Search Results (221)

The bioaccessibility of flavonoids (namely, their release from the food matrix and their stability under gastrointestinal conditions) is pivotal in establishing their bioavailability and biological effects. Bioaccessibility is affected by several factors, including the food matrix. Previous studies suggested that flavonols and flavan-3-ols were higher in solid foods rather than in beverages. Therefore, this study investigated the bioaccessibility of red-skinned onion flavonols and dark chocolate flavan-3-ols during in vitro gastrointestinal digestion of whole foods and the corresponding phenolic compounds extracts, with the aim of ascertaining a possible food matrix effect. Results showed that the presence of the food matrix protected flavonols and flavan-3-ols from degradation during digestion. The bioaccessibility of total flavonols and flavan-3-ols determined by mass spectrometry was 79.0% and 80.8% for red-skinned onion and dark chocolate, respectively, whereas it was 57.5% and 47.3% for the corresponding extracts. Degradation of flavonols occurred mainly during intestinal digestion by deglycosylation and oxidative reactions, whereas for flavan-3-ols, it occurred during gastric digestion mainly by hydrolysis. Therefore, this study highlighted the importance of the food matrix in protecting flavonols and flavan-3-ols from degradation during digestion, underscoring the significance of consuming phenolic compounds in whole foods rather than supplements or extracts. 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

Onion (Allium cepa L.) peels represent a major agro-industrial by-product and are a rich source of polyphenols, with recognized antioxidant properties. This study compared the polyphenolic profile of two onion cultivars peels: red “Rossa di Tropea” and yellow “Recas”. Their digestive stability, intestinal bioavailability, and antioxidant activity were evaluated. Hydroalcoholic extracts were characterized by HPLC-DAD, subjected to a static gastrointestinal digestion model, and assessed for transport across differentiated Caco-2 monolayers. Antioxidant properties were determined using DPPH, FRAP, Cellular Antioxidant Activity (CAA), and intracellular glutathione (GSH) assays. Red peels contained a higher total polyphenol content (28.44 mg/g DW) than yellow peels (15.61 mg/g DW), including anthocyanins uniquely present in the red cultivar. Digestive stability varied markedly between cultivars, with yellow peels showing greater intestinal recovery (72.7%) than red peels (49.1%). Glycosylated flavonols were more stable and exhibited moderate intestinal transport (Papp = 1.1–9.9 × 10⁻⁶ cm·s⁻¹), whereas quercetin aglycone showed low permeability. Red peel extracts demonstrated stronger chemical antioxidant activity, while yellow peels were more effective in cell-based assays, displaying higher CAA values and inducing a pronounced increase in intracellular GSH. Overall, onion peel extracts exhibit promising antioxidant and biological properties. However, their limited bioavailability highlights the need for formulation strategies to enhance gastrointestinal stability and intestinal uptake, supporting their potential use as sustainable functional ingredients. Full article

Agro-industrial by-products are rich in polyphenols with potential applications as natural antimicrobials in food systems. This study evaluated the total polyphenol content (TPC) and antimicrobial activity of orange (Citrus sinensis), onion (Allium cepa), cacao (Theobroma cacao), and tamarillo (Solanum betaceum) peel extracts against Listeria monocytogenes, individually and in combination with Saccharomyces cerevisiae. TPC was quantified using the Folin–Ciocalteu method, and minimum inhibitory concentrations (MICs) were determined using broth microdilution. Statistical analysis (two-way ANOVA, p < 0.05) assessed the effect of extract type and yeast addition on MIC values. The highest TPC was recorded in Theobroma cacao peel extract (85.3 ± 2.1 mg GAE/g DW). All extracts inhibited L. monocytogenes, with MICs ranging from 2.5 to 10 mg/mL. This was reduced to 1.25–5 mg/mL when combined with S. cerevisiae, indicating synergism (F = 11.42, p = 0.003). These results suggest that polyphenol-rich peel extracts enhanced by S. cerevisiae can be incorporated into beverage preservation systems, aligning with clean-label trends. This study integrates quantitative and mechanistic analyses to link extraction methods, polyphenol content, and synergistic inhibition with Saccharomyces cerevisiae, providing a coherent analytical framework for sustainable antimicrobial strategies. Full article

