Search Results (130)

Interest in non-centrosymmetric crystalline materials exhibiting second harmonic generation (SHG) has increased due to their potential applications in optical sensing and biosensing. Saccharide-based metal complexes are particularly attractive systems, as chiral sugars can promote non-centrosymmetric crystal packing. In this work, a new lanthanum–β-d-fructose compound, [La(C₆H₁₂O₆)(H₂O)₅]Cl₃ (LaFRUCl), was synthesized using a simple and low-cost method and characterized by single-crystal X-ray diffraction. The compound crystallizes in the orthorhombic space group P2₁2₁2₁ and consists of infinite (La³⁺–fructose)_n chains extending along the [001] direction, forming a one-dimensional Metal–Organic Framework. The nonlinear optical response was evaluated using the Kurtz–Perry powder technique with a Nd:YAG laser (1064 nm) and compared to a sucrose reference. The measured SHG efficiency is comparable to that of previously reported alkaline earth metal–sugar analogs. While the compound’s SHG emission is significant, evaluation of its structural stability under aqueous or physiological conditions is be required before considering biological applications. Full article

Microfibrillated cellulose (MFC) derived from wood sources is a biodegradable and eco-friendly reinforcing material for polymer composites. However, the high polarity of MFC is a challenge in homogeneous distribution into the hydrophobic PLA matrix, which limits its reinforcing efficiency. In this study, lignin-containing MFC (LMFC) with different residual lignin contents was prepared to investigate its dispersion behavior and reinforcing effect in polylactic acid (PLA). The aspect ratio and neutral sugar composition of LMFC remained similar regardless of lignin content, whereas the dispersion degree in PLA, quantified using a log-normal distribution model, increased from 24.2% to 35.1% with increasing lignin content. Mechanical testing showed that LMFC incorporation enhanced tensile strength and elastic modulus while reducing elongation at break. Higher residual lignin content in LMFC positively affected the tensile strength of the LMFC–PLA composites. Dynamic mechanical analysis revealed an increase in storage modulus and a decrease in loss factor with higher lignin content and LMFC loading (1–10 wt%), indicating enhanced interfacial interactions. Differential scanning calorimetry showed reductions in glass transition temperature (5–8 °C) and cold crystallization temperature (8–16 °C) compared to neat PLA. These findings indicate that residual lignin in LMFC enhances dispersion and interfacial interactions in PLA, leading to improved mechanical and thermal performance and highlighting its potential as an effective reinforcing component in sustainable biocomposites. Full article

This study aimed to investigate the flavor quality and starch physicochemical properties of three orange-fleshed sweet potato varieties commonly cultivated in northeastern China. Fresh and baked samples were evaluated using sensory analysis, electronic nose and tongue, gas chromatography-mass spectrometry for volatile compound profiling, and chemical methods for starch characterization. Liankaoshu 1 exhibited the highest sensory score (88.6), reflecting superior taste and aroma. A total of 70 volatile organic compounds were identified, including β-damascenone, maltol, and β-ionone, as key contributors to baked flavor. Significant varietal differences were found in starch content, particle size, and crystalline structures, with Pushu 32 showing CA-type crystals, Yanshu 25 A-type, and Liankaoshu 1 B-type. Baking increased maltose and soluble sugar levels, which were strongly correlated with sensory attributes. Spearman correlation analysis revealed that sweetness and overall sensory scores were significantly and positively correlated with maltose, soluble sugar, and reducing sugar contents, as well as starch particle size parameters (p ≤ 0.05). These results indicate that starch structural characteristics and saccharification efficiency play critical roles in regulating flavor formation during baking, providing a theoretical basis for sweet potato breeding and processing optimization. Full article

