluyveromyces marxianus (from non-cocoa fermentation) as starter culture candidates. The microorganisms and volatile compounds were analyzed during the cocoa fermentation process, and the most abundant were correlated with predominant microorganisms. Results showed that Kluyveromyces marxianus, isolated from mezcal fermentation, was identified as the dominant yeast by high-throughput DNA sequencing. A total of 63 volatile compounds identified by HS-SPME-GC-MS were correlated with the more abundant bacteria and yeast using Principal Component Analysis and Agglomerative Hierarchical Clustering. This study demonstrates that yeasts from other fermentative processes can be used as starter cultures in cocoa fermentation and lead to the formation of more aromatic esters, decrease the acetic acid content.

Perspectives on carboxylates generation from Ecuadorian agro-wastes.

Carboxylates generation from banana (peel and pulp), coffee, and cacao fermentation agro-waste, upon uncontrolled and controlled pHs of 6.6 (heat-driven methanogens inactivation) and 5.2 (pH inactivation), was studied. Regarding volatile fatty acids (VFAs), acetic was the highest for cocoa (96.2 g kg-1TVS) at pH 4.5. However, butyric was relevant for banana pulp (90.7 g kg-1TVS), at controlled pH 6.6. The highest medium chain fatty acid (MCFAs) level was hexanoic (cocoa, 3.5 g kg-1TVS), while octanoic reached a maximum of 2.8 g kg-1TVS for coffee at pH 6.6. At pH 5.2 MCFAs yield was relatively low. Uncontrolled pH conditions, using banana resulted in superior VFAs production compared to controlled conditions. Thus, pH became a determining variable when deciding the time and kind of carboxylic acid to be recovered. The bacterial community at the end of the chain elongation process was dominated by phyla Firmicutes, and Clostridium as the most common genera.

Polymer-Based Wound Dressings Loaded with Essential Oil for the Treatment of Wounds: A Review.

Wound healing can result in complex problems, and discovering an effective method to improve the healing process is essential. Polymeric biomaterials have structures similar to those identified in the extracellular matrix of the tissue to be regenerated and also avoid chronic inflammation, and immunological reactions. To obtain smart and effective dressings, bioactive agents, such as essential oils, are also used to promote a wide range of biological properties, which can accelerate the healing process. Therefore, we intend to explore advances in the potential for applying hybrid materials in wound healing. For this, fifty scientific articles dated from 2010 to 2023 were investigated using the Web of Science, Scopus, Science Direct, and PubMed databases. The principles of the healing process, use of polymers, type and properties of essential oils and processing techniques, and characteristics of dressings were identified. Thus, the plants Syzygium romanticum or Eugenia caryophyllata, Origanum vulgare, and Cinnamomum zeylanicum present prospects for application in clinical trials due to their proven effects on wound healing and reducing the incidence of inflammatory cells in the site of injury. The antimicrobial effect of essential oils is mainly due to polyphenols and terpenes such as eugenol, cinnamaldehyde, carvacrol, and thymol.

Fatty acids and volatile compound of cooked green licuri (Syagrus coronata) and naturally ripe licuri almonds from native flora, popularly consumed in Brazil.

The present study was carried out to investigate the proximate composition, fatty acid (FA) profile and volatile compounds (VC) of cooked green licuri (Syagrus coronata) - an unripe stage that is then cooked - and naturally ripe licuri almonds. The FA profiles were determined by gas chromatography (GC) and the VC composition was evaluated using headspace-solid-phase microextraction coupled with GC-MS. The cooked green licuri presented higher moisture, and lower contents of ashes, proteins and lipids than naturally ripe licuri almonds. The FA profiles of cooked green licuri and naturally ripe licuri almonds showed that saturated FAs were predominant (80%) in both samples, and the concentrations of lauric, palmitic, and oleic acids in naturally ripe licuri almonds were higher than those in cooked green licuri. Limonene was the predominant compound in naturally ripe licuri almonds. The main class of VC in the cooked green licuri were aldehydes, with 3-methyl-butanal and furfural being the main species. Alcohols, such as 3-methyl-butanol and 2-heptanol, were the main class of VC in naturally ripe licuri almonds. Among the volatile compounds, 1-hexanol and 2-nonanone contributed to the aroma of cooked green licuri almonds, whereas 2-heptanone, ethanol, and limonene contributed to the aroma of naturally ripe licuri almonds (almonds not subjected to any cooking process). In a word, cooked green licuri and naturally riped licuri almonds, despite having different proximate compositions, present similar fatty acid profile and distinct aromatic characteristics. Therefore, cooked green licuri and naturally riped licuri almonds are an alternative source of nutrient and could be investigated for the use in the food industry to enhance flavor and aroma to new products.