The present study aimed to design a process of brown onion skin transformation by sequential extraction to a cellulose-based immobilization carrier, along with detailed analysis of obtained extracts, pointing to approaching a “zero-waste” model of circular economy. The process of brown onion skin transformation started with semi-continuous sequential subcritical extraction via consecutive use of five solvents of increasing polarity (96, 75, 50, and 25% ethanol and water), followed by alkaline liquefaction of solid residue by 10% aqueous solution of sodium hydroxide. The designed BOS transformation process resulted in 16.62 g of cellulose-based immobilization carrier derived from 100 g of brown onion skin. Extracts obtained by semi-continuous sequential subcritical extraction contained 37 mg/g of proteins, 40 mg/g of sugars, 17.5 mg/g of uronic acids, 28 mg/g of polyphenols, and 36 mg/g of flavonoids, while those obtained by alkaline liquefaction 19 mg/g of proteins, 58 mg/g of sugars, 10 mg/g of uronic acids, 6.6 mg/g of polyphenols, and 0.5 mg/g of flavonoids. The suitability of the cellulose-based enzyme immobilization carrier was evaluated by B. cepacia lipase immobilization by adsorption, where a maximal 31 U of lipase activity per 1 g of wet carrier was achieved. Based on the results obtained, it seems that the proposed process of brown onion skin transformation shows the possibility of being used for the production of a cellulose-based immobilization carrier, approaching the “zero-waste” model of a circular economy. Full article

Background: We evaluated certain factors relative to onion (Allium spp.) and onion-derived polyphenols. Methods: We searched PubMed, Scopus, and Google Scholar from 2010 to 20 October 2025 without language limits. Eligible designs comprised of in vitro, animal, and human studies assessing onion, onion extracts, or isolated onion-derived polyphenols with bone outcomes. Two reviewers independently screened, extracted, and assessed risk of bias (RoB 2 for RCTs; SYRCLE for animals). Results: We included X studies (a in vitro, b animal, and c human RCTs; N samples). In vitro limitations included the following: heterogeneous models, short human follow-up, small samples, and moderate-to-serious risk of bias in animals. Reports included improvements in bone mineral density (BMD), bone mineral content (BMC), bone turnover markers, and osteoclast/osteoblast activity. Onion extracts consistently inhibited RANKL-induced osteoclastogenesis while sparing osteoblast function. In animals, onion or quercetin/kaempferol preserved BMD and improved mineral content and (in several models) fracture healing. In one small RCT of onion juice (8 weeks), antioxidant status improved with a trend to attenuated BMD loss; a resveratrol RCT was excluded/included as a benchmark. Conclusions: Pre-clinical evidence suggests anti-resorptive and osteogenic effects of onion-derived polyphenols; human evidence is limited and characterized by low certainty. Longer RCTs are needed to define effective doses and clinical relevance. Full article

This study explores the development of functional fermented beverages using fibre-rich residues derived from olive pruning, vineyard pruning, chicory root, and red onion, obtained after subcritical water extraction of polyphenols. Two microbial strains, Lactiplantibacillus plantarum and Bacillus subtilis, were evaluated for their fermentation performance across different fibre matrices, with and without sugar supplementation. Key parameters including microbial growth, pH evolution, and reducing sugar content were monitored, and Lactiplantibacillus plantarum showed superior acidification and viability (>9 log CFU/mL), especially in sugar-enriched formulations, while Bacillus subtilis showed a limited performance. Based on fermentation efficiency, three sugar-supplemented formulations were selected to scale-up: olive pruning fibre and vineyard pruning fibre fermented with Lactiplantibacillus plantarum and olive pruning fibre fermented with Bacillus subtilis. Red onion fibre extract was excluded from scale-up experiments due to its high viscosity, which made it impossible to measure reducing sugars, consistent with its high water-holding capacity. Fermentation significantly increased antioxidant capacity, reaching up to 750 µmol Trolox equivalents/L and 18 mg of gallic acid equivalents/L in L. plantarum-fermented samples, confirming microbial release of bound phenolics and formation of bioactive metabolites. The resulting beverages were microbiologically stable (final pH < 4.5), sensorially acceptable, and potentially antioxidant-rich, supporting their role in sustainable food system development and circular bioeconomy. Full article

Grifola frondosa is a rare fungus valued for its nutritional and medicinal properties; however, its bacterial spot disease has been largely overlooked. Thus, this study systematically investigated, isolated, and identified the pathogen and evaluated control strategies for bacterial spot disease affecting G. frondosa cultivation in Qingyuan County, Zhejiang Province. Through integrated morphological, physiological and biochemical analysis, and multi-locus phylogenetic analyses (16S rRNA, gyrB), Priestia aryabhattai was identified as the causal pathogen. This pathogen exhibited host specificity, infecting only G. frondosa and Pleurotus ostreatus, inducing primordial growth arrest and causing spots on the stipe of mature fruiting bodies. Control assessments revealed significant antimicrobial efficacy for four chemical agents, benziothiazolinone, copper sulfate, ethylicin and tetramycin, three plant extracts, garlic, leek and onion, and two biocontrol strains, Chlorophyllum molybdites and Aspergillus fumigatus. Scanning electron microscopy (SEM) demonstrated that these treatments caused ultrastructural damage to the pathogen’s cells, including membrane shrinkage, depression, and perforation. These findings establish key pathogenic characteristics and provide a scientific foundation for integrated disease management, supporting sustainable G. frondosa cultivation. Full article