Background: Paeonia lactiflora Pall. produces substantial quantities of nectar during the bud stage. In the production of cut flowers, this nectar attracts contaminants that compromise the quality of the flowers. The current practice of rinsing flowers with clean water escalates production costs. Consequently, reducing nectar secretion during the bud stage has emerged as a significant technical challenge for the industry. Nonetheless, insufficient fundamental knowledge concerning the structure of P. lactiflora nectaries and the physiology of nectar secretion impedes the development of pertinent regulatory technologies. Methods: This study established a “nectar secretion index” to evaluate nectar production in various P. lactiflora cultivars. Nectar sugar concentration and composition were measured using a refractometer and gas chromatography–mass spectrometry (GC-MS). Observations of changes in nectary epidermal morphology and anatomical structure during nectar secretion were conducted using scanning electron microscopy and light microscopy. Key Results: The quantity of nectar secreted by various P. lactiflora cultivars can differ. The indices were not significantly correlated with flowering period, flower color, or flower type. At the peak of nectar secretion, the sugar concentration of nectar secretion by different cultivars’ flower buds varied. Sucrose is the primary sugar component in this nectar. Nectar is secreted along the basal margins of the bracts and sepals on the abaxial surface of all cultivars. Specialized raised stomata are located on the upper epidermis, through which nectar is secreted. In contrast, the epidermal stomata located outside nectar-secreting areas exhibit a normal morphology. Specialized stomata do not secrete nectar concurrently. The stomatal aperture and the percentage of nectar-secreting stomata at the secretion sites are significantly higher in high-nectar-producing cultivars than in low-nectar-producing cultivars. Anatomical observations of bract nectaries indicate that, irrespective of nectar production levels, specialized stomata are consistently located adjacent to vascular bundles. During the initial stage of nectar secretion, no starch was detected in the bract nectaries. In contrast, the stomata in non-secretory epidermal cells of bracts maintain a normal morphology, and calcium oxalate crystals were observed within the subepidermal tissues. Throughout the nectar secretion process, the content of photosynthetic pigments and the Fv/Fm ratio in the bracts and sepals of various cultivars correlated with nectar secretion volume. Conclusions: This study, informed by observations of numerous P. lactiflora cultivars, elucidates the structural characteristics of its nectaries and the nectar secretion properties of various cultivars during the bud stage. It confirms that these nectaries are classified as extrafloral nectaries, specifically structural nectaries consisting of specialized raised stomata and closely associated vascular bundles beneath them. No significant differences in nectary structure or location were noted among cultivars with differing nectar yields. However, both the aperture of nectary stomata and the percentage of nectar-secreting stomata exhibited a significant positive correlation with secretion levels. The intrinsic photosynthetic potential at the nectary sites varies significantly among cultivars. The nectar is not derived from stored cellular starch but likely originates simultaneously from both photosynthesis and phloem transport. These findings provide a theoretical foundation for the development of subsequent regulatory technologies. Full article

D-Tagatose is a rare sugar of interest as a low-calorie sweetener, and enzymatic isomerization of D-galactose is a practical production route. L-arabinose isomerase (L-AI; EC 5.3.1.4) is a promising catalyst for the above process, but many characterized L-AIs perform best at alkaline pH and high temperature and often require substantial divalent metal supplementation (e.g., Mn²⁺/Co²⁺), which complicates food-grade processing. Lactic acid bacteria (LAB) are attractive sources of food-compatible enzymes, yet structural information for LAB-derived L-AIs has been limited. Here, we report the 2.6 Å X-ray crystal structure of L-AI from Latilactobacillus sakei 23K (LsAI) and define its oligomeric assembly. Although the asymmetric unit contains a single monomer, crystallographic symmetry reconstructs a D₃-symmetric homohexamer composed of two face-to-face trimers, consistent with a higher-order assembly in solution. Interface analysis shows predominantly polar interaction networks, and normalized B-factor mapping reveals localized flexibility near active-site-proximal regions. These findings provide a structural basis for understanding LAB-derived L-AIs and support structure-guided engineering toward food-grade, low-metal biocatalysts for rare-sugar production. Full article

Background: Saffron (Crocus sativus L.) corms, often discarded as agricultural by-products, are a promising and sustainable source of bioactive metabolites with potential therapeutic relevance. However, their anticancer potential remains largely underinvestigated. Objectives: This study aimed to compare the phytochemical composition of hydroethanolic extracts from fresh (HEEF) and stored (HEES) saffron corms and to evaluate their anticancer effectiveness against colorectal cancer cells. Methods: Phytochemical profiling was performed using HPLC-ESI-QTOF-MS/MS. Cytotoxicity against T84 and SW480 colorectal cancer cell lines was determined by the crystal violet assay. Apoptosis-related protein modulation was assessed by Western blotting. Additionally, molecular docking, molecular dynamics simulations, and MM/GBSA calculations were used to investigate ligand–target binding affinities and stability. Results: Both extracts contained diverse primary and secondary metabolites, including phenolic acids, flavonoids, triterpenoids, lignans, anthraquinones, carotenoids, sugars, and fatty acids. HEES showed higher relative abundance of key bioactive metabolites than HEEF, which was enriched mainly in primary metabolites. HEES showed significantly greater dose-dependent cytotoxicity, particularly against SW480 cells after 24 h (IC₅₀ = 34.85 ± 3.35). Apoptosis induction was confirmed through increased expression of caspase-9 and p53 in T84 cells. In silico studies revealed strong and stable interactions of major metabolites, especially 3,8-dihydroxy-1-methylanthraquinone-2-carboxylic acid with COX2 and crocetin with VEGFR2. Conclusions: Stored saffron corms possess a richer bioactive profile and show enhanced anticancer effects in vitro compared with fresh saffron corms, suggesting that they may represent a promising source of compounds for the future development of colorectal cancer therapeutics. Full article