Evaluation of nutritional, technological, oxidative, and sensory properties of low-sodium and phosphate-free mortadellas produced with bamboo fiber, pea protein, and mushroom powder.

This study examined the effects of replacing alkaline phosphate (AP) with bamboo fiber (BF), isolated pea protein (PP), and mushroom powder (MP) on the nutritional, technological, oxidative, and sensory characteristics of low-sodium mortadellas. Results indicated that this reformulation maintained the nutritional quality of the products. Natural substitutes were more effective than AP in reducing water and fat exudation. This led to decreased texture profile analysis (TPA) values such as hardness, cohesiveness, gumminess, and chewiness. The reformulation reduced the L* values and increased the b* values, leading to color modifications rated from noticeable to appreciable according to the National Bureau of Standards (NBS) index. Despite minor changes in oxidative stability indicated by increased values in TBARS (from 0.19 to 0.33 mg MDA/kg), carbonyls (from 2.1 to 4.4 nmol carbonyl/mg protein), and the volatile compound profile, the sensory profile revealed a beneficial increase in salty taste, especially due to the inclusion of MP, which was enhanced by the synergy with BF and PP. In summary, the results confirmed the potential of natural alternatives to replace chemical additives in meat products. Incorporating natural antioxidants into future formulations could address the minor oxidation issues observed and enhance the applicability of this reformulation strategy.

White wine vinification and an expanded insight into pellicular macerations: bibliometric and bibliographic review.

BACKGROUND: Pellicular macerations in the vinification of white wines involve the contact of grape skins and seeds with the must before, during or after alcoholic fermentation. Pre-fermentative pellicular maceration aims to enrich the must with volatile compounds and aroma precursors. Fermentative maceration occurs during alcoholic fermentation, whereas post-fermentative maceration is carried out after this process, associated with orange, amber or skin-contact wines, which have experienced a growing global demand in recent years. In this context, this research aimed to conduct a bibliometric review on pellicular macerations in white wines using two search strategies on the specific platform for the period from 2010 to 2023. Additionally, we sought to identify research trends in this segment of the wine industry through a comprehensive literature review of the retrieved documents. RESULTS: The results emphasized more studies on pre-fermentative pellicular maceration than on long-duration macerations during and after alcoholic fermentation. Alternative maceration techniques, such as grape freezing, were also observed as study subjects, including their effects on final wines. The research identified a wide variety of grapes explored in studies related to pellicular macerations of the Vitis vinifera L. species, with approximately 50 distinct nomenclatures identified. Regarding pre-fermentative macerations, the contact time varied from 2 to 60 h, with the temperature range 1-20 °C. CONCLUSION: The specific search for extended skin contact white wines revealed a limited number of available documents, indicating that studies related to this product style are promising and necessary, given the growing commercial relevance of this product profile. © 2024 Society of Chemical Industry.

Optimization of HS-SPME/GC-MS Method for Determining Volatile Organic Compounds and Sensory Profile in Cocoa Honey from Different Cocoa Varieties (Theobroma cacao L.).

