Search Results (94)

The formation mechanism of black streak defects in hot-rolled steel sheets was investigated to address the influence of the process parameters on the surface quality during the production of 304 stainless steels. Macro-/microstructural characterization revealed that the defect regions contained necessary mold slag components (Ca, Si, Al, Mg, Na, K) which originated from the initial stage of solidification in the mold region of the continuous casting process, indicating obvious slag entrapment during continuous casting. On this basis, a three-dimensional coupled finite-element model for the molten steel flow–thermal characteristics was established to evaluate the effects of typical casting parameters using the determination of the critical slag entrapment velocity as the criterion. Numerical simulations demonstrated that the maximum surface velocity improved from 0.29 m/s to 0.37 m/s with a casting speed increasing from 1.0 m/min to 1.2 m/min, which intensified the meniscus turbulence. However, the increase in the port angle and the depth of the submerged entry nozzle (SEN) effectively reduced the maximum surface velocity to 0.238 m/s and 0.243 m/s, respectively, with a simultaneous improvement in the slag–steel interface temperature. Through MATLAB (version 2023b)-based reverse optimization combined with critical velocity analysis, the optimal mold slag properties were determined to be 2800 kg/m³ for the density, 4.756 × 10⁻⁶ m²/s for the kinematic viscosity, and 0.01 N/m for the interfacial tension. This systematic approach provides theoretical guidance for process optimization and slag design enhancement in industrial production. Full article

The increasing demand for sustainable protein sources highlights Hermetia illucens (Black Soldier Fly, BSF) as a promising alternative. However, microbiological safety remains a key concern. This study investigated the microbial diversity of BSF larvae, comparing two processing methods: (1) boiling followed by drying and (2) drying alone. Microbial diversity was assessed via 16S rRNA sequencing, while bacterial loads were quantified using culture-based methods on samples from a French company. A systematic review complemented this analysis by synthesizing the existing knowledge on BSF microbiota. The rearing conditions varied, with substrate pH ranging from 4.1 to 9.0 and ambient temperatures between 24.6 °C and 42.7 °C. Mesophilic bacteria, spores, and lactic acid bacteria reached up to 8.6, 7.7, and 8.5 log CFU/g in the substrates and larvae, while yeasts, molds, and sulfite-reducing bacteria remained below 4.8 log CFU/g. Boiling reduced most loads below detection thresholds, particularly for yeasts, molds, and ASR. Salmonella, Listeria monocytogenes, Cronobacter sp., and coagulase-positive staphylococci were absent, whereas Clostridium perfringens and Escherichia coli were variably detected. Metabarcoding showed shifts in composition, with Proteobacteria, Bacteroidota, Actinobacteriota, and Firmicutes (Bacillota and Clostridiota) dominating. Process 1 more effectively reduced the bacterial loads, though Bacillus and Clostridium remained. Campylobacter sp. detection in powders raises food safety concerns. Full article

The presence of filamentous fungi with toxigenic ability from the Aspergillus genera is frequently found in maize kernels, and this can lead to decay and mycotoxin contamination of the kernels. In this study, we morphologically and molecularly characterized 45 isolates of Aspergillus section Nigri originating from maize and small grains (wheat, triticale, and spelt) in Serbia. Based on morphological traits, they were classified into two morpho groups. Representative isolates from both morpho groups were further molecularly characterized through sequencing of ITS, CaM and RPB2 genes in order to compare species composition, which could affect specific mycotoxicological risks. Morpho GroupI was molecularly identified as Aspergillus welwitschiae and morpho GroupII as Aspergillus tubingensis. Phylogenetic analysis of the CaM gene revealed that the Serbian Aspergillus welwitschiae isolate belongs to the H8 haplotype, while A. tubingensis isolates clustered into two subclusters. This is the first report of A. tubingensis as the causal agent of black mold of small grains (wheat, triticale and spelt) in Serbia. This distribution underscores the ecological preferences of species within the genus Aspergillus Section Nigri across various agricultural products. It emphasizes the importance of comprehending their occurrence, distribution, aggressiveness and potential for mycotoxin production in food safety assessments. Full article

This study focuses on the development and characterization of biodegradable polymer composites consisting of a polypropylene (PP) matrix, carbon black pigment, and hybrid fillers. The fillers incorporated into these composites consisted of a blend of fibers and particles derived from natural, biodegradable materials, such as flax fibers (FFs) and wood flour (WF) particles. The compositions of polymer material were expressed as PP/FF/WF weight ratios of 100/0/0, 70/5/25, and 70/10/20. The polymer materials were prepared using conventional plastic processing methods like extrusion to produce composite mixtures, followed by melt injection to manufacture the samples needed for characterization. The structural characterization of the polymer materials was conducted using optical microscopy and X-ray diffraction (XRD) analyses, while thermal, mechanical, and dielectric properties were also evaluated. Additionally, their biodegradation behavior under mold exposure was assessed over six months. The results were analyzed comparatively, and the optimal composition was identified as the polymer composite containing the highest flax fiber content, namely PP + 10 wt.% flax fiber + 20 wt.% wood flour. Full article

