Design of Recyclable Carboxylic Metal-Organic Framework/Chitosan Aerogels for Oil Bleaching.

Novel hierarchical metal-organic framework/chitosan aerogel composites were developed for oil bleaching. UiO-66-COOH-type metal organic frameworks (Zr-MOFs) were synthesized and integrated onto a chitosan matrix with different contents and named MOF-aerogel-1 and MOF-aerogel-2. Due to the compatibility of chitosan, the carboxylic zirconium MOF-aerogels not only maintained the inherent chemical accessibility of UiO-66-COOH, but the unique crystallization and structural characteristics of these MOF nanoparticles were also preserved. Through 3-dimensional reconstructed images, aggregation of the UiO-66-COOH particles was observed in MOF-aerogel-1, while the MOF was homogeneously distributed on the surface of the chitosan lamellae in MOF-aerogel-2. All aerogels, with or without immobilized MOF nanoparticles, were capable of removing carotenoids during oil bleaching. MOF-aerogel-2 showed the most satisfying removal proportions of 26.6%, 36.5%, and 47.2% at 50 °C, 75 °C, and 100 °C, respectively, and its performance was very similar to that of commercial activated clay. The reuse performance of MOF-aerogel-2 was tested, and the results showed its exceptional sustainability for carotenoid removal. These findings suggested the effectiveness of the MOFaerogel for potential utilization in oil bleaching treatments.

Characterization and application in yogurt of genipin-crosslinked chitosan microcapsules encapsulating with Lactiplantibacillus plantarum DMDL 9010.

Microcapsules could improve the protection of probiotics in the lyophilization and gastrointestinal digestion process. The purpose of this study was to prepare Lactiplantibacillus plantarum DMDL 9010 (LP9010) microcapsules by cross-linking chitosan with genipin and to determine the encapsulation efficiency, morphological characterization, storage stability and the application of the microcapsules in fermentation. The results showed that the LP9010 microcapsules embedded in 1.00 wt% genipin cross-linked chitosan were in a uniform spherical shape with a smooth surface and satisfying agglomeration. The LP9010 microcapsules demonstrated the reasonable thermal stability and persistence of biological activity in the range of -20 °C to 25 °C. Additionally, yogurt obtained from the ST + LB + ELP9010 strain formulation with the addition of microencapsulated LP9010 had smaller particles, better taste, and better stability compared with the yogurt obtained from other strain formulations. As detected by GC-MS, the yogurt formulated with ST + LB + ELP9010 as a strain retained more flavor substances and the content of flavor substances was greater than that of the yogurt obtained from other strain formulations. Therefore, genipin cross-link chitosan could be a suitable microencapsulated material for producing yogurt fermentation strains.

High hydrostatic pressure (HHP) reinforces solid encapsulation of d-limonene into V-type starch and its application in strawberry storage.

The formation of inclusion complexes (ICs) between V-type starch and flavors is traditionally conducted in an aqueous system. In this study, limonene was solid encapsulated into V6-starch under ambient pressure (AP) and high hydrostatic pressure (HHP). The maximum loading capacity reached 639.0 mg/g after HHP treatment, and the highest encapsulation efficiency was 79.9 %. X-ray Diffraction (XRD) results showed that the ordered structure of V6-starch was ameliorated with limonene, which avoided the reduction of the space between adjacent helices within V6-starch generated by HHP treatment. Notably, HHP treatment may force molecular permeation of limonene from amorphous regions into inter-crystalline amorphous regions and crystalline regions as the Small-angle X-ray scattering (SAXS) patterns indicated, leading to better controlled-release behavior. Thermogravimetry analysis (TGA) revealed that the solid encapsulation of V-type starch improved the thermal stability of limonene. Further, the release kinetics study showed that a complex prepared with a mass ratio of 2:1 under HHP treatment sustainably released limonene over 96 h and exhibited a preferable antimicrobial effect, which could extend the shelf life of strawberries.

