Search Results (193)

Biodiesel, as one of the alternatives to fossil fuels, faces significant challenges in large-scale industrial production due to its high production costs. In addition to raw material costs, catalyst costs are also a critical factor that cannot be overlooked. This review summarizes various methods for preparing biodiesel catalysts from solid waste. These methods not only enhance the utilization rate of waste but also reduce the production costs and environmental impact of biodiesel. Finally, the limitations of waste-based catalysts and future research directions are discussed. Research indicates that solid waste can serve as a catalyst carrier or active material for biodiesel production. Methods such as high-temperature calcination, impregnation, and coprecipitation facilitate structural modifications to the catalyst and the formation of active sites. The doping of metal ions not only alters the catalyst’s acid-base properties but also forms stable metal bonds with functional groups on the carrier, thereby maintaining catalyst stability. The application of microwave-assisted and ultrasound-assisted methods reduces reaction parameters, making biodiesel production more economical and sustainable. Overall, this study provides a scientific basis for the reuse of solid waste and ecological protection, emphasizes the development potential of waste-based catalysts in biodiesel production, and offers unique insights for innovation in this field, thereby accelerating the commercialization of biodiesel. Full article

Pectin is a multifunctional polysaccharide whose structural attributes, including degree of esterification (DE), molecular weight (MW), and branching, directly affect its gelling, emulsifying, and bioactive properties. Conventional pectin extraction relies on acid- or alkali-based methods that degrade the pectin structure, generate chemical waste, and alter its physicochemical and functional properties. Although novel methods such as ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE), and enzyme-assisted extraction (EAE) are recognized as environmentally friendly alternatives, they frequently use acids or alkalis as solvents. This review focuses on pectin extraction methods that do not involve acidic or alkaline solvents such as chelating agents, super/subcritical water, and deep eutectic solvents (DESs) composed of neutral components. This review also discusses how these alternative extraction methods can preserve or modify the key structural features of pectin, thereby influencing its monosaccharide composition, molecular conformation, and interactions with other biopolymers. Furthermore, the influence of these structural variations on the rheological properties, gelling behaviors, and potential applications of pectin in the food, pharmaceutical, and biomedical fields are discussed. This review provides insights into alternative strategies for obtaining structurally intact and functionally diverse pectin by examining the relationship between the extraction conditions and pectin functionality. Full article

Edible mushrooms are well-known for their culinary and nutritional values. Additionally, they serve as a natural source of polyphenols, a group of bioactive compounds that significantly treat diseases associated with oxidative stress. The polyphenolic profile of mushrooms mainly consists of phenolic acids and flavonoids, whose chemical properties have attracted the attention of both the food and pharmaceutical industries. Consequently, methods for extracting polyphenols from mushrooms encompass conventional techniques (maceration and Soxhlet extraction) as well as innovative or green methods (ultrasound-assisted extraction, microwave-assisted extraction, pressurized liquid extraction, supercritical fluid extraction, enzyme-assisted extraction, and pulsed electric field extraction). Nonetheless, extraction with pressurized liquids and supercritical fluids is considered the most suitable method, as they function in a gentle and selective manner, preserving the integrity of the phenolic compounds. The use of mushroom-derived phenolic compounds in food and pharmaceutical formulations continues to face challenges concerning the safety of these extracts, as they might contain unwanted substances. Future applications should incorporate purification systems to yield highly pure extracts, thereby creating safe polyphenol carriers (for food and pharmaceutical products) for consumers. Full article

This study establishes a multiphysics coupling model of acoustics, mechanics, and electrostatics through COMSOL, systematically explores the sound field distribution and stress–strain characteristics of tailing particles in sand silos under different frequencies of ultrasonic radiation, and proposes an optimization scheme for the sound field. The simulation results show that under 28 kHz ultrasonic radiation, the amplitude of sound pressure in the sand silo (173 Pa) is much lower than that at 40 kHz (1220 Pa), which can avoid damaging the original settlement mode of the tail mortar. At the same time, the periodic fluctuation amplitude of its longitudinal sound pressure is significantly greater than 25 kHz, which can promote settlement by enhancing particle tensile and compressive stress, achieving the best comprehensive effect. The staggered placement scheme of the transducer eliminates upward disturbance in the flow field by changing the longitudinal opposing sound field to oblique propagation, reduces energy dissipation, and increases the highest sound pressure level in the compartment to 130 dB. The sound pressure distribution density is significantly improved, further enhancing the settling effect. This study clarifies the correlation mechanism between ultrasound parameters and tailings’ settling efficiency, providing a theoretical basis for parameter optimization of ultrasound-assisted tailing treatment technology. Its results have important application value in the optimization of tailings settling in metal mine tailing filling. Full article

