Search Results (303)

Pectin is a naturally occurring biopolymer extensively used for applications in the pharmaceutical, biotechnology, and food industries, and is abundantly present in lemon by-products. Although lemon peels represent a highly promising raw material, the structure of pectin is strongly influenced by extraction and drying processes, and the resulting attributes remain insufficiently understood. The present study systematically investigates the impact of conventional hot acid extraction using three different acidifying agents (citric, sulphuric, and hydrochloric) in combination with two drying techniques (oven-drying and freeze-drying) on the physicochemical, structural, thermal, and viscosity–shear rate properties of pectin obtained from lemon by-products (Citrus limon, Portuguese Eureka variety) following the prior recovery of bioactive compounds (essential oils and phenolic compounds). The results demonstrated that citric acid extraction followed by freeze-drying yielded the highest pectin recovery, at approximately 26.7%, highlighting the suitability of this approach for efficient by-product valorisation. Oven-dried pectins exhibited higher moisture contents (8.5–10%) and lower lightness values (L* = 57.02–65.67), indicating darker colouration compared to freeze-dried pectins (L* = 78.82–83.75). All extracted pectins presented a degree of esterification (DE ≥ 50%), classifying them as high-methoxyl pectins. The galacturonic acid (GalA) content ranged from 37.6 to 48.9% for oven-dried samples and increased to 44.1–58.6% for freeze-dried samples. Furthermore, pectin obtained from lemon by-products exhibited a well-defined structural organisation and enhanced thermal stability, especially for freeze-dried pectin samples, and suitable rheological properties, with no statistically significant variations observed between different acids or drying conditions, supporting its technological suitability for applications in the food, cosmetic, and pharmaceutical industries. Full article

The widespread application of plain S235JR steel across various industries often involves its exposure to degradative conditions, such as the organic acid concentrations typically found in various foodstuffs. This study investigates the corrosion behavior of S235JR steel immersed in several common beverages. The corrosion of steel S235JR was evaluated by gravimetric and electrochemical study. Statistical modeling via multiple linear regression and ANOVA was utilized to verify the experimental dataset. Based on the results, the highest early-stage corrosion occurs in coffee and tomato juice, though apple cider vinegar stands out for its steadily intensifying corrosive effect over the immersion period. Conversely, the presence of citric acid in lemon and orange juices appears to act as an inhibitor, leading to the lowest observed corrosion rates. The strong correlation between electrochemical parameters ($I_{corr}$ and $E_{ocp}$) and physical mass loss confirms that the chemical nature of each beverage significantly governs the corrosion kinetics of S235JR. Full article

Background and Objectives: Melissa officinalis (lemon balm) contains phenolic constituents with antioxidant and cytotoxic activities; however, evidence regarding aqueous leaf extracts in lung adenocarcinoma models and reconstructed human airway tissues remains limited. The novelty of the present study lies in the integrated evaluation of the same aqueous extract through phytochemical and antioxidant characterization, a three-dimensional reconstructed tracheobronchial tissue model, and complementary short- and long-term biological endpoints in A549 lung adenocarcinoma cells. Materials and Methods: Antioxidant activity was evaluated using the DPPH assay, total phenolic content (TPC) using the Folin–Ciocalteu method, and the targeted phenolic profile using UHPLC–MS/MS. EpiAirway^TM tissues were exposed to 1000 µg/mL extract for 24 h, and tissue metabolic viability was assessed using the MTT assay. A549 cells were treated with 20–1000 µg/mL extract for 24 h and evaluated using complementary metabolic, lysosomal, mitochondrial, morphological, membrane-integrity, and clonogenic endpoints. Results: The extract exhibited concentration-dependent DPPH radical-scavenging activity, with an estimated IC₅₀ of 1.37 mg/mL (95% CI: 1.00–1.88 mg/mL), and a TPC of 10.84 ± 0.03 mg GAE/g dry extract. The most abundant targeted analytes were the unresolved 3,5-dihydroxybenzoic acid/3,4-dihydroxybenzoic acid group (2.09 ± 0.60 µg/mL) and the p-coumaric acid/trans-p-coumaric acid group (1.31 ± 0.04 µg/mL). EpiAirway^TM tissue viability was 85.87% following exposure to 1000 µg/mL. In A549 cells, metabolic viability decreased to approximately 59% and 53% at 500 and 1000 µg/mL, respectively, whereas neutral red uptake declined to approximately 50% at 1000 µg/mL. Treatment was also associated with mitochondrial membrane depolarization, concentration-dependent cellular and nuclear alterations, apoptotic-like and necrotic staining patterns, and a reduction in clonogenic capacity to approximately 21% at 1000 µg/mL. Conclusions: The aqueous M. officinalis leaf extract exhibited measurable antioxidant activity, did not cause a marked acute reduction in EpiAirway^TM tissue metabolic viability under the single exposure condition tested, and produced concentration-dependent cytotoxic and sustained antiproliferative effects in A549 cells. These exploratory findings do not establish comprehensive respiratory safety, a specific cell-death mechanism, or tumor selectivity. Nevertheless, the integrated experimental approach supports further investigation using standardized multiple extract batches, matched malignant and non-malignant lung epithelial models, and quantitative molecular endpoints. Full article

