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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]

The cell wall microstructure has been recognized to modulate the digestibility and bioaccessibility of nutrients in whole pulse foods, while the role of cell wall integrity is unclarified in the hydrolysis of intracellular nutrients during human gastrointestinal transit. Intact pea cells were isolated to prepare a series of cell wall integrity subjected to cooking and followed by the in vitro hydrolysis of starch and protein properties using the INFOGEST 2.0 in vitro simulation. Thermal properties showed that cell samples either in raw or cooked form with different wall integrity exhibited similar and higher starch gelatinization temperatures compared to the isolated starch counterpart. It was found that intact pea cells showed the limited hydrolysis extent of the maltose (16.2%) and NH 2 (6.7%) compared to the damaged cells. In addition, intact cells also withheld the cell wall integrity throughout gastrointestinal digestion with minor rupture, and presented the higher protein molecular weight (70 kDa) in the SDS-PAGE profiles. Results suggested that the in vitro starch and protein digestion properties are modulated by the cell wall integrity, which may lead to lower glycemic response and open up the possibilities of designing health food products. [ABSTRACT FROM AUTHOR]

The purpose of this study was to develop and characterize chitosan (Ch)-based films incorporated with varying molecular weight (Mw) and acetylation degree (AD) chitosan-depolymerization-products (CDP), to be applied as drug delivery materials. As compared to Ch-film, optical and antioxidant potentials of Ch/CDP-based films were improved, particularly using low Mw and AD-CDP. Whereas, films water resistance, mechanical and antibacterial properties increased as CDP-Mw increased and AD decreased. For the thermal and swelling behaviors, better values were obtained using higher Mw and AD-CDP. Further, to assess their in vitro ciprofloxacin (CFX)-release behavior, loaded-CFX Ch/CDP-based films, crosslinked using glutaraldehyde, were prepared. Expect of elongation at break, crosslinked CFX-loaded films showed increased optical, water resistance, tensile strength and thermal properties, as compared to unloaded films. The CFX-release profiles indicated that a slower and sustained release was observed, particularly when using lower Mw and AD-CDP, and mainly for the crosslinked films during 48 h. These films can release CFX for up to 54% in 6 and 24 h, at pH 1.2 and 7.4, respectively. Through this study, novel biodegradable, swellable and pH-sensitive crosslinked Ch/CDP-based films may be considered as suitable and promising drug delivery systems. [Display omitted] • Chitosan/chitosan-depolymerization-products (Ch/CDP)-based films were prepared and characterized. • CDP molecular weight (Mw) and acetylation degree (AD) highly influenced films physicochemical and biological properties. • Films crosslinking with glutaraldehyde improved their swelling and ciprofloxacin release behavior. • Low Mw and AD CDP-loaded-films showed lower swelling and a controlled ciprofloxacin release. [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]

Common buckwheat starch (CBS) has extensive using value in the human diet. In this study, the molecular structure and physicochemical properties of CBS isolated from five cultivars collected from three regions of China were studied. Variations in molecular structure, crystalline structure, complexity, water solubility (WS), swelling power (SP), pasting properties, and thermal characteristics were recorded among the starches. The CBS had both similarities and differences in its properties by comparison with maize starch (MS) and potato starch (PS). The average molecular weight (M W) and amylopectin average chain length (ACL) of CBS ranged from 3.86 × 107 g/mol to 4.68 × 107 g/mol and from 21.29% to 22.68%, respectively. CBS and MS were divided into one subgroup and showed typical A diffraction patterns, while PS was divided into two subgroups and exhibited a typical B polymorphic pattern. The WS and SP of all the starches significantly increased with increasing temperature and had great variation at 70 °C and 90 °C. Pearson's correlation analysis showed that the molecular structure of starches greatly affected the physicochemical properties. This study revealed that the physicochemical properties of CBS could be affected by the molecular structures. • Common buckwheat and maize starches showed typical A diffraction patterns. • Structural complexity of five common buckwheat cultivars were similar. [ABSTRACT FROM AUTHOR]

