Search Results (137)

In this work, a simple chemical- and thermal-free procedure was developed for the green synthesis of AgNPs using pomegranate (Punica granatum) peel extract as both reducing and stabilizing agents under ambient conditions. The pomegranate extract exhibited a high total phenolic content of 126.37 ± 5.29 mg GAE/g DW, indicating the abundance of bioactive phytochemicals capable of promoting nanoparticle formation. The synthesis parameters were optimized by varying reaction time and extract concentration, with the optimum conditions identified as 18 mg/mL extract concentration and 48 h reaction time based on UV–Vis analyses. The synthesized AgNPs at the optimized condition exhibited a characteristic surface plasmon resonance band at 430–440 nm and were predominantly quasi-spherical with an average particle size of 36.9 ± 14.2 nm determined by TEM. Dynamic light scattering (DLS) analysis yielded an intensity-weighted average hydrodynamic diameter of 72.5 ± 2.4 nm, while the number-weighted distribution confirmed that the suspension was predominantly composed of smaller nanoparticles that were consistent with the TEM observations. The synthesized AgNPs also exhibited a zeta potential of −33.5 ± 0.6 mV, indicating good colloidal stability. XRD and EDX analyses confirmed the formation of crystalline metallic AgNPs, while FTIR results suggested the involvement of phytochemicals in nanoparticle stabilization. The AgNPs also showed concentration-dependent antibacterial activity against E. coli and S. aureus, with MIC (MBC) values of 18.75 (37.5) and 9.375 (150) µg/mL, respectively. In addition, the cytotoxicity assessment using L929 fibroblasts yielded an IC₅₀ value of 86 µg/mL, with a selectivity index of 4.59 and 9.17 against E. coli and S. aureus, respectively, indicating an excellent degree of preferential toxicity toward bacterial cells. Full article

Finger lime (Citrus australasica) is an emerging high-value fruit species, yet the chemical profiles of Mediterranean-cultivated varieties remain underexplored. This study presents the first chemical characterization of two finger lime varieties, Pink Ice and Green Crystal, grown in Greece, providing the first report on the volatile and non-volatile composition of Green Crystal. Peel essential oils were extracted and analyzed through GC-MS across two harvesting periods (H1 and H2), while methanolic extracts were assessed for their total phenolic content (TPC) and DPPH radical scavenging activity. Non-volatile untargeted profiling was performed on stage H1 extracts using UHPLC-MS/MS. The results revealed a significant chemical divergence between the varieties. Green Crystal exhibited an unprecedented p-cymene/β-phellandrene/citronellal/citronellol volatile chemotype, while Pink Ice displayed a limonene/p-cymene/sabinene/terpinen-4-ol chemotype. Maturity of the fruit significantly influenced monoterpene distribution, with an increase in monoterpene hydrocarbons at the expense of oxygenated derivatives. TPC peaked at stage H1, showing a significant maturity-dependent decline in both varieties, whereas DPPH radical scavenging capacity remained stable across both harvests. UHPLC-MS/MS analysis annotated 58 metabolites, including several compounds reported for the first time in the species. Variety-specific tendencies were observed, with Pink Ice exhibiting greater diversity in flavanones, flavonols, and simple coumarins, whereas Green Crystal exhibited greater diversity in flavones, furanocoumarins, and HMG (hydroxy-3-methylglutaric acid)-flavonoid conjugates. These findings demonstrate that variety selection and harvesting timing are critical parameters for optimizing the commercial and bioactive value of Mediterranean-grown finger lime, highlighting the significant potential for expanded cultivation in the region. Full article