This study aimed to evaluate how the dosage, type of herbal preparation (plant material, dry extract, or isolated compound), along with simulated digestion-related factors, i.e., digestion stage (gastric vs. intestinal) and corresponding physicochemical and biochemical environment, influence the in vitro bioaccessibility of lemon balm phytochemicals. Simulated in vitro digestion revealed that the bioaccessibility of rosmarinic acid (RA), total phenolics, and antioxidant activity strongly depended on the application form, dose, and digestion stage. Isolated RA exhibited the highest gastric in vitro bioaccessibility, which markedly decreased during intestinal digestion. Dry extracts provided consistently higher in vitro bioaccessibility of RA, TPC (Total Phenolic Content), ABTS (ABTS scavenging activity), and FRAP (Ferric Reducing Antioxidant Power) than powdered plant material, particularly at doses of ≥25 mg. Intestinal digestion enhanced the in vitro bioaccessibility of phenolics and antioxidant activity from plant material under physicochemical conditions, whereas biochemical digestion factors generally reduced in vitro bioaccessibility, especially at lower doses. Overall, higher doses ensured more stable in vitro bioaccessibility across all analysed parameters. Full article

Steam distillation residues (SDRs) of aromatic plants were utilized to produce antioxidant extracts using hydroalcoholic solvents with increasing percentages of ethanol (0, 50, 75 and 100% v/v). The phenolic composition and antioxidant power were measured and compared to the corresponding fresh aromatic plants (FAPs). The largest amount of polyphenols, ranging from 14.15 (lemon balm FAP) and 19.61 (lavender SDR) mg gallic acid equivalents/g dry matter (DM), was found in 0% ethanol (pure water) extracts. The phenolic content of lavender and spearmint SDR extracts was higher than that of the corresponding FAP extracts, while the opposite was observed with lemon balm. Rosmarinic acid was the most abundant hydroxycinnamic acid detected, ranging from 608.65 µg/g DM in lemon balm 50% ethanol FAP extract to 697.47 µg/g DM in spearmint 50% ethanol SDR extract. The lavender and spearmint SDR extracts exhibited higher antioxidant power than the FAP extracts, while the extracts from fresh lemon balm were more antioxidant than the SDR. The lavender 50% ethanol SDR extract showed the highest scavenging activity (67.16%) and ferric reducing power (16.60 mg ascorbic acid equivalents/g DM). These results prove that spent aromatic residues can be utilized to produce antioxidant blends for various industrial applications. Full article

The main causes of lemon fruit senescence and deterioration are fungal diseases and postharvest quality loss. Edible coatings have been proposed to delay quality loss in fresh produce by reducing moisture loss and helping preserve external appearance. Natural functional coatings are increasingly being investigated as potential alternatives to synthetic waxes and preservatives due to environmental and consumer safety concerns. The effect of a natural edible coating based on Opuntia ficus-indica mucilage on extending the shelf-life of lemons during cold storage was investigated. Lemon fruits were treated with the mucilage-based edible coating and subsequently stored under controlled cold conditions. Coated and uncoated lemon fruits were evaluated for their physicochemical properties, including weight loss, total soluble solids, pH, titratable acidity, color, and microbiological analysis, as well as total polyphenol content and antioxidant activity, over a 60-day storage period at 5 ± 0.5 °C and 95% relative humidity. The results showed that the mucilage-based coating improved lemon fruit storage performance, effectively preserving key physicochemical and microbiological parameters over 60 days of cold storage (p ≤ 0.05). In particular, the treatment maintained fruit firmness, reduced weight loss (up to 45%), increased juice content (up to 1.8-fold), and delayed microbial decay compared to control samples. Coated fruits also exhibited higher total polyphenolic content and antioxidant activity than control samples at the end of storage. In addition, using mucilage extracted from cactus pear cladode waste provides a sustainable way to add value to the product, with promising industrial applications as an alternative to synthetic fruit coatings. Full article