This study aimed to develop an analytical method using HS-SPME/GC-MS to determine the volatile organic compound (VOC) profiles and evaluate the sensory attributes of cocoa honey from four cocoa varieties (CCN51, PS1319, SJ02, and Parazinho). Using a multivariate factorial experimental design, the HS-SPME/GC-MS method was optimized to determine the VOC profiles. Twenty previously trained tasters participated in the ranking descriptive analysis, while 108 consumers participated in the acceptance and purchase intention tests. A total of 84 volatile organic compounds were identified from various chemical classes, including acids, alcohols, aldehydes, esters, ketones, monoterpenes, oxygenated monoterpenoids, sesquiterpenes, and oxygenated sesquiterpenoids. Palmitic acid was the compound found in the highest concentration in all varieties (5.13-13.10%). Multivariate analysis tools identified key compounds for differentiation and grouping of the samples. The results revealed that the variety significantly influenced both the VOCs' concentrations and sensory profiles. The CCN51, PS1319, and SJ02 varieties exhibited the highest diversity of VOCs and sensory attributes. Notably, the SJ02 and CCN51 varieties demonstrated superior acceptability and purchase intention, with means ranging from 7.21 and 7.08 to 3.71 and 3.56, respectively. These results indicate their potential as promising sources of cocoa honey for the food industry.

Cladosporium psychrotolerans strain T01 enhances plant biomass and also exhibits antifungal activity against pathogens.

An increasing number of microorganisms are being identified to enhance plant growth and inhibit phytopathogens. Some Cladosporium species form beneficial associations with plants, either as endophytes or by colonizing the rhizosphere. Herein, we evaluated the influence of the Cladosporium psychrotolerans (T01 strain) fungus on the in vitro growth of Arabidopsis thaliana plantlets through direct and split interactions. After 9 days post-inoculation with C. psychrotolerans, Arabidopsis plantlets exhibited a notable increase in fresh weight and lateral roots, particularly in split interactions. Chlorophyll content increased in both plant-fungus interaction conditions, whereas the primary root was inhibited during direct interaction. We observed an increase in the GUS signal from the Arabidopsis auxin-inducible DR5:uidA marker in lateral root tips in both contact and split fungal interactions, and primary root tips in a split interaction. Arabidopsis and tomato plants cultivated in soil pots and inoculated with C. psychrotolerans (T01 strain) showed a positive effect on biomass production. GC/MS analysis detected that the T01 strain emitted volatile organic compounds (VOCs), predominantly alcohols and aldehydes. These VOCs displayed potent inhibitory effects, with a 60% inhibition against Botrytis cinerea and a 50% inhibition against C. gloeosporioides. Our study demonstrates that C. psychrotolerans T01 has the potential to enhance biomass production and inhibit pathogens, making it a promising candidate for green technology applications.

Exploring the Potential of Myrcia Genus Essential Oils: A Review of Biological Activities and Recent Advances.

The present study provides a comprehensive analysis of the chemical composition of essential oils from species of the Myrcia genus and their applications. The compiled results highlight the chemical diversity and biological activities of these oils, emphasizing their potential importance for various therapeutic and industrial applications. The findings reveal that Myrcia essential oils present a variety of bioactive compounds, such as monoterpenes and sesquiterpenes, which demonstrate antimicrobial activities against a range of microorganisms, including Gram-positive and Gram-negative bacteria, as well as yeasts. Furthermore, this study highlights the phytotoxic activity of these oils, indicating their potential for weed control. The results also point to the insecticidal potential of Myrcia essential oils against a range of pests, showing their viability as an alternative to synthetic pesticides. Additionally, species of the genus Myrcia have demonstrated promising hypoglycemic effects, suggesting their potential in diabetes treatment. This comprehensive synthesis represents a significant advancement in understanding Myrcia essential oils, highlighting their chemical diversity and wide range of biological activities. However, the need for further research is emphasized to fully explore the therapeutic and industrial potential of these oils, including the identification of new compounds, understanding of their mechanisms of action, and evaluation of safety and efficacy in different contexts.

Comprehensive Characterization of Tuber maculatum, New in Uruguay: Morphological, Molecular, and Aromatic Analyses.

Although only a few species of Tuber account for the major truffle sales volume, many species that are not considered delicacies are finding their way to the market, especially in regions where the traditionally appreciated ones do not occur. This is the case for whitish truffles. Specimens of whitish truffles were collected in pecan (Carya illinoinensis) orchards in Uruguay in October 2021. Morphological and molecular methods were used to characterize and assess their identity as Tuber maculatum Vittad. An SPME extraction of volatile compounds and GC-MS analyses were performed to characterize the aromatic profile of these specimens and evaluate their potential applications. Among the 60 VOCs detected, 3-octenone (mushroom odor), 3-octanol (moss, nut, mushroom odor), and 2H-pyran-2-one (no odor), followed by octen-1-ol-acetate (no odor) and 2-undecanone (orange, fresh, green odor) were the major compounds in T. maculatum fruiting bodies. The attributes of exotic edible mushrooms of commercial value in the region are highlighted. In particular, this work emphasizes the characteristics of truffles as a byproduct of pecan cultivation.