This investigation assessed the phenolic composition, and the in vitro and in silico antioxidant potential of peels from six potato varieties (Arizona, Spunta, Fabula, Manito, Argos, and Touareg) cultivated in Algeria. 80% ethanol was applied to macerate potato peels, and standard procedures were followed for phytochemical analyses. The in vitro antioxidant capacity was evaluated by the scavenging methods of DPPH (1,1-diphenyl-2-picrylhydrazil) and ABTS ((2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)) radicals. AutoDock Vina was employed to perform molecular docking analyses. LC–MS/MS analyses revealed significant variability in phenolic compounds among the varieties, with chlorogenic acid being the predominant compound, reaching the highest concentration in Touareg peels (51.28 µg/g). The Manito variety exhibited the highest total phenolic and flavonoids contents of 643.53 ± 2.59 mg GAE/100 g DW and 144.42 ± 2.40 mg QE/100 g DW, respectively and the strongest ABTS radical scavenging activity (IC₅₀ = 473.81 ± 1.35 µg/mL). Molecular docking analysis suggested potential interactions of catechin and chlorogenic acid with oxidative stress-related enzymes namely myeloperoxidase, xanthine oxidase, and 5-lipoxygenase, providing complementary insights into their possible biological relevance. The integration of in vitro and in silico results demonstrates that the Manito variety is the most promising candidate for the sustainable valorization of potato peels as a natural source of antioxidants. Full article

Peeling behavior of soft materials is important in a wide range of applications, e.g., electronics, healthcare, etc. When applied on soft substrates, soft adhesives demonstrate unique mechanical behaviors compared to adhesives applied on rigid substrates. Adhesive properties can be conveniently measured by “peel testing”. The focus of this work is characterization of commercial glues on fabric substrates using commonly used peel tests. We investigate energy dissipation on textile substrates. For practical applications, we aim to develop a systematic approach for selecting adhesives for soft, flexible substrates. Here, we developed a multi-criteria framework for evaluating adhesives using data from peel tests. The criteria used here consider the shape and stability of the T-peel trace. The results of the multi-criteria evaluation were compared to traditionally used peel strength and fracture energy. Although E6000 produced the highest peel force ($1.82\pm 0.27 \mathrm{N} \mathrm{m}{\mathrm{m}}^{-1}$) and the largest apparent fracture energy, ${\mathrm{G}}_{\mathrm{c}}$ ($8673\pm 1545 \mathrm{J} {\mathrm{m}}^{-2}$), it showed large force oscillation ($\mathrm{S}\mathrm{S}\mathrm{A}=4.05\pm 0.83 \mathrm{N}$). Fabri-Fuse was selected based on its low oscillation ($\mathrm{S}\mathrm{S}\mathrm{A}=0.69\pm 0.29 \mathrm{N}$), lowest $\mathrm{C}\mathrm{o}{\mathrm{V}}_{{\mathrm{F}}_{\mathrm{c}\mathrm{i}}}$(4.0%), high peel stability index (PSI), and high displacement at break. Functional evaluation showed that Fabri-Fuse increased strain-to-electrical-failure to $34.95\pm 2.43\mathrm{\%},$ higher than direct printing on fabric or printing on E6000 (highest peel strength). These results suggest that metrics that consider the shape of the peel trace and inter-sample repeatability provide a useful alternative for selecting adhesives other than highest peel strength. Full article

