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Protein-surfactant interactions have been an ongoing topic of interest for many decades. Applications involving complexes of proteins and surfactants are relevant in food, pharmaceuticals, hygiene, molecular characterization, and other fields. In this study, the interactions of polymerized whey proteins (PWP) and sodium dodecyl sulfate (SDS) at high concentrations are investigated. Different characterization techniques are used, including electrical conductivity, turbidity, isothermal titration calorimetry, dynamic light scattering, dilute solution viscometry, rheology, and surface hydrophobicity to elucidate information on the modes and extent of interactions. Results indicate that PWP-SDS interactions produce highly extended, worm like micelles, with SDS decorating PWP chains and covering non-polar residues. PWP can host SDS up to quite high surfactant to protein ratios (SPR), producing solutions that are highly viscous with shear thickening properties, yet with no networking or gelation. Interestingly, dilution of high viscosity PWP-SDS solutions leads to even smaller size of PWP-SDS molecular complex as compared with PWP without SDS. The current study extends the vision of protein surfactant interactions by examining concentration range beyond that found in literature. The results reveal insights that can help expand studies on other systems and find applications in various fields including coatings, cosmetics, food ingredients, drug transport, and disease treatment. • Concentrated protein-surfactant interactions produce highly extended, worm-like micelles. • Surfactant decorates proteins chains and covers the non-polar residues. • Concentrated protein-surfactant solutions are highly viscous with shear thickening properties. • The behavior of protein surfactant-solutions is highly concentration dependent. [ABSTRACT FROM AUTHOR]

The prebiotic capacity of Pectin Oligosaccharides (POS) is influenced by structural factors such as molecular size, composition, and degree of esterification, which affect their interaction with the gut microbiota. While existing literature has predominantly examined POS derived from apple and citrus pectins, the extrapolation of these findings to other pectin sources remains complex due to variations in their composition. This study focused on obtaining POS with prebiotic potential from pisco grape pomace through controlled enzymatic hydrolysis, resulting in three molecular size fractions: <3 kDa, 3–10 kDa, and > 10 kDa. The POS fractions were analyzed using FTIR, HPSEC, HPLC, and MALDI-TOF-MS techniques to characterize their physical-chemical properties. Each fraction presented distinct compositions, with the <3 kDa fraction showing a higher concentration of galacturonic acid and glucose, while the >10 kDa fraction was also composed of rhamnose and arabinose. Notably, the <3 kDa fraction supported greater biomass growth of the probiotic strain Lactobacillus casei ATCC 393 compared to the other fractions. In contrast, the non-probiotic strain Escherichia coli ATCC 25922 achieved the lowest biomass with this fraction. Consequently, the <3 kDa POS fraction exhibited the highest prebiotic index. This fraction, composed of oligomers from the rhamnogalacturonan region and arabino-oligosaccharides with a degree of polymerization between two and five, highlights its potential for further research and applications. Therefore, investigating other sources and optimizing extraction conditions could lead to developing novel prebiotic formulations that supply specific probiotic strains for a symbiotic product. [ABSTRACT FROM AUTHOR]

Plasticized PLA plastic films are being increasingly used in, among others, packaging and agriculture sectors in an attempt to address the rapid growth of municipal waste. The present paper aims to review the recent progress and the state-of-the-art in the field of fully bio-renewable tough blends of PLA with green plasticizers aimed at developing flexible packaging films. The different classes of green substances, derived from completely bio-renewable resources, used as potential plasticizers for PLA resins are reviewed. The effectiveness of these additives for PLA plasticization is discussed by describing their effects on different properties of PLA. The performance of these blends is primarily determined by the solvent power, compatibility, efficiency, and permanence of plasticizer present in the PLA matrix of resulting films. The various chemical modification strategies employed to tailor the phase interactions, dispersion level and morphology, plasticization efficiency, and permanence, including functionalization, oligomerization, polymerization and self-crosslinking, grafting and copolymerization, and dynamic vulcanization are demonstrated. Sometimes a third component has also been added to the plasticized binary blends as compatibilizer to further promote dispersion and interfacial adhesion. The impact of chemical structure, size and molecular weight, chemical functionalities, polarity, concentration, topology as well as molecular architectures of the plasticizers on the plasticizer performance and the overall characteristics of resulting plasticized PLA materials is discussed. The morphological features and toughening mechanisms for PLA/plasticizer blends are also presented. The different green liquids employed show varying degree of plasticization. Some are more useful for semi-rigid applications, while some others can be used for very flexible products. There is an optimum level of plasticizer in PLA matrices above which the tensile ductility deteriorates. Esters-derivatives of bio-based plasticizers have been shown to be very promising additives for PLA modification. Some plasticizers impart additional functions such as antioxidation and antibacterial activity to the resulting PLA materials, or compatibilization in PLA-based blends. While the primary objective of plasticization is to boost the processability, flexibility, and toughness over wider practical conditions, the bio-degradability, permeability and long-term stability of microstructure (and thereby properties) of the plasticized films against light, weathering, thermal aging, and oxidation deserve further investigations. [Display omitted] [ABSTRACT FROM AUTHOR]

Applications of natural fibres are expanding, and sustainable alternatives are needed to support this growing demand. We investigated the production of fibres using alginates from Saccharina latissima (SAC), Laminaria digitata (LAM), Sacchoriza polyschides (SACC), and Himanthalia spp. (HIM). After extraction (3 % w / v biomass) using a sustainable protocol based on citric acid, crude alginate represented 61–65 % of the biomass dry weight for SAC and LAM, and 34–41 % for SACC and HIM when experiments were performed at small scale (1.5 g of starting material). Interestingly, scaling-up extraction (60 g of starting material) decreased yields to 26–30 %. SAC and LAM alginates had the highest M/G (mannuronic acid/guluronic acid) ratios and molecular weights when compared to those from SACC and HIM (M/G:1.98 and 2.23, MW: 302 and 362 kDa, vs 1.83 and 1.86, 268 and 168 kDa). When the four types of alginates were tested for spinning fibres cross-linked with CaCl 2 , only SAC and LAM alginates produced fibres. These fibres showed no clumps or cracks under stretching action and presented a similar Young's modulus (2.4 and 2.0 GPa). We have demonstrated that alginate extracted from S. latissima and L. digitata can be successfully spun into functional fibres cross-linked with CaCl 2. • Alginates from four species were extracted using a citric acid protocol. • The biochemical characteristics of the four alginates were determined. • Molecular size, m/g ratio and structure correlated with fibre formation. • Saccharina and Laminaria alginates formed consistent fibres. • The fibres produced showed structural homogeneity and similar Young's modulus. [ABSTRACT FROM AUTHOR]

