Search Results (329)

This study presents a comparative evaluation of four drying methods for carrot, red beet, and pumpkin pomace to produce natural functional food ingredients. The work addresses the valorization of 35–45% vegetable processing waste—a rich source of bioactive compounds—aligning with circular bioeconomy principles and Kazakhstan’s goals for deep processing of agricultural raw materials. The compared methods were convective drying (CD), ultrasound pretreatment + convective drying (US + CD), vacuum-microwave drying (VMD), and ultrasound pretreatment + vacuum-microwave drying (US + VMD). Drying kinetics, water activity, physicochemical and functional properties of powders, retention of bioactive compounds, color characteristics, thermal stability, and sensory attributes were assessed. Kinetics were fitted using Midilli et al., Page, and Weibull models. US + VMD provided the highest drying acceleration (6–11 times faster than CD), reaching final moisture of 5.1–5.9%, water activity a_w 0.27–0.31 in 80–170 min, and bioactive compound retention of 90–95% (carotenoids 92–95%, betalains 90–94%). It also delivered superior flowability (Carr’s index 22.5–30.4%), dispersibility (80–88% in 30 s), and thermal stability (75–85% at 200 °C). Acceleration varied by raw material: maximum for beet (up to 11×) due to soluble sugars and nitrates, minimum for pumpkin (5.5–8×) due to dietary fibers and pectins, and intermediate for carrot (6–9×) influenced by carotenoids’ dielectric properties. The results highlight US + VMD’s strong potential for producing functional powders to replace synthetic additives in food systems. Effective method selection and parameter optimization require consideration of raw material type and rheological characteristics. Full article

Phenolic compounds are plant-derived antioxidants crucial for human health and food preservation. Their bioactive potential including anti-inflammatory, antimicrobial, and anti-carcinogenic properties makes them a vital focus in nutritional, pharmaceutical, and agricultural research. This review critically evaluates the methodologies for their extraction, detection, and quantification to accurately assess antioxidant activity. Oxidative stress in biological systems and food matrices necessitates accurate analytical methodologies for assessing antioxidant behavior, which include both in vitro, in vivo and ex vivo approaches. Sample pretreatment and extraction techniques are critical for reliable analysis and vary depending on the matrix, compound polarity, and target phenolic subclass. We compare conventional extraction techniques (Soxhlet, maceration) with advanced methods like ultrasound-assisted, microwave-assisted, and supercritical fluid extraction. Detection methods reviewed include spectrophotometric assays (e.g., DPPH, FRAP, ORAC), electrochemical sensors, and chromatographic techniques (e.g., HPLC, HPLC−MS). While each method has distinct advantages, a lack of standardization remains the primary challenge, driven by variations in protocols and the vast chemical diversity of phenolics. This review underscores the critical need for integrated, standardized approaches to ensure the accurate and comparable evaluation of antioxidant activity in research and industry. Full article

Microwave pretreatment of native soybeans in the preparation of yuba remains underexplored, and the impact of this treatment on the resulting yuba quality is still unclear. In this study, soybeans were subjected to microwave pretreatment for 30–120 s before conventional soaking. CLSM revealed soybean microstructural changes, including cell-wall degradation and improved dispersion of proteins and lipids. FTIR and SDS-PAGE results of yuba indicated that hydrogen bond cleavage and the formation of new cross-links reduced protein coiling and polar group exposure, while stabilizing aliphatic chains, ultimately yielding a stronger and more compact yuba network structure. Mechanical and rehydration results further indicated that microwave treatment positively affected yuba quality. The 90 s pretreatment was identified as the optimal condition, exhibiting the highest elongation at break (126.36% increase) and rehydration capacity, along with improved color attributes, including higher lightness (L*) and yellowness (b*) values. These changes are likely attributable to disulfide-mediated protein reorganization, which creates greater spatial availability and thereby facilitates lipid incorporation. This study elucidates how microwave pretreatment drives the reorganization of soybean protein and lipid components, thereby influencing their distribution during film formation and providing a foundation for the tailored design of yuba with targeted mechanical properties. Full article