In recent years, the World Health Organization has highlighted biofilm-derived multidrug-resistant bacteria as a critical threat to both global health and the environment. Although various testing methods are available, crystal violet and Congo Red methods are among the most frequently used methods for biofilm detection in the literature. However, inconsistent findings across studies have raised concerns. To address these issues and offer valuable insights for researchers in the field, this study used clinically relevant standard bacterial strains (ATCC or NCTC strains) to perform biofilm assays with both methods and compare the results. To investigate the effect of different sugar sources on biofilm formation, various sugar substrates were also examined using both biofilm methods under controlled culture conditions in this study. When the results were evaluated, significant differences were found between the two methods closely related to sugar content. Of the 22 strains tested, 17 (77%) showed different biofilm results in a sugar-free environment. Similar inconsistencies were also observed with glucose (32% of strains) and sucrose (50% of strains). With fructose, some strains (P. aeruginosa strains, E. faecalis ATCC 29212, K. pneumoniae High Level ESBL, K. pneumoniae BAA 1706, A. baumannii BAA 747) were negative with Congo Red and positive with crystal violet, while others (S. mutans ATCC 25175, E. coli NCTC 13846, E. coli ATCC 25922) gave the opposite results. Fructose caused inconsistencies in approximately 45% of strains. The highest agreement between the two methods (approximately 68%) was observed when glucose was used as the carbon source. Full article

Ice cream is a frozen aerated dessert composed of milk solids, sugars, stabilizers, and fat—with the latter being a key component in defining its structural and sensory properties. This study evaluated the influence of four fat sources—low-trans vegetable fat (T1), butter (T2), UHT cream (T3), and fresh cream (T4)—on the physical and structural characteristics of ice cream, including overrun, melting resistance, texture, color, and rheology, at different stages of processing (before and after maturation). Oscillatory rheological analysis revealed predominantly elastic behavior (G′ > G″) after maturation in all samples, indicating a stable viscoelastic solid structure. Formulations containing T3 and T1 showed the highest overrun values, indicating greater air incorporation, whereas the butter-based formulation (T2) showed the lowest overrun values. Melting resistance followed the following order: T3 > T4 > T2 > T1; therein, the UHT cream formulation exhibited the greatest thermal stability, which was likely due to protein denaturation and aggregation induced by high-temperature processing. Texture analysis showed that the T1 formulation required the lowest maximum extrusion force, while T2 required the highest, reflecting an inverse correlation with overrun values. T1 also displayed the most distinct rheological profile, which was likely due to its specific crystallization behavior and reduced destabilization of the fat globule membrane—which favored the development of a more structured internal network. These findings demonstrate that both the source and processing of fat have a significant impact on the formation of the structural matrix and the final functional properties of ice cream. The results offer technical insights for the development of formulations tailored to specific physical characteristics, optimizing texture, stability, and performance throughout the production process. Full article

Ice nucleation temperatures and associated ice growth rates are critical parameters in defining the initial ice morphology template, which governs dry layer resistance during sublimation and therefore impacts primary drying kinetics and overall process time. In this study, we developed a through-vial impedance spectroscopy (TVIS) method to determine both ice nucleation temperature and average ice growth rate, from which future estimation of average ice crystal size may be possible. Whereas previous TVIS applications were limited to solutions containing simple, uncharged solutes such as sugars, our adapted approach enables the analysis of conductive solutions (5% sucrose with 0%, 0.26%, and 0.55% NaCl), covering osmolarities below and above isotonicity. We established that the real part capacitance at low and high frequencies—either side of the dielectric relaxation of ice—provides the following: (i) a temperature-sensitive parameter for detecting the onset of ice formation, and (ii) a temperature-insensitive parameter for determining the end of the ice growth phase (unaffected by temperature changes in the frozen solution). This expanded capability demonstrates the potential of TVIS as a process analytical technology (PAT) for non-invasive, in situ monitoring of freezing dynamics in pharmaceutical freeze-drying. Full article