Metal accumulation in cacao (Theobroma cacao L.) cultivation represents an important agronomic and food-safety concern, particularly in acidic tropical soils where cadmium (Cd) and other trace metals can become bioavailable and translocate to plant tissues. Green magnetic nanomaterials offer a potential strategy for reducing metal mobility in agricultural substrates, but their performance depends on surface chemistry, dose, and plant genotype. In this study, we synthesized and evaluated MCRES, defined here as a maghemite–Citrus reticulata extract system, a biofunctionalized γ-Fe₂O₃-based nanosystem prepared by coupling iron oxide nanoparticles (NPs) with a 3% (w/v) Citrus reticulata peel extract. The objective was to determine whether citrus-mediated biofunctionalization could produce a scalable magnetic nanoamendment capable of modifying Cd and naturally occurring Ni partitioning in cacao seedlings. MCRES was recovered magnetically and dried, yielding 8.44 g of product from 10 g of precursor. Rietveld analysis performed in X ray diffractograms confirmed phase-pure cubic γ-Fe₂O₃ with a lattice parameter of 0.8332 nm, a crystallite size of 11.3(1) nm, and satisfactory refinement quality (χ² ≈ 1.34). Transmission electron microscope images showed quasi-spherical NPs with a log-normal size distribution centered at 7.5 nm. Magnetic measurements showed superparamagnetic-like behavior at 300 K, high saturation magnetization values of 62 emu g⁻¹ at 300 K and 71 emu g⁻¹ at 5 K, and elevated effective anisotropy values obtained from the Law of Approach to Saturation fitting. MCRES was applied at 0, 1, 2, 4, and 6 g pot⁻¹ to cacao seedlings containing Cd-amended Ultisol with naturally occurring Ni. Plant responses were genotype and dose dependent: TSH-1188 genotype showed limited dose sensitivity for most biometric variables, whereas ICS-95 genotype showed significant dose effects, with maximum growth at the 2 g pot⁻¹ treatment. Metal-partitioning results indicated that Cd remained comparatively mobile toward shoots, whereas Ni was preferentially retained in roots. In TSH-1188 genotype, the Ni translocation factor decreased from 3.07 in the control to 0.85–1.00 at higher MCRES doses. Compared with previous work on non-biofunctionalized nanomaghemite, these results suggest that citrus-mediated biofunctionalization produces a distinct Cd/Ni partitioning response. Overall, MCRES is recommended as a promising nursery-scale green nanoamendment for reducing metal mobility in cacao cultivation, but its agronomic use should be optimized according to genotype and dose. Future work should include side-by-side comparisons with unfunctionalized γ-Fe₂O₃, Citrus reticulata extract alone, and non-contaminated controls under field conditions to validate its long-term effectiveness and environmental safety. Full article

Pancreatic lipase (PL) inhibition is a promising dietary strategy for obesity management. In this study, the inhibitory mechanisms and structural basis of polyphenols extracted from different sugarcane fractions were investigated using in vitro enzyme assays, spectroscopy, and molecular docking analyses. PL inhibitory activity was evaluated using p-nitrophenyl laurate (pNPL) as the substrate, with all assays performed in triplicate and results statistically analyzed. Among the extracts, sugarcane peel polyphenols (SP) exhibited the strongest inhibition, with a half-maximal inhibitory concentration (IC₅₀) of 31.56 mg/mL, significantly lower than that of sugarcane juice polyphenols (SJ, 55.86 mg/mL) and sugarcane bagasse polyphenols (SB, 65.31 mg/mL). Enzyme kinetic analyses revealed a reversible mixed-type inhibition mechanism. In contrast to crude extracts, individual phenolic monomers showed substantially lower IC₅₀ values (0.13–1.33 mg/mL), highlighting the intrinsic dilution. Compositional analysis identified ferulic acid, gallic acid, chlorogenic acid, and schaftoside as key contributors to PL inhibition. Fourier transform infrared (FTIR) and fluorescence spectroscopy demonstrated that polyphenols altered PL secondary structure by modulating α-helix and β-sheet contents and perturbed the microenvironment of tryptophan (Trp) and tyrosine (Tyr) residues. Molecular docking further indicated that these compounds bind within or near the substrate-binding channel via hydrogen bonding and hydrophobic interactions, engaging critical residues including Ser152, His263, and Phe77, and potentially influencing conformational elements involved in active-site accessibility. Collectively, these results suggest that sugarcane, particularly its peel, represents a valuable natural source of PL inhibitors. Despite the relatively high IC₅₀ values of crude extracts, their inhibitory activity arises from multicomponent contributions and supports their potential application as dietary modulators of fat digestion rather than as pharmaceutical lipase inhibitors. Full article

