Microbiological Properties Research Articles

Effects of different processing methods on physicochemical and microbiological properties of kefir ice cream

In this study, kefir ice cream was produced using two different methods. In method 1, the ice cream mixture was incubated with kefir starter culture until a pH value of 6.1 or 5.5 was reached, and in method 2, the ice cream mixture was blended with kefir to reach a pH value of 5.5 or 6.1. Kefir ice cream produced by method 2 had a higher overrun and lower firmness than that produced by method 1. When comparisons were made based on the pH value of the ice cream mixture, kefir ice cream produced from the ice cream mixture with a pH of 6.1 instead of 5.5 had a higher overrun and melting rate and a lower firmness. The slightly higher counts on MRS agar, M17 agar, MSE agar, DSM 254 medium, and YGC agar were determined in the kefir ice cream samples produced by method 1 or produced from an ice cream mixture with a pH of 5.5. Although it is unknown if the number of bacteria on MRS agar detected in the samples, where the number was greater than 6 log cfu g−1 even after 90 days of storage, are probiotics or not, kefir ice cream has the potential to be a probiotic product. In this study, it has been demonstrated that kefir ice creams with different physicochemical and microbiological properties can be produced by altering the ice cream production method and pH value of the ice cream mixture.

Environmental impact of an anthropogenic groundwater temperature hotspot

Heat emitted by buildings and other infrastructure accumulates in the subsurface. This additional heat can cause a pronounced shift in thermal boundary conditions of the important groundwater ecosystem. Shallow groundwater systems in Central Europe are often inhabited by communities of fauna adapted to cold and stable conditions as well as microorganisms, whose activity is dependent on ambient temperatures. At a local groundwater temperature hotspot of up to 23 °C, caused by a water park, we assessed the environmental impact of this thermal alteration on the shallow groundwater system. The results show that the overall groundwater quality at the site is influenced by anthropogenic land use, compared to wells in a nearby water protection zone. However, neither hydrochemical nor ecological characteristics of groundwater from wells in the vicinity of the water park indicate any significant dependence on temperature. Hence, we conclude that in this eutrophic and anoxic aquifer moderate heat stress does not lead to significant alterations in terms of hydrochemistry as well as microbiological properties. Due to the overall low oxygen concentrations (<1 mg/l), stygofauna is present only occasionally and cannot be used as bioindicators. These results have to be verified for other aquifer types and would benefit from a more in-depth analysis of microbial community composition.

High-pressure processing for pickled crabs: Safety, quality and flavor assessment and correlation analysis of spoilage indicators

Pickled aquatic products are often susceptible to spoilage, which can significantly affect their edibility and flavor. This study aimed to improve the safety and quality aspects of pickled crabs by treated with high-pressure processing (HPP, 400 MPa for 5 min). The physical, chemical, microbiological, and flavor properties of the crabs before and after HPP were assessed, correlation and cluster analysis and orthogonal partial least squares discriminant analysis (OPLS-DA) were conducted on specific indicators influencing crab spoilage. The results indicated that HPP effectively reduced the total viable count, psychrophilic bacteria count (PBC), and Escherichia coliform (E. coli) count during storage at 4 °C (reduced by 30.61%, 36.72%, 100%, day 0, respectively; 19.02%, 21.95%, 100%, day 42, respectively). Moreover, HPP treatment reduced the total volatile basic nitrogen (TVBN) content (35.33 mg/100 g to 31.81 mg/100 g) and the production of putrescine (1858.7 mg/kg to 1293.04 mg/kg) and cadaverine (753.47 mg/kg to 422.08 mg/kg) in the end of storage stage, which extend the shelf life of the pickled crab by 12 days. Furthermore, the application of HPP facilitated the penetration of ethanol into the crab meat, thereby enhancing the development of the characteristic pickled crab flavor. The OPLS-DA analyses indicated that TVBN, TBA, and histamine as deteriorative factors for quality deterioration are key factors determining spoilage of crab, which are significantly correlated with other corruption products. This study provides valuable insights into improving the safety and flavor of crab products, establishing a theoretical basis for ensuring quality control throughout the production process.

