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Lignin can be used as a sustainable alternative to bisphenol A (BPA) to prepared lignin-based epoxy resins. Lignin effects including molecular weight, phenolic content, G/S unit ratio and flexible/rigid linkage ratio on epoxy synthesis and performance were summarized comprehensively. The incorporation of lignin with a higher molecular weight would lead to the higher rigidity of epoxy crosslinking network. Higher contents of ether bonds in lignin would provide higher structural flexibility of lignin incorporated epoxy thermosets. Lignin with higher contents of phenolic hydroxyls was more beneficial for improving the reactivity of its epoxy products after glycidylation. Due to the excellent charring capacity of lignin, higher contents of residue char can be produced at higher additions of lignin at high temperatures, while the loss of crosslinking density caused by the increasing lignin addition (especially for the macromolecular lignin) would deteriorate the thermal stability of their thermosets. Several applications of lignin-based epoxy resins were also mentioned based on their mechanical, thermal and chemical properties, such as coatings (with anticorrosion and UV-blocking), adhesives (with highly crosslinking network, excellent mechanical, and thermal properties) and flame retardants (with high charring capability). [Display omitted] [ABSTRACT FROM AUTHOR]

Bacterial cellulose (BC), an important category of polysaccharides, was investigated as a texture improver in bakery products. This study focused on the changes in the conformational and thermal properties of gluten in the wheat dough system as affected by BC. Significant reductions in the free-SH content, fluorescence intensity, and surface hydrophobicity index (H 0) were observed as a result of the increased BC addition. The electrophoresis profile (SDS–PAGE) and size exclusion (SE-HPLC) revealed the variation in molecular weight distribution, and the increase in the content of the 40–91 kDa molecular weight was at the expense of a decrease in the amount of the corresponding 10–40 kDa. When 0.1 % BC was added, both the α -helix and β -sheet contents increased as a result of enhanced chemical interactions, thereby contributing to the gluten matrix with higher thermal stability. Further supplementation interfered with the current ordered gluten structure, which could be supported by the lower α -helix/ β -sheet content ratio and the decreased degradation temperature (T d) of gluten with 0.2 % BC. However, the observed decrease in the ratio of β -turns to β -sheets and weight loss at 600 °C indicated that a reconstructed gluten matrix induced by extra BC addition was formed to maintain the structural stability. [Display omitted] • BC mainly influenced the cross-linking of 10–91 kDa gluten molecules. • BC increased gluten aggregation by increasing β -sheet mainly through hydrogen bond. • More ordered and thermal stable gluten structure were formed by moderate BC added. • New linkages reinforced the thermal stability of extra BC and gluten mixture system. [ABSTRACT FROM AUTHOR]

Crowded environments, commonly found in the food system, are utilized to enhance the properties of soybean proteins. Despite their widespread application, little information exists regarding the impact of crowded environments on the denaturation behaviors of soybean proteins. In this study, we investigated how crowding agents with varying molecular weights, functional groups, and topology affect the denaturation behavior of glycinin under crowded conditions. The results reveal that thermal stability in PEG crowded environments is mainly influenced by both preferential hydration and binding. The stabilization is primarily enthalpy-driven, with aggregation contributing additional entropic stabilization. Specifically, ethylene glycol and diethylene glycol exhibit temperature-dependent, bilateral effects on glycinin stability. At the denaturation temperature, hydrophobic interactions play a predominant role, decreasing glycinin's thermal stability. However, at a molecular weight of 200 g/mol, there is a delicate balance between destabilizing and stabilizing effects, leading to no significant change in thermal stability. With the addition of PEG 400, 1000, and 2000, besides preferential hydration, additional hard-core repulsions between glycinin molecules enhance thermal stability. Methylation modification experiments demonstrated that 2-methoxyethyl ether exerted a more pronounced denaturing effect. Additionally, the cyclization of PEG 1000 decreased its stabilizing effect. [ABSTRACT FROM AUTHOR]

Poor properties of native cassava starch film such as low mechanical properties and high water uptake are the limitations of biodegradable starch films. Dual modification is an alternative way to improve the properties. Characteristics and properties of oxidized, crosslinked and dually modified starch films by hydrogen peroxide oxidation and glutaraldehyde crosslinking were examined. Sequence of the dual modification was also studied. All starch films were prepared by casting technique using glycerol plasticizer. The oxidation and crosslinking of modified starch were confirmed by carbonyl and carboxyl contents as well as degree of crosslinking. The lowest and highest molecular weights of the modified starch were observed for the oxidized starch and crosslinked starch, respectively. Moreover, swelling power and moisture absorption of dually modified starch films was clearly lower than those of singly modified films. Additionally, both good stiffness and extensibility was also obtained from the dually modified films especially for the crosslinked-oxidized film. Moreover, thermal property and biodegradability were also determined. [ABSTRACT FROM AUTHOR]

Natural polysaccharides are concerned for their high biological activity and low toxicity. Two kinds of polysaccharides were extracted from Hippophae rhamnoide L. by microwave-assisted aqueous two-phase system. Under the optimal conditions predicted by RSM model (K 2 HPO 4 /ethanol (18.93 %/28.29 %), liquid to material ratio 77 mL/g, power 625 W and temperature 61 °C), the yield of total polysaccharides reached 35.91 ± 0.76 %. Moreover, the polysaccharides extraction was well fitted to the Weibull model. After purification by Sepharose-6B, the polysaccharides from top phase (PHTP, purity of 81.44 ± 1.25 %) and bottom phase (PHBP, purity of 88.85 ± 1.40 %) were obtained. GC, FT-IR, methylation and NMR analyses confirmed the backbone of PHTP was composed of a repeated unit →4)- β -D-Glc p -(1 → 2)- α -L-Rha p -(1 → 4)- β -D-Gal p -(1 → 4)- α -D-GalA p -(1 → 3)- α -L-Ara f -(1 → 3)- α -D-Man p -(1→, while the repeated unit in PHBP was →3)- α -L-Ara f -(1 → 2)- α -L-Rha p -(1 → 4)- β -D-Glc p -(1 → 3)- α -D-Man p -(1 → 4)- β -D-Gal p -(1 → 4)- α -D-GalA p -(1→. Compared with PHTP (6.46 × 106 g/mol), PHBP with relatively low molecular weight (8.2 × 105 g/mol) exhibited the smaller particle size, better water-solubility, thermal and rheological property, stronger anti-glycosylation and α -amylase inhibitory effects. Moreover, PHTP and PHBP displayed a reversible inhibition on α -amylase in a competitive manner. This study provides a high-efficient and eco-friendly method for polysaccharides extraction, and lays a foundation for sea buckthorn polysaccharides as potential therapeutic agents in preventing and ameliorating diabetes. [Display omitted] • MA-ATPE of two polysaccharides from sea buckthorn fruits was optimized by RSM model. • There were different repeated units in the backbone structures of PHTP and PHBP. • PHBP exhibited better physical and thermal stability, rheological property than PHTP. • PHTP and PHBP were novel natural agents for preventing and ameliorating diabetes. [ABSTRACT FROM AUTHOR]