Linseed oil-in-water Pickering emulsions are stabilized by both sulfated CNCs (sCNCs) and octylamine-modified CNCs (oCNCs). oCNCs with hydrophobic moieties grafted on the surfaces of otherwise intact nanocrystals provided emulsions exhibiting stronger resistance to creaming of oil droplets, compared with unmodified sCNCs. sCNCs were not able to completely stabilize linseed oil in water at low CNC concentrations while oCNCs provided emulsions with no unemulsified oil residue at the same concentrations. Oil droplets in oCNC emulsions were smaller than those in samples stabilized by sCNCs, corresponding with an increased hydrophobicity of oCNCs. Cryo-SEM imaging of stabilized droplets demonstrated the formation of a CNC network at the oil–water interface, protecting the oil droplets from coalescence even after compaction under centrifugal force. These oil droplets, protected by a stabilized CNC network, were dispersed in a water-based commercial varnish, to generate a composite coating. Scratches made on these coatings self-healed as a result of the reaction of the linseed oil bled from the damaged droplets with oxygen. The leakage and drying of the linseed oil at the location of the scratches happened without intervention and was accelerated by the application of heat.

Elevated postprandial glucose (PPG) is a significant driver of non-communicable diseases globally. Carbohydrate-rich foods are a major determinant of PPG. Currently there is a limited understanding of how starch structure within a food-matrix interacts with the gut luminal environment to control PPG. We use pea seeds (Pisum sativum), as a model-food, to explore the contribution of starch structure, food-matrix and intestinal environment on PPG.Using stable isotope [ C] labelled seeds, coupled with synchronous gastric, duodenal and plasma sampling in vivo, we demonstrate that maintenance of cell structure and changes in starch morphology are closely related to lower glucose availability in the small intestine, resulting in acutely lower PPG and promoting changes in the gut bacterial composition associated with long term metabolic health improvements. This work offers huge potential to improve the design of food products targeted at moderating PPG and therefore lowering the risk of non-communicable diseases.

Polysaccharides from fermented carrot pulp (WSP-p) show better anti-diabetic effects than those from un-fermented carrot pulp (WSP-n), and functional properties of polysaccharides depend on their structure. In this study, both WSP-p and WSP-n were separated into three homogeneous fractions as WSP-p-1, WSP-p-2, WSP-p-3, WSP-n-1, WSP-n-2 and WSP-n-3.The weight-average molecular weight of all of fractions from WSP-p showed a downward trend compared with the corresponding fraction from WSP-n. The functional groups in WSPp and WSP-n were similar. The morphologies of WSP-p-2 and WSP-p-3 from SEM were similar to those of WSP-n-2 and WSP-n-3, but there were more fragmented particles adhered to WSP-n-1 than to WSP-p-1. Monosaccharide composition and methylation analysis confirmed that WSP-p-1, WSP-p-2, WSP-n-1 and WSP-n-2 were typical rhamnogalacturonan I-type polysaccharides with 1,4-linked -D-galacturonic acid residues, but WSP-p-3 and WSPn-3 contained predominantly homogalacturonan regions with 1,4-GalpA linkages. 1 H and 13 C NMR of fractions from WSP-p showed the similar spectra to those from WSP-n. These findings suggest that probiotic fermentation mainly cleaved the linkages between repeating units within polysaccharides during fermentation, and not only reduced their molecular weight but also improved the homogeneity in their molecular size distribution, which improves their biofunctions.

Bacterial cellulose (BC) consists of a complex threedimensional organization of ultrafine fibers which provide unique material properties such as softness, biocompatibility, and water-retention ability, of key importance for biomedical applications. However, there is a poor understanding of the molecular features modulating the macroscopic properties of BC gels. We have examined chemically pure BC hydrogels and composites with arabinoxylan (BC−AX), xyloglucan (BC−XG), and high molecular weight mixed-linkage glucan (BC−MLG). Atomic force microscopy showed that MLG greatly reduced the mechanical stiffness of BC gels, while XG and AX did not exert a significant effect. A combination of advanced solid-state NMR methods allowed us to characterize the structure of BC ribbons at ultra-high resolution and to monitor local mobility and water interactions. This has enabled us to unravel the effect of AX, XG, and MLG on the short-range order, mobility, and hydration of BC fibers. Results show that BC−XG hydrogels present BC fibrils of increased surface area, which allows BC−XG gels to hold higher amounts of bound water. We report for the first time that the presence of high molecular weight MLG reduces the density of clusters of BC fibrils and dramatically increases water interactions with BC. Our data supports two key molecular features determining the reduced stiffness of BC−MLG hydrogels, that is, (i) the adsorption of MLG on the surface of BC fibrils precluding the formation of a dense network and (ii) the preorganization of bound water by MLG. Hence, we have produced and fully characterized BC−MLG hydrogels with novel properties which could be potentially employed as renewable materials for applications requiring high water retention capacity (e.g. personal hygiene products).

Highlights Produced starch hydrogels through high temperature-pressure gelatinisation. Employed a range of NMR methods to probe the molecular mobility and water dynamics. Reported for the first time highly dynamic starch chains in the solvent phase of gels. Correlated the degree of chain structural mobility with bulk properties. Revealed a previously unknown level of molecular organisation in starch gels.

No abstract

We use a pH-driven annealing process to convert between co-assembled and self-sorted networks in multicomponent gels. The initially formed gels at low pH are co-assembled, with the two components coexisting within the same self-assembled structures. We use an enzymatic approach to increase the pH, resulting in a gel-to-sol transition, followed by a hydrolysis to lower the pH once again. As the pH decreases, a self-sorted network is formed by a two-stage gelation process determined by the pK a of each component. This approach can be expanded to layered systems to generate many varied systems by changing composition and rates of pH change, adapting their microstructure and so allowing access to a far greater range of morphologies and complexity than can be achieved in single component systems.

Conventional composite formulation of cellulose nanocrystals (CNCs) with thermoplastics involves melt compounding or in situ polymerisation. In this rather unconventional approach, polypropylene (PP) microparticles were finely suspended and stabilized, at varying weight loadings, in aqueous suspensions of amphiphilic CNCs to enable adsorption of the nanoparticles onto the thermoplastic. In order to achieve these suspensions, CNCs were modified with either octyl or hexadecyl groups. These modifications imparted hydrophobic properties to the CNCs, hence increasing interfacial adhesion to the PP microparticles. The modification, however, also retained the sulfate half ester groups that ensured dispersibility in aqueous media. The CNCs were evidently coated on the PP microparticles as revealed by confocal microscope imaging and had no detrimental effect on the melt properties of the PP-based composites. The approach is demonstrated to increase the Young’s moduli of CNC-thermoplastic composites prepared in optimum suspension loadings of 0.5 wt. % octyl-modified and 0.1 wt % hexadecyl-modified CNCs. This procedure can be extended to other thermoplastics as the ability to aqueously process these composites is a major step forward in the drive for more sustainable manufacturing.