Effect of edible coating of gelatin-sodium alginate with the addition of green tea (Camellia sinensis) extract on the characteristics of star fruit (Averrhoa carambola L.) during storage.

Star fruit has a good nutritional value but was very easy to damage. Edible coating can be used to extend the shelf life of star fruit. Green tea had been added to improve the mechanical properties and functional value of edible coating. This study aimed to evaluate the application of edible coating gelatin-sodium alginate with the addition of green tea to the physicochemical and microbiological characteristics of star fruit. This research was conducted by making edible coating solutions from gelatin, sodium alginate, glycerol, and green tea of various concentrations (0%, 5%, 10%, and 15%). The coating solution was applied to star fruit and stored for 1, 6, and 13 days to determine the effect of coating on the physicochemical and microbiological properties of star fruit. The results showed that adding green tea was not significantly different from the color change of the coating solution. However, there was a change in viscosity and pH along with the concentration of green tea extract (p < 0.05). FTIR analyses indicated that an interaction existed between gelatin-sodium alginate and green tea extract. The addition of green tea to star fruit with an edible coating of gelatin and sodium alginate could prevent weight loss (25.84%), reduce respiration rate (11.035mg CO2/kg/h), maintain fruit anatomy, protect against color change, inhibit pH changes (4.22), total titrated acid (0.22%), increase vitamin C (244.55mg/g), and even reduce damage for up to 13 days of storage. This study indicates that edible coating with the addition of green tea might be effective to retain the quality and extend the storage life star fruit.

Effects on the antioxidant, physicochemical, microbiological, and sensory properties of bread when supplemented with Umbu flour

Umbu fruit is rich in vitamin C and presents excellent antioxidant activity, yet its industrial processing uses only the pulp, while the residues are discarded. The residues present important nutritional properties, able to fight free radicals in the human body, and in the form of flour, might contribute reduce food insecurity and environmental waste. In view of this, our objective was to develop bread using flour from the husks and seeds of Umbu fruit as a partial replacement for wheat flour, and to assess its physical, physical-chemical, bioactive, microbiological, and sensory properties. For this, flour was prepared from Umbu wastes and used in the production of breads in concentrations of 0, 10, 20, and 30%. Respectively, the control at 0% = PC, 10% = P10, 20% = P20, and 30% = P30. Physical-chemical characterization, determination of total phenolic compounds and vitamin C, instrumental colorimetry, microbiological and sensory analyses were performed. The P20 and P30 breads presented lower humidity and pH, with higher ash, protein, lipids, acidity, total phenolic compounds, and vitamin C than the control. By instrumental color, the P20 and P30 breads were both darker and greener than the controls (PC). For microbiological analysis, all formulations were within norms established for human consumption. By sensory analysis, the breads supplemented with the Umbu residues flour were well received, yet with lower test values than the controls for all attributes and for intentions purchase. Yet in view of the above, flour made from Umbu residues remains a promising ingredient for incorporation into both breads and other bakery industry products.

Correction: In-pack sonication of chicken breast: effects of ultrasound conditions on physicochemical and microbiological properties, and shelf-life of optimally processed meat during frozen storage

Correction: In-pack sonication of chicken breast: effects of ultrasound conditions on physicochemical and microbiological properties, and shelf-life of optimally processed meat during frozen storage

Effect of edible film prepared with plasma‐activated water and olive leaf extract (Olea europaea L.) as a potential packaging in cooked meat product