In our study, two high efficiency cellulose degrading strains were screened, isolated and identified as Cochliobolus kusanoi and Aspergillus puulaauensis by 18S rDNA gene sequencing. In addition, the composite microbial system was constructed to develop the synergistic effect among different strains. Under the optimum conditions, the yield of soluble dietary fiber from tea residues by mixed fermentation method (MF-SDF) dramatically increased compared to single strain fermentation. The structural analysis demonstrated that all samples possessed the representative infrared absorption peaks of polysaccharides, whereas MF-SDF revealed more loose structure, lower crystallinity and smaller molecular size. For the adsorption capacities indexes, MF-SDF also owned the highest adsorbing capacity for the water molecule, oil molecule, cholesterol molecule and nitrite ion. Overall, our data showed that mixed fermentation method could be better choices to improve the functional properties of dietary fiber, and screening of cellulose degrading strains could provide new thinkings for the study of dietary fiber modification and realize high-quality utilization of crop residues. • High efficiency cellulose degrading strains were screened, isolated and identified. • The composite microbial system was successfully constructed. • The fermentation effects of different strains were compared and analyzed. • The structural properties of MF-SDF were changed. • The MF-SDF owned the highest WHC, OHC, CAC and NIAC. [ABSTRACT FROM AUTHOR]

On the basis of revealing the interaction mechanism between corn starch (CS) and water-extractable arabinoxylan (WEAX) with high/low molecular weight (H-WEAX, L-WEAX), the degree of gelatinization (DG) on structural behaviors and in vitro digestibility of CS-WEAX complexes (CS/H, CS/L) was evaluated. With the increased DG from 50 % to 95 %, the water adsorption capacity of CS/L was increased 64 %, 58 %, 47 %, which were higher than that of CS/H (39 %, 54 %, 33 %). The gelatinization of starch was inhibited by WEAX, resulting in the enhancement of crystallinity, short-range ordered structure and molecular size of CS-WEAX complexes. Stronger interaction was detected in CS/L than with CS/H as proved by the increased hydrogen bonds and electrostatic force. Complexes exhibited higher resistant starch content (RS) at diverse DG, especially for CS/L. Notability, RS content of samples with 50 % DG were increased from 27.72 % to 32.89 % (CS/H), 36.96 % (CS/L). Except for the reduction of gelatinization degree by adding WEAX, the other possible mechanisms of retarding digestibility were explained as the small steric hindrance of L-WEAX promoted encapsulation of starch granules, limiting enzyme accessibility. Additionally, the fragmentation of CS granules with high DG promoted the movement of H-WEAX, reducing the difference in digestibility compared to CS/L. [Display omitted] • The addition of WEAX obviously reduced the in vitro digestibility of CS. • The RS content of WEAX-starch complexes was obviously enhanced for starch with 50 % DG. • L-WEAX could retain higher crystallinity, short-range ordered structure of starch. • G5-CS/L exhibited stronger hydrogen bonds and electrostatic force. • The spatial hindrance of H-WEAX decreased at high DG level. [ABSTRACT FROM AUTHOR]

Pea protein isolate (PPI) was used as a carrier matrix to load tannic acid (TA) due to its multiple cavity structures and reaction sites, after that, magnesium ion (M) was further added to form more stable carrier structures. PPI was covalently bound with TA to form TA-PPI complexes in alkaline conditions, then M induced the aggregation of TA-PPI to produce M-TA-PPI complexes. TA mainly interacted with free amino groups and sulfhydryl groups of PPI, thereby decreasing their content in complexes. TA further decreased the α-helix content and increased the β-sheet and β-turn content in TA-PPI complexes correspondingly, nevertheless the M would decline these changes in M-TA-PPI complexes. As a result of binding, TA and M jointly increased the average molecular size of complexes. The higher TA addition amount (10–20 mg/g PPI) was conducive to the stronger intramolecular interactions (more hydrophobic interactions and disulfide bonds), gel structure (higher hardness value) and storage modulus in M-TA-PPI gels. Compared with TA-PPI complexes, M-TA-PPI complexes showed higher stability in gastric digestion and higher TA releasement and antioxidant capacity of its digesta in intestinal digestion. This kind of metal-phenolics-protein complexes may have potentials to be a stable and efficient carrier for loading gastric sensitive polyphenols. [Display omitted] • Tannic acid (TA) covalently binding with pea protein (PPI) to form TA-PPI complexes. • Magnesium ion (M) induces TA-PPI to aggregate as tighter M-TA-PPI complexes. • M-TA-PPI complexes reserve more bioactive TA after gastric digestion. • M-TA-PPI complexes release more bioactive TA during intestinal digestion. • M-TA-PPI is a potential carrier for delivering gastric sensitive compounds. [ABSTRACT FROM AUTHOR]

Gene encoding endoglucanase, Rf GH5_4 from R. flavefaciens FD-1 v3 was cloned, expressed in Escherichia coli BL21(DE3) cells and purified. Rf GH5_4 showed molecular size 41 kDa and maximum activity at pH 5.5 and 55 °C. It was stable between pH 5.0–8.0, retaining 85% activity and between 5 °C–45 °C, retaining 75% activity, after 60 min. Rf GH5_4 displayed maximum activity (U/mg) against barley β-D-glucan (665) followed by carboxymethyl cellulose (450), xyloglucan (343), konjac glucomannan (285), phosphoric acid swollen cellulose (86), beechwood xylan (21.7) and carob galactomannan (16), thereby displaying the multi-functionality. Catalytic efficiency (mL.mg−1 s−1) of Rf GH5_4 against carboxymethyl cellulose (146) and konjac glucomannan (529) was significantly high. TLC and MALDI-TOF-MS analyses of Rf GH5_4 treated hydrolysates of cellulosic and hemicellulosic polysaccharides displayed oligosaccharides of degree of polymerization (DP) between DP2-DP11. TLC, HPLC and Processivity-Index analyses revealed Rf GH5_4 to be a processive endoglucanase as initially, for 30 min it hydrolysed cellulose to cellotetraose followed by persistent release of cellotriose and cellobiose. Rf GH5_4 yielded sufficiently high Total Reducing Sugar (TRS, mg/g) from saccharification of alkali pre-treated sorghum (72), finger millet (62), sugarcane bagasse (38) and cotton (27) in a 48 h saccharification reaction. Thus, Rf GH5_4 can be considered as a potential endoglucanase for renewable energy applications. [Display omitted] • Endoglucanase, Rf GH5_4 hydrolyzes both cellulosic and hemicellulosic substrates. • k cat /K m for β-D-glucan was 875.7 and for konjac glucomannan, 529 mL.mg−1 s−1. • Multifunctional Rf GH5_4 endoglucanase hydrolyzes xyloglucan and xylan. • Rf GH5_4 efficiently saccharified lignocellulose of sorghum, finger millet & cotton. • Rf GH5_4 released the highest TRS (72 mg/g) from pre-treated sorghum stalk. [ABSTRACT FROM AUTHOR]