Regulating the dissolution and interfacial behavior of minerals via external force fields is considered a promising strategy for enhancing the flotation of soluble minerals. This study explored the potential of ultrasound-assisted pulp conditioning in improving ultrafine smithsonite flotation. Specifically, we systematically evaluated the effects of ultrasonic pretreatment (UP) on the physicochemical properties of smithsonite suspensions (focusing on surface erosion behavior) and assessed subsequent flotation performance using flotation tests and modern analytical techniques. It has been found that UP can significantly modify smithsonite suspension characteristics, including particle morphology, ionic composition, electrokinetic properties, and pulp pH. Flotation results demonstrate that UP yields higher recovery compared to traditional stirring (TS) conditioning, especially at medium-to-high sodium oleate (NaOL) concentrations. Comparative analysis reveals that ultrasonic-assisted dissolution and ion-selective migration are the main factors driving improved flotation performance. Unlike TS, UP promotes greater zinc ion release, facilitates the dissolution–hydrolysis–precipitation equilibrium, generates more and finer nanoparticles in the bulk phase, and induces the deposition of hydrozincite on smithsonite surfaces. These changes increase active zinc sites for more stable NaOL adsorption, thereby enhancing the flotation of ultrafine smithsonite particles. Full article

The valorization of agri-food by-products is a critical pathway toward building sustainable food systems, reducing waste, and advancing the circular economy. This review aims to identify recent advances, key challenges, and future perspectives in this field. We conducted a critical and systematic synthesis of 159 peer-reviewed studies (2019–2025) selected based on quality and thematic relevance from leading international databases. The analysis focuses on emerging technologies such as ultrasound-assisted extraction, microencapsulation, spray drying, lyophilization, deep eutectic solvents, and colloidal systems, emphasizing their efficiency in recovering bioactive compounds from agro-industrial by-products. Significant challenges include industrial scalability, economic feasibility, regulatory compliance, and consumer acceptance. This paper also discusses current applications in functional foods and nutraceuticals, outlining promising directions for the sector. Although challenges remain, the findings offer valuable insights for researchers, industry, and policymakers aiming to foster sustainable innovation and implement strategies aligned with circular economy principles. Full article

The microencapsulation of bioactive compounds from rapeseed oil using sodium alginate, in the presence and absence of an ultrasonic (US) field, is reported. A Box–Behnken experimental design is used to investigate the influence of process parameters on the microencapsulation yield; then, the response surface methodology is applied, to find their values ensuring its optimum yield. The operating parameters investigated are the ratio of sodium alginate to rapeseed oil, the microencapsulation time and the concentration of the calcium chloride solution. The US bath was used at its nominal power, and the microencapsulation temperature was kept at 20 °C, with a thermostat, for all experiments. A detailed study on the comparison of the two microencapsulation techniques (in the presence and absence of the US field) was carried out. Good results were obtained in the presence of the US field for optimal conditions, when the microencapsulation yield was 90.25 ± 0.02%, higher than the microencapsulation process performed in the absence of the US field, 87.11 ± 0.02%. The results also showed that the use of the US field (optimal conditions) led to an increase in encapsulation efficiency, total phenolic content and antioxidant capacity (76.56 ± 0.02%, 324.85 ± 0.01 mg GAE/g and 57.05 ± 0.12 mg/mL). The physicochemical description of microcapsules was performed using modern characterization methods. These results indicate that by increasing the microencapsulation yield of bioactive compounds through sonication, the process aims to achieve a uniform size distribution of microcapsules. Full article