AbstractThis research determined the use of edible film (EF) prepared with olive leaf extract (OLE) and plasma‐activated water (PAW) on the shelf life and quality of cooked meat (M. longissimus thoracis et lumborum) product. The characterization of PAW composition and the antioxidant activity and the total phenolic content (TPC) of OLE were determined. Also, physicochemical and microbiological properties and lipid oxidation of cooked meat product coated with EF stored at +4°C for 14 d were evaluated. Cold plasma treatment increased the nitrite/nitrate concentrations and ORP value and decreased the pH value of distilled water (DW). The amount of TPC, IC50 value, and the antioxidant activity of OLE were 71.52 mg GAE/g, 0.46 mg/mL, and 77.39%, respectively. The combined use of OLE and PAW in EF during storage reduced the pH of cooked meat product. Furthermore, the addition of OLE in EF increased the b* values and reduced the a* values of cooked meat product, whereas the addition of PAW did not influence the CIE L*, a*, b* color values. The use of EF prevented lipid oxidation in cooked meat product during storage, especially the addition of OLE to the EF reduced the TBARS values. In this research, the addition of OLE to EF prepared with PAW has a promising application potential in the preservation of RTE‐cooked meat products. Also, these findings suggested that OLE, a by‐product from production of olive oil, might be applied as active packaging in biodegradable films.

Development, characterization and stability of a novel sport drink based on thermal water, apple juice and hibiscus

Isotonic drinks are sports beverages that replenish minerals and rapidly absorbable carbohydrates. We proposed to surpass traditional formulations of isotonic drinks by integrating thermal water, which remains unexploited as a source of electrolytes in isotonic despite the high mineral content. The novel formula combined thermal water with apple juice and hibiscus extract (as sources of sugars and color, respectively, and bioactive compounds). Through comprehensive analysis of chemical, physicochemical, and microbiological properties over 45 days at 4°C and 25°C, the results unveiled an isotonic drink with satisfactory characteristics for this product category: pH of 3.72, 7.93 mg/100 mL of total sugars, and 148.30 mg/100 mL minerals, predominantly sodium (34.99 mg/100 mL) and potassium (73.20 mg/100 mL). It showed significant phenolic compounds, notably chlorogenic acid (2.75±0.10 mg/100 mL), and antioxidant activity (472.72 µmol Trolox eq/100 mL). It maintained a vibrant red hue derived from hibiscus anthocyanins (delphinidin 3-O-sambubioside and cyanidin 3-O-sambubioside, totaling 4.06±0.03 mg/100 mL), and demonstrated microbiological stability throughout the storage period in both temperatures studied. Therefore, by harnessing the potential of thermal water, this study paves the way for a novel approach to developing sports beverages and can serve as a model for countries rich in thermal springs.

HYGIENIC PAPERS MODIFIED BY FUNCTIONAL BIOPOLYMER-BIOCIDE COMPOSITIONS IN A PILOT RESEARCH INSTALLATION

The aim of this work was to demonstrate the process of manufacturing and applying functionalising additives using a pilot research installation. As part of the optimisation evaluation, hygienic papers functionalised with biopolymer-biocide compositions based on chitosan, starch and Gemini surfactants were prepared. The microbiological properties and susceptibility to biodegradation of prototype hygienic papers (prepared in EPICOM) were assessed. In particular, the minimum amount of biopolymer and bioactive agent were determined to ensure the finished product exerted antibacterial activity against Staphylococcus aureus, Bacillus subtilis and Escherichia coli and was more than 90% biodegradable in a compost environment. Under optimal conditions, the hygienic paper exerted excellent antibacterial activity against S. aureus and E. coli as well as good activity against B. subtilis. Moreover, the hygienic paper showed more than 90% biodegradability in compost conditions within 8 weeks.

Hyaluronic acid-solid lipid nano transporter serum preparation for enhancing topical tretinoin delivery: skin safety study and visual assessment of skin.