Background/Objectives: Onion (Allium cepa) peems are an underutilized by-product rich in polyphenols. This study evaluated the physicochemical profile, and bioactive potential (antidiabetic, antimicrobial, antioxidant, and anticoagulant) of Moroccan red onion peels using integrated in vivo, in vitro, and in silico approaches. Methods: Moisture, pH, ash content, and mineral elements were determined, followed by phytochemical screening and three extractions: decoction E0, aqueous Soxhlet E1, and hydroethanolic Soxhlet E2 (70/30; ethanol/water, v/v). The measurement of polyphenols, flavonoids, and tannins was carried out using colorimetric methods, while the molecular profile was studied by high-performance liquid chromatography coupled to ultraviolet detection and electrospray ionization mass spectrometry (HPLC/UV-ESI-MS). Biological activities were determined using 2,2-diphenyl-1-picrylhydrazyl, ferric reducing antioxidant power, and total antioxidant capacity assays (in vitro antioxidant); microdilution (antimicrobial); prothrombin time and activated partial thromboplastin time (anticoagulant); and α-amylase/α-glucosidase enzymatic inhibition and oral glucose tolerance tests on normoglycemic rats. Also, acute toxicity was evaluated, and molecular interactions between these proteins and ligands (docking, molecular dynamics, and MM-PBSA) were analyzed. Results: Physicochemical analyses showed an acidic pH (3.06) and high ash content (15.21%), with the concentration of regulated elements remaining within FAO/WHO limits. The extractive content was between 6.90% E0 and 19.18% E2. The E1 extract had the maximum amount of total polyphenols (178.95 mg GAE/g); on the other hand, E2 was the richest in flavonoids by 121.43 mg QE/g. The HPLC/ESI-MS analysis of E0 revealed 20 compounds, among which flavonoids (84.93%) were predominant, with isorhamnetin (30.26%), followed by quercetin and its glycosylated forms. E1 showed the most potent antioxidant effects (IC₅₀ DPPH, 22.38 µg/mL, as that of ascorbic acid). The antibacterial activity of E0 was especially potent towards Enterobacter cloacae and Pseudomonas aeruginosa (MIC 75 µg/mL). A mild dose-dependent anticoagulant effect was seen. Antidiabetic activity was found to be outstanding: α-amylase (IC₅₀ 62.75 µg/mL) and α-glucosidase (IC₅₀ 8.49 µg/mL, stronger than acarbose) inhibitions were corroborated in vivo by a considerable decrease in the glycemic area under the curve. The molecular docking study in silico demonstrated strong molecular interactions, especially for quercetin 4′-O-glucoside with good binding energies. Conclusions: A. cepa peels from Morocco can be considered a safe plant matrix containing bioactive flavonoids with strong antioxidant and selective antimicrobial activities and promising antidiabetic effects, supported by molecular modeling. Full article

As a strategy to valorise onion peel (OP), a phenolic-rich extract was obtained and microencapsulated using the double emulsion technique for improved stability. Both free and microencapsulated OP extracts were added to fresh cheese to enhance its nutritional composition. The extract exhibited a high total phenolic content (TPC) and strong antioxidant capacity towards ABTS and DPPH radicals, with IC₅₀ of 9.5 and 36.1 mg_Extract∙L⁻¹, respectively. The extract demonstrated inhibitory capacities of 71% against α-amylase and 82% towards β-glucosidase. Quercetin was identified as the main phenolic compound, while potassium was the predominant mineral. The microencapsulation yielded an encapsulation efficiency of 91%, with an average particle size of 17.9 µm. Incorporating free and microencapsulated OP extract into the fresh cheese reduced syneresis, a favourable outcome, while preserving moisture levels, protein and ash content, and the pH. The incorporation of the free and microencapsulated OP extract enhanced the TPC and DPPH scavenging capacity of the cheeses. Results demonstrated the potential of using OP extract to enhance the antioxidant properties of fresh cheese, and to reduce syneresis, while promoting sustainability. These outcomes are particularly relevant from an industrial point of view, since an increase in antioxidant content might contribute to extending the product shelf-life. Full article