Seafood processing generates large volumes of by-products that are often underutilized despite their potential as sources of high-value bioactive lipids. In this study, a hybrid process integrating microwave (MW) pretreatment with Soxhlet (SOX) extraction was developed and optimized to intensify the recovery of astaxanthin (ASX)- and ω-3 PUFA-rich oil from green tiger shrimp (Penaeus semisulcatus) residues. Response surface methodology (RSM) comprising 22 experimental runs was applied to optimize key MW process variables, including power (100–400 W) and irradiation time (30–90 s). Both factors significantly influenced oil yield, with optimal operating conditions identified at 400 W and 75 s. MW pretreatment promoted structural disruption of shrimp shells, as confirmed by scanning electron microscopy, thereby enhancing solvent penetration and mass transfer. Solvent selection further affected extraction performance: hexane:isopropanol (1:1, v/v) achieved the highest oil yield (3.86 g/100 g dry weight), while hexane:acetone produced extracts with the highest ASX concentration (1032.24 µg/g oil), ω-3 PUFA content (29.85%), and antioxidant activity (93.30% DPPH scavenging). Colorimetric analysis supported these results, with increased redness (a* = 18.12) correlating with ASX enrichment. Overall, this integrated MW-SOX process represents an effective process-intensification strategy for sustainable shrimp waste valorization and production of bioactive lipid fractions. Full article

This study investigated microwave pretreatment (0–900 W) of peanuts as a source modification strategy to reduce the stability of peanut oil body emulsions (POBEs) and improve aqueous enzymatic extraction. Results indicated that higher power treatment (≥540 W) significantly destabilized POBE. The optimal condition at 720 W increased POBE extraction yield and demulsification rate by 16.82% and 46.32%, respectively, compared with the control. This destabilization was attributed to marked changes in interfacial properties, including decreased apparent viscosity, lowered absolute ζ-potential (from 35.93 mV to 27.09 mV), increased particle size (from 1177.16 nm to 1976.98 nm), and the microstructure of droplet aggregation. Compositional analysis revealed that microwave treatment induced POBE reorganization, characterized by increased lipid and phospholipid contents alongside reduced moisture, solid, and protein levels. Further interfacial protein analysis revealed that exposure triggered protein conformational unfolding, hydrophobic group exposure, and subsequent aggregation, which weakened protein adsorption at the interface and reduced the mechanical strength of the interfacial film. These findings elucidate the mechanism of microwave-induced emulsion instability, providing a theoretical basis for enhancing oil extraction efficiency through raw material pretreatment. Full article

This study evaluated the influence of four thermal pretreatment techniques—autoclaving, hot-air oven treatment, hot-water immersion, and microwave irradiation—on Parthenium hysterophorus biomass to improve its biodegradability and biogas generation potential under batch anaerobic digestion. Among the investigated methods, hot-air oven pretreatment at 110 °C for 90 min exhibited the most significant enhancement in biomass solubilization, as indicated by a 51.5% rise in soluble chemical oxygen demand (sCOD) and an increase in volatile fatty acids (VFAs) compared with the untreated control. These compositional improvements facilitated faster hydrolysis and led to a 25.73% higher cumulative methane yield in biochemical methane potential (BMP) assays. Structural analysis revealed pronounced alterations in the lignocellulosic matrix, with reductions in hemicellulose and partial delignification improving substrate accessibility. Complementary characterisation using field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) confirmed the disruption of crystalline cellulose regions and modification of functional groups, supporting the observed biochemical improvements. Collectively, the results demonstrate that hot-air oven pretreatment is a practical and energy-efficient approach for enhancing the digestibility of P. hysterophorus biomass, promoting its utilisation as a sustainable feedstock for renewable biogas production and environmental management of this invasive weed. Full article

Mycelium-based composites (MBCs) have emerged as promising biofabricated materials that align with circular economy and clean technology goals by utilizing fungal networks to transform lignocellulosic residues into functional, biodegradable composites. Despite the MBC’s potentials, the intrinsic nature of the fungal strain, substrate physico-chemical composition and engineering property variability remain significant hurdles that should be critically surmounted. Substrate treatment is central to determining growth kinetics, microstructural uniformity, and mechanical performance in MBC production. This review highlights recent advancements in physical, chemical, biological, and hybrid pretreatment methods, including comminution, pasteurization, alkali hydrolysis, enzymatic conditioning, microwave-assisted hydrolysis, ultrasound pretreatment, steam explosion, plasma activation, and irradiation. These technologies collectively enhance substrate digestibility, aeration, and permeability while reducing contamination. Optimization parameters—temperature, pH, C:N ratio, moisture content, particle size, porosity, and aeration—are examined as critical process levers influencing hyphal density, bonding efficiency, and composite uniformity. Evidence suggests that properly engineered substrate treatments accelerate colonization, strengthen hyphal networks, and significantly improve compressive, tensile, and flexural material properties. The review discusses emerging process control tools such as AI-assisted modeling, micro-CT porosity analysis, and sensor-integrated bioreactors that enable reproducible and energy-efficient fabrication. Collectively, the findings position substrate engineering as a foundational technology for scaling high-performance mycelium composites and advancing sustainable material innovation. Full article