Ultrasound-assisted extraction (UAE) using water as a green solvent is a promising non-thermal technique for the extraction of total dietary fiber (TDF) and betaine from red beetroot (Beta vulgaris L.) peel. Compared to conventional thermal extraction (CE), UAE has proven to be a more efficient alternative method for the extraction of TDF and betaine. The pretreatment of beet was carried out using pulsed electric field (PEF) technology, with the specific energy of the PEF treatment set at 1.6 kJ/kg. To achieve the maximum betaine concentration of 24.80 µg/mL, the optimum UAE parameters were 50% amplitude with an extraction time of 3 min using distilled water as extraction solvent. The optimum TDF yield of 44.07% was achieved at 75% amplitude, 6 min treatment time and 50% ethanol solution as extraction solvent. These conditions can effectively supplement UAE, especially in the extraction of bioactive compounds from red beetroot peel. However, the TDF obtained in the residue must be evaporated for further use, which increases energy consumption. Ethanol concentration had no statistically significant effect (p > 0.05) on the TDF results, suggesting that distilled water could replace ethanol as a solvent in UAE. This substitution offers environmental and economic advantages, as water is more environmentally friendly and less expensive than ethanol. In addition, the use of distilled water eliminates the need to evaporate ethanol, which is particularly advantageous when the extracted material is intended for fortification or improvement of the technological and functional properties of food products. Full article

Female infertility is a multifaceted condition affecting millions of women worldwide, with causes ranging from hormonal imbalances and genetic predispositions to lifestyle and environmental factors. Traditional diagnostic approaches, such as hormonal assays, ultrasound imaging, and genetic testing, often require extensive time, resources, and expert interpretation. In recent years, artificial intelligence (AI) has emerged as a transformative tool in the field of reproductive medicine, offering advanced capabilities for improving the accuracy, efficiency, and personalization of infertility diagnosis and treatment. AI technologies demonstrate significant potential in analyzing vast and complex datasets, identifying hidden patterns, and providing data-driven insights that enhance clinical decision-making processes in assisted reproductive technologies (ART) services. This narrative review explores the current advancements in AI applications in female infertility diagnostics and therapeutics, highlighting key technological innovations, their clinical implications, and existing limitations. It also discusses the future potential of AI in revolutionizing reproductive healthcare. As AI-based technologies continue to evolve, their integration into reproductive medicine is expected to pave the way for more accessible, cost-effective, and personalized fertility care. Full article

Rosa damascena Mill., widely recognized for its remarkable skincare benefits, is extensively used in the cosmeceutical industry. This study introduces a novel green approach to extract bioactive compounds from R. damascena for cosmeceutical applications while also evaluating its stability in terms of physical, chemical, and biological properties. R. damascena petals were extracted using deionized water instead of organic solvents, using various green extraction methods, including infusion, microwave, ultrasound, pulsed electric field, and micellar extraction. Their chemical composition was analyzed using high-performance liquid chromatography. The extract with the highest concentration of bioactive compounds was further evaluated for its cosmeceutical properties and stability and compared with its individual chemical components. Various factors influencing stability were evaluated, including pH level (5, 7, and 9), temperature (4 °C, 30 °C, and 45 °C), and light exposure. The findings indicate that the extract obtained through microwave-assisted extraction (MAE) contained the highest concentration of bioactive constituents, with corilagin being the most abundant, followed by cyanidin-3,5-O-diglucoside, gallic acid, ellagic acid, L-ascorbic acid, and rutin, respectively. Additionally, MAE exhibited excellent antioxidant, whitening, and anti-skin-aging effects, demonstrating significantly higher activities than both the positive control (L-ascorbic acid for antioxidant effects, kojic acid for anti-tyrosinase effects, and epigallocatechin gallate and oleanolic acid for anti-skin-aging effects) and the individual chemical constituents. However, the physico-chemical and biological stability of MAE was influenced by pH, temperature, and light exposure, and as such, light-protected and controlled temperature (not exceeding 30 °C) is essential to maintain the extract’s efficacy in skincare products, and optimal formulation strategies are strongly recommended to ensure long-term stability. Full article

This comprehensive review explores the extraction and utilization of marine collagen, a sustainable alternative to traditional mammalian sources. The review covers conventional extraction methods like acid and pepsin solubilization, highlighting their limitations and contributing to the search for improved efficiency and sustainability. It also delves into innovative extraction technologies, such as ultrasound-assisted extraction, deep eutectic solvents, and supercritical carbon dioxide, showing their potential to revolutionize the field. The significance of collagen hydrolysis in generating bioactive peptides with diverse functionalities is also discussed, emphasizing their potential applications in various sectors. By providing an analysis of marine collagen extraction and its implications, this review presents a perspective for leveraging this valuable bioresource, promoting a circular economy, and satisfying the increasing demand for high-quality collagen in diverse industries. Full article

