Search Results (245)

Background/Objectives: Citrus × paradisi Macfad., Rutaceae. peel is a rich source of naringin (NR), but its poor solubility and low bioavailability limit applications. This study aimed to improve NR delivery by comparing microencapsulation, liposomal microencapsulation, and buccal films containing either pure NR or grapefruit peel extract. Methods: Four spray-dried powder formulations—spray-dried NR (NS), liposomal NR (NLS), spray-dried extract (ES), and liposomal extract (ELS)—were produced using maltodextrin, β-cyclodextrin, and HPMC as wall materials. Buccal films (EP1, EP2, NP1, NP2) were prepared via solvent casting with HPMC, alginate (ALG), or polyvinyl alcohol (PVA). All samples were evaluated for solubility, moisture content, mucoadhesion, and in vitro release under simulated gastric, intestinal, and salivary conditions. Results: NR powders had the highest absolute solubility (306.42 ± 10.34 µg/mL), whereas ELS showed the lowest due to low loading. However, relative to theoretical NR content, ELS achieved the highest dissolution efficiency (55.3%), followed by NLS (42.7%), outperforming NS (5.6%) and ES (91.8%) in sustained release potential. Dual encapsulation (NLS, ELS) slowed gastric release and maintained intestinal delivery, while non-liposomal powders released rapidly. In buccal films, NP2 (NR + PVA) showed the highest release (69.97 ± 3.01 µg/mL; 40.9% efficiency) and strongest mucoadhesion (0.47 N·s). Extract-based films had lower absolute NR release but higher relative efficiency to content, likely due to co-extracted compounds enhancing wettability and matrix erosion. Conclusions: Liposomal microencapsulation improves relative dissolution efficiency and sustains intestinal release, while PVA-based buccal films enhance both release and mucoadhesion. Polymer choice and active ingredient composition are critical for optimising oral delivery of NR. These results demonstrate the potential of the proposed systems in the pharmaceutical or dietary supplement field, especially in improving the oral delivery of poorly soluble flavonoids. A graphical summary is included, visually summarising the main formulation strategies and results. Full article

The effect of varying sodium alginate (SA) concentrations (1%, 2%, and 3%; SA1–SA3) on the encapsulation of tangerine (Citrus reticulata Blanco ‘Cho Khun’) peel extract (TPE, 0.5% w/v) into hydrogel beads was evaluated. Overall, the results showed that increasing SA concentration significantly altered bead characteristics: lightness (L*) decreased from 56.35 to 45.57, red-green axis (a*) shifted negatively from −1.32 to −6.87, and yellow-blue axis (b*) increased from −17.81 to 6.41. Moisture content (97.85% to 93.16%) and water activity (0.96 to 0.93) declined with higher SA, while hardness increased (4.12 to 5.17 g). ζ-potential values shifted from −29.10 mV (SA1) to −39.10 mV (SA3), confirming enhanced electrostatic stabilization. FTIR spectra revealed characteristic alginate functional groups, and morphological analysis showed smoother, denser beads at higher SA concentrations. Phenolic (47.86–48.51 mg GAE g⁻¹ DW) and flavonoid (34.02–36.68 mg QE g⁻¹ DW) contents were well-retained, supporting antioxidant activities (DPPH 70.34–72.54%; ABTS 65.66–66.91%). Antimicrobial tests demonstrated > 4-log reductions against E. coli and P. aeruginosa. Sensory evaluation revealed that higher SA concentrations improved texture and taste. Overall, SA encapsulation, particularly at 3%, effectively stabilized TPE, preserving its functional properties for potential food and nutraceutical applications. Full article