Second-harmonic generation microscopy is applied to mesquite honey samples with different fructose adulteration concentrations. As a proof of principle, mesquite honey is selected for this test, as it has a monofloral and spreadable-like-butter consistency, besides its economic relevance in the central region of Mexico. Second-harmonic generation microscopy is an optical method that images microstructures, such as sugar crystals in bee honey, without the interference of the liquid phase. Each recorded image is spectrally registered using the photomultiplier detector of the microscope, resulting in several gray-level histograms that are numerically analyzed using signal and image processing techniques. Several samples are prepared, adulterated, and analyzed for this purpose. The inspection requires only a microscopic amount of honey, making it a suitable technique for rare and exotic honey samples that are harvested in limited quantities. The analysis of the experimental results reveals that the second-harmonic generation microscopy signal is sensitive to liquid fructose adulteration in honey, with its signal decreasing as the amount of added fructose increases. Full article

The paper presents a study of changes in selected physicochemical properties of honeys during their refrigerated storage at 8 ± 1 °C for 24 weeks. On the basis of the study of primary pollen, the botanical identification of the variety of honeys was made—rapeseed, multiflower and buckwheat honey. The samples were stored for 24 weeks in dark, hermetically sealed glass containers in a refrigerated chamber (8 ± 1 °C, 73 ± 2% relative humidity). The comprehensive suite of analyses comprised sugar profiling (ion chromatography), moisture content determination (refractometry), pH and acidity measurement (titration), electrical conductivity, color assessment in the CIELab system (ΔE and BI indices), texture parameters (penetration testing), rheological properties (rheometry), and microscopic evaluation of crystal morphology; all data were subjected to statistical treatment (ANOVA, Tukey’s test, Pearson correlations). The changes in these parameters were examined at 1, 2, 3, 6, 12, and 24 weeks of storage. A slight but significant increase in moisture content was observed (most pronounced in rapeseed honey), while all parameters remained within the prescribed limits and showed no signs of fermentation. The honeys’ color became markedly lighter. Already in the first weeks of storage, an increase in the L* value and elevated ΔE indices were recorded. The crystallization process proceeded in two distinct phases—initial nucleation (occurring fastest in rapeseed honey) followed by the formation of crystal agglomerates—which resulted in rising hardness and cohesion up to weeks 6–12, after which these metrics gradually declined; simultaneously, a rheological shift was noted, with viscosity increasing and the flow behavior changing from Newtonian to pseudoplastic, especially in rapeseed honey. Studies show that refrigerated storage accelerates honey crystallization, as lower temperatures promote the formation of glucose crystals. This accelerated crystallization may have practical applications in the production of creamed honey, where controlled crystal formation is essential for achieving a smooth, spreadable texture. Full article

Fresh-cut potato slices are prone to browning. Although freezing is an effective method of preserving food, freezing and thawing cause inevitable damage to potato tissues. This study explored the freeze-protective effects of trehalose and sorbitol under atmospheric pressure impregnation and vacuum impregnation by analyzing their influences on the cell structural and textural characteristics of frozen–thawed potato slices. The results showed that both trehalose and sorbitol can significantly improve the quality of frozen–thawed potato slices. Vacuum impregnation resulted in a higher total sugar content in the impregnated potato slices than atmospheric pressure impregnation (p < 0.05). Sorbitol impregnation significantly reduced cell damage and nutrient loss of frozen–thawed potato slices; specifically, under vacuum impregnation conditions, the juice loss rate and relative electrical conductivity decreased to 7.58 ± 0.47% and 32.90 ± 1.83 mS/cm, respectively. Texture analysis showed that sorbitol impregnation resulted in significantly higher puncture hardness and TPA hardness in frozen–thawed potato slices than trehalose impregnation. Furthermore, observations of cell activity and transmission electron microscopy of potato tissues verified sorbitol’s advantages in maintaining cell structure integrity and reducing ice crystal damage. Hence, sorbitol vacuum impregnation is highly recommended as a pretreatment in potato quick freezing processes. This study provides a theoretical basis and technical support for the improvement of the quality of quick-frozen potato products, and for the later processing and manufacturing of frozen potato slices. Full article

