The effects of storage methods and glycerol on the aging of breadcrumbs were studied using solid-state (13)C CP/MAS NMR. After baking, a shift in C(1) peaks from triplet (A-type) to singlet (V-type) was observed. Addition of glycerol reduced the carbon peak intensities of fresh and aged breads, which correlated well with the DSC amylopectin "melting" enthalpy (r(2) = 0.91). Upon storage of bread with crust in hermetically sealed containers (when moisture migrated from the crumbs to the crust), the (13)C CP/MAS NMR peak intensity increased more rapidly during aging than when the bread was stored without crust. Although addition of glycerol retarded the starch retrogradation, as observed by (13)C CP/MAS NMR and DSC, it accelerated the firming rate. Therefore, bread firming in this case was controlled not only by starch retrogradation but also by other events (such as local dehydration of the matrix or gluten network stiffening).
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Chem Asian J
January 2025
Qingdao University of Science and Technology, College of Polymer Science and Engineering, 53 ZHENGZHOU ROAD, 266000, Qingdao, CHINA.
Constructing highly conjugated three-dimensional covalent organic frameworks (3D COFs), particularly those with luminescent features, remains a significant challenge. In this work, we successfully synthesized a 3D COF, named 3D-Py-SP-COF, using a rigid and orthogonal spirobifluorene building block for the spatial 3D structure construction and planar pyrene as luminescent units. The incorporation of the pyrene and the unique rigid 3D network structure endow 3D-Py-SP-COF with fluorescent properties.
View Article and Find Full Text PDFPolymers (Basel)
December 2024
Institute of Chemistry, Federal University of Uberlândia, Uberlândia 38400-902, Brazil.
Cellulose tosylate (MCC-Tos) is a key derivative for surface modification and a crucial precursor for cellulose compatibilization in click reactions, enabling its functionalization for advanced applications. Replacing tosyl groups with alkyne groups broadens cellulose's potential in biocompatible reactions, such as thiol-yne click chemistry and protein/enzyme immobilization. To achieve this, we optimized the heterogeneous synthesis of MCC-Tos using a Doehlert matrix statistical design, evaluating the influence and interaction of the reaction conditions.
View Article and Find Full Text PDFJ Magn Reson
December 2024
Oral Product Development, Pharmaceutical Technology & Development, Operations, AstraZeneca, Gothenburg, Sweden.
A new 3.2 mm H-F-X magic angle spinning dynamic nuclear polarization NMR (MAS DNP-NMR) probe was developed with a unique coil design with separate radiofrequency channels for H excitation and C or F detection to enable acquisition of H-F cross-polarization (CP) MAS experiments, direct-detected F spectra with proton decoupling, and acquisition on C with simultaneous double decoupling on the H and 19F channels as well as H-F-C double-CP experiments under low temperature MAS DNP conditions. We use these sequences to study AZD2811, which is an active pharmaceutical ingredient (API), in its pure dry state as well as in its corresponding drug delivery formulation consisting of drug-loaded polymeric nanoparticles (PNPs).
View Article and Find Full Text PDFJ Sep Sci
December 2024
Institute of Pharmaceutical Sciences, Pharmaceutical (Bio-)Analysis, University of Tübingen, Tübingen, Germany.
The present work reports on the preparation, characterization, and evaluation of a set of novel triphenyl-modified silica-based stationary phases without and with embedded ion-exchange sites for mixed-mode liquid chromatography. The three synthesized triphenyl phases differed in additionally incorporated ion-exchange sites. In one embodiment, allyltriphenylsilane was bonded to thiol-modified silica by thiol-ene click reaction, leading to particles with no ion-exchange sites.
View Article and Find Full Text PDFFood Chem
December 2024
Institute of Agro-Product Processing, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, PR China; School of Food and Biological Engineering, Jiangsu University, Zhenjiang, 212013, PR China. Electronic address:
Mung bean hull polyphenols (MBPs) have the potential to retard starch digestion by altering its multi-scale structures. However, the regulatory mechanism and the key structural characteristics that contribute to digestion resistance remain unclear. In this study, MBPs were non-covalently interacted with wheat starch (WS) under hydrothermal treatments.
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