This study presents an efficient, environmentally benign approach for synthesizing chitosan-entrapped titanium dioxide (TiO₂) nanocomposites utilizing aqueous orange peel extract playing its role in reduction and stabilization of the nanoparticles and exploring its anticancer activity in vitro. TiO₂ nanoparticles were initially synthesized via a modified sol-gel method incorporating the orange peel extract. Subsequently, these nanoparticles were entrapped within a chitosan matrix. The orange peel extract was thoroughly characterized using analysis of phytochemicals present, and Gas Chromatography–Mass Spectrometry (GC–MS) analysis of a reconstructed methanolic extract to identify potential biomolecules responsible for the reduction and capping processes. The synthesized chitosan-entrapped TiO₂ nanoparticles were subjected to comprehensive characterization using various analytical techniques, like UV–visible spectroscopy, Dynamic Light Scattering (DLS) and Zeta Potential analysis, X-ray Diffraction (XRD), FTIR, High-Resolution Scanning Electron Microscopy (HR-SEM) and Energy-Dispersive X-ray Spectroscopy (EDAX). An absorption peak was observed at 296 nm, a hydrodynamic diameter of 400 nm, a+ 35.88 mV zeta potential, and an SEM image showing a diameter in the range of 300–645 nm, indicating polymer entrapment with enhanced size. Brine shrimp assay, MTT assay using normal fibroblasts, 3T3-L1, and zebrafish embryo assay were done to observe the biocompatibility of the synthesized nanostructure. The concentration of 50 μg/mL was found to be inert in both in vitro and in vivo. Furthermore, cervical cancer cells, SiHa, were treated with the nanoparticles to exhibit their cancer-killing capability with an IC₅₀ value of 30.74 μg/mL. The results demonstrate the effectiveness of orange peel extract as a sustainable agent for TiO₂ nanoparticle synthesis and the successful formation of a stable chitosan-entrapped nanocomposite. This approach offers a promising pathway for producing functional metal oxide nanomaterials with reduced environmental impact and enhanced properties for diverse biomedical applications. Future studies using other types of cancer cells and animal models for cancerous tumors need to be explored. Full article

Background: Pometia pinnata (matoa) peel powder attenuates high-fat diet-induced adiposity and hepatic lipid accumulation in rats, but the responsible compounds remain unclear. This study aimed to identify the bioactive compounds that may contribute to this phenotype, with an emphasis on pancreatic lipase inhibition as a candidate mechanism. Methods: Rats received high-fat diets containing matoa peel powder, or its water- or ethanol extraction residue. Visceral fat accumulation, hepatic lipid deposition, and serum lipid profiles were evaluated. An ethanol extract was fractionated by activity-guided column chromatography based on pancreatic lipase-inhibitory activity, and structures were identified by nuclear magnetic resonance analysis. Static in vitro gastrointestinal digestion was performed to assess inhibition of fatty acid release by the extract or isolated compounds. Results: The visceral adiposity- and hepatic lipid-modulating effects observed with matoa peel powder were retained in the water extraction residue but not in the ethanol extraction residue, suggesting removal of bioactive constituents by ethanol extraction. The ethanol extract inhibited pancreatic lipase (IC₅₀ = 740 µg/mL). Two active compounds—hederagenin saponin and protocatechuic acid—were isolated, and both inhibited pancreatic lipase (IC₅₀ = 149 µmol/L and 404 µmol/L, respectively). Under simulated digestion in vitro, the ethanol extract and protocatechuic acid reduced free fatty acid release, whereas hederagenin saponin did not. Conclusions: Matoa peel powder contains ethanol-soluble constituents, including pancreatic lipase-inhibitory compounds that may contribute to the modulation of adiposity and hepatic lipid metabolism in high-fat-diet-fed rats. The attenuation of individual-compound activity under simulated digestion is consistent with matrix- and intestinal milieu-dependent effects, and supports a multi-component mechanism involving saponins, phenolics (protocatechuic acid), and their intestinal biotransformation products. Full article