• M w of pectin had a prominent role in modifying starch pasting viscosities. • PH was found more effective in reducing breakdown and setback viscosity. • NP imparted higher viscoelasticity to the starch pastes while PH retarded it. • NP produced harder gels while PH made softer gels. The influence of native pectin (NP) and its hydrolysate (PH) in modifying hydration, thermal, pasting, rheological and textural properties of barley starch was assessed. The addition of NP and PH significantly modified the hydration properties of barley starch. The swelling and solubility of barley starch increased in the presence of NP while PH decreased it in a concentration dependent manner. The differential scanning calorimetry results showed that gelatinization temperatures increased in the presence of NP/PH whereas decrease in enthalpy was observed. In addition, only NP was found effective in increasing peak viscosity of the barley starch during pasting while PH decreased it. PH was observed to be more efficient in terms of reducing setback and final viscosity. Moreover, the NP addition caused an increase in magnitude of G' and G" while lower values were obtained with PH suggesting an increase in the elasticity of barley starch pastes with NP and an increased viscous behavior in case of PH. This was further confirmed by scanning electron microscopy which revealed interconnected flakes network in starch pastes containing NP. Overall these results revealed that molecular weight and concentration of pectin played an important role in modifying starch functional properties. [ABSTRACT FROM AUTHOR]

A native polysaccharide (RCPI) with sugar content of 79.94 ± 0.57% was isolated from raspberry fruits. A degraded polysaccharide (DRCPI) with sugar content of 83.82 ± 0.71% was obtained from the crude polysaccharides after degradation by Fe2+-H 2 O 2 treatment. The molecular weights of RCPI and DRCPI were determined to be 411,000 and 8010 Da, respectively. GC analysis revealed that both RCPI and DRCPI were composed of the same monosaccharides (rhamnose, arabinose, xylose, mannose, glucose, galactose, and galacturonic acid) in different molar ratios. IR and NMR spectroscopy confirmed that RCPI and DRCPI possessed similar structural characteristics, although DRCPI displayed higher antioxidant activities and greater thermal stability. Furthermore, DRCPI exhibited excellent rheological properties. These data provide evidence to support the application of raspberry-derived polysaccharides in functional foods. • Two novel polysaccharides (RCPI and DRCPI) from raspberry fruits were obtained. • RCPI (native) and DRCPI (degraded by Fe2+-H 2 O 2) had similar structural characteristics. • DRCPI presented stronger antioxidant and α-amylase inhibitory capacities than RCPI. • DRCPI possessed more excellent viscoelastic behavior and greater thermal stability. [ABSTRACT FROM AUTHOR]

The accumulation efficiency and the properties of polyhydroxyalkanoates (PHAs) produced from acidified waste glycerol (AWG) and its derivatives via an enriched microbial consortium derived from soil, were investigated in this study. AWG consisted mainly from short chain fatty acids, 1,3 propanediol and residual glycerol, which were also evaluated individually as substrates. Accumulation capacity and yields were estimated after solvent extraction and purification and PHAs were further analyzed in terms of their chemical structure, thermal properties, molecular masses and mechanical properties. The lowest accumulation capacity was noticed for non-acidified waste glycerol as carbon source which led to the generation of P(3HB), whereas for the other carbon sources co -polymers of 3HB with 3HV or 3HHx were produced. Average molecular mass weights were quite high in all cases reaching ~1.8 × 10 6 Da. The thermal properties and the mechanical behavior of PHAs were shown to be highly affected by their monomeric composition, whereas it was also concluded that DSC and DMA results were in good agreement. [ABSTRACT FROM AUTHOR]

Cress seed gum (CSG) was fractionated using stepwise extraction with water, yielding three fractions (F1, F2, F3) whose average molecular weights ranged from 863 to 1080 kDa. The chemical composition (monosaccharide, ash, moisture, CHN and uronic acid contents) and molecular weight of the fractions varied significantly. Generally, the major identical peaks of FT-IR spectra for three fractions and whole cress seed gum were similar. The results of DSC and TGA indicated that F3 had the highest thermal stability and considering the initial decomposition temperature, the decreasing order of thermal stability was F3 > F2 > F1. Cress seed gum and its fractions exhibited non-Newtonian shear thinning behavior which the Herschel-Bulkley model was successfully described the steady shear flow behavior of samples, and apparent viscosity followed the order of F3 > F2 > F1. F3 exhibited the best surface tension reducing ability compared to other fractions and CSG. All the samples had good emulsifying capability (>97%) and stability (>96%). The emulsion capacity increased slightly along the series of F1, F2 and F3, whereas, emulsion stability decreased along the same series. CSG and F3 showed the highest and the lowest foaming capacity and stability, respectively. [ABSTRACT FROM AUTHOR]