The impact of pretreatment methods on the fermentation quality and nutritional profile of bamboo silage was assessed to determine the optimal ensiling strategy. Tender bamboo underwent microwave, ultrasound, alkali, and irradiation pretreatments. Subsequently, a four-factor, three-level L9 (3⁴) orthogonal experiment was employed, utilizing pretreated bamboo as the substrate. The experiment evaluated the effects of silage time (30, 45, 60 days), moisture content (55%, 60%, 65%), cellulase addition [2, 4, and 6 mg/g FM (Fresh weight)], and silage inoculant addition (0.5, 5, 50 mg/g FM). Results indicated that γ-ray irradiation pretreatment effectively reduced lignin and cellulose content while increasing reducing sugars levels approximately fourfold compared to the control group. Six out of the nine treatment groups exhibited superior comprehensive fermentation quality scores, with silage time demonstrating the most significant influence on the fermentation quality of tender bamboo silage. The order of influence was silage time > silage inoculant level > moisture content > cellulase, with a silage time of 30 days, a silage inoculant level of 0.5 mg/g FM, a moisture content of 65%, and a cellulase level of 2 mg/g FM, all contributing to enhanced fermentation quality. Regarding nutritional composition, silage time significantly impacted crude protein and soluble sugar levels, with optimal levels observed at 30 and 60 days, respectively. Moisture content primarily affected soluble sugar levels, followed by neutral detergent fiber, with an optimal level of 55%. Other factors showed minimal effects. Based on fermentation quality and nutritional component analysis, and prioritizing fermentation quality while considering cost-effectiveness, the optimal ensiling conditions for bamboo were determined to be a silage time of 30 days, a moisture content of 65%, an addition of 2 mg/g FM of cellulase, and an addition of 0.5 mg/g FM of silage inoculant. Full article

Usnic acid (UA) is one of the most extensively studied specialized metabolites of lichens, attracting considerable interest due to its antimicrobial, anti-inflammatory, and cytotoxic properties. The efficiency of UA extraction from lichens depends on multiple interrelated biological and technological factors. This systematic review aims to synthesize and critically evaluate reported strategies for UA extraction from wild-grown lichen biomass, with particular emphasis on extraction efficiency, practicality, and application potential. This systematic literature review, based on the Scopus database was conducted by including original research articles reporting UA extraction from wild-growing lichens. The analysis covered species selection, sample pre-treatment, solvent type, and extraction methodology. A total of 117 studies were included. Due to the predominantly non-polar nature of UA, higher extraction efficiencies were generally achieved using solvents, including acetone, supercritical CO₂, vegetable oils, and lipophilic green solvent systems. Pre-treatment strategies such as grinding or flaking significantly enhanced extraction performance by improving mass transfer. Alongside conventional methods (maceration, reflux, Soxhlet), non-conventional techniques such as Supercritical Fluid Extraction (SFE), Ultrasound- (UAE), and Microwave-Assisted Extraction (MAE) enabled faster and more selective UA extraction with reduced solvent use. Notably, SFE have been reported as particularly promising in terms of selectivity, process control, and potential suitability for scale-up, with commercially available supercritical CO₂ extracts of Usnea species supporting the feasibility of this approach. This review provides a consolidated and application-oriented overview of UA extraction, highlighting strategies that balance efficiency, selectivity, sustainability, and practical implementation. Full article