Antileishmanial and Antifungal Activities of Volatile Oils from Cinnamomum Cassia Bark and Schinus Molle Leaves.

This study reports on the chemical composition and antileishmanial and anticandidal activities of volatile oils (VOs) of Schinus molle dried leaves (SM), Cinnamomum cassia branch bark (CC) and their blends. Major constituents of SM were spathulenol (26.93 %), ß-caryophyllene (19.90 %), and caryophyllene oxide (12.69 %), whereas (E)-cinnamaldehyde (60.11 %), cinnamyl acetate (20.90 %) and cis-2-methoxycinnamic acid (10.37 %) were predominant in CC. SM (IC50=21.45 µg/mL) and CC (IC50=23.27 µg/mL) displayed good activity against L. amazonensis promastigotes, besides having good or moderate activity against nine Candida strains, with Minimum Inhibitory Concentration (MIC) values ranging from 31.25 to 250 µg/mL. While the three SM and CC blends were not more active than the VOs tested individually, they exhibited remarkably high antileishmanial activity, with IC50 values ranging between 3.12 and 7.04 µg/mL, which is very similar to the IC50 of amphotericin B (positive control).

Simultaneous biofiltration of H2S, NH3, and toluene using compost made of chicken manure and sugarcane bagasse as packing material.

Offensive odors from wastewater treatment plants (WWTP) are caused by volatile inorganic compounds such as hydrogen sulfide and ammonia and volatile organic compounds (VOCs), such as toluene. To treat these pollutants, biofiltration is an effective and economical technology used worldwide due to its low investment and environmental impact. In this work, a laboratory-scale prototype biofilter unit for the simultaneous biofiltration of hydrogen sulfide, ammonia, and toluene was evaluated by simulating the emission concentrations of the El Salitre WWTP Bogotá, Colombia, using a compost of chicken manure and sugarcane bagasse as packing material for the biofilter. The prototype biofilter unit was set to an operation flow rate of 0.089 m3/h, an empty bed residence time (EBRT) of 60 s, and a volume of 0.007 m3 (6.6 L). The maximum removal efficiency were 96.9 ± 1.2% for H2S, at a loading rate of 4.7 g/m3 h and a concentration of 79.1 mg/m3, 68 ± 2% for NH3, at a loading rate of 1.2 g/m3 h and a concentration of 2.0 mg/m3, and 71.5 ± 4.0% for toluene, at a loading rate of 1.32 g/m3 h and a concentration of 2.3 mg/m3. The removal efficiency of the three compounds decreased when the toluene concentration was increased above 40 mg/m3. However, a recovery of the system was observed after reducing the toluene concentration and after 7 days of inactivity, indicating an inhibitory effect of toluene. These results demonstrate the potential use of the prototype biofilter unit for odor treatment in a WWTP.

Extraction Kinetics of Brazilian Green Propolis and Chemical Characterization of its Volatiles.

Propolis is a natural resinous product produced by Apis mellifera bees from the exudates of various plants. The color of propolis (green) is a consequence of its botanical origin, as bees collect young tissues and leaves of Baccaris dracunculifolia. This study evaluated the chemical composition and extraction kinetics of essential oils obtained from Brazilian green propolis by hydrodistillation. Hydrodistillation was performed for 360 min and analyzed at different times (30, 60, 120, 240, and 360 min), allowing the calculation of the accumulated content (% w/w) and the identification of the essential oil chemical profile. The GC/FID and GC/MS analysis led to the annotation of 60 compounds with estragole (13.30 %), benzyl propanoate (14.59 %), and (E)-nerolidol (13.57 %) as the main compounds. The optimum conditions for extraction of phenylpropanoids (PP), hydrocarbons (HD), monoterpenes (MT), and oxygenated monoterpenes (OMT) are between 30 and 120 min. In comparison, sesquiterpenes (ST) and oxygenated sesquiterpenes (OST) are extracted more efficiently between 240 and 360 min. The optimal extraction speed determination is essential for industrial-scale processing to obtain components such as sesquiterpenes, which have a high economic value in the cosmetic/perfumery and pharmaceutical industries.