Glycogen is a complex branched glucose polymer found in many tissues and acts as a blood-glucose buffer. In the liver, smaller β glycogen particles can bind into larger composite α particles. In mouse models of diabetes, these liver glycogen particles are molecularly fragile, breaking up into smaller particles in the presence of solvents such as dimethyl sulfoxide (DMSO). If this occurs in vivo, such a rapid enzymatic degradation of these smaller particles into glucose could exacerbate the poor blood-glucose control that is characteristic of the disease. High-amylose resistant starch (RS) can escape digestion in the small intestine and ferment in the large intestine, which elicits positive effects on glycemic response and type 2 diabetes. Here we postulate that RS would help attenuate diabetes-related liver glycogen fragility. Normal maize starch and two types of high-amylose starch were fed to diabetic and non-diabetic mice. Molecular size distributions and chain-length distributions of liver glycogen from both groups were characterized to test glycogen fragility before and after DMSO treatment. Consistent with the hypothesis that high blood glucose is associated with glycogen fragility, a high-amylose RS diet prevented the fragility of liver-glycogen α particles. The diets had no significant effect on the glycogen chain-length distributions. • Diabetes results in poor blood-glucose control. • Diabetic glycogen is molecularly fragile. • A resistant starch diet improved blood-glucose control. • A resistant starch diet attenuated glycogen fragility. [ABSTRACT FROM AUTHOR]

Glycogen-like particles (GLPs) were built up from sucrose by applying de novo one-pot enzymatic process of amylosucrase (ASase; 6 U·mL−1) and glycogen branching enzymes (GBEs; 0.001 and 0.005 U·mL−1). Due to different chain-length transferring patterns of GBEs, structurally differentiated GLPs were synthesized. Yields of GLPs synthesized at pH 7.0 and 30 °C were improved by increasing the GBE/ASase ratio. Branching degrees of GLPs obviously was increased along with the ratio of GBEs, of which result was directly supported by shortened branch-chain length with greater GBE activity. Long branch chains seemed to play as efficient acceptor molecules to bind newly transferred branch chains especially at lower ratio of GBE/ASase, resulting in greater molecular weight and size of GLP with higher proportion of them. Molecular weight, size, and density of GLPs were ranged from 7.37 × 105 to 1.94 × 108 g·mol−1, from 23.70 to 52.65 nm, and from 7.99 to 374.32 g·mol−1·nm−3, respectively. By increasing GBE/ASase ratio, more compact GLP architecture was fabricated due to increased weight and reduced size with exception of a unique GBE. GLPs were efficiently synthesized by two different glycosyltransferases, and their chemical structures were controllable by source and ratio of GBEs due to their different branch-chain transferring specificity. • Glycogen-like particle (GLP) was synthesized by one-pot dual enzyme system. • Nano-size GLP structure was highly dependent on type of branching enzymes. • Size and density of GLP were controllable by changing enzyme activity ratio. • GLP yield reached max. 44.5% by branching enzyme activity of Synechocystis sp. [ABSTRACT FROM AUTHOR]

Waxy hull-less barley kernels and their isolated starches were exposed to different microwave conditions (power 640, 720, and 800 W, time 60, 120 and 180 s) and changes in morphology, particle size, digestibility, rheological properties, and molecular structure were measured and analyzed. Microwave treatment caused roughness and deformation of granular surfaces, and an increase in granule size. After treatment, the in vitro digestibility of starch was increased, i.e., the RDS increased, but the RS decreased. Microwave treatment decreased the K values of the in-kernel MWI WHBS. Dynamic rheological results showed that the in-kernel MWI WHBS pastes had lower T G ′max , and higher G ′ max , G ′ 90 °C , G ′ 25 °C , G ′ 0.1Hz and G ′ 20Hz after treatment. The chain-length distribution did not significantly change after microwave treatment. However, the results for molecular size distributions showed that the peaks of amylopectin (R h = ~100 nm) shifted left and right, indicating that the molecular volume might become smaller or larger under different processing conditions. The primary effects of microwave treatment may be loosening the molecular structure and cutting main chains of amylopectin. • Microwave irradiation was applied on starches from waxy hull-less barley. • Changes in molecular sizes of starch might affect their functional properties. • Microwave irradiation acted on loosening molecular structure and cutting C chains. [ABSTRACT FROM AUTHOR]

In this study, three lignin fractions F1, F2, and F3 were obtained from eucalyptus kraft lignin (EKL) by solvent extraction with ethyl acetate, acetone, and acetone/water. The antioxidant activity of these lignin fractions were measured and evaluated by using the DPPH radical scavenging activity, ABTS radical cation scavenging activity and ferric reducing antioxidant power analysis. These lignin fractions were also characterized by applying Gel permeation chromatography, Fourier transform infrared, 31P NMR and 2D HSQC NMR techniques. The three different lignin fractions had rather different average molecular sizes, as well as different phenolic and methoxy functional contents. The ethyl acetate fraction (F1) with the lowest average molecular weight (2342 g/mol) and the highest phenolic hydroxyl content (4.2457 mmol/g) and methoxy groups (6.2714 mmol/g) showed high homogeneity and the highest antioxidant activity. Its DPPH scavenging activity, ABTS + scavenging activity, and ferric reducing the antioxidant power were 68.67%, 75.57%, and 91.89 μmol/g, respectively. Moreover, the antioxidant activity of F1 and F2 was found to be higher than that of butylated hydroxytoluene. Therefore, solvent extraction was shown to be an effective way to separate lignin fractions with high homogeneity, high antioxidant activity, which could lead to application of lignin with higher value. [Display omitted] • The antioxidant activity of kraft lignin was enhanced by organosolv extraction. • Ethyl acetate extractives had the highest antioxidant activity. • The decrease of M w and the increase of phenolic hydroxyl group were caused by the rupture of β-O-4 linkages. • Low molecular weight lignin contains high phenolic hydroxyl groups with high homogeneity and high antioxidant activity. [ABSTRACT FROM AUTHOR]