Amylose content and pre-freezing regulate the structure and oil absorption of polyelectrolytes-based starch cryogel.

Starch cryogel is a potential material for oil absorption. This study provided a facile and convenient polyelectrolyte-based preparation strategy of starch cryogel, in which the structural properties of the cryogel were regulated by amylose content and pre-freezing without long-time retrogradation. Sodium laurate was used as a guest model to form starch-fatty acid salt complex (polyelectrolyte). The amount of amylose content and sodium laurate added led more polyelectrolytes, significantly increased V-type crystallinity from 3.72 % to 22.40 % and complexing index from 4.32 % to 28.48 %. As the uniform pore structure improved the oil absorption ability of starch cryogel, the starch cryogel prepared by waxy maize starch followed by quick pre-freezing showed the highest specific surface area (9.87 m2/g) and oil absorption capacity (32.94 g/g). Our findings suggest that polyelectrolyte properties have great potential in the preparation of starch-based cryogels, which could be applied in the design of novel starch-based porous materials.

Structural, antioxidant, and immunomodulatory activities of an acidic exopolysaccharide from Lactiplantibacillus plantarum DMDL 9010.

This study investigated the structural, antioxidant, and immunomodulatory activities of acidic exopolysaccharide (EPS-LP2) isolated from Lactiplantibacillus plantarum DMDL 9010. EPS-LP2 is composed of fucose (Fuc), arabinose (Ara), galactose (Gal), glucose (Glc), mannose (Man), and D-fructose (Fru) with a molar ratio of 0.13: 0.69: 8.32: 27.57: 62.07: 0.58: 0.46, respectively. Structural analysis of EPS-LP2 exhibited a smooth irregular lamellar surface, rod-like structure with swollen ends and slippery surfaces, and good thermal stability. Based on the methylation and NMR analysis, sugar residues including t-Manp, t-Glcp, 2-Manp, 6-Galp, 6-Glcp, and 4-Glcp were found to exist in EPS-LP2. In the 50∼400 µg/ml range, EPS-LP2 showed negligible neurotoxicity to RAW264.7 cells. Moreover, EPS-LP2 could protect RAW264.7 cells from oxidative injury by lowering the generation of reactive oxygen species (ROS), malondialdehyde (MDA), and the secretion of lactate dehydrogenase (LDH). In contrast, an increase in superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and the concentrations of glutathione (GSH) were observed. Immunoreactivity assays showed that EPS-LP2 could suppress the expression of NO, tumor necrosis factor-α (TNF-α), and interleukin 6 (IL-6) and inhibit the activation of the mitogen-activated protein kinase (MAPK)/nuclear factor-κB-gene binding (NF-κB) cell pathway. Conclusively, EPS-LP2 could be a potential natural antioxidant and immunomodulatory agent in functional foods and medicines.

Lactiplantibacillus plantarum DMDL 9010 alleviates dextran sodium sulfate (DSS)-induced colitis and behavioral disorders by facilitating microbiota-gut-brain axis balance.

Previous studies have found that probiotic supplements can ameliorate mental behavioral disorders. This study investigated the effects of Lactiplantibacillus plantarum DMDL 9010 (LP9010) intake on the depression-like behavior induced by dextran sodium sulfate (DSS) and its possible mechanism. Male C57BL/6N mice were fed with DSS to establish the model of ulcerative colitis. LP9010 intake reduced the DSS-induced inflammatory response, and repaired intestinal barrier damage, as well as lightened depression-like behavior. LP9010 supplementation also inhibited neuroinflammation by up-regulating the levels of neurotransmitters, especially 5-HT, NE, DA, and 5-HIAA. Moreover, the intake of LP9010 reorganized the gut microbiome by increasing the relative abundance of Bacteroidetes and Firmicutes, and decreasing the relative abundance of Proteobacteria and Verrucomicrobia. Furthermore, treatment with LP9010 increased the levels of short-chain fatty acids, such as butyric acid and propionic acid. In conclusion, LP9010 intake was a promising probiotic intervention strategy for the prevention of colitis-induced behavioral disorders through the microbiota-gut-brain axis.