The Management of Irrigation and Potassium Fertilization to Mitigate the Effect of Light Frosts on the Phenolic and Volatile Compounds in Virgin Olive Oils.

The frequency of early frosts has increased in recent years, which are injurious to olive growing, causing losses in the yield and quality of virgin olive oil. In this research, it was studied how the management of agronomic factors mitigates frost damage in Arbequina olives, minimizing the loss of phenols and volatiles in virgin olive oil, at different fruit ripening stages. A Box-Behnken design and multivariate analysis were performed, with three levels of irrigation, potassium fertilization, and foliar copper application (15 treatments). Virgin olive oil was extracted from fresh and frozen olives. Light frost caused a significant decrease in the total phenols and secoiridoid compounds in and the antioxidant capacity of the frost-affected oils, which were perceived as more pungent and had the slight defect of "frostbitten olives". According to the Box-Behnken design, an 86% reference evapotranspiration (ET0) or higher with 100 potassium oxide units (UK2O) and a 100% ET0 or higher with 250 UK2O would be required to minimize the effect of light frost on phenols and volatiles. Partial Least Squares Regression-Discriminant Analysis (PLS-DA) differentiated the virgin olive oils according to their ripening stage and fresh and frost conditions. Moreover, PLS-DA positively correlated a 75-100% ET0 and 0 Uk2O with the dialdehydic form of the decarboxymethyl ligstroside aglycone (p-HPEA-EDA), the dialdehydic form of the decarboxymethyl oleuropein aglycone (3,4-DHPEA-EDA), the dialdehydic form of the ligstroside aglycone (p-HPEA-EDA-DLA), and with fruity, pungent, and bitter attributes. Precision agronomic management based on the needs of the crop itself would avoid unnecessary stress on olive trees and oil damage.

Volatile Constituents of Some Myrtaceous Edible and Medicinal Fruits from the Brazilian Amazon.

Native and exotic fruits from the Amazon have varied characteristics, with aroma being a decisive factor in their acceptance for medicinal use as a nutraceutical supplement. This work aimed to analyze the chemical constituents of the volatile concentrates of some Myrtaceous fruit species sampled in the Brazilian Amazon. The fruit's pulps were subjected to simultaneous distillation-extraction, and gas chromatography-mass spectrometry was used to analyze their volatile chemical composition. In the volatile concentrate of Eugenia stipitata (Araçá-boi) α-pinene (17.5%), citronellyl butanoate (15.6%), and pogostol (13.5%) were identified as primary constituents; Eugenia uniflora (Ginja) concentrate comprised curzerene (30.5%), germacrone (15.4%), atractylone (13.1%), and (E)-ß-ocimene (11.1%); in Myrciaria dubia (Camu-Camu), α-pinene (55.8%), (E)-ß-ocimene (13.1%), and α-terpineol (10.0%) were present; in Psidium guajava (Goiaba) were (2E)-hexenal (21.7%), hexanal (15.4%), caryophylla-4(12),8(13)-dien-5-ß-ol (10.5%), caryophyllene oxide (9.2%), and pogostol (8.3%); and in Psidium guineense (Araçá), limonene (25.2%), ethyl butanoate (12.1%), epi-ß-bisabolol (9.8%), and α-pinene (9.2%) were the main constituents. The analyzed volatile concentrates of these fruit species presented a significant diversity of constituents with a predominance of functional groups, such as monoterpenes, sesquiterpenes, and fatty acid derivatives, originating from the plant's secondary metabolism and playing an important role in their nutritional and medicinal uses.

Ultrasound-Assisted Nanoemulsion Loaded with Optimized Antibacterial Essential Oil Blend: A New Approach against Escherichia coli, Staphylococcus aureus, and Salmonella Enteritidis in Trout (Oncorhynchus mykiss) Fillets.