Sorghum steaming properties are important for both flavor and brewing efficiency of baijiu (Chinese alcohol liquor). However, it is currently unclear with respects to structural factors that affect sorghum steaming properties during baijiu production. In this study, starch fine molecular structures were characterized by size-exclusion chromatography and fluorophore-assisted carbohydrate electrophoresis for 8 sorghum varieties used in baijiu production. Starch crystalline structures and ordering of double helices were characterized by the X-ray diffraction and differential scanning calorimetry. Results showed that only small differences were observed for starch molecular size distributions and chain-length distributions in the raw sorghum flour. Of significance, the leached starch content and molecular size during steaming was very different among these sorghum varieties. Furthermore, Spearman correlation analysis showed that there was no significant correlation between starch fine structural parameters with the leached starch content. On the other hand, the correlation analysis showed that leached starch molecular size was negatively correlated with starch crystallinity, while positively correlated with the onset and peak gelatinization temperatures. It is concluded that the sorghum steaming property is controlled by the starch crystalline structures instead of starch fine molecular structures. These results could help the baijiu industry to produce baijiu with more desirable properties. • Sorghum steaming properties were investigated. • Small differences were observed for starch fine molecular structures of 8 sorghums. • Starch crystalline structure was significantly different. • The leached starch content was significantly different. • The leached starch molecular size was significantly different. [ABSTRACT FROM AUTHOR]

Yam is a dual-purpose crop as both medicine and food. However, the mechanism controlling the eating quality of yam remains to be elucidated. This study explored the influence of starch multiscale structure on the texture of yam. The results indicated that FS and RC yam have higher hardness and chewiness, while BZ, XM, and PL yam possess waxiness, Fineness, and Stickiness. Statistically, high amylose (AM) can increase hardness, chewiness, and compactness; and average molecular size (R h) is positively correlated with stickiness, fineness, and waxiness. Specifically, medium- and long-chain amylose (1000 < X ≤ 10,000) and amylopectin (24 < X ≤ 100), particularly medium-chain amylose (1000 < X ≤ 5000) and long-chain amylopectin (24 < X ≤ 36), primarily affect sensory and rheological stickiness. The long chains of amylose form a straight chain interspersed in the crystalline and amorphous regions to support the entire lamellar structure. Higher proportion of amylose long chains, promoting the starch's structural rigidity, which in turn enhanced its hardness-related attributes. Moreover, a higher ratio of long chains within amylopectin results in tightly intertwined adjacent outer chains, forming double helix crystalline zones. This consequently augmenting the texture quality linked to stickiness-related attributes. [Display omitted] • Quantitative descriptive analysis revealed the sensory texture of 11 yam varieties. • High amylose content increases hardness, chewiness, and compactness of yam starch. • Starch molecular size is positively correlated with stickiness, fineness, and waxiness. • Medium amylose and amylopectin chains primarily affect the stickiness of yam. [ABSTRACT FROM AUTHOR]

Glycogen is a highly branched glucose polymer that is an energy storage material in fungi and animals. Extraction of glycogen from its source in a way that minimizes its molecular degradation is essential to investigate its native structure. In this study, the following extraction methods were compared: sucrose gradient density ultracentrifugation, thermal alkali, hot alcohol and hot water extractions. Molecular-size and chain-length distributions of glycogen were measured by size-exclusion chromatography and fluorophore-assisted carbohydrate electrophoresis, respectively. These two fine-structure features are the most likely structural characteristics to be degraded during extraction. The results show that the thermal alkali, hot alcohol and hot water extractions degrade glycogen molecular size and/or chain-length distributions, and that sucrose gradient density ultracentrifugation with neither high temperature nor alkaline treatment is the most suitable method for fungal glycogen extraction. [ABSTRACT FROM AUTHOR]

The goal of this paper was to evaluate the influence of a range of plasma generation voltages on the physicochemical, structural, and technological properties of Aria (Goeppertia allouia) starch. Untreated (0 kV) and high voltages of cold plasma generation (7, 10, 14, and 20 kV) treated samples were evaluated according to their amylose content, pH, groups carbonyl/carboxyl, molecular size distribution, structure and technological properties (empirical viscosity, hydration properties, thermal analysis and gel strength). The applied voltage of 14 kV resulted in the greatest depolymerization of the starch chains, while 20 kV allowed the formation of oxidized complexes, promoting crosslinking of the starches chain. The cold plasma technique did not affect the levels of resistant starches, but increased the starch digestibility. The increased carbonyl and carboxyl groups also influenced the paste viscosity, improved hydration properties. This study suggests that the cold plasma technique can be useful in the controlled modification of starches, producing starches with different technological properties. • Dielectric barrier plasma modifies physicochemical properties of aria starches. • Different plasma generation voltages were applied: 7, 10, 14, and 20 kV. • 14 kV showed greater reduction in amylose content. • Aria starch presented phase transition from type-A to type-B crystal with cold plasma. [ABSTRACT FROM AUTHOR]

Three water-soluble pectic polysaccharides (WKBP-P2, P3 and P4) were isolated from white kidney bean by ion exchange combined with size-exclusion methods. The structural features were characterized by GC–MS, NMR spectroscopy and HPSEC-MALLS-RI. It was found that three pectic polysaccharides were the major water-extracted polysaccharides in white kidney bean. All the WKBP-P2, P3 and P4 were probably composed of various structural regions including homogalacturonan (HG), xylogalacturonan (XGA), rhamnogalacturonan I (RG-I) regions in backbone, and arabinan region mainly as side chain. However, these pectic polysaccharides were significantly different in molar ratios of these structural regions and molecular size. WKBP-P2 was HG-predominant pectin (partially methyl-esterified) with weight-average molecular weight (M w) of 1.2 × 104 g/mol, and contained minor RG-I, arabinan and probable XGA regions. WKBP-P3 (M w of 4.0 × 104 g/mol) primarily embraced XGA, HG, arabinan regions and minor RG-I region. WKBP-4 with highest M w (4.5 × 105 g/mol) had the most arabinan region (51.3%), which was probably the side chain linked to the backbone composed of RG-I, HG and slight XGA regions. These findings provided a structural basis for study on polysaccharides from white kidney bean, which was benefit for development of functional food. [Display omitted] • Pectic polysaccharides (WKBP-P2, P3 and P4) were isolated from white kidney bean. • WKBP-P2 (M w of 1.2 × 104 g/mol) was characterized by the predominance of HG. • WKBP-P3 (M w of 4.0 × 104 g/mol) probably consisted of XGA, HG and minor RG-I. • WKBP-P4 (M w of 4.5 × 105 g/mol) had 51.3% arabinan, certain HG, RG-I and slight XGA. [ABSTRACT FROM AUTHOR]