From 2020 to 2021, crop production increased by 54% globally, and the popularity of commercial agriculture to increase profitability is gradually increasing. However, global warming and climate issues make it difficult to maintain stable crop production. To improve crop production efficiency, techniques for efficiently managing large-scale commercial farmland are needed. This study proposes a satellite image-based soil moisture and onion yield prediction technique as a methodology for managing large-scale farmland. This preemptive soil moisture management technique effectively manages increased soil pressure, resulting in soil drying due to rising temperatures. To remotely identify agricultural land, vegetation indices were extracted from satellite image data, and K-means clustering was applied. Ensemble machine learning is performed on soil images collected from satellite images. This model combines soil physical properties with soil environmental factor information to develop a model. The results show that soil color information obtained from satellite images is highly correlated with soil organic matter content. The proposed model is validated using crop yield data and environmental factor data obtained from actual crop production experiments. Consequently, the proposed methodology can be effectively applied to manage large-scale farmland and enables decision-making to improve profitability. Full article

Onion solid wastes (OSW) are a promising source of natural antioxidants with potential applications in food preservation. This study optimized pressurized liquid extraction parameters—ethanol concentration, liquid-to-solid ratio, temperature, and time—using response surface methodology to maximize the recovery of total polyphenols, total anthocyanins, and antioxidant activity. The optimal extracts yielded 37.02 mg GAE/g dw for total polyphenols and 592.73 µg CyE/g dw for total anthocyanins. Antioxidant activity was evaluated using the FRAP assay and the DPPH method. HPLC-DAD analysis identified quercetin, spiraeoside, and protocatechuic acid as major polyphenolic compounds. The optimal extract was encapsulated via spray drying using gum arabic as the wall material. Parameters such as encapsulation efficiency, loading capacity, and process yield were evaluated. The encapsulated extract was incorporated into mayonnaise, and its effect on oxidative stability was monitored over 14 days. Results demonstrated significant antioxidant protection, comparable to synthetic preservatives such as potassium sorbate and butylated hydroxytoluene. This study highlights the potential of OSW-derived antioxidants as sustainable, natural additives for food systems. Full article

The purpose of this study was to identify the potential inhibitory effects of extracts of garlic, ginger, and onion on Escherichia coli and Staphylococcus aureus, which had been previously isolated from milk of dairy cows with mastitis. Garlic, ginger, and onions were crudely pressed, and the extracts were filtered and tested for their ability to inhibit bacterial growth at a wide range of concentrations, from undiluted to 1:512 (2⁻⁹). Their inhibitory properties were compared to positive controls containing ampicillin and ceftiofur, and negative controls containing only the nutrient medium and bacteria. Each plate contained quality control organisms E. coli ATCC 25922 and S. aureus ATCC 25923. The colorimetric microdilution method with resazurin as an indicator of bacterial growth was used to determine the minimum inhibitory concentrations. In addition, the minimum bactericidal concentrations of the extracts were assessed. The minimum inhibitory concentrations of garlic extracts were 1.56 µL/mL and 3.12 µL/mL for E. coli and S. aureus, respectively. The minimum bactericidal concentrations of garlic extract against E. coli and S. aureus were 12.5 and 25 µL/mL, respectively. For both ginger and onion, no inhibition was detected at the full concentration of the extracts, but garlic extract demonstrated in vitro inhibition against both E. coli and S. aureus. Future studies should evaluate the ability of garlic extracts to achieve an inhibitory concentration in milk and explore its potential activity in naturally infected mammary glands. Full article