Dill is a valuable herb recognized for its rich nutritional composition and bioactive properties. Drying is an efficient preservation technique for maintaining its quality characteristics and ensuring longer storage stability. Incorporating ultrasonic pretreatment before the drying process can significantly reduce energy consumption (SEC) and greenhouse gas emissions. To the best of our knowledge, this is the first study to comprehensively evaluate ultrasound-assisted hybrid microwave–convective drying of dill (Anethum graveolens L.) leaves, focusing on the combined effects on drying kinetics, energetic and exergetic performance, providing an indirect emission estimate and multiple quality attributes. This study aimed to evaluate the drying kinetics, energy and exergy performance parameters, greenhouse gas emissions, quality properties (water activity, rehydration ratio and color) and antioxidant capacity of dill leaves dried by the microwave–hot-air (MW-HA) technique combined with ultrasonic (US) pretreatment. The experiments were conducted at MW power levels of 20%, 40%, and 60% (corresponding to a total output of 900 W), air temperatures of 40 and 60 °C, and US pretreatment durations of 0, 10, and 30 min. The results illustrated that rising MW power, air temperature and US duration significantly reduced the drying time, SEC and greenhouse gas emissions. At higher process conditions, specifically, 40% MW power, 60 °C drying temperature, and 30 min US pretreatment, the maximum energy efficiency (10.17%) and exergy efficiency (11.35%) were obtained. In terms of quality attributes, the best results were achieved at 40% MW power, 60 °C air temperature, and 10 min ultrasonic pretreatment, with reduced water activity (0.258), minimal color variation (ΔE = 11.44), improved rehydration ratio (3.88), and high retention of antioxidant activity. These findings demonstrate the potential of ultrasound pretreatment to enhance drying performance by reducing energy use and emissions while improving quality and antioxidant retention in dill, offering new guidelines for sustainable processing of this herb. Future studies should optimize microwave–hot-air-drying conditions to balance energy efficiency, exergy, and product quality. Full article

Due to its relatively low apparent density, as well as high water absorption and crushing value, recycled aggregate (RA) is difficult to directly apply in practical concrete production. Existing studies have proposed a variety of pretreatment methods for RA. To further deepen the understanding of their effectiveness in improving the properties of RA and to provide guidance for its practical application, a comprehensive investigation is necessary. The pretreatment methods of RA can be classified into three main categories: physical strengthening, chemical enhancement, and bio-deposition. In this study, physical strengthening includes mechanical grinding and microwave heating, chemical strengthening includes acid treatment, polymer treatment, and carbonation curing, and biological strengthening refers to biological strengthening techniques. Different strengthening methods improve the properties of RA and the corresponding recycled aggregate concrete (RAC) to varying degrees. However, it is essential to control the external treatment conditions appropriately during the strengthening process. In addition, the source of RA and its inherent physical characteristics also have a significant influence on the treatment outcomes. Therefore, the optimal strengthening conditions should be determined based on the specific properties of each type of RA. This study systematically summarizes and discusses the influencing factors associated with each strengthening method, and the discussion section compares the pros and cons from different perspectives. Furthermore, within the context of engineering decision-making for sustainable and durable construction materials, the study also addresses the limitations of current strengthening technologies and proposes potential directions for future research. Full article

In this study, the effects of combined thermal and biochemical pretreatments on the yield and quality of cold-pressed pomegranate seed oil (PSO) were systematically investigated. Convective and microwave roasting were applied individually and in combination with acid or with a commercial pectolytic–cellulolytic enzyme preparation, allowing a comparative evaluation of their synergistic effects under identical cold-pressing conditions. Microwave and convective roasting reduced the seed moisture content from 6.06% to 3–4%, whereas acid pretreatment significantly decreased the seed pH from 4.63 to 3.25–3.33. Lipase activity ranged from 0.061 to 0.191 U/g, with the highest activity in untreated seeds and the lowest in microwave-treated seeds, indicating pretreatment-induced enzyme inactivation. Among all treatments, microwave–acid pretreatment achieved the highest oil yield (11.20%) and the lowest free fatty acid content, whereas microwave–enzyme pretreatment resulted in the lowest peroxide value and the longest oxidative induction period, indicating superior oxidative stability. All pretreatments reduced peroxide value, p-anisidine value, and free fatty acidity compared with the control. Microwave-treated oils exhibited the highest carotenoid content (67.85 mg/kg), while enzyme-treated oils exhibited the lowest carotenoid content (12.05 mg/kg). Total phenolic content was highest in the control oils and decreased following pretreatment. Correlation analysis revealed that oil yield was negatively correlated with seed pH and lipase activity, demonstrating that acid-induced matrix modification and lipase suppression are key mechanisms governing oil recovery. Overall, this study provides new mechanistic insight into the structure enzyme quality relationships in PSO extraction and demonstrates that pretreatment selection should be guided by the intended end use. Microwave–acid pretreatment is most suitable for yield-driven applications (e.g., cosmetic or technical applications), whereas microwave–enzyme pretreatment offers an optimal balance between oxidative stability and quality preservation for food and nutraceutical applications. Full article