The aim of this study was to explore the relationship between the structural and functional properties of starch isolated from Atlantic potatoes at different stages of growth without the effect of varieties and growth environment. The molecular size and chain-length distribution of amylopectin significantly varied with growth. The M w and M n of amylopectin ranged from 2.976 × 107 to 4.512 × 107 g/mol and 1.275 × 107 to 2.295 × 107 g/mol, respectively, suggested that the polydispersity varied with growth. The average chain length of amylopectin during potato growth showed small but significant changes and ranged from DP 23.59 to 24.73. Overall, A fp chains, A crystal chains, and B1 chains increased with growth, and B2 and B3 chains decreased with growth. There was wide variation in starch pasting, gelatinization, retrogradation, in vitro starch digestibility, swelling power, solubility, and gel stability properties. Specifically, potato starch harvested at the earliest time had the highest resistant starch content. The variation trend of swelling power and solubility was similar, reached highest value at 42 days, were 20.38 g/g and 8.83%, respectively. Correlation analysis revealed that the physicochemical properties were significantly affected by amylopectin fine structure. The results of this study enhance our understanding of the structure–function relationship of potato starch. • The fine structure of starches over the growth period of potatoes was dissected. • Structure and properties of starch changed over the growth period of potatoes. • Desired starch property can be obtained by controlling potato growth time. • Relationship between structure and properties of starch was explored. [ABSTRACT FROM AUTHOR]

This study investigated the physicochemical characteristics of protease-treated wheat starch (PT-WST) to understand the role of starch granule-associated proteins (SGAPs) and the potential capability of PT-WST to provide a nutrient delivery system (NDS). Protease treatment was conducted at 4 °C and 37 °C (PT04 and PT37), respectively. A model delivery system was assessed with PT37 granules infiltrated by λ-carrageenan (λC) under variations of molecular size (λC hydrolysates produced from 0, 2.5, 100, and 500 mM HCl solution), agitation time, and temperature. Protein-specific (3-(4-carboxybenzyl)quioline-2-carboxaldehyde) or non-reactive (methanolic merbromin) fluorescent dye staining revealed that removal of SGAPs on surfaces and channels were more effective for PT37 than for PT04. Consistent amylose content, swelling, and gelatinization temperature before and after protease treatment suggested minimal impact on the starch structure. PT37 presented higher solubility and pasting viscosity than PT04. This resulted from excessive SGAP removal, which enhanced entrapment capacity. λC molecular size and agitation temperature showed a negative correlation with the content of λC entrapped within PT37, and this content depended on the interplay between the agitation time and λC molecular size. As λC molecular size decreased, the λC distribution became uniform throughout the granules, which confirmed the potential of PT-WST as a carrier for NDS. • Protease treatment (PT) removed starch-associated surface/channel proteins (SGAPs). • The SGAP removal in wheat starch (WST) granules was more pronounced at 37 °C. • SGAPs affect solubility, pasting, and retrogradation of WST. • λ-Carrageenan (λC) entrapped into PT-WST decreased with λC size and temperature. • λC hydrolysates diffused into PT-WST matrix from cavity and laterally from channel. [ABSTRACT FROM AUTHOR]

The development and application of new selenium-enriched polysaccharides has become a critical topic in recent years. In this study, a natural selenium-enriched polysaccharide fraction (Se-POP-21) produced by Pleurotus ostreatus was purified, characterized, and investigated the antioxidant and antitumor activities in vitro. The Se-POP-21 was mainly composed of mannose, glucose, galactose and arabinose, with a molar ratio of 18.01:2.40:26.15:7.34, of which molecular weight was 15,888 Da and the selenium content was 5.31 μg/g. Spectral analysis demonstrated that Se-POP-21 represented a non-triple helix pyranopolysaccharide and selenium occurred in the form of C-O-Se and Se O. Molecular size and morphology studies showed that Se-POP-21 exhibited a spherical shape with a particle size distribution between 100 and 200 nm, even though Se-POP-21 aggregates were also found with a size between 500 and 600 nm. In addition, Se-POP-21 showed strong scavenging capacity to DPPH and hydroxyl radical. More, cell experiments showed that Se-POP-21 could reduce viability of A549, SKOV3, HepG2 and MCF-7 cells, induce apoptosis and inhibit metastasis of A549 cells. A potential mechanism was that Se-POP-21 inhibited the epithelial-to-mesenchymal transition of cancer cells. Se-POP-21 featured no significant effect on normal cells. Se-POP-21 showed great potential to develop into a natural antioxidant or low-toxic antitumor drug. Unlabelled Image • A water-soluble selenium polysaccharide (Se-POP-21) produced by Pleurotus ostreatus was purified. • Se-POP-21 had potent antioxidant capacity. • Se-POP-21 reduced viability, induced apoptosis and inhibited metastasis of A549 cells. [ABSTRACT FROM AUTHOR]

Ionically crosslinked hydrogels based on TEMPO nanocelullose and alginate were prepared to develop a generalized pH value, temperature and biopolymer concentration dependent mathematical model. The distinctive attention was in the demonstration of hydrogen bonds effects in the mathematical model, prevailing especially in the field of low crosslink densities of TEMPO nanocellulose hydrogel in acid medium. Accordingly, alginate hydrogels were subjected to the research as comparable samples with less significant hydrogel bonds effect. The equation was built upon the determination of the average mesh size in a TEMPO nanocellulose and alginate hydrogel network and studying its changes in different pH release environments. Based on rheological measurements of TEMPO nanocellulose and alginate from the basic and acidic release environment, the mechanism of swelling and shrinkage was thoroughly discussed as well as the influence of substituent groups, ionic interactions and hydrogen bonds in different pH medium were evaluated. Due to the protonation of carboxylic groups, TEMPO nanocellulose and alginate hydrogels shrink in an acid environment. The presented approach will accelerate, improve and reduce the cost of research in the field of controlled release technology with target drug delivery. • Design of alginate and TEMPO nanocellulose hydrogels for clinical studies • Rheological measurements of hydrogels in acidic and basic release environments • Effect of ionic and hydrogen interactions on the properties of TOCNF hydrogels • Implementation of a pH-dependent release of different molecule size FITC-Dextran • Mathematical prediction of drug diffusion coefficient with respect to medium pH [ABSTRACT FROM AUTHOR]