Citrus by-products are increasingly recognized as a valuable source of bioactive compounds (BCs), particularly flavonoids. Their incorporation into food matrices as functional ingredients aligns with sustainability goals and consumer demand for health-promoting products. However, challenges such as poor stability and undesirable sensory properties limit their direct use in food systems. This study aimed to develop and evaluate functional cookies enriched with microencapsulated flavonoid-rich extracts derived from lemon and orange peels. Flavonoids were extracted with hydroethanolic solvent and characterized by HPLC-DAD. The extracts exhibited high total flavonoid contents: 1960.1 mg/L for orange and 845.7 mg/L for lemon. The extracts were encapsulated using a 1% sodium alginate and 1.36% corn starch blend, producing thermally stable microbeads with flavonoid retention higher than 85% after heating at 230 °C for 30 min. These microbeads were incorporated into gluten-free oat and buckwheat cookies, delivering 166.11 mg/100 g (orange) and 177.13 mg/100 g (lemon) of flavonoids in the product, which covers approximately one-third of the recommended daily intake. Sensory analysis using triangle tests (ISO 4120) (n = 23) showed no significant difference (p > 0.05) between control and enriched cookies, indicating successful masking of potential bitterness or astringency associated with flavonoids. These results demonstrate the effectiveness of microencapsulation in protecting citrus flavonoid-rich extracts and support the development of sustainable, health-oriented bakery products. Moreover, this approach promotes the valorization of agro-industrial by-products, contributing to a more circular food supply chain. Full article

This is the first work to screen an optimal extraction method for Citrus reticulata Blanco cv. Tankan peel polysaccharides (CPP). The CPP was extracted using hot water extraction (HWE), acid extraction (AAE), enzyme extraction (EAE), high-pressure extraction (HPE), and ultrasound extraction (UAE), named CPP-W, CPP-A, CPP-E, CPP-P, and CPP-U, respectively. Results showed that CPP-A and CPP-P had higher extraction yields than other CPPs. The five CPPs varied chemically in molecular weight, monosaccharide composition, and microstructure, but shared similar IR spectra and core glycosidic linkages, indicating differential degradation while preserving core structures during extraction. Among these CPPs, CPP-A, CPP-E, and CPP-U exhibited stronger immunological activities, attributed to high galacturonic acid and low molecular weight. Moreover, CPPs significantly promoted secretion of cytokines (nitric oxide, NO; prostaglandin E₂, PGE₂; interleukin-6, IL-6; tumor necrosis factor-α, TNF-α) by activating downstream inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2)-related mitogen-activated protein kinases (MAPK) pathways. Overall, CPP-E possessed high extraction yield, low molecular weight, and strong immuno-stimulatory activity, suggesting that enzyme-assisted extraction was the optimal approach for extracting CPP. Full article

This study explores the sequential valorization of orange peel waste (OPW) through photo-fermentation using real dark fermentation effluents (DFE) as substrates for hydrogen production using Rhodobacter capsulatus B10. Three DFE types—differing in prior biocompound extraction method—and their concentrations at three levels (25, 35, and 45%) were evaluated. The highest hydrogen yield (126.5 mL H₂ g⁻¹ VFA) was achieved with DFE derived from essential oil-extracted OPW at a concentration of 25%. The highest DFE concentration reduced the hydrogen yield due to intensified medium opacity and potential substrate inhibition. Kinetic modeling revealed that the Modified Gompertz and T_i-Gompertz models best described hydrogen production dynamics. This study presents the first evidence of hydrogen production via photo-fermentation using real effluents derived from OPW processing, demonstrating a novel route for citrus waste reuse within a biorefinery framework. These findings underscore the innovation and relevance of integrating waste valorization with clean energy production, while also identifying key operational challenges to be addressed. Full article

Inflammatory pain is a worldwide health problem, affecting primarily women. Nonetheless, most research conducted in this field has involved male subjects, and only 10% of the results have been obtained using females. Gold Lotion (GL) is a formulated product made from the peels of six citrus fruits that have been proven, via experimental data, to possess several biological properties, such as anti-inflammatory, anticancer, and antibacterial activities. This research aims to investigate the response to GL administration in two models of peripheral inflammation to assess potential sex differences. Carrageenan was used to induce mechanical allodynia and maximal edema within hours, serving as a model of acute inflammation, while Complete Freund’s Adjuvant (CFA) was used to obtain similar results within days, resulting in a model of chronic inflammation. Acute GL administration reduced mechanical allodynia in both models and both sexes, with no anti-inflammatory effects observed. In conclusion, this study demonstrates the potential of GL to alleviate inflammatory pain in both males and females, thereby broadening its therapeutic applications. Full article