The use of nanosized particles is becoming more popular for the topical treatment of skin conditions. In this research work, we created and investigated the effects of solid lipid nanoparticles (SLN) containing hyaluronic acid and tretinoin. Solvent emulsification diffusion method was used to prepare the SLN formulation and characterized for their physicochemical properties. Fourier transform infrared spectroscopy was used to confirm that hyaluronic acid and tretinoin were incorporated in the SLN. Furthermore, X-ray diffractogram, thermal analysis including DSC and TGA and in vitro dissolution, permeation tests were also performed along with microbial assessment. Clinical studies in human were performed to evaluate the effect of the SLN on skin wrinkles. The SLN was 750 ± 31.29nm in size, with a zeta potential of 13.07 ± 0.75mV and a narrow polydispersity index of 0.24 ± 0.12. The entrapment efficiency of tretinoin was found to be 90.07 4.79%. Clinical studies in healthy human volunteers demonstrated that 90% of the tested individuals had improved skin conditions (reduction in wrinkles), by at least one grade after 4weeks of treatment. Regarding the development on SLN, it was found that the internal phase concentration did not considerably affect the physicochemical and microbiological properties. Therefore, Hyaluronic acid has potential for the development of SLN applicable to cosmetic formulations, especially for skin. These findings show that the developed SLN have potential for use as cosmetics in the future.

Incorporation of mixed strawberry and acerola jam into Greek-style goat yogurt with autochthonous adjunct culture of Limosilactobacillus mucosae CNPC007: Impact on technological, nutritional, bioactive, and microbiological properties

This study aimed to assess the impact of adding strawberry and acerola jam, along with Limosilactobacillus mucosae CNPC007, on the technological, nutritional, bioactive, and microbiological properties of Greek-style goat yogurt. Six yogurt formulations were developed: without and with the addition of L. mucosae CNPC007 (CY and PY, respectively), and with 10 % and 15 % jam (CY10, CY15, PY10, and PY15, respectively). The inclusion of jam enriched the yogurt with phenolic compounds and significantly enhanced antioxidant activity, as measured by FRAP and ABTS assays. The highest values were observed after 28 days of storage in the PY15 formulation (0.177 ± 0.01 and 3.43 ± 0.01 µmol TEAC/g, respectively), compared to CY (0.013 ± 0.01 and 0.19 ± 0.01 µmol TEAC/g, respectively) and PY (0.010 ± 0.01 and 0.23 ± 0.01 µmol TEAC/g, respectively). This increase was likely driven by the presence of anthocyanins and flavonoids in the jam, as indicated by heatmap correlation analysis. DPI and EPI were also influenced by the addition of jam and L. mucosae CNPC007, with EPI increasing in the PY10 and PY15 formulations, reaching approximately 40 % after 28 days. The incorporation of jam resulted in a decrease in the L* (<90) and an increase in the b* (>14) color parameters. Additionally, jam-enriched formulations exhibited higher syneresis and lower water retention capacity (WRC) throughout storage compared to control formulations, with average syneresis exceeding 26 % and WRC falling below 75 % after 28 days. In general, all yogurt formulations showed a reduction in lactose, an increase in glucose and galactose, and the production of lactic acid during storage. The lower lactose content observed after 28 days of storage in the PY (0.84 ± 0.01 g/100 g), PY10 (0.82 ± 0.01 g/100 g), and PY15 (0.98 ± 0.01 g/100 g) formulations indicates active sugar metabolism by L. mucosae CNPC007. All formulations met microbiological safety standards, confirming their suitability for consumption. Formulations containing L. mucosae CNPC007 showed viable cell counts exceeding the minimum recommended to produce health benefits (>7 log CFU/g) throughout the 28-day refrigerated storage and after in vitro digestion. These findings underscore the potential of combining tropical fruit jams with probiotics to develop a multifunctional, value-added yogurt product that delivers substantial health benefits to consumers.

Impact of organic and conventional farming practices on the multidimensional characteristics of flour and indirectly on bread

The demand for organic and locally sourced products is on the rise. This study investigates the impact of farming practices (organic versus conventional) on the microbiological, microscopic, and physical-chemical properties of 'Caaveiro' flour, alongside the physical-chemical, instrumental texture parameters, and sensory attributes of breads, using two fermentation methods (sourdough versus mixed leavening). 'Caaveiro' flour and bread, recognized under the Protected Geographical Indication ‘Galician Bread’, were employed as a case study. Organic flours exhibited higher counts of aerobic plate microorganisms, yeasts, and molds, yet these levels posed no health risks. Overall, farming practices demonstrated negligible influence on the evaluated flour and bread characteristics. Instead, fermentation method emerged as the predominant factor shaping bread attributes. Consequently, promoting organic production could help maintain the distinctive qualities of traditional breads under Protected Geographical Indications.