The perpetually changing cellular conditions, nucleotide sequence, and environmental effects including osmotic stress have multiple effects on DNA, leading to several conformational alternations and subsequently influencing their activity, too. In this work, single-molecule FRET microspectroscopy has been employed to monitor the breathing dynamics as an effect of molecular crowding in the stem region of Fork-DNA. The structural integrity greatly alters with the presence or absence of nucleotide overhangs and on the nature and concentration of the crowding agent, thus affecting the stability of the stem region and hence the forked DNA. The multiple hydrogen bonds and hydrophobic interactions between the polynucleotide strands appear to be altered with osmotic crowding. This induces increased flexibility in the double helix and allows DNA to breath. The conformational alternation of the DNA happens in nanometer resolution, that is been monitored by the change in the FRET efficiency between the dyes attached to two different strands of the DNA. The nature and molecular weight of crowding agents control the degree of spatial breathing in the stem of Fork-DNA. These constant fluctuations between the entropically favorable partially folded structures to an enthalpically favorable folded structure are not only valuable for elucidating nucleic acid structure but might play an important role in enzyme kinetics. Unlabelled Image • Single-molecule FRET has been employed to study breathing in the stem of Fork-DNA. • The role of concentration and size of molecular crowder has been elaborated. • Detailed kinetics using HMM and free energy of each state of fluctuating Fork-DNA has been calculated, • Enthalpically and entropically favorable states have been identified. [ABSTRACT FROM AUTHOR]

In previous studies, we successfully prepared lotus-seed starch nanoparticles (LS-SNPs) using enzymatic methods. To further improve their performance, we studied the structural, physical and chemical properties of LS-SNPs prepared by high-pressure homogenization (HPH)-assisted enzymatic hydrolysis (EH). HPH treatments at different pressures and frequencies have a significant effect on the particle size and molecular weight of LS-SNPs. Structural analyses showed that LS-SNP and H-LS-SNP both comprised B-type starch crystals. As the homogenization pressure and frequency were increased, the relative crystallinity of H-LS-SNP first increased and then decreased, indicating that HPH treatment affected the double-helix structure of LS-SNPs. The results also show that moderate HPH treatment was beneficial for enzymatic hydrolysis, but when the HPH treatment was further increased, it destroyed the ordered structure of LS-SNPs. Our research showed that H-LS-SNPs with the smallest particle size and the highest crystallinity were obtained under pressure of 150 MPa, a homogenization frequency of five times the original, and a material-to-liquid ratio of 3%. The results indicate that HHP-assisted EH is a suitable method for preparing SNPs. These findings provide new ideas for the preparation of SNPS to meet the needs of food industry. Unlabelled Image • The highest crystallinity of lotus seed starch nanoparticles (LS-SNPs) is 77.22%. • The method to prepare LS-SNPs was environmentally and high-efficiency. • The relationship between high-pressure homogenization (HPH) and mechanism of LS-SNPs was explored. • The optimal HPH conditions for preparation of LS-SNPs were selected. [ABSTRACT FROM AUTHOR]

This work evaluated for the first time the effect of dual modification of cassava starch by using ozone (O 3) and dry heating treatment (DHT). The dual modification was capable to promote fissures on the surface of the starch granule (DHT + O 3), affected the starch amorphous domains, presented greater degree of starch oxidation (DHT + O 3) and different profiles of starch molecular size distribution. These modifications resulted in starches with different properties. Moreover, the sequence of treatments was decisive for the hydrogel properties: while DHT + O 3 resulted in formation of stronger gels, O 3 + DHT resulted in weaker gels. In conclusion, this proposed dual modification was capable to produce specific modified starch when compared with the isolated treatments, also expanding the potential of cassava starch applications. Unlabelled Image • Ozone (O 3) and dry heating (DHT) treatments were combined for starch modification. • Both structure and properties were evaluated. • Each process and combination differently changed the starch amorphous domain. • The sequence of the combined treatments influenced the starch properties. • DHT + O 3 treatment presented stronger gel, while O 3 + DHT had a poor gel formation. [ABSTRACT FROM AUTHOR]

Herbal bioactive compounds have captured pronounced attention considering their health-promoting effects as well as their functional properties. In this study, the binding mechanism between milk protein bovine β-lactoglobulin (β-LG), oleuropein (OLE) and safranal (SAF) found in olive leaf extract and saffron, respectively via spectroscopic and in silico studies. Fluorescence quenching information exhibited that interactions with both ligands were spontaneous and hydrophobic interactions were dominant. Also, the CD spectroscopy results demonstrated the increase in β-sheet structure and decrease in the α-helix content for both ligands. Size of β-LG-OLE complex was higher than β-LG-SAF due to the conformation and larger molecular size. Molecular docking and simulation studies revealed that SAF and OLE bind in the central calyx of β-LG and the surface of β-LG next to hydrophobic residues. Lastly, OLE formed a more stabilized complex compared to SAF based on the molecular dynamic simulation results. Unlabelled Image • The association constant of safranal with β-LG was higher than oleuropein. • Size of complexes increased as the concentration of ligands enhanced. • Hydrogen bonds formed between Ser116 and Glu55 (β-LG) with oleuropein and safranal, respectively. • The complex of oleuropein-β-LG was more stable compared to safranal-β-LG. [ABSTRACT FROM AUTHOR]

This study investigated the effects of acid degradation of amylopectin on the structure, pasting, and rheological properties of waxy maize starch. It is found that: 1) the amount of amylopectin short-chains with degree of polymerization (DP) ~ 15–50 increased while that of amylopectin long-chains with DP ~ 50–200 decreased by acid hydrolysis; 2) acid hydrolysis produced smaller amylopectin molecules with a narrower size distribution; 3) acid hydrolysis had a minor effect on the crystalline and granular structures of native starch; 4) the pasting viscosity of acid hydrolyzed starch during heating and the consistency coefficient, K , of starch gels increased, whereas the flow behavior index, n , decreased. Correlation analysis was used to clarify the molecular causes for the variations of pasting and rheological properties of acid hydrolyzed starch. • Sulfuric acid hydrolysis decreases starch molecular size and size distribution. • Amylopectin chains with DP > 36 are degraded while those with DP24–36 are formed. • Starch crystallinity is decreased while starch granular structure is retained. • Molecular causes for the variations of starch viscosity are put forward. [ABSTRACT FROM AUTHOR]

