This study investigated the effects of roasting temperature (130 degrees C, 150 degrees C, 180 degrees C) and grinding fineness (10, 50, and 100 mesh) on the nutritional quality and physicochemical properties of high-resistant starch rice flour (Youtangdao 3). The results revealed that the process of whole-grain moist roasting, followed by milling and sieving, markedly enhanced the resistant starch (RS) content while concurrently reducing the fraction of rapidly digestible starch (RDS). Specifically, roasting at 130 degrees C with coarse grinding (R130-10) yielded the highest absolute RS content (27.45 g/100 g). However, for fine-particle fractions essential for food texture, roasting at 150 degrees C (R150-100) proved optimal by achieving the highest RS proportion within the starch matrix (89.36% by Englyst method). Structural analysis via X-ray diffraction (XRD) and scanning electron microscopy (SEM) revealed that roasting facilitated the reorganization of starch chains. This molecular rearrangement led to a pronounced increase in crystallinity and induced distinct morphological alterations within the granules. Furthermore, Rapid Visco Analyzer (RVA) profiling indicated a substantial decline in peak viscosity for all roasted samples, indicating a significant loss of pasting ability and an increase in structural rigidity. In conclusion, the combination of moderate roasting temperature and precise particle size control effectively optimizes the nutritional value of high-RS rice flour. These insights provide a theoretical basis for developing high-RS rice flour ingredients.
Olive leaf extract (OLE) contains polyphenolic compounds with reported antioxidant and antimicrobial activities. In this study, OLE obtained by Naviglio extraction was incorporated into zirconia-based sol-gel hybrids at theoretical contents of 8, 25, 33, and 50 wt%. Colorimetric analysis showed that OLE acted as a natural coloring agent, producing composition-dependent changes from yellow to orange-brown tones. FT-IR spectra retained the characteristic bands of the zirconia-based matrix together with OLE-related contributions, while shifts in the O-H and Zr-O regions indicated changes in the local chemical environment after incorporation. Thermal analysis showed a progressive increase in the onset temperature of the main degradation stage, from 296.2 degrees C for bare ZrO2 to 320.4 degrees C for ZrO2/OLE50%, suggesting a stabilizing effect of OLE within the hybrid matrix. Release experiments in 95% (v/v) ethanol showed a clear dependence on OLE content. ZrO2/OLE8% released almost completely within 5-6 h, whereas ZrO2/OLE25% showed an initial burst followed by slower release, reaching 75-80% after 24 h. ZrO2/OLE33% and ZrO2/OLE50% showed slower release without a clear burst phase and released less than 30%. Agar-diffusion tests showed no enhancement of antibacterial activity against Escherichia coli or Enterococcus faecalis. These preliminary findings provide a basis for further investigation into the valorization of olive leaf extract as a natural component for the development of colored functional hybrid materials.
(1) Background: The mitochondrial permeability transition pore (mPTP) contributes to mitochondrial dysfunction under pathological conditions. Cyclophilin D (CypD), a key regulator of sustained mPTP opening, represents an important molecular target. However, systematic strategies for selecting an appropriate CypD crystal structure for virtual screening and efficiently identifying CypD-binding natural polyphenols remain limited. (2) Methods: Six CypD crystal structures were evaluated by receiver operating characteristic analysis using reported CypD inhibitors and approximately 4000 decoys. The optimal receptor structure was subsequently used to screen 484 dietary polyphenols by molecular docking. Selected top-ranked candidates were further characterized by 15N-1H HSQC NMR titration and surface plasmon resonance (SPR). (3) Results: PDB 6R8L exhibited the best virtual-screening performance, particularly in early enrichment. Several polyphenol glucuronides ranked among the top candidates. NMR analysis showed that apigenin 7-glucuronide and luteolin 7-glucuronide induced pronounced chemical shift perturbations at CypD residues F60, M61, I117, and W121, with F60, M61, and W121 located within or near the docking-predicted S1 binding region. SPR independently confirmed direct binding, yielding KD values of 66 mu M and 84 mu M for apigenin 7-glucuronide and luteolin 7-glucuronide, respectively. (4) Conclusions: Integrating systematic receptor evaluation, molecular docking, and complementary NMR and SPR characterization provides a practical workflow for identifying and characterizing natural CypD-binding compounds. Apigenin 7-glucuronide and luteolin 7-glucuronide were identified as micromolar CypD-binding candidates, highlighting polyphenol glucuronides as a chemical class warranting further investigation in CypD ligand discovery.
A nonionic type V deep eutectic solvent (DES) combining hydrophobic (-)-menthol and hydrophilic resorcinol was prepared and investigated as a solvent for amphiphilic caffeine. Differential scanning calorimetry and thermogravimetric analysis were first used to determine the eutectic composition and characterize its thermal behavior. The menthol-to-resorcinol molar ratio of 2:1 was subsequently selected for physicochemical investigation. Clear homogeneous solutions containing up to 0.701 mol & centerdot;kg-1 caffeine were prepared, corresponding to 136 g of caffeine per kilogram of DES. Density, speed of sound, and viscosity were measured over the temperature range from 293.15 to 313.15 K. These data were used to evaluate the thermal expansion, volumetric and acoustic properties, intermolecular free length, and concentration and temperature dependences of viscous flow. The viscosity results were further analyzed using the Arrhenius, Jones-Dole, and Eyring-Feakins approaches and compared with the behavior of caffeine in water, ethylene glycol, and methyl salicylate. DFT calculations and molecular electrostatic potential surfaces were used to examine the local organization of the DES and the possible incorporation of caffeine through interactions with both its polar and less-polar regions. The combined experimental and computational approach provides a molecular and thermodynamic basis for evaluating this DES as a caffeine-solubilizing and delivery medium.
Humic acids (HAs) represent structurally heterogeneous supramolecular systems whose characterization by CP/MAS 13C NMR spectroscopy strongly depends on experimental conditions. Among these, contact time is one of the most important parameters controlling the efficiency of polarization transfer and the relative contribution of individual carbon groups. The aim of this study was to evaluate the influence of contact time on the apparent CP/MAS 13C NMR signal distribution of HAs isolated from different horizons of a permafrost peat soil (Hemic Folic Cryic Histosol) and to characterize their cross-polarization dynamics using kinetic modeling. A series of CP/MAS 13C NMR spectra was acquired at contact times ranging from 0.01 to 10 ms. Signal intensities of major structural groups were analyzed using both the classical three-parameter model and an extended four-parameter model of cross-polarization dynamics. The results demonstrated pronounced contact-time-dependent variations in the apparent CP/MAS signal distribution among alkyl, aryl, and carboxyl/amide structural domains. Short contact times preferentially enhanced proton-rich aliphatic and carbohydrate structures, whereas longer contact times increased the relative contribution of aromatic and carboxyl/amide fragments. The extended model provided a better fit for selected structurally heterogeneous spectral regions, particularly aromatic and heteroatom-containing domains, whereas the classical model adequately described the relatively homogeneous aliphatic regions. The fitted CP-dynamic parameters provided effective comparative descriptors of the investigated HAs under the experimental conditions employed and demonstrated consistent depth-dependent differences within the investigated peat profile. These depth-dependent differences may reflect changes associated with peat accumulation and long-term cryogenic preservation; however, this interpretation requires confirmation using independently replicated peat profiles.