Gastric cancer remains a leading cause of cancer-related mortality worldwide. Citrus fruits are rich in polyphenols, exerting antioxidant and chemo-preventive activities, and lemon peel represents a valuable source of such bioactive compounds. Previous studies showed that Citrus limon peel extracts (LPE) inhibited the activity of some enzymes of the antioxidant system and reduced the interleukin-6-dependent invasiveness of gastric and colon cancer cells. In the present study, we have investigated the effects of LPE on the human gastric adenocarcinoma AGS and MKN-28 cells and on the activity of a crucial redox enzyme, catalase (CAT). Indeed, LPE significantly reduced the cell viability and clonogenic potential of the gastric cancer cells and induced morphological changes indicative of cytotoxicity. Moreover, LPE modulated the intracellular redox homeostasis by decreasing levels of the hydrogen peroxide-related reactive oxygen species (ROS) while increasing those of superoxide anions and decreasing levels of superoxide dismutases (SODs). Western blotting analysis revealed that LPE downregulated CAT, SOD-1, SOD-2, and monoamine oxidase A (MAO-A) protein expression level in both cell lines. Finally, the extract inhibited CAT activity in a dose-dependent manner (IC₅₀ = 0.008 ± 0.003 mg/mL; K_i = 0.012 ± 0.002 mg/mL). These findings indicate that LPE exerts cytotoxic and redox-modulating effects through the inhibition of antioxidant enzymes and the alteration of ROS balance. Therefore, the agro-industrial by-product LPE could be considered as a promising natural source of polyphenolic compounds with potential applications in the prevention and therapy of gastric cancer. Full article

This study prepared carbon dots (CDs) from agricultural waste pineapple peel via an eco-friendly microwave method, optimizing their performance through copper ion and chitosan doping. Multiple characterization techniques and performance tests were employed for systematic analysis. Antioxidant assays revealed that PP-CDs have excellent concentration-dependent free radical scavenging activity: the DPPH IC₅₀ values of Pineapple Peel Carbon Dots (PP-CDs), Copper-Doped Pineapple Peel Carbon Dots (Cu-PP-CDs) and Chitosan-Doped Pineapple Peel Carbon Dots (CS-PP-CDs) are 0.79, 0.95 and 0.98 mg/mL, while their ABTS IC₅₀ values are 0.22, 0.40 and 0.26 mg/mL, respectively. Antibacterial tests showed modified CDs have enhanced activity: Cu-PP-CDs exhibit inhibition zones of 23.1 ± 0.13 mm (E. coli) and 17.3 ± 0.05 mm (S. aureus) with MICs of 2.5 and 5.0 mg/mL, while CS-PP-CDs have respective zones of 12.8 ± 0.08 mm and 16.3 ± 0.12 mm with a 5.0 mg/mL MIC for both strains. All CDs present a quasi-spherical morphology and emit yellow fluorescence under UV excitation, with PP-CDs showing the strongest intensity. This study provides technical support for high-value utilization of pineapple peel and development of multifunctional CDs, which have food field potential but face large-scale production and toxicological evaluation challenges. Full article

Plantain (Musa paradisiaca L.) is a tropical monocotyledonous, succulent plant of the Musaceae family commonly grown for food in the tropical regions of the African, Asian, and South American continents, where its parts are also sought for ethnomedicinal purposes in the treatment of burns, inflammation, and diabetes, among others. In the present preliminary exploratory study, the ethanol extract of the underutilized Musa paradisiaca peel (MPE) was evaluated for its in vitro inhibitory effects on α-amylase and α-glucosidase, as well as its in vivo hypoglycemic activity and potential biochemical toxicity. MPE (100, 200, 400 mg/kg) was orally administered to normal experimental rats for 30 days, following which the lipid profile, antioxidant status, and serum/tissue indices of hepatic, renal, and cardiac functions were evaluated. MPE produced significant inhibition (p < 0.05) of α-amylase (37%) and α-glucosidase (46%) at 120 µg/mL in vitro. The effect was lower than that of acarbose (IC₅₀ = 44.4 ± 1.14 and 15.60 ± 0.01 µg/mL, respectively). A modest blood glucose-lowering effect of MPE was observed at the highest tested dose (400 mg/kg) following subacute oral administration. During this treatment period, no biochemical alterations of toxicological importance were caused by MPE, as the organ–body weight ratio and serum/tissue indicators of organ function/damage were not adversely altered. In conclusion, MPE demonstrated inhibitory activity against both α-amylase and α-glucosidase, which may contribute to its potential hypoglycemic effects. Additionally, the findings indicate that the peel extract is non-toxic in rats following sub-acute administration at doses up to 400 mg/kg body weight. Further studies involving diabetic models and chronic exposure will substantiate and extend these preliminary observations. Full article