High-pressure homogenization (HPH) is a common physical method used for starch modification. In this study, starch molecular structure in terms of chain-length distribution (CLD) and molecular size is characterized to explore the structural variations during HPH and its internal relations. It is found that: 1) the molecular size is significantly reduced by HPH treatments and further gradually decreases with HPH pressure increasing; 2) HPH degrades the long amylose chains with degree of polymerization (DP) ~ 2000–20,000 into short- and intermediate-amylose chains with DP ~ 100–1000 and DP ~ 1000–2000; 3) by HPH treatment, the proportion of amylopectin chains with DP ~ 6–12 and DP ~ 12–24 decreases while that with DP ~ 24–36 and DP ~ 36–100 increases, whereas, the amylopectin CLDs between HPH treated starch samples are not significantly varied; and 4) by a subtraction analysis, the molecular size of HPH treated starches shows a strong correlation with the proportion of degraded long amylose chains, indicating these long amylose chains might play a critical role in maintaining the large molecular size of starch. This study provides a further understanding of molecular features from the individual chains assembling into a whole branched molecule. [ABSTRACT FROM AUTHOR]

Two phenolic compounds (p -cresol and pyrogallol) were introduced into the benzyl position of poplar lignin by a phase separation method to obtain lignin-based derivatives with different structural properties called poplar lignophenols (LPs). The maximum protein adsorption capacity of LPs is 50–70 times greater than that of the industrial lignin under the same conditions. The interaction between poplar LPs and bovine serum albumin (BSA) near its isoelectric point (pH = 4.5) was studied using a quartz crystal microbalance with dissipation monitoring (QCM-D). The adsorption and desorption of BSA molecules on different LPs were investigated at various pH values of the buffer solution (2.1, 6.4, and 10.0), and the interaction mechanism between LP and BSA species was examined. The obtained results showed that hydrogen bonding was the strongest binding force between LPs and BSA as compared with hydrophobic and electrostatic interactions. The findings of this work can help to establish a relationship between the contents of hydroxyl groups, molecular structures, and molecular sizes of LPs and proteins under different pH conditions. [Display omitted] • Cresol and pyrogallol have been successfully introduced on lignin benzyl position respectively. • The ratio and linkage of lignin basic C 9 structural units have been accurately expressed. • The coated LPs films on gold-coated quartz crystals were uniform and showed good repeatability. • The interaction between LPs and BSA were proved to be dominated by hydrogen bonds in this study. • In future, it can be expected to play an important role in the recovery of alkali resistant enzymes. [ABSTRACT FROM AUTHOR]

Newcastle disease virus (NDV) has been explored to a great extent to understand the biology of negative-sense RNA viruses. Nucleoprotein (N) is the most abundant protein in the virus particles, and its primary function is to encapsidate the virus genome for its transcription, replication, and packaging. Here, we report the structural investigations of the N protein of NDV (NDV-N) in solution. The N gene of NDV was cloned and expressed in E. coli as a soluble protein of ~53 kDa in size. The FE-TEM imaging of the purified NDV-N displayed a nearly spherical shape with a diameter of 28 nm and the DLS analysis of the purified NDV-N displayed a monodispersed nature, with averaged hydrodynamic radius, 26.5 nm. The conformational behavior of the NDV-N in solution was studied by SAXS analysis, which suggested two ring structures of NDV-N formed by thirteen monomeric units each. Each ring interacts with RNA molecules and forms a large molecule with a size of ~1450 kDa and are stacked on each other in a spiral arrangement. More profound knowledge of the N protein structure will help us in deciphering the control of viral RNA synthesis at the early stage of NDV life-cycle. [ABSTRACT FROM AUTHOR]

The evolution of the starch fine structure during growth and its impact on the gelatinization behavior of cassava starch (CS) was investigated by isolating starch from South China 6068 (SC 6068) cassava harvested from the 4th to 9th growth period. During growth, the short-range ordered structure, crystallinity as well as particle size distribution of starch were increased. Meanwhile, the starch molecular size and amylopectin (AP) proportion increased, while the proportion of amylose (AM) exhibited a decreasing tendency. The chains of short-AM (X ~ 100–1000) were mainly significantly reduced, whereas the short and medium-AP chains (X ~ 6–24) had the most increment in AP. The solubility, thermal stability, shear resistance, and retrogradation resistance of starch were enhanced after gelatinized under the influence of the results mentioned above. This study presented a deeper insight into the variation of starch fine structure during growth and its influence on gelatinization behavior, which would provide a theoretical basis for starch industrial applications. [Display omitted] [ABSTRACT FROM AUTHOR]

Two chia mucilages with different viscosities, obtained by extraction conditions optimized in a previous work, were homogenized by high pressure homogenization (HPH). Particle size, molecular weight, zeta potential, FTIR spectrum, rheological properties, water absorption capacity, water holding capacity and iron binding capacity were determined on both mucilages treated and without treatment. Homogenization led to a significant reduction in viscosity respect to chia mucilage controls, which can be related to the decrease in particle size and molecular weight. A high iron binding capacity was obtained for both mucilages. FTIR spectra of both mucilages with iron showed displacements in bands related with stretching of carboxylic uronic acids, suggesting the interaction site with this mineral. This interaction was also verified by particle size determination with a displacement to higher sizes in the presence of iron. Potential zeta showed a significant reduction in the presence of iron. A model to explain the binding between chia mucilage and iron is proposed. HPH appears as an alternative to expand chia mucilage functionality reducing the viscosity of chia mucilage solutions for the offer of a new ingredient also with optimal levels of hydration and iron binding capacity. [Display omitted] • Technological properties of chia mucilage (CM) were studied. • High pressure homogenization (HPH) modified the structure of CM. • HPH reduced particle size and viscosity of CM. • CM treated by HPH maintained optimal hydration and iron binding properties. [ABSTRACT FROM AUTHOR]

Ionic strength condition is a crucial parameter for food processing, but it remains unclear how ionic strength alters the structure and digestibility of binary complexes containing starch and protein/protein hydrolysates. Here, the binary complex with varied ionic strength (0–0.40 M) was built by native corn starch (NS) and soy protein isolate (SPI)/hydrolysates (SPIH) through NaCl. The inclusion of SPI and SPIH allowed a compact network structure, especially the SPIH with reduced molecule size, which enriched the resistant starch (RS) of NS-SPIH. Particularly, the higher ionic strength caused the larger nonperiodic structures and induced loosener network structures, largely increasing the possibility of amylase for starch digestion and resulting in a decreased RS content from 19.07 % to 15.52 %. In other words, the SPIH hindered starch digestion while increasing ionic strength had the opposite effect, which should be considered in staple food production. [ABSTRACT FROM AUTHOR]

Nano starch exhibits many advantages for application in diverse fields. Amaranth starch consisted of starch particle aggregates, isolated amaranth starch, and few natural nano starch (NNS), while NNS (0.92 ± 0.12 μm) was successfully isolated for the first time. Compared with the isolated amaranth starch, NNS showed smaller particle size but larger molecular weight, suggesting that the molecules arranged densely. NNS had a weak A-type crystal structure because of its more content of short starch chains, but higher amylose content resulted in the increase of its gelatinization temperature. The special NNS, owning several different physicochemical properties from amaranth starch, can open new ways for the production and application of nano biomass materials. [ABSTRACT FROM AUTHOR]