This study aimed to evaluate the effect of adding shredded black chokeberry (Aronia melanocarpa) pomace on the quality of heat-treated and vacuum-packed pork burgers stored for 14 days at +4 °C. Four burger treatments—Control (BC) and products with 2%, 3.5%, and 5% chokeberry pomace (B2, B3.5, and B5, respectively)—were analyzed for physicochemical properties (thermal loss, shrinkage, content of selected chemical components, pH, color parameters, and shear force) and microbial quality (aerobic mesophilic microorganisms, psychrotrophic bacteria, lactic acid bacteria, Enterobacteriaceae, Pseudomonas spp., Brochothrix thermosphacta, and yeasts and molds). The addition of chokeberry pomace increased (p < 0.05) the thermal loss of pork burgers from 23.5% (BC) to 30.8% (B5) and decreased (p < 0.05) the pH from 6.93 (BC, day 1) to 6.74 (B5, day 14). The introduction of pomace into the pork burgers also significantly (p < 0.05) affected the content of chemical components. However, the nutritional value of pork burgers remained high, with a protein content not lower than 26.68% (BC) and a fat content not exceeding 13.96% (B5). The most affected quality feature of the pork burgers was color. Products B2, B3.5, and B5 exhibited lower L* and b* parameters (p < 0.05) while showing higher a* values. The b* parameter had negative values for products B3.5 and B5 on days 7 and 14. The use of chokeberry pomace did not deteriorate the microbial quality of pork burgers, as indicated by the maximum total count of aerobic mesophilic microorganisms, which reached 4.4 × 10³ cfu/g (B3.5). Moreover, on the final day of storage, moderate antimicrobial properties of chokeberry pomace were observed, with a lower (p < 0.05) number of lactic acid bacteria and Pseudomonas spp. in products B2–B5 compared to BC. The results indicate that incorporating shredded chokeberry pomace into burger-type ground pork products does not present major technological difficulties. However, raw shredded fruit pomace is a perishable microbiological material and requires rapid processing. Further research on the use of chokeberry pomace in burger-type meat products is recommended due to its nutritional value and health-promoting properties. However, this research should include a comprehensive sensory evaluation of the finished product. Full article

Red grapes often suffer from postharvest diseases like blue mold and black mold caused by Penicillium expansum and Aspergillus niger. Biological control using beneficial yeasts and bacteria is an effective method to manage these diseases. Rhodotorula sp. and Bacillus sp. are effective microorganisms for the control of postharvest diseases of red grapes. This study combined two yeast strains (Rhodotorula graminis and Rhodotorula babjevae) and two bacterial strains (Bacillus licheniformis and Bacillus velezensis) to investigate their biological control effects on major postharvest diseases of red grapes and explore the underlying physiological mechanisms. Research showed that compound microorganism W3 outperformed the others; it reduced spore germination and germ tube growth of P. expansum and A. niger, while its volatiles further inhibited pathogen growth. Additionally, the treatment enhanced the antioxidant capacity of grapes and increased resistance to pathogens by boosting peroxidase activities, superoxide dismutase, catalase and ascorbate peroxidase, phenylalanine ammonolyase, and polyphenol oxidase. Furthermore, the combined treatment increased the activity and accumulation of antifungal compounds such as total phenols and flavonoids, thereby improving disease resistance and reducing decay. Therefore, composite microorganisms combining various antagonistic strains may offer a viable substitute for tackling postharvest diseases in red grapes. Full article

This study examined the effect of partially replacing semi-reinforcing carbon black grade N550 (up to 10 pts. wt.) and fully replacing industrial chalk with natural shungite mineral in industrial formulations of elastomer compositions intended for manufacturing various rubber technical products. It has been shown that due to the high content of carbon and silicon components in the composition of shungite mineral micropowders, their use as a filler in elastomer formulations significantly improves the physical and mechanical properties of rubber technical products (RTPs) manufactured using such compositions. It was determined that the use of SM as a partial replacement for carbon black in rubbers intended for molded rubber technical products contributes to a reduction in Mooney viscosity (up to 26.8%) and optimal vulcanization time (up to 23.7%), achieving rubbers with the required set of physical–mechanical properties and with an enhancing sealing capability (up to 19.7%). It has been established that the use of shungite mineral micropowders as a complete replacement for industrial chalk increases the strength of rubber products (RTPs) by up to 18.5% and enhances their resistance to liquid aggressive environments. Full article