Pectin is a renewable polysaccharide valued for its gelling, stabilising, and encapsulating properties, with broad applications in food, pharmaceutical, and industrial sectors. However, extraction conditions critically affect its yield, structural integrity, and functional performance. Despite citrus peel being a major source of pectin, large amounts remain underutilised as waste. This study systematically investigates how different acid types influence the extraction efficiency and structural quality of pectin derived from citrus peel. Dried citrus peel powder was extracted using four acids—sulphuric, hydrochloric, acetic, and citric—under controlled conditions at 80 °C. Extractions were performed at a fixed time of 90 min for all acids, with additional time trials for sulphuric acid. Extracted pectins were evaluated for gravimetric yield, colour, solubility, degree of esterification (DE) by titration and FTIR, and structural features using FTIR and ¹H NMR spectroscopy. Results showed that sulphuric and hydrochloric acids yielded the highest pectin recoveries (30–35% and 20–25%, respectively) but caused significant degradation, evident from dark colour, broad FTIR peaks, low DE (<10%), and poor solubility. In contrast, acetic and citric acid extractions resulted in moderate yields (8–15%) but preserved the pectin backbone and maintained higher DE (>30%) compared to the mineral acid-extracted samples and the commercial low methoxyl (LM) standard, as confirmed by clear FTIR and NMR profiles. These findings demonstrate the trade-off between extraction yield and structural integrity, underscoring the potential of mild organic acids to produce high-quality pectin suitable for value-added applications. Optimising acid type and extraction conditions can support sustainable waste valorisation and expand the industrial use of citrus-derived pectin. Full article

Orange allergy is estimated to account for up to 3–4% of food allergies. Major allergens identified in orange (Citrus sinensis) include Cit s 1 (germin-like protein) and Cit s 2 (profilin), while Cit s 3 (non-specific lipid transfer protein, nsLTP) and Cit s 7 (gibberellin-regulated protein) have also been described. The objective of this study was to investigate the presence and IgE-binding capacity of germin-like proteins in citrus fruits other than oranges. We describe five patients with immediate allergic reactions after orange ingestion. All patients underwent skin prick tests (SPT) to aeroallergens and common food allergens, prick-by-prick testing with orange, lemon, and mandarin (pulp, peel, seeds), total IgE, specific IgE (sIgE), anaphylaxis scoring (oFASS), and the Food Allergy Quality of Life Questionnaire (FAQLQ-AF). Protein extracts from peel and pulp of orange, lemon, and mandarin were analyzed by Bradford assay, SDS-PAGE, and IgE immunoblotting using patient sera. Selected bands were identified by peptide mass fingerprinting. A 23 kDa band was recognized by all five patients in orange (pulp and peel), lemon (peel), and mandarin (peel). This band was consistent with Cit s 1, a germin-like protein already annotated in the IUIS allergen database for orange but not for lemon or mandarin. Peptide fingerprinting confirmed the germin-like identity of the 23 kDa bands in all three citrus species. Germin-like proteins of approximately 23 kDa were identified as IgE-binding components in peel extracts of orange, lemon, and mandarin, and in orange pulp. These findings suggest a potential shared allergen across citrus species that may contribute to allergic reactions independent of LTP sensitization. Full article

This research analyzes the innovative development of carnauba wax coatings enriched with essential oils (EOs: lemon, orange, grapefruit, clove, oregano, and cinnamon) or fruit by-products (FBPs: avocado, tomato, carrot, orange, lemon, and grapefruit) to improve postharvest preservation of organic oranges and lemons. Six EOs and six FBPs were evaluated for total phenolic content (TPC) and in vitro antifungal activity against Penicillium digitatum. Based on results, grapefruit, oregano, and clove EOs were selected for lemons, while avocado, orange, and grapefruit FBPs were selected for oranges. An in vivo test at 20 °C for 15 days with carnauba wax coatings assessed antifungal performance. Clove EO and avocado FBP showed strong in vitro inhibition and consistent hyphal suppression (~100 and ~82%, respectively). In vivo, coatings with grapefruit EO and avocado FBP significantly reduced fungal decay and sporulation (~75%) in lemons and oranges, respectively. Coated fruits also retained weight losses by ~25% compared to uncoated ones. These findings suggest that phenolic-rich natural extracts, especially from agro-industrial residues like avocado peels, offer a promising and sustainable strategy for postharvest citrus disease control. Further studies should test coating effectiveness in large-scale trials under refrigeration combined with other preservation strategies. Full article