Beyond the surface: microbiological and biochemical attributes as indicators of soil quality in Atlantic Forest ecosystem

The objective of this study was to determine the biochemical and microbiological attributes in areas with different vegetation covers (mature forest, secondary forest, and sugar cane monoculture) and seasonal changes, and to compare the sensitivity of these attributes types (mycorrhizal, enzymatic, and carbon attributes) in response to changes in vegetation cover and season. Soil samplings were conducted over two years (one per semester, during the dry and wet periods of 2007 and 2008) in three types of areas: (I) mature forest; (II) secondary forest; and (III) sugar cane crop. The enzymatic activity of fluorescein diacetate, dehydrogenase, saccharase, basal carbon respiration, the carbon content of microbial biomass, the microbial coefficient, total and easily extracted glomalin soil-related proteins, mycorrhizal colonization, the number of glomerospores, total organic carbon, fulvic and humic acid content, and the fulvic/humic acid ratio were analyzed. In general, mycorrhizal parameters were more sensitive in distinguishing areas with different types of vegetation cover. Additionally, carbon stocks in areas of mature and secondary forest were higher compared to areas cultivated with sugar cane. The study reveals that mycorrhizal properties, such as root colonization and GRSP fractions, are more sensitive indicators of soil health than soil C attributes, providing a cost-effective alternative for evaluating soil health in the Atlantic Forest. The confirmed hypothesis supports the effectiveness of microbiological activity and C dynamics in discerning significant changes between sugar cane cultivation and forested areas. The study underscores the vital role of conserving forested areas, serving as crucial carbon reservoirs, and emphasizes the potential for enhanced sustainability through conservation practices and rapid soil function recovery in secondary forests within the Atlantic Forest.

Development and Evaluation of Oromucosal Spray Formulation Containing Plant-Derived Compounds for the Treatment of Infectious and Inflammatory Diseases of the Oral Cavity.

According to data in the literature, natural products and essential oils are often used in dental practice. To develop a new oromucosal spray for the treatment of infectious and inflammatory diseases of the oral cavity, clove CO2 extract and essential oils of lavender and grapefruit were used as active pharmaceutical ingredients. Clove extract was obtained by the method of subcritical extraction from various raw materials, the choice of which was based on the yield of the CO2 extract and the study of its phytochemical and microbiological properties. Based on the results of microscopic and diffraction analyses, the rational time of ultrasonic exposure for the emulsion of active pharmaceutical ingredients was established. Mucoadhesive polymers were used as stabilizers of the two-phase system and prolongators. This article discusses the impact of the type and concentration of mucoadhesive polymers on the stability of the emulsion system; the viscous, textural, adhesive, and film characteristics of oromucosal spray; and the parameters determining sprayability.

Advanced Micro/Nanocapsules for Self-Healing Coatings

The concept of intelligence has many applications, such as in coatings and cyber security. Smart coatings have the ability to sense and/or respond to external stimuli and generally interact with their environment. Self-healing coatings represent a significant advance in improving material durability and performance using microcapsules and nanocontainers loaded with self-healing agents, catalysts, corrosion inhibitors, and water-repellents. These smart coatings can repair damage on their own and restore mechanical properties without external intervention and are inspired by biological systems. Properties that are affected by either momentary or continuous external stimuli in smart coatings include corrosion, fouling, fungal, self-healing, piezoelectric, and microbiological properties. These coating properties can be obtained via combinations of either organic or inorganic polymer phases, additives, and pigments. In this article, a review of the advancements in micro/nanocapsules for self-healing coatings is reported from the aspect of extrinsic self-healing ability. The concept of extrinsic self-healing coatings is based on the use of capsules or multichannel vascular systems loaded with healing agents/inhibitors. The result is that self-healing coatings exhibit improved properties compared to traditional coatings. Self-healing anticorrosive coating not only enhances passive barrier function but also realizes active defense. As a result, there is a significant improvement in the service life and overall performance of the coating. Future research should be devoted to refining self-healing mechanisms and developing cost-effective solutions for a wide range of industrial applications.