Acoustic vibrations may induce different changes in plants that perceive them, and plants themselves can also emit acoustic signals. The aim of this review was to cover the past ten years of plant acoustic research and its shortcomings, with a focus on the reflecting, sensing, and emission of ultrasound by plants. Ultrasonication may alter plant growth and development, and an increasing number of studies are being carried out to investigate its effects on both in vitro plant culture and greenhouse or field plant production, as well as on the biochemical and molecular functions of plants. In this paper, we summarized the progress in the use of ultrasound in horticulture and agriculture for enhancing plant growth and development, either in vitro or in vivo, improving yield and crop quality and increasing stress tolerance, as well as for special methodological applications, like sonication-assisted Agrobacterium-mediated transformation. Some research gaps, such as the lack of a precise mechanism for plant ultrasound emission, the possible participation of some reactive radicals in ultrasound signaling, the effect of ultrasound on the epigenome, the role of ultrasound in plant-to-plant communication, and whether there is a specific, sound perceiving organ, etc., were also presented. In addition, a predictive vision is described of how ultrasonication of plants and ultrasound detection emitted by plants can be used in the future to develop green and sustainable agricultural and horticultural technologies. Furthermore, based on our current knowledge, a proposal is presented to combine them with machine learning and artificial intelligence for developing novel production technologies. Full article

Pectin is a complex and versatile polysaccharide crucial for various industries. It functions as a thickener, gelling agent, emulsifier, and low-calorie food. Its anti-inflammatory and immunomodulatory properties have attracted biomedical interest, while its biodegradability and biocompatibility make it valuable for biomaterial applications. The effectiveness of these applications depends on the quality of pectin extraction procedures. While traditional extraction methods exist, green methodologies and alternative techniques have improved pectin’s physicochemical properties—a significant advantage for industrial applications. Pectin can be extracted from various sources, with its molecular structure and functional groups analyzed through different characterization techniques. Modern green extraction methods include ultrasound-assisted extraction, pulsed ultrasound-assisted extraction, pulsed electric field, moderate electric field mediated extraction, microwave-assisted extraction, subcritical water extraction, enzyme-assisted extraction, ohmic heating-assisted extraction, ultrasound-assisted microwave extraction, ultrasound-assisted ohmic heating extraction, hydrothermal processing, high-pressure processing extraction, and dielectric barrier discharge extraction. This review examines these methods’ advantages and disadvantages, along with their applications and future possibilities; it serves as a comprehensive guide for researchers exploring new pectin-rich sources and green extraction technologies for commercial applications. Full article

Aluminum matrix composites reinforced with silicon carbide particles (SiCp/Al) are widely used in aerospace fields with excellent properties, such as high specific strength, high specific stiffness, and high thermal conductivity. Due to the heterogeneous structure, its microstructure is one of the determinants of workpiece life, and ultrasonic vibration can improve the surface quality after grinding. Therefore, in this study, ultrasonic vibration-assisted grinding (UVAG) orthogonal tests were designed to study the surface morphology of SiCp/Al and the form of SiC particle removal under different machining parameters based on the SEM observation of the material surface, and to analyze the percentage of different kinds of grinding forces. The results show that the existence of particle fracture force depends on the relative sizes of the maximum undeformed chip thickness and the critical chip thickness. Through surface roughness testing and analysis, the influence of processing parameters on the surface roughness of the material is explored, and it is found that the application of ultrasound reduces the surface roughness of the material, which can be used as a guideline for the surface quality of the grinding process and the optimization of the process parameters. Full article

Coffee is one of the most widely consumed beverages worldwide. This has motivated the coffee industry to adopt sustainable practices, with an increased emphasis on environmentally friendly extraction methods. The objective of this study was to explore, through a bibliometric analysis, the identification of influential researchers, institutions, emerging topics, and gaps concerning the valorization of coffee by-products and residues using green extraction techniques. A total of 7306 scientific publications on green extraction were identified, 72 specifically addressing coffee or its by-products. The analysis highlights a focus on innovative green technologies, such as natural deep eutectic solvents, ultrasound-assisted or microwave-assisted extraction. These methods enable the efficient and sustainable extraction of bioactive compounds, including polyphenols, chlorogenic acid, caffeine, with potential applications in food, pharmaceutical, and energy industries. Despite this, research on coffee by-products remains limited, partly due to their use in other applications, such as biochar, animal feed, and construction materials, which do not rely heavily on green technologies. Key contributors to the field include countries such as Spain, Italy, Brazil, and China. This study emphasizes the potential of coffee waste to generate high-value products through sustainable methodologies, identifies noteworthy research and key actors in the field, and underscores the necessity for further innovation and collaboration. Full article