This study aimed to obtain and characterize an oil-in-water nanoemulsion (NE) loaded with an in vitro optimized bactericidal essential oil blend of 50% oregano, 40% thyme, and 10% lemongrass and to evaluate its potential at three different concentrations (0.5%, 1%, and 2%) in the inactivation of Escherichia coli, Staphylococcus aureus, and Salmonella enterica serotype Enteritidis inoculated in rainbow trout fillets stored at 4 °C for 9 days. Regarding the NE, the nanometric size (<100 nm) with low polydispersion (0.17 ± 0.02) was successfully obtained through ultrasound at 2.09 W/cm2. Considering the three concentrations used, S. Enteritidis was the most susceptible. On the other hand, comparing the concentrations used, the NE at 2% showed better activity, reducing S. Enteritidis, E. coli, and S. aureus by 0.33, 0.20, and 0.73 log CFU/g, respectively, in the trout fillets. Thus, this data indicates that this is a promising eco-friendly alternative to produce safe fish for consumption and reduce public health risks.

Chemical composition and sensory profiling of coffees treated with asparaginase to decrease acrylamide formation during roasting.

Acrylamide is an amide formed in the Maillard reaction, with asparagine as the primary amino acid precursor. The intake of large amounts of acrylamide has induced genotoxic and carcinogenic effects in hormone-sensitive tissues of animals. The enzime asparaginase is one of the most effective methods for lowering the formation of acrylamide in foods such as potatoes. However, the reported sensory outcomes for coffee have been unsatisfactory so far. This study aimed to produce coffees with reduced levels of acrylamide by treating them with asparaginase while retaining their original sensory and bioactive profiles. Three raw samples of Coffea arabica, including two specialty coffees, and one of Coffea canephora were treated with 1000, 2000, and 3000 ASNU of the enzyme. Asparagine and bioactive compounds (chlorogenic acids-CGA, caffeine, and trigonelline) were quantified in raw and roasted beans by HPLC and LC-MS, while the determination of acrylamide and volatile organic compounds was performed in roasted beans by CG-MS. Soluble solids, titratable acidity, and pH were also determined. Professional cupping by Q-graders and consumer sensory tests were also conducted. Results were analyzed by ANOVA-Fisher, MFA, PCA and Cluster analyses, with significance levels set at p ≤ 0.05. Steam treatment alone decreased acrylamide content by 18.4%, on average, and 6.1% in medium roasted arabica and canefora coffees. Average reductions of 32.5-56.0% in acrylamide formation were observed in medium roasted arabica beans when 1000-3000 ASNU were applied. In the canefora sample, 59.4-60.7% reductions were observed. However, steam treatment primarily caused 17.1-26.7% reduction of total CGA and lactones in medium roasted arabica samples and 13.9-22.0% in canefora sample, while changes in trigonelline, caffeine, and other evaluated chemical parameters, including the volatile profiles were minimal. Increasing enzyme loads slightly elevated acidity. The only sensory changes observed by Q-graders and or consumers in treated samples were a modest increase in acidity when 3000 ASNU was used in the sample with lower acidity, loss of mild off-notes in control samples, and increased perception of sensory descriptors. The former was selected given the similarity in chemical outcomes among beans treated with 2000 and 3000 ASNU loads.

Role of Volatile Organic Compounds Produced by Kosakonia cowanii Cp1 during Competitive Colonization Interaction against Pectobacterium aroidearum SM2.