In this study, activated biochars derived from spent coffee grounds (CAC-600) and lemon pomace (LAC-600) were prepared through pyrolysis with FeCl₃ activation and evaluated for the selective adsorption of Acid Blue 74 (AB74), a dye widely used in the denim textile industry. FeCl₃ activation significantly increased the surface area and pore development relative to the pristine biochars, while also promoting the formation of Fe₂O₃ phases on the activated biochars surfaces. The activated biochars exhibited comparable adsorption capacities of 39.44 and 37.16 mg·g⁻¹ for CAC-600 and LAC-600, respectively, indicating that adsorption performance was governed mainly by the activation process rather than by the precursor biomass. Isotherm and kinetic models revealed heterogeneous adsorption behavior involving surface interactions combined with internal diffusion. The materials showed stable adsorption performance within a pH range of 4–10. Competitive adsorption experiments demonstrated preferential adsorption of AB74 over Acid Red 1 (AR1), confirming the selectivity of LAC-600 and CAC-600. Density Functional Theory (DFT) calculations revealed a cooperative adsorption mechanism combining π-surface interactions with localized Fe-oxide anchoring sites on the graphene-based model, increasing the adsorption energy by approximately 24 kcal·mol⁻¹ relative to carbon-only systems. These findings demonstrate the potential of Fe-activated agro-industrial biochars as adsorbents for dye removal from aqueous media. Full article

This study evaluated how a lemon essential oil–rutin–chitosan coating (CS-LEO/NE-R), prepared from a 5:95 (v/v) lemon essential oil/rutin-containing nanoemulsion and a chitosan solution containing 1.5% chitosan, 1% acetic acid, and 5% glycerol, combined with controlled freezing-point storage preserves seasoned white snakehead fillets. Compared with controlled freezing-point storage alone, the combined treatment significantly inhibited oxidation, volatile nitrogen accumulation, texture softening, and microbial growth. On Day 10, the coating group recorded a total viable count of 4.98 log CFU/g, which was below the national limit (5 log CFU/g), whereas the control group went beyond this limit by Day 7. This extended the microbiological and physicochemical acceptability period by approximately 3 days under the present experimental conditions. Untargeted metabolomics revealed 2267 metabolites, and the differentially abundant ones mainly comprised amino acids, heterocyclic compounds, aldehydes, ketones, and esters. KEGG enrichment suggested that changes in linoleic acid metabolism, terpenoid related annotations, the actin cytoskeleton, and the phospholipase D signaling pathway were associated with delayed quality deterioration. This work provides a theoretical basis for the composite biopreservation of aquatic products. Full article

Lemon processing by-products are rich in flavonoids, limonoids, and phenolic acids, but their direct utilization is limited by glycoside-dominant flavonoid profiles, bitterness-associated limonoids, and insufficiently defined valorization strategies. This study compared eight food-relevant microorganisms, including lactic acid bacteria, Bacillus, yeast, and filamentous fungi, using a common aerobic submerged fermentation framework for lemon by-products. Rather than evaluating fermentation as a single uniform process, the study aimed to determine whether different microbial groups could redirect the same substrate toward distinct functional remodeling profiles. Targeted HPLC analysis of flavonoids, limonoids, and phenolic acids, together with DPPH and ABTS radical-scavenging assays, revealed clear strain-dependent differences in metabolite remodeling and antioxidant outcomes. L. plantarum showed the most consistent antioxidant enhancement profile, characterized by increased hesperetin and phenolic acid responses together with low DPPH and ABTS IC₅₀ values. L. pentosus promoted flavonoid remodeling but showed a more timing-sensitive antioxidant response. S. cerevisiae tended to preserve glycosylated flavonoids and showed a release-oriented phenolic acid profile with strong early ABTS activity. R. stolonifer exhibited the most pronounced limonoid remodeling, including marked limonin reduction and obacunone accumulation, suggesting potential relevance for bitterness-oriented applications. These findings demonstrate that different microorganisms can be functionally classified according to their dominant remodeling tendencies, including antioxidant enhancement, flavonoid conversion, glycosylated flavonoid preservation, phenolic acid release, and limonoid-associated debittering. This functional classification provides a practical basis for selecting microorganisms according to the intended application of lemon by-product valorization. Full article