Assessment of the Ecotoxicity of Thallium According to the Biological Properties of Soils

In laboratory model experiments, the ecotoxicity of Tl was assessed by changing the microbiological, biochemical and phytotoxic properties of soils in the South of Russia: ordinary chernozem (Haplic Chernozem (Loamic)), seropesks (Eutric Arenosol) and brown forest slightly unsaturated soil (Eutric Cambisol), differing in granulometric composition, pH and organic matter content. As a rule, there was a direct relationship between the concentration of Tl and the degree of deterioration of the studied soil properties. Tl nitrate showed higher ecotoxicity than oxide. The strongest ecotoxic effect of Tl was manifested on chernozem and seropesks 10 days after contamination, on brown forest soil — 30 days later. Restoration of biological properties of soils was observed for 90 days. Ordinary chernozem showed the greatest resistance to Tl contamination, and seropeski showed the least. The results obtained indicate a high ecotoxicity of Tl.

Stability of physicochemical and microbiological properties of Geniotrigona thoracica honey after moisture reduction and long-term storage in different containers

Stingless bee honey is nutritious but prone to fermentation due to high moisture content and improper storage, leading to quality deterioration. This study investigates the impact of container types and storage time on the properties of minimally treated Geniotrigona thoracica honey using clay pots. The moisture content of the raw honey was reduced from 28.2 g/100 g to 19.5 g/100 g after clay pot storage. The treated honey was then divided into four different containers: glass jars (clear and amber) and polyethylene terephthalate jars (clear and amber), and stored at 27 ± 2 °C for 365 days. After 365 days, moisture content slightly decreased in all containers, with honey in amber glass jar showing the lowest at 16.8 g/100 g. As moisture decreased, TSS increased, indicating sugar concentration. Ash content, viscosity, and free acidity increased over time, while pH values slightly decreased but stayed within acceptable limits. Honey colour increased with honey in amber glass jar showed the darkest honey (286 ± 2 mm Pfund) after 365 days. For all samples, the total phenolic content increased indicating enhanced antioxidant properties. While the hydroxymethylfurfural level increased but remained within standards with honey stored in amber PET jar had the lowest level (10.8 ± 0.2 mg/kg). Overall, moisture reduction with clay pots and proper storage containers can maintain and enhance honey quality during extended storage, with all samples meeting quality standards throughout.

Product development of gac fruit juice incorporated with lime juice

Gac fruit is widely cultivated in Thailand. It has elevated amounts of phytochemical compounds such as lycopene and β-carotene, with the aril section being the richest in these compounds. Lime juice is a healthy drink that is generally consumed for its nutritive value. The purpose of this study was to carry out an assessment to identify the appropriate proportion of lime for blended lime and gac fruit juice processing. This research consisted of four experiments. Fresh gac fruit juice (as a control sample; 0% and blended gac fruit juice with 5%, 10% and 15% concentrations of lime juice were analysed. Physical properties were examined, including brightness and colour (L*, a* and b* values), as well as chemical properties such as total acidity percentage, pH, vitamin C, total soluble solids, β-carotene, antioxidant inhibition percentage (DPPH assay) and lycopene. For the assessment of microbiological properties, a total plate count was carried out. A sensory evaluation for colour, odour, flavour, mouthfeel as well as overall acceptability was performed by thirty untrained panelists using the 9-point hedonic scale. Concerning the physical properties, it was determined that an increase in the amount of lime juice caused an escalation in external colour, odour and sediments. Analysis of the chemical properties revealed that all treatments were significantly different (p&lt;0.05), except for β-carotene and total soluble solids. The chemical properties showed that lycopene, antioxidant inhibition percentage (as DPPH assay) and β-carotene were within the ranges of 647.32- 650.48 µg/g, 4.23-4.65% and 441.95-444.16 µg/g, respectively; they were not significantly different except for the antioxidant inhibition percentage and β-carotene. An increase in the amount of lime juice caused an increase in the external appearance of vitamin C sediments and total acidity percentage. The findings of the microbiological analysis demonstrated that the total plate count met the standard regulations, while the sensory evaluation revealed that the flavour, mouthfeel and overall acceptability for experiment no. 3 (10% of lime juice) obtained the highest values of 7.37, 6.90 and 7.33, respectively.