Amyloid Fibril Templated MOF Aerogels for Water Purification.

Design and fabrication of versatile adsorbents for universal water purification following green chemistry principles remain challenging. Here, it is shown that amyloid fibrils from protein waste can be used as a functional scaffold for metal organic framework (MOF) biomimetic mineralization. The resulting amyloid fibrils/ZIF-8 hybrid aerogels can effectively remove nine different heavy metal ions from water due to their hierarchical porous structure. Importantly, amyloid fibrils/ZIF-8 hybrid aerogels can efficiently remove Hg2+ and Pb2+ from water over five consecutive adsorption-regeneration cycles. Furthermore, a dual removal pathway of adsorption and catalytic degradation is observed in the synthetic dyes, indicating that the aerogel preserves its porous nature and maintains the integrity of versatile functional ligands within ZIF-8. Finally, it is shown that these hybrid aerogels can also perform successfully in oil-water separation. Considering the facile synthesis procedure, high removal efficiency, affordable cost, and regeneration possibilities, the amyloid fibrils/ZIF-8 hybrid aerogel stands as an ideal candidate for addressing open challenges in wastewater treatment and water purification.

Immobilization of chitosan grafted carboxylic Zr-MOF to porous starch for sulfanilamide adsorption.

A novel hierarchical porous starch-chitosan-UiO-66-COOH composite for the treatment of pharmaceutical-bearing sewage was developed. UiO-66-COOH-type carboxylic zirconium metal organic framework (Zr-MOF) was synthesized and immobilized within porous starch through a facile chitosan-adhesive strategy. The porous starch offered a stable macro-porous structural skeleton to accommodate the UiO-66-COOH nanoparticles, and chitosan played the role of an affinity agent to strengthen the decoration effect via electrostatic interaction and hydrogen bonding with carboxylic Zr-MOF particles and porous starch, respectively. The carboxylic Zr-MOF composite not only preserved the intrinsic accessibility of UiO-66-COOH but also maintained unique crystallization and thermal properties. The adsorption of sulfanilamide into the porous starch-chitosan-UiO-66-COOH composite conformed to pseudo-second-order kinetic and Langmuir isothermic models, demonstrating that adsorptions could be considered as homogeneous monolayer chemisorption. The Zr-O group within the carboxylic Zr-MOF composite displayed high affinity for sulfanilamide and possibly played a crucial role in sulfanilamide adsorption.

Insight into the formation, structure and digestibility of lotus seed amylose-fatty acid complexes prepared by high hydrostatic pressure.

Lotus seed amylose-fatty acid complexes were prepared using high hydrostatic pressure and the relationship between their structural properties and digestibility was investigated. The formation of lotus seed amylose-fatty acid complexes increased the values of weight molar mass (Mw), number molar mass (Mn), polydispersity index and resistant starch content compared to those of amylose controls. Mw and Mn values of lotus seed amylose and complexes decreased with an increase in high hydrostatic pressure from 500 MPa to 600 MPa, suggesting that the lotus seed amylose was decomposed into short glucan chains. The presence of single helical lotus seed amylose-fatty acid complexes and double helical retrograded amylose was investigated using Raman spectroscopy and imaging. The results from Raman spectra and in vitro digestion showed that the content of both single helical LSA-fatty acid complexes and double helical retrograded LSA were responsible for digestibility of the complex matrix.

Understanding the crystal structure of lotus seed amylose-long-chain fatty acid complexes prepared by high hydrostatic pressure.