Residues generated during fruit processing constitute an abundant and underutilized biomass rich in bioactive compounds, pigments, structural polysaccharides, lipids, and fermentable carbohydrates. Although their potential for biorefinery applications is widely recognized, existing studies are often fragmented, focusing on isolated products, which limits a comprehensive understanding of integrated valorization strategies. To address this gap, this study presents an integrative review supported by bibliometric analysis to identify global research trends, dominant technological pathways, and key challenges associated with the use of fruit residues in biorefineries. The review covers technologies for extracting phenolic compounds, essential oils, pigments, and structural fibers, as well as lipid recovery, enzyme production, and biochemical routes for bioethanol, biohydrogen, and biogas generation. The review reveals that emerging technologies, such as pressurized fluid extraction, microwave-assisted extraction, and ultrasound-assisted extraction, enable efficient recovery of antioxidant compounds, high-purity pectin, and fermentable sugars, particularly when applied in sequential and integrated processing schemes. Bioethanol production is the most extensively investigated route, with yields strongly dependent on biomass composition and pretreatment strategies, identifying banana, cashew, apple, mango, coconut, and palm residues as promising feedstocks. In addition, biohydrogen production via dark fermentation and anaerobic digestion for biogas generation shows high technical feasibility, especially when integrated with upstream extraction steps. Overall, integrated valorization of fruit residues emerges as a key strategy to enhance economic performance and environmental sustainability in agro-industrial systems. Full article

White radish is a nutritious root vegetable that provides dietary fiber, essential vitamins and minerals, and a range of bioactive compounds. This study aimed to determine how steam and microwave blanching, pulsed electric field, ultrasound, osmotic dehydration with inulin or trehalose, and coating with spices such as turmeric or sweet paprika influence the characteristics of convective infrared dried white radish slices. To assess the effect of each pretreatment, moisture content, water activity, shrinkage, density, texture, color parameters, structural characteristics (SEM and µ-CT), vapor adsorption, thermal changes, and antioxidant properties were analyzed. Osmotic dehydration with inulin most effectively limited shrinkage and color change, stabilized the microstructure, and resulted in the highest relative phenolic content and antioxidant activity (TPC, DPPH). Spice-coated samples showed low shrinkage, low hardness and breaking work, and vivid color. Furthermore, µ-CT microstructure analysis showed that these samples had the highest porosity, with those with paprika reaching 57.5%. In contrast, blanching, ultrasound, and PEF led to greater structural changes and increased hygroscopicity. Multivariate analyses confirmed the significant influence of the type of pre-treatment on the quality characteristics of the dried material. Osmotic dehydration and spice coating proved to be the most effective methods for obtaining structurally stable and visually attractive dried white radish slices with attractive bioactive compounds. Full article

This study investigated the effects of microwave (MW) pre-treatment (45 kJ total irradiated microwave energy) and magnetic nanoparticles (MPs) on the anaerobic digestion (AD) of meat-processing sludge, integrating biokinetic modeling with dielectric parameter measurements. Five different sludge variants were examined: native (non-treated control); MP-only control; microwave pre-treated sludge, and MW + MP combination with the nanoparticles either retained in the fermentation medium or removed prior to anaerobic digestion. Cumulative biomethane production was evaluated using the modified Gompertz, Logistic, and Weibull models, and key kinetic parameters (maximum achievable methane yield, maximum rate of product formation, and λ-values) were compared across the different treatments. The results revealed that the highest production rate, along with the highest biomethane potential, could be achieved when combining MW treatment with magnetic nanoparticles which were retained in the fermentation medium during AD. Based on the biokinetic analysis, this combined method increased biomethane potential by 52% to 390 mL CH₄/gVS and maximum methane production rate by 85% to 37 mL CH₄/gVS/day compared to the untreated control. The measurement of relative permittivity (${\epsilon }^{\prime }$) exhibited progressive changes during digestion, and the maximum rate of change in ${\epsilon }^{\prime }$ strongly correlated with the maximum methane production rate across all samples (R² > 0.98). These results highlight the potential of microwave–metal oxide nanoparticle pre-treatment for process enhancement and to demonstrate the suitability of dielectric parameter measurement as a rapid, non-invasive indicator of biochemical activity during anaerobic digestion. Full article