Honey quality and authenticity are influenced by floral origin, processing, and storage, with implications for composition and sensory appeal. This study offers a comparative assessment of eight monofloral honey samples, representing five botanical varieties: acacia, linden, rapeseed, lavender, and thyme. For acacia, linden, and rapeseed, both producer-sourced and commercial honeys were analyzed, while lavender and thyme samples were available only from local beekeepers. The botanical origin of each sample was confirmed using morphological markers of pollen grains. Physicochemical characterization included acidity, pH, moisture content, refractive index, hydroxymethyl furfural (HMF), proline concentration, and carbohydrate profiling by HPLC-RID. Acacia honey exhibited the lowest acidity and HMF levels, alongside the highest fructose/glucose (F/G) ratios, indicating superior freshness, lower crystallization risk, and a sweeter flavor profile. In contrast, rapeseed honey showed elevated glucose levels and the lowest F/G ratio, confirming its tendency to crystallize rapidly. All samples recorded proline concentrations well above the quality threshold (180 mg/kg), supporting their authenticity and proper maturation. The estimated glycemic index (eGI) varied between 43.91 and 62.68 and was strongly inversely correlated with the F/G ratio (r = −0.98, p < 0.001). Sensory evaluation highlighted acacia honey from producers as the most appreciated across visual, tactile, and flavor attributes. Correlation analyses further revealed consistent links between sugar composition and both physical and sensory properties. Overall, the findings reinforce the value of integrated analytical and sensory profiling in assessing honey quality and authenticity. Full article

Sucrose is by far the most abundant disaccharide found in nature, consisting of two simple hexose units: d-glucose and d-fructose. This exceptionally inexpensive and widely accessible raw material is produced in virtually limitless quantities. The vast majority is consumed in the food industry either in its native form—as commercial table sugar—or, to a lesser extent, as the basis for artificial sweeteners such as palatinose and sucralose. Beyond its dietary use, sucrose serves as a feedstock for the production of bioethanol, liquid crystals, biodegradable surfactants, and polymers. However, the application of this valuable and extremely cheap raw material (100% optical purity and eight stereogenic centers with precisely defined stereochemistry) in the synthesis of more sophisticated products remains surprisingly limited. In this short review, we focus on the strategic use of the sucrose scaffold in the design and synthesis of fine chemicals. Special attention will be paid to macrocyclic derivatives incorporating the sucrose backbone. These water-soluble structures show promise as molecular receptors within biological environments, offering unique advantages in terms of solubility, biocompatibility, and stereochemical precision. Full article

Background: This study evaluated the polyphenolic composition, antibacterial activity, molecular docking interactions, and pharmacokinetic properties of Romanian oak and fir honeydew honeys. Methods: Spectrophotometric methods quantified total phenolic, flavonoid contents and antioxidant activity, and individual polyphenols were identified via HPLC-MS. Antibacterial efficacy against Gram-positive and Gram-negative bacteria was evaluated by determining the bacterial inhibition percentage and minimum inhibitory concentrations. The bioactive compounds identified via LC-MS analysis were used to further delineate the possible antibacterial activities in silico. Molecular docking was carried out to predict the binding interactions and complex formation of the identified compounds against protein crystal structures of the bacteria used in this study. Additionally, the pharmacokinetic profile of compounds with high inhibitory potential was assessed via ADMET (absorption, Distribution, Metabolism, Excretion, toxicity) predictors to ascertain their value. Results: Fir honeydew honey showed higher total phenolic (844.5 mg GAE/kg) and flavonoid contents (489.01 mg QUE/kg) compared to oak honeydew honey, correlating with more potent antioxidant activity (IC50 = 5.16 mg/mL). In vitro antimicrobial tests indicated a stronger inhibitory effect of fir honeydew honey, especially against Gram-positive strains like S. aureus, S. pyogenes, and L. monocytogenes, alongside certain Gram-negative strains such as E. coli and H. influenzae. Oak honeydew honey displayed selective antimicrobial action, particularly against P. aeruginosa and S. typhimurium. The docking outcomes showed rutin, rosmarinic acid, beta resorcylic acid, quercetin, ferulic acid, and p-coumaric acid have high inhibitory activities characterised by binding affinities and binding interactions against shiga toxin, riboflavin synthase, ATP-binding sugar transporter-like protein, undecaprenyl diphosphate synthase, putative lipoprotein, sortase A, and immunity protein, making them key contributors to the honey’s antimicrobial activity. Moreover, beta-resorcylic acid, quercetin, ferulic acid, and p-coumaric acid revealed interesting ADMET scores that qualify honey to serve as a good antimicrobial agent. Conclusions: These findings support their potential use as natural antibacterial agents and emphasise the value of integrating chemical, biological, and computational approaches for multidisciplinary characterisations. Full article