To determine the optimal conditions of pressurized liquid extraction (PLE) and microwave-assisted extraction (MAE) of polyphenols from black chokeberry leaves (BCL), temperature, time and sample-to-solvent ratio (SSR) were varied to obtain maximum polyphenols yield. The extracts were analyzed for total polyphenols (TP) as well as individual ones (UPLC ESI MS²) and antioxidant capacity (FRAP, DPPH and ORAC). Moreover, the biological activity of the selected extracts was additionally determined. The optimal PLE and MAE conditions were 150 °C, 5 min extraction time and SSR 1:30 g/mL (TP 80.0 mg GAE/g dm), and 70 °C, extraction time 5 min and SSR 1:30 g/mL (TP 36.4 mg GAE/g dm), respectively. Both methods yielded similar polyphenol profiles (43 compounds) but differed quantitatively. MAE extracts contained more flavonols and phenolic acids, while PLE extracts had higher procyanidins and flavan-3-ols. Furthermore, the PLE extract exhibited a superior antioxidant capacity. This BCL extract also showed that it can protect against oxidative and DNA damage and can induce free radical formation and DNA damage, albeit at different doses. Moreover, it had a moderate antimicrobial activity against S. aureus and B. subtilis, while no antimicrobial activity was observed against Gram-negative bacteria as well as yeasts, lactic acid bacteria and molds. Full article

The aim of this work was to study the fermentation of black table olives under slightly pressurized CO₂ (spCO₂). The olives were marinated in brine with a low salt content and processed using both the traditional two-phase method and a new single-phase method. SpCO₂ is a new technical tool, positively tested in previous studies on the production of low-salt table olive, as a third barrier to microbial growth in brine. The tests performed with the cultivar Leccino, using a brine acidified with 0.5% (w v⁻¹) citric acid and enriched with 0%, 3%, and 6% (w v⁻¹) NaCl, showed the absence of bacteria and molds in the brine from the first days of incubation. Fermentation was governed by six yeast species, mainly represented by Candida boidinii and Saccharomyces cerevisiae, with a maximum total number of 6.30 Log CFU mL⁻¹ and 4.28 Log CFU mL⁻¹ in the brine with 3% and 6% (w v⁻¹) NaCl, respectively. The best debittering results were obtained when the olives were processed in the presence of spCO₂ with the single-phase method, using brine with 6% (w v⁻¹) NaCl, validating the important role played by spCO₂ in the production of low-salt black table olives. Full article

The bone plates used in surgery to assist in fracture healing are often manufactured by metal injection molding (MIM) using a feedstock material consisting of metal powder and polymer binder. However, if the local powder concentration is too low or uneven, black lines may be formed, which impair the product appearance. Furthermore, if the melding temperature is too low, it can lead to meld lines and reduced mechanical properties. Accordingly, this study combines mold flow analysis simulations with the single-objective Taguchi robust design method to determine the MIM processing conditions that optimize the powder concentration and melding temperature. Grey relational analysis (GRA) is then used to establish the processing conditions that simultaneously optimize both MIM objectives. It is found that the processing conditions determined through GRA provide a significant improvement over the original design; however, the experimental outcomes are poorer than those achieved through the single-objective Taguchi experiments since the melt temperature effect suppresses that of all the other processing conditions. Consequently, a robust multi-criteria optimization (RMCO) technique is employed to improve the optimization outcome by identifying the dominant factors in the MIM process and fixing them at optimal levels to redesign the Taguchi experiments to optimize the non-primary factors. It is shown that the RMCO method eliminates interference between the multiple factors and hence provides an improved multi-objective optimization outcome. Overall, the integrated framework proposed in this study advances the optimization of the MIM process for bone plates and leads to improved product quality and performance. Full article

Rainfall, particularly in continental climates with a monsoonal tendency, impacts the microbial niches during the growth of mountain cultivated ginseng. With shifts in the microbial community, diseases in ginseng cultivated and protected under rain shelter conditions may ultimately be altered. Such cultivation may influence microflora dynamics through variations in meteorological parameters; however, this is not yet clear. The present study found that rain shelter cultivation affected the distribution of fungal communities within mountain cultivated ginseng. This led to an improved community structure in the ginseng rhizosphere, characterized by the proliferation of antagonistic fungi and a reduction in pathogenic fungi. A correlation analysis of meteorological factors found that soil temperature and humidity were the primary meteorological factors affecting mountain cultivated ginseng. It is evident that rain shelter cultivation regulated the microecological environment of the mountain cultivated ginseng’s rhizosphere and resulted in positive outcomes. A disease investigation supported this finding. The incidence of ginseng root diseases, such as rust and root rot, was reduced by 5–6%. The incidence of ginseng leaf diseases, including gray mold and black spot, was reduced by 5–10%. This research provides evidence to address the dynamics of microbial ecology under rain shelter cultivation and its benefits for sustainable mountain cultivated ginseng management. Full article