A comprehensive assessment of the effect of different light spectra on the growth, development, and nutritional composition of Mentha longifolia L. cv. “Vesenniy Aromat” (mint) and Melissa officinalis L. cv. “Limonnyy Aromat” (lemon balm) grown in hydroponic conditions in closed artificial agroecosystems was conducted. The growing period was 75 days for mint and 87 days for lemon balm. The photon flux density (PFD) in the range of 400–800 nm was ~140 µmol·m⁻²·s⁻¹, and the light period was 16 h. Five lighting options and four spectral color ratios were used in the treatments—blue (B), green (G), red (R), and far red (FR), and 3:66:27:4 (HPL (control)); 16:42:39:3 (White LED); 96:3:1:0 (Blue LED); 1:1:98:0 (Red LED) and 25:3:72:0 (Red + Blue LEDs)—in a growth chamber for cultivation with controlled environmental conditions. Under White LED, M. longifolia L. plants were compact, with a large number of leaves and high plant biomass. The effect of Red + Blue LEDs had a general trend for M. longifolia L. and M. officinalis L. in terms of improving plant morphology (leaf area, number of leaves, and plant biomass), elemental composition (contents of potassium, magnesium, calcium, and phosphorus) and reducing the accumulation of nitrates in the plants. Blue spectrum lighting significantly affected the content of leaf pigments, quercetin, rosmarinic acid, and essential oils of mint and lemon balm. Red spectrum lighting significantly reduced the accumulation of nitrates in the vegetative mass of plants. Precise regulation of metabolic processes, taking into account the spectral quality of light, can contribute to improving the economic efficiency of the growth, development, and productive potential of mint and lemon balm grown under controlled conditions. Full article

Aloysia triphylla (lemon verbena, LV) herbal tea is a rich source of phenolic compounds with recognized antioxidant and antiglycoxidant properties, although their stability during digestion remains insufficiently understood. This study evaluated the impact of simulated gastrointestinal digestion on the phenolic composition and bioactivity of LV infusion using a standardized in vitro model. Total phenolic, flavonoid, and phenolic acid contents were determined spectrophotometrically, while individual compounds were analyzed by HPLC. Antioxidant activity was assessed using complementary assays (DPPH•, ABTS•, FRAP, ORAC, and nitric oxide scavenging), and antiglycation activity was evaluated using a BSA/D-ribose model. Digestion did not significantly affect total phenolic and phenolic acid contents, whereas flavonoids moderately decreased during the intestinal phase. Verbascoside underwent partial degradation, leading to increased levels of isoverbascoside and caffeic acid. Despite these transformations, antioxidant capacity was maintained or enhanced, particularly in ABTS and ORAC assays, suggesting a contribution of digestion-derived metabolites. Antiglycation activity remained stable after digestion. Pre-column HPLC analyses identified verbascoside and its derivatives as the main contributors to radical scavenging and methylglyoxal trapping activities. These findings indicate that LV infusion retains its bioactive potential after digestion and supports its relevance as a functional beverage. Full article

Heat stress (HS) alters rumen function and may compromise fermentation efficiency in dairy cows. This in vitro study evaluated the effects of six additives—betaine, sodium bicarbonate, bentonite clay, protected fat, Saccharomyces cerevisiae yeast, and Melissa officinalis (lemon balm)—on ruminal fermentation under increasing incubation temperatures (39.0 °C, 40.5 °C, 41.5 °C). This study was designed as an initial in vitro screening approach aimed at evaluating additive resilience under a conservative, worst-case thermal challenge. The highest incubation temperature (41.5 °C) was not used to reproduce the exact physiological rumen environment but rather served to identify additives capable of maintaining fermentation when exposed to extreme conditions that may occur during severe heat load. These results therefore constitute a preliminary step before in vivo validation under realistic HS scenarios. Fermentation was assessed after 24 h by measuring gas production, pH, redox potential, volatile fatty acids (VFAs), and ammonia (NH₃) and performing protozoa counts. Temperature alone produced limited effects in the control, with numerical increases in gas, acetate, total VFAs, and NH₃ at 41.5 °C. Betaine and yeast maintained overall stable fermentation across all temperatures, preserving gas production, pH, redox potential, and VFA profiles. Sodium bicarbonate increased the pH but reduced gas production. Lemon balm enhanced VFAs and propionate at 39.0 °C but showed reduced activity at high temperature. Protected fat and bentonite clay resulted in lower gas production with minimal influence on other parameters. The protozoa counts were not affected by temperature and showed statistically detectable differences among additives. Overall, betaine and yeast exhibited the highest thermal stability and appear to be suitable candidates for inclusion in feeding strategies aimed at supporting rumen fermentation during periods of HS. Full article