This research presents a novel, sustainable, and eco-friendly method for the rapid green synthesis of nanoparticles with antibacterial properties. This method employs steam distillation to extract reducing and stabilizing agents from orange peel waste, followed by ultrasound-assisted synthesis. To the best of our knowledge, this is the first reported integration of these two techniques for nanoparticle production. The extracted materials were then subjected to rigorous characterization through a combination of analytical techniques, including FTIR, HPLC, and TEM. These analytical approaches enabled a comprehensive analysis of the synthesized NPs, revealing their size distribution within the range of 1.5 to 14 nm. Among the synthesized nanomaterials, AgNPs exhibited the most potent antibacterial activity, with statistically significant minimum inhibitory concentrations (MICs) of 16 ppm for E. coli ATCC and 32 ppm for resistant E. coli and E. faecalis strains. This study underscored the promise of valorizing citrus waste for nanomaterial synthesis and introduced a novel, scalable methodology for producing bioactive nanoparticles, promoting a more sustainable technology for this purpose. Notably, this research aligns with United Nations Sustainable Development Goal 12, which promotes responsible consumption and production by transforming organic waste into high-value functional nanomaterials for biomedical and environmental applications. Full article

Background: Contemporary agriculture heavily relies on synthetic chemicals to ensure high yields and food security; however, their overuse has led to health issues and the development of pesticide resistance in pests. Researchers are now exploring natural, eco-friendly alternatives for pest control. Methods: This study evaluated two ethanol-based formulations (1.25% and 2.50%, v/v) derived from the tangerine peel (Citrus reticulata L. var. Clementina) against conventional chemical treatments and an untreated control group in the cultivation of potatoes (Solanum tuberosum L. var. Capiro). A randomised block design was used, with three blocks per treatment containing 45 plants. The experiment was conducted during the wet season (February–April 2023). Results: According to visual inspections and yellow traps, following weekly application from days 30 to 105 post-planting to monitor pest (e.g., Frankliniella occidentalis, Aphididae) and beneficial insect (e.g., Coccinellidae, Apis mellifera) populations, the 2.50% formulation performed similarly to chemical treatments against pests, whilst being harmless to beneficial insects. Post-harvest analysis showed that the formulations achieved 73% of conventional yields, with comparable tuber damage and levels of Premnotrypes vorax larvae. Conclusions: Toxicological tests confirmed the eco-friendliness of the formulations, making them suitable for small-scale Andean ‘chakras’ in organic farming and honey production, without the use of chemicals. Full article

Citrus peel, a significant by-product of fruit processing, represents a rich source of carotenoids with strong antioxidant and health-promoting properties. The present study evaluated two green extraction techniques, cloud point extraction (CPE) and supramolecular solvent (SUPRAS)-based extraction, for carotenoids recovered from citron, orange, and tangerine peels. Whereas SUPRAS methods rely on a supramolecular solvent made of water, ethanol, and octanoic acid, CPE methods use surfactants and water, and both show a high potential to extract lipophilic components. CPE demonstrated superior efficiency in extracting total carotenoids and enhancing antioxidant activity, with orange peel extracts showing the highest concentrations. CPE and SUPRAS extracts were subsequently encapsulated using freeze-drying with chickpea protein isolate, achieving high encapsulation efficiencies (82.40–88.97%). The use of encapsulation technology is an effective strategy to protect carotenoids from environmental stressors. Color, morphological, and FTIR analyses confirmed the successful encapsulation and retention of carotenoids. Environmental impact was assessed using the EcoScale tool, revealing excellent sustainability for CPE (92 points) and satisfactory performance for SUPRAS-based extraction (70 points). The use of Generally Recognized As Safe (GRAS) solvents and plant-derived encapsulation materials makes this method highly suitable for clean-label product development across the food, cosmetic, and nutraceutical industries. In summary, the results point to a practical and sustainable approach to citrus waste valorization into valuable, health-promoting ingredients—supporting both circular economy goals and eco-friendly innovation. Full article