This present study aimed to investigate the recovery of polyphenols from red onion peel (OPP) and pomace of Merlot (MWP) and Syrah (SWP) grape varieties, using a common biphasic solvent (70/30 ethanol/water) and a new biphasic and eco-friendly solvent that has been developed in our laboratory (ethanol of grape origin). Moreover, overnight and ultrasonic-assisted extractions were carried out to investigate whether the extraction method could affect the obtained results. Results showed that 70% ethanol achieved a significantly (p < 0.05) higher yield in total phenolic content (TPC) and total flavonoid content (TFC), while the extracts with ethanol of grape origin exhibited considerably higher antioxidant activity as evidenced by the DPPH and complementary by FRAP assays. The overnight and ultrasonic-assisted extraction played a significant (p < 0.05) role in achieving better extraction of bioactive components such as phenolic compounds. Color parameters were also determined, showing that the presence of yellow, blue and red color tones depend on the extraction method and solvent, due to the different compositional characteristics of pigments, mainly anthocyanins. In addition, physicochemical parameters such as pH and total soluble solids (TSSs) of the extracts were also measured. Finally, the composition of ethanol of grape origin was characterized by means of Ultraviolet–Visible (UV-Vis) and Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy, which confirmed the presence of ethanol and acetic acid. This study brings new results regarding the prospect of using new solvents for the recovery of bioactive compounds from agricultural by-products, and the development direction of scientific research or industrial production, based on ultrasonic-assisted and overnight extraction methods. Full article

With rising living standards, consumer demand for fresher food continues to increase. Consequently, the development of multifunctional packaging materials that enable real-time freshness monitoring, delay spoilage, and ensure environmental sustainability has become a central research focus. The present study developed an antibacterial and pH-responsive smart packaging film, formulated from a κ-carrageenan/gelatin (CG) matrix. This film incorporated anthocyanins extracted from red onion skin (ROSA) and citronella essential oil encapsulated in β-cyclodextrin (OBDs) as functional additives, herein referred to as the CGR/OBDs composite film. The composite films exhibited strong pH sensitivity, ammonia responsiveness, color stability, effective barrier properties, and notable antioxidant activity (96.4% ABTS and 79.3% DPPH radical scavenging rates). The sustained release of citronella essential oil over approximately 40 h conferred excellent antibacterial performance, with inhibition rates of 94.8% against Staphylococcus aureus (S. aureus) and 91.6% against Escherichia coli (E. coli). Application in shrimp preservation further demonstrated an extended shelf life and real-time freshness monitoring through distinct colorimetric shifts. The findings highlight the potential of CGR/OBDs films as visual indicators for food freshness in intelligent packaging, offering a promising strategy to enhance food safety and reduce waste. Full article

Every year, significant amounts of agro-industrial residues are generated. These residues contain several antioxidant compounds that can be extracted and applied to cosmetic products. In this study, phenolic-rich extracts from different agro-industrial residues (chestnut shell—CS, grape seed—GS, kiwi peel—KP, onion peel—OP, and pomegranate peel—PP) were obtained and their antioxidant potential and biocompatibility towards human fibroblasts (HFF-1) were evaluated. The total phenolic content ranged from 37.6 mg of gallic acid equivalents (GAE)/g for KP to 343.9 mg_GAE/g for CS. Moreover, CS, GS, OP, and PP extracts exhibited strong antioxidant properties, while KP showed more moderate potential. Biocompatibility tests demonstrated that CS and GS extracts were non-cytotoxic at concentrations below 500 mg/L, while OP and PP were safe up to 1000 mg/L. KP extracts were biocompatible up to 10,000 mg/L. This work demonstrated the bioactive potential of various agro-industrial residues for application in the cosmetic industry, given their antioxidant capacity. Additionally, it was the first to establish safe application limits for Soxhlet-extracted compounds, ensuring their safety to consumers. This research emphasises the importance of evaluating the biocompatibility of each extract before its incorporation into cosmetics, as their composition is highly variable. Full article

Human noroviruses (HuNov) are the major cause of foodborne illness globally. Several HuNoV outbreaks have been linked to contaminated ready-to-eat seaweed products. Standard protocols such as the ISO 15216 show limited efficiency in extracting foodborne viruses from seaweed products. Therefore, we evaluated the efficiency of an extraction protocol based on porcine gastric mucin conjugated magnetic beads (PGM-MBs) to recover HuNoVs from Wakame seaweed salad. Compared to other HuNoV extraction methods, the PGM-MB method was more efficient. We then aimed to further improve this protocol by modifying several factors such as the buffers, pH, bead concentration, centrifugation and incubation time. The optimized PGM-MB method yielded 19 ± 3% and 17 ± 4% recovery, for HuNoV GI and GII, respectively. The limit of detection (LOD₉₅) for Wakame seaweed salad was 131 and 56 genomic equivalents per 25 g for HuNoV GI and GII. Although some variability in recovery efficiency was observed between the PGM sources, the optimized PGM-MB protocol effectively extracts HuNoVs from Wakame seaweed salads of various brands and other commodities such as dates, green onions, and salted seaweed. These results support the implementation of the optimized PGM-MB method as a viable alternative for HuNoV surveillance in complex food matrices. Full article