Due to the complex pathophysiology and serious outcomes of autoimmune myocarditis, we sought to determine whether ethanolic lemon balm extract (LBE) could attenuate disease progression and development of dilative cardiomyopathy (DCM). EAM was induced in Dark Agouti rats by immunization with porcine myosin. Fifty animals were allocated to five groups: healthy controls, untreated EAM, and EAM treated with LBE (50, 100, or 200 mg/kg) for six weeks. Hemodynamic parameters were monitored, and echocardiography assessed cardiac structure and function. Inflammatory, oxidative, fibrotic, and apoptotic markers were analyzed. Immunological profiling revealed that LBE significantly decreased proinflammatory cytokines (IL-1, IL-6, TNF-α, IL-4, IL-17) while restoring anti-inflammatory IL-10 levels (p < 0.05). Antioxidant activity was confirmed by reduced levels of O₂⁻, H₂O₂, and TBARS, accompanied by significant increases in SOD, CAT, and GSH activity (p < 0.05), and upregulation of SOD1 and SOD2 gene expression. Additionally, LBE (200 mg/kg) markedly reversed fibrotic remodeling through suppression of TGF-β expression and collagen deposition, as shown by Sirius Red staining, and mitigated apoptosis by modulating Bax/Bcl-2 balance and reducing TUNEL-positive cells. Collectively, these findings suggest that LBE exerts strong cardioprotective effects in EAM by regulating inflammatory, oxidative, fibrotic, and apoptotic pathways, thereby preventing myocarditis progression toward DCM. Full article

The high consumption of citrus fruits generates large amounts of peel bioresidues, whose valorization represents an important strategy for sustainable agri-food systems. This study aimed to characterize the nutritional, chemical, and bioactive properties of flours obtained from orange (FL), tangerine (FT), lime (FLA), and lemon (FLO) peels, and to evaluate their potential as functional food ingredients. The flours were evaluated for proximate composition, organic acids, phenolic compounds, fatty acids, free sugars, and bioactive properties. Lime flour showed the highest protein, ash, dietary fiber, and total phenolic contents, with hesperidin identified as the predominant compound. The corresponding extracts exhibited relevant antioxidant, antimicrobial, antiproliferative, and nitric oxide (NO) production inhibitory activities, with lime flour presenting the strongest overall bioactive potential. Based on these results, lime flour was selected for application in a food model by partially replacing wheat flour (10% and 20%) in “Madalenas”, a traditional Portuguese muffin cake. The incorporation of lime flour improved product preservation compared with the control formulation and samples containing a synthetic preservative (potassium sorbate). These findings highlight the potential of citrus peel flours, particularly lime flour, as natural functional ingredients and sustainable alternatives for food formulations, contributing to waste valorization and circular economy approaches in the agri-food sector. Full article

The aroma of lemon is an important indicator of its quality, but there is still a lack of comparative research on the flavor components of different varieties of lemon and the interaction between olfactory receptors. This study conducted a combined analysis of volatile components in the peel and flesh of six varieties of lemons using GC-MS and GC-IMS. The random forest algorithm in machine learning was used to screen differential metabolites and perform molecular docking with all 389 olfactory receptors to analyze their potential interaction relationships. Hydrophobic interactions and hydrogen bonds are the most common interactions between odor molecules and olfactory receptors, and amino acids such as PHE, TYR, ASN, and HIS have the highest frequency of interaction. These findings offer crucial insights into the molecular mechanisms underlying lemon flavor. They also furnish a theoretical foundation for enhancing and utilizing lemon flavor quality. Full article