This paper presents an innovative approach using high hydrostatic pressure to prepare lotus seed amylose-long-chain fatty acid (stearic acid, oleic acid, and linoleic acid) complexes. The aim of this work was to investigate the spherocrystal structure and distribution of fatty acid within complexes. Wide-angle X-ray diffraction diffractograms indicated the presence of typical V6-type polymorphs and B-type non-complexed amylose. The V6-type complexes were further confirmed as V6III polymorph from nuclear magnetic resonance. The degree of crystallinity and the complex index value decreased as the preparation pressure of the complexes increased, and the amylose-oleic acid complexes exhibited the highest relative crystallinity and complex index value in all of the conditions. Small-angle X-ray scattering indicated a larger proportion of crystalline and more compact structure within complexes than that of lotus seed amylose. The morphology of complexes with the spherulite form was determined from scanning electron microscopy images, and the distribution of fatty acid molecules within the spherulites of complexes was estimated using nuclear magnetic resonance, confocal laser scanning microscopy, and small-angle X-ray scattering. The results demonstrated that the fatty acids were within and between the amylose helix, and they were also trapped inside the amorphous lamellae of the complexes. This work provides an in-depth study of the spherocrystal structure within lotus seed amylose-long-chain fatty acid complexes and proposes a new model for spherulites.

Structural and thermal properties of amylose-fatty acid complexes prepared via high hydrostatic pressure.

An innovative approach of high hydrostatic pressure was used to prepare lotus seed amylose-fatty acid complexes. The objective of this study was to investigate their structure and thermal properties. WAXD pattern of amylose changed from B-type to B- and V6-type hybrid polymorphs, and its relative crystallinity increased upon the addition of fatty acids. Carboxyl group observed by FTIR indicates the formation of complexes. SAXS was performed to measure the lamellar structure of complexes. The complexes were more compact and had lower amounts of amorphous regions compared with amylose controls. Entrapped fatty acids, higher melting temperature, and enthalpy change of complexes but not of the controls were detected by DSC. The distribution of fatty acid molecules in the complex matrix was estimated through NMR. Under different pressures, the complexes exhibited dissimilar characteristics with the increase in aliphatic chain length, as observed by WAXD, FTIR, DSC and NMR.

Slowly digestible properties of lotus seed starch-glycerine monostearin complexes formed by high pressure homogenization.

Starch-lipid complexes were prepared using lotus seed starch (LS) and glycerin monostearate (GMS) via a high-pressure homogenization process, and the effect of high pressure homogenization (HPH) on the slow digestion properties of LS-GMS was investigated. The digestion profiles showed HPH treatment reduced the digestive rate of LS-GMS, and the extent of this change was dependent on homogenized pressure. Scanning electron microscopy displayed HPH treatment change the morphology of LS-GMS, with high pressure producing more compact block-shape structure to resist enzyme digestion. The results of Gel-permeation chromatography and Small-angle X-ray scattering revealed high homogenization pressure impacted molecular weight distribution and semi-crystalline region of complexes, resulting in the formation of new semi-crystalline with repeat unit distance of 16-18 nm and molecular weight distribution of 2.50-2.80 × 105 Da, which displayed strong enzymatic resistance. Differential scanning calorimeter results revealed new semi-crystalline lamellar may originate from type-II complexes that exhibited a high transition temperature.

C-type starches and their derivatives: structure and function.

The C-type starches are widely distributed in seeds or rhizomes of various legumes, medicinal plants, and crops. These carbohydrate polymers directly affect the application of starchy plant resources. The structural and crystal properties of starches are crucial parameters of starch granules, which significantly influence their physicochemical and mechanical properties. The unique crystal structure consisting of both A- and B-type polymorphs endows C-type starches with specific crystal adjustability. Furthermore, large proportions of resistant starches and slowly digestible starches are C-type starches, which contribute to benign glycemic response and proliferation of gut microflora. Here, we review the distribution of C-type starches in various plant sources, the structural models and crystal properties of C-type starches, and the behavior and functionality relevant to modified C-type starches. We outline recent advances, potential applications, and limitations of C-type starches in industry, aiming to provide a theoretical basis for further research and to broaden the prospects of its applications.