Physicochemical composition and amino acid profile of the beverage of Ungurahua (Oenocarpus bataua) from the Amazonian Region of Ecuador.

Oenocarpus bataua, also known as Ungurahua, is a palm species indigenous to Ecuador's Amazon region. The fruit is used for oil extraction and beverage production. This research aimed to evaluate a beverage made from O. bataua by characterizing its physicochemical properties, amino acid profile, formulation, and sensory and microbiological properties. The research employed quantitative, exploratory, and experimental methodologies utilizing a bifactorial design (3 × 2). This research investigated the effect of cooking and the type of sweetener on the quality of sweetened products. Six treatments were applied, and sensory analysis was performed to determine the optimal treatment. The most effective treatment was a2b2 (cooked for 30 min at 65 ±3°C and sweetened with panela). Upon further analysis, this treatment had a moisture content of 94.7%, ash content of 0.85%, protein content of 0.59%, ethereal extract EE of 2.18%, fiber content of 0.80%, non-nitrogenous extract-ENN of 0.85%, pH of 4.37, Brix of 1.80°, and titratable acidity of 1.92%. A comparison of O. bataua beverages with similar beverages indicated their acceptable nutritional value. Amino acid profile analysis showed the presence of 10 amino acids, of which 8 were essential, and 10 were non-essential. Histidine had the highest concentration in the beverage, with an average of 77%. To ensure the safety and quality of the beverage, a microbiological analysis was performed in compliance with NTE-INEN 3028 standards. No mesophilic aerobes, Salmonella spp., or total coliforms were detected. Therefore, the proposed beverage is safe and nutritionally valuable because of its high amino acid content, balanced physicochemical composition, and sufficient microbiological composition.

Fungal secondary metabolite gliotoxin enhances enzymatic activity in soils by reshaping their microbiome

Gliotoxin (GT) is a sulfur-containing epidithiodioxopiperazine produced by various filamentous fungi, including those used in biological plant protection (Trichoderma virens). The pronounced antimicrobial effect of GT on a variety of fungi and bacteria makes it a promising agent for controlling phytopathogens in agricultural systems. In this study, we aim to investigate the microbiological properties of the soil microbiome after the introduction of GT. GT was applied at doses of 10, 25, 50, 100 and 500 μM kg−1 soil. Soil sampling was carried out after 1, 7, 14, 30, 60 and 90 days of incubation. It was found that GT significantly stimulated the respiratory activity of soil microorganisms and maintained this activity throughout the experiment. Carbon of microbial biomass, on the contrary, decreases under the influence of GT and is restored at the end of the experiment only in microcosms with 10 and 25 μM GT. Separate estimates of bacterial and fungal biomass showed that the bacterial community increased in biomass on day 14, while fungal biomass increased on day 30 after the treatment. Under the influence of GT, the activity of soil enzymes involved in the carbon (CB, βG, βX), nitrogen (NAG, LAP) and phosphate (AP) cycles significantly increased. High-throughput amplicon sequencing of the ITS and 16S rDNA markers revealed that the soil fungal community is more susceptible to GT than the bacterial community. This was reflected in changes in alpha-diversity indices and in the pattern of changes in the abundance of some microbial genera. Thus, on the one hand, the data obtained provides insight into the biological effects of GT on the soil microbial community. On the other hand, it sets the direction for further research into the ecological role of antibiotics produced by soil and rhizosphere microorganisms.