Domestic food waste and agro-industrial by-products (AIBPs) occurring throughout the food chain, including production, processing, and storage, have become a global sustainability concern. Interestingly, this waste and these by-products contain a significant amount of commercially vital bioactive compounds, including polyphenols and carotenoids. Remarkably, discarded by-products such as fruit and vegetable peels contain more bioactive compounds than edible pulp. Thus, valorizing this waste and these by-products for commercially vital bioactive products can solve their disposal problems and help alleviate climate change crises. Additionally, it can generate surplus revenue, significantly improving food production and processing economics. Interestingly, several bioactive extracts derived from citrus peel, carrot pomace, olive leaf, and grape seed are commercially available, highlighting the importance of agro-food waste and by-product valorization. Considering this background information, this review aims to provide holistic information on major AIBPs; recovery methods of bioactive compounds focusing on polyphenols, carotenoids, oligosaccharides, and pectin; microencapsulation of isolated bioactive for enhanced physical, chemical, and biological properties; and their commercial application. In addition, green extraction methods are discussed, which have several advantages over conventional extraction. The concept of the circular bio-economy approach, challenges in waste valorization, and future perspective are also discussed. Full article

With conventional fuels dwindling and emissions rising, there is a necessity to develop and assess innovative substitute fuel for compression ignition (CI) engines. This study investigates the potential of magnesium oxide (MgO) nanoparticles as a sustainable additive to enhance the performance and reduce emissions of used cooking oil (UCO) biodiesel–diesel blends in CI engines. MgO nanoparticles were biosynthesized using Citrus aurantium peel extract, offering an environmentally friendly production method. A single-cylinder CI engine was used to test the performance of diesel fuel (B0), a 20% biodiesel blend (B20), and B20 blends with 30 ppm (B20M30) and 60 ppm (B20M60) MgO nanoparticles. Engine performance parameters (brake thermal efficiency (BTE), brake-specific fuel consumption (BSFC), and exhaust gas temperature (EGT)) and emission characteristics (CO, NO_x, unburnt hydrocarbons (HCs), and smoke opacity) were measured. The B20M60 blend showed a 2.38% reduction in BSFC and a 3.38% increase in BTE compared to B20, with significant reductions in unburnt HC, CO, and smoke opacity. However, NO_x emissions increased by 6.57%. The green synthesis method enhances sustainability, offering a promising pathway for cleaner and more efficient CI engine operation using UCO biodiesel, demonstrating the effectiveness of MgO nanoparticles. Full article

This study investigates the impact of rootstock selection on the essential oil (EO) composition of clementine mandarin (Citrus clementina Hort. ex Tan.) var. SRA 63 cultivated in southern Greece. EOs were extracted from the peel and leaves of trees grafted on four commonly used rootstocks: Cleopatra mandarin, sour orange, Troyer citrange, and Swingle citrumelo. The GC-MS analysis revealed significant qualitative and quantitative differences in EO profiles across the different rootstock combinations. In peel EOs, limonene was the dominant compound, particularly in trees grafted onto Cleopatra mandarin and Swingle citrumelo, while Troyer citrange favored a more diverse chemical profile rich in oxygenated monoterpenes, sesquiterpenes, and aldehydes. Leaf EOs were characterized by high levels of sabinene, linalool, and limonene, with Swingle citrumelo promoting sabinene production and Troyer citrange enhancing limonene content and sesquiterpene diversity. Sour orange showed an intermediate effect, increasing both compound diversity and abundance. These results underscore the critical role played by rootstock in modulating the biosynthesis of volatile compounds, likely through physiological and molecular interactions with the scion. These findings offer valuable insights into optimizing EO yield and quality in citriculture and support the broader goal of valorizing Citrus by-products through targeted agricultural practices. This research contributes to the implementation of targeted agricultural practices (rootstock choice) for the development of high-value Citrus-based products with specific quality traits. Full article