This study focuses on the optimization of modern extraction techniques for selected by-product materials, including apple, lemon, and tangerine peels, and onion skins, using artificial neural network (ANN) models. The extraction methods included ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE) with water as the extractant, as well as maceration (MAC) with natural deep eutectic solvents (NADES). Key parameters, such as total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activities, including reducing power (EC₅₀) and free radical scavenging capacity (IC₅₀), were evaluated to compare the efficiency of each method. Among the techniques, UAE outperformed both MAE and MAC in extracting bioactive compounds, especially from onion skins and tangerine peels, as reflected in the highest TPC, TFC, and antioxidant activity. UAE of onion skins showed the best performance, yielding the highest TPC (5.735 ± 0.558 mg CAE/g) and TFC (1.973 ± 0.112 mg RE/g), along with the strongest antioxidant activity (EC₅₀ = 0.549 ± 0.076 mg/mL; IC₅₀ = 0.108 ± 0.049 mg/mL). Tangerine peel extracts obtained by UAE also exhibited high phenolic content (TPC up to 5.399 ± 0.325 mg CAE/g) and strong radical scavenging activity (IC₅₀ 0.118 ± 0.099 mg/mL). ANN models using multilayer perceptron architectures with high coefficients of determination (r² > 0.96) were developed to predict and optimize the extraction results. Sensitivity and error analyses confirmed the robustness of the models and emphasized the influence of the extraction technique and by-product type on the antioxidant parameters. Principal component and cluster analyses showed clear grouping patterns by extraction method, with UAE and MAE showing similar performance profiles. Overall, these results underline the potential of UAE- and ANN-based modeling for the optimal utilization of agricultural by-products. Full article

Grapefruit is rich in flavanones, particularly naringin and narirutin. This study investigated the effects of temperature, time, and solid-to-liquid ratio on microwave-assisted pressurized CO₂–H₂O (MWP-CO₂-H₂O) extraction of flavonoids from grapefruit and optimized the parameters for maximum total flavonoid content (TFC) using response surface methodology. Independent variable ranges were 110–160 °C, 4.00–14.00 min, and 1:10.00–1:40.00 g/mL. Optimum conditions were 128 °C, 13.88 min, and 1:31.35 g/mL, yielding a TFC of 27.96 ± 1.29 mg naringin equivalent/g dry weight. Under these conditions, extraction yield, total phenolic content, ferric reducing ability of plasma, cupric reducing antioxidant capacity, and DPPH IC₅₀ were 55.17 ± 1.90% (dry basis), 25.42 ± 1.39 mg gallic acid equivalent/g, 39.16 ± 1.61 µmol trolox equivalent/g, 81.64 ± 0.29 µmol trolox equivalent/g, and 1.60 ± 0.01 mg/mL, respectively. Compared to conventional extraction (CE), MWP-CO₂-H₂O produced higher TFC, phenolic content, and antioxidant activity, while reducing extraction time by 13.68-fold. These results highlight grapefruit peel waste as a sustainable source of bioactive compounds and demonstrate that MWP-CO₂-H₂O is an environmentally sustainable, efficient alternative to conventional methods. Full article