Wheat (Triticum aestivum L.) is one of the most agriculturally and economically important crops in the world. Wheat fungal diseases are becoming more severe and frequent due to global climate change, threatening wheat yields and security. While fungal diseases such as fusarium head blight, stripe rust, and powdery mildew have been extensively studied, the newly emerged fungal pathogens in wheat are still under-researched. In May 2023, black mold symptoms were observed on wheat spikes in Xinxiang City, Henan Province, China. However, the causal agent of this disease was not known. We employed a combination of morphological examination and molecular techniques to identify the pathogen. The internal transcribed spacer (ITS) region, translation elongation factor 1-alpha (tef1), and actin (act) genes of the fungus were partially sequenced (accession no. OR186209, PQ271633 and PQ271632) and showed 99.59–100% identity with the previously reported Cladosporium cladosporioides, which affects wheat, pokeweed, and black-eyed pea. The pathogenicity of this fungus was confirmed by fulfilling Koch’s postulates. Through a rigorous screening process, we found Simplicillium aogashimaense, Trichothecium roseum, and Bacillus velezensis as effective biocontrol agents, with B. velezensis demonstrating the most potent antagonistic activity against the Cladosporium mold. This discovery showed the potential of B. velezensis as a biocontrol agent for wheat disease management. The findings underscore the importance of the present study in advancing the control of this disease. Full article

Morchella spp. (true morels) are precious edible mushrooms consumed around the world, with a delicious taste, rich nutritional value, and unique healthcare effects. Various fungi and bacteria have been reported to colonize the ascocarps of Morchella, damaging their fruiting bodies and leading to serious economic losses in cultivation. The species identification of these colonizing organisms is crucial for understanding their colonization mechanisms on morels. Slime molds, which have characteristics of both “fungi” and “animals”, can occasionally colonize crops and edible fungi. However, there have been no reports of dictyostelid cellular slime molds (dictyostelids) colonizing plants and fungi to date. In this study, we discovered that dictyostelids colonized the surface of one wild ascoma of Morchella in the forest of Chongqing, China, with the tissues being black and rotten. Macro- and micro-morphological observations, along with molecular phylogenetic analyses, identified the specimens investigated in this study as Dictyostelium implicatum and Morchella sp. Mel-21. The results provide new knowledge of dictyostelid colonization on organisms and contribute to the diversity of species colonizing true morels. Moreover, this is also the first report of dictyostelids distributed in Chongqing, China. This study enhances our insights into the life history and potential ecological significance of dictyostelids and updates their distribution area in China. Further research will be conducted to uncover the mechanisms behind the colonization observed in this study. Full article

The genus Aspergillus contains several species that are important plant pathogens. Plant pathogenic Aspergillus spp. affect agricultural crops in the field as well as after harvest, often associated with corn ear rot, cotton boll rot, peanut yellow mold, black mold of onion and garlic, fruit rot on grapes, pomegranates, olives, citrus, and apples. Coffee berries and coffee beans as well as tree nuts are also frequently infected by Aspergillus spp. Some of the plant pathogenic Aspergillus spp. are also mycotoxigenic, produced mycotoxin in the plant tissues leading to contamination of agricultural products. Over the years, reports of plant diseases caused by Aspergillus in various crops have increased, suggesting they are commonly encountered plant pathogens. This review focuses on agricultural crops or cultivated plants infected by Aspergillus spp. The compilation of plant pathogenic Aspergillus spp. provides information to mycologists, particularly those involved in plant pathology and crop protection, with updated information on plant diseases caused by various species of Aspergillus. The updated information also includes the locality or location, province, state and the country. The knowledge on the prevalence and geographic distribution of plant pathogenic Aspergillus spp. is beneficial in the application of crop protection. Full article

This study investigates the enhancement of polylactic acid (PLA) properties through the incorporation of graphene nanoplatelets (GNPs) and carbon black (CB) for applications in 3D printing and injection molding. The research reveals that GNPs and CB improve the electrical conductivity of PLA, although conductivity remains within the insulating range, even with up to 10% wt of nanoadditives. Mechanical characterization shows that nanoparticle addition decreases tensile strength due to stress concentration effects, while dispersants like polyethylene glycol enhance ductility and flexibility. This study compares the properties of materials processed by injection molding and 3D printing, noting that injection molding yields isotropic properties, resulting in better mechanical properties. Thermal analysis indicates that GNPs and CB influence the crystallization behavior of PLA with small changes in the melting behavior. Dynamic Mechanical Thermal Analysis (DMTA) results show how the glass transition temperature and crystallization behavior fluctuate. Overall, the incorporation of nanoadditives into PLA holds potential for enhanced performance in specific applications, though achieving optimal conductivity, mechanical strength, and thermal properties requires careful optimization of nanoparticle type, concentration, and dispersion methods. Full article