The competitive colonization of bacteria on similar ecological niches has a significant impact during their establishment. The synthesis speeds of different chemical classes of molecules during early competitive colonization can reduce the number of competitors through metabolic effects. In this work, we demonstrate for the first time that Kosakonia cowanii Cp1 previously isolated from the seeds of Capsicum pubescens R. P. produced volatile organic compounds (VOCs) during competitive colonization against Pectobacterium aroidearum SM2, affecting soft rot symptoms in serrano chili (Capsicum annuum L.). The pathogen P. aroidearum SM2 was isolated from the fruits of C. annuum var. Serrano with soft rot symptoms. The genome of the SM2 strain carries a 5,037,920 bp chromosome with 51.46% G + C content and 4925 predicted protein-coding genes. It presents 12 genes encoding plant-cell-wall-degrading enzymes (PCDEWs), 139 genes involved in five types of secretion systems, and 16 genes related to invasion motility. Pathogenic essays showed soft rot symptoms in the fruits of C. annuum L., Solanum lycopersicum, and Physalis philadelphica and the tubers of Solanum tuberosum. During the growth phases of K. cowanii Cp1, a mix of VOCs was identified by means of HS-SPME-GC-MS. Of these compounds, 2,5-dimethyl-pyrazine showed bactericidal effects and synergy with acetoin during the competitive colonization of K. cowanii Cp1 to completely reduce soft rot symptoms. This work provides novel evidence grounding a better understanding of bacterial interactions during competitive colonization on plant tissue, where VOC synthesis is essential and has a high potential capacity to control pathogenic microorganisms in agricultural systems.

Mexican Coccoloba uvifera L. Leaf and Fruit Extracts: Identification of Pentacyclic Triterpenes and Volatile Profile by GC-MS.

Mexican Coccoloba uvifera fruit contains polyphenols, flavonoids, and anthocyanins, while in the leaves, lupeol, α- and ß-amyrin have been previously identified by HPLC. However, the low resolution by HPLC of pentacyclic triterpenes (PTs) is a limitation. Moreover, the volatile profile of C. uvifera fruit is still unknown. Therefore, this study aimed to identify PTs in C. uvifera leaf and fruit extracts by CG-MS analysis and to determine the volatile profile of C. uvifera pulp by headspace solid-phase microextraction. The results showed trimethylsilylated compounds of standards lupeol, α- and ß-amyrin, indicating that the silylation reaction was suitable. These trimethylsilylated compounds were identified in leaf and fruit extracts. The fruit volatile profile revealed the presence of 278 esters, 20 terpenes, 9 aldehydes, 5 alcohols, and 4 ketones. The fruit showed a high content of esters and terpenes. Due to their flavour properties, esters are essential for the food, cosmetics, and pharmaceutics industries. Moreover, terpenes in the fruit, such as menthone, ß-elemene, junipene, and ß-caryophyllene have the potential as anticancer and phytopathogen agents. The results indicated that GC-MS is an alternative to HPLC approaches for identifying PTs. Besides, identifying volatile compounds in the fruit will increase the value of this plant and expand its application. Identifying PTs and volatile compounds in Mexican C. uvifera leads to a better understanding of the potential benefits of this plant. This would increase the consumption of Mexican C. uvifera fresh or as functional ingredients in nutraceutical or pharmaceutical products.

Novel Pseudomonas Species Prevent the Growth of the Phytopathogenic Fungus Aspergillus flavus.

In response to the escalating demand for sustainable agricultural methodologies, the utilization of microbial volatile organic compounds (VOCs) as antagonists against phytopathogens has emerged as a viable eco-friendly alternative. Microbial volatiles exhibit rapid diffusion rates, facilitating prompt chemical interactions. Moreover, microorganisms possess the capacity to emit volatiles constitutively, as well as in response to biological interactions and environmental stimuli. In addition to volatile compounds, these bacteria demonstrate the ability to produce soluble metabolites with antifungal properties, such as APE Vf, pyoverdin, and fragin. In this study, we identified two Pseudomonas strains (BJa3 and MCal1) capable of inhibiting the in vitro mycelial growth of the phytopathogenic fungus Aspergillus flavus, which serves as the causal agent of diseases in sugarcane and maize. Utilizing GC/MS analysis, we detected 47 distinct VOCs which were produced by these bacterial strains. Notably, certain volatile compounds, including 1-heptoxydecane and tridecan-2-one, emerged as primary candidates for inhibiting fungal growth. These compounds belong to essential chemical classes previously documented for their antifungal activity, while others represent novel molecules. Furthermore, examination via confocal microscopy unveiled significant morphological alterations, particularly in the cell wall, of mycelia exposed to VOCs emitted by both Pseudomonas species. These findings underscore the potential of the identified BJa3 and MCal1 Pseudomonas strains as promising agents for fungal biocontrol in agricultural crops.