Staple foods with starch and protein components are usually consumed after thermal processing. To date, how including protein hydrolysates (with varied hydrolysis degrees) tailors the structure and digestion features of starch-based matrix with thermal processing has not yet been sufficiently understood. Here, corn starch (CS), soy protein isolate (SPI), and soy protein isolate hydrolysates (SPIH) with different hydrolysis time (5–60 min) were used to prepare starch-based binary matrices. With the addition of SPI or SPIH during thermal processing, the resultant binary systems exhibited higher thermal stability (breakdown visibility was increased by 1.9–10.8 times), denser networks, and fewer short-range orders (R 995/1022 was decreased by up to 15.3 %). These structural changes allowed an inhibited starch digestion within the binary system, especially with increased SPI or SPIH content. Compared with CS, the content of resistant starch (RS) for CS-SPI binary complex (10:3 w /w) increased from 9.89 % to 16.69 %. Compared to SPI, SPIH inclusion displayed a stronger inhibitory effect on starch digestion since the reduced molecule size of SPIH probably enhanced its interplays with starch or amylase. For instance, the 10:3 w /w starch-SPIH 60 binary matrix possessed the highest RS content (19.07 %). • Including soy protein isolate hydrolysates (SPIH) slowed starch digestion. • Prolonging SPIH hydrolysis time more effectively enriched resistant starch. • SPIH inclusion increased the network density of obtained starchy binary system. • SPIH inclusion endowed the obtained binary system with more crystallites. • SPIH inclusion endowed the obtained binary system with smaller nanostructures. [ABSTRACT FROM AUTHOR]

This study was to improve the physical and oxidative stability of sodium caseinate (NaCas)-stabilized oil-in-water (O/W) emulsions with arabinoxylan hydrolysates (AXHs). AXHs with different molecular sizes were prepared using xylanase treatment for 0 (AXH0), 30 (AXH30), 60 (AXH60), and 120 (AXH120) min, respectively. Compared with the emulsion without AXHs, all AXHs emulsions showed increased coalescence stability, evidenced by no change occurred in the droplet size with the pH variation from 7.0 to 5.0. Moreover, at pH 7.0 and 5.0, AXH60 and AXH120 emulsions showed no flocculation, coalescence, or creaming before and after 21 d storage. All the AXH samples showed excellent antioxidant capacities, demonstrated by the slow accumulation of lipid hydroperoxides and thiobarbituric acid reactive substances during storage. In sum, rice bran arabinoxylans hydrolyzed ≥60 min possess a potential as effective antioxidants to form physically and oxidatively stable O/W emulsions at pH above the emulsifier pI, and substances with high antioxidant activity below the emulsifier pI still need to be explored. [Display omitted] • AXH60/AXH120 emulsions had no flocculation, coalescence or creaming at pH 7 and 5. • AXHs increased coalescence stability of emulsions with pH variation from 7 to 5. • AXHs decreased lipid oxidation products in emulsions. [ABSTRACT FROM AUTHOR]

In this work, the effects of four different extraction methods, acid (HCl), alkali (NaOH), enzymes (cellulase/pectinase), and buffer (pH 7.0) on the physicochemical properties and functionalities of burdock pectin were systematically investigated and compared. Buffer extraction gave a low yield (2.8 %) and is therefore limited in its application. The acid treatment hydrolyzed the neutral sidechains and gave a homogalacturonan content of 72.6 %. By contrast, alkali and enzymes preserved the sidechains while degrading the polygalacturonan backbone, creating a rhamnogalacturonan-I dominant structure. The branched structure, low molecular weight, and high degree of methylation (42.3 %) contributed to the interfacial adsorption, emulsifying capacity, and cellular antioxidant activity of the enzyme-extracted product. For the acid-extracted product, the strong intramolecular electrostatic repulsion restricted the formation of a contact interface to prevent coalescence of the emulsion. In addition, they did not have sufficient reducing ends to scavenge free radicals. Although a high branching size (5.0) was adopted, the low degree of methylation (19.5 %) affected the emulsifying capacity of the alkali-extracted products. These results provide useful information for pectic polysaccharides production with tailored properties. [Display omitted] • Acid, alkali, enzymes and buffer were used to extract pectic polysaccharides from burdock. • Acid treatment yielded homogalacturonan-rich pectic polysaccharides • Alkaline or enzyme extraction provided the rhamnogalacturonan-I dominant structure. • The emulsifying and antioxidant capacity of acid-extracted samples were constrained. • The small molecular size and branched structure favored the enzyme-extracted samples. [ABSTRACT FROM AUTHOR]

This study was aimed to investigate the properties of pyrodextrins under different preparation conditions and the effects of pyrodextrins on the retrogradation of fresh rice noodles. Pyrodextrins were made by heating corn starch with and without lactic acid at 180 °C ranging from 1 to 6 h. The molecular weights of pyrodextrins gradually decreased, whereas the branching degree increased and the chain length shrank with the prolongation of heating time. The changes of acid-heat-treated pyrodextrins were more pronounced than those of dry-heat-treated pyrodextrins under the same treatment time. The acid-heat-treated pyrodextrins displayed higher water solubility and lower viscosity, suggesting that they could no longer gel. These results suggest that starch retrogradation could be limited by pyrodextrins, especially acid-heat-treated pyrodextrins. Then, the pyrodextrins were added to fresh rice noodles and the eating and cooking qualities were examined during storage. After 35 days of storage, the pyrodextrin with acid heating at 180 °C for 4 h showed the most effective inhibition on starch retrogradation and was suitable for fresh rice noodles as an anti-retrogradation agent. The study might supply new perspectives on restraining starch retrogradation and promoting the fresh rice noodle industry. • Heating time affected molecular size, branching degree and chain length. • With the decreasing molecular size of pyrodextrin, solubility increased. • Pyrodextrin could retard the retrogradation of fresh rice noodles. • Pyrodextrin improved the cooking qualities of rice noodles during storage. [ABSTRACT FROM AUTHOR]

In this study, biodegradable films were produced from cassava starch modified by ozone at different levels. The films were produced by casting technique using native and ozonated cassava starch, glycerol as the plasticizer, and water as the solvent. Films were characterized in term of their mechanical, barrier and functional properties, morphology, crystallinity, colour, and opacity. The morphology of the ozonated films was more homogeneous in comparison to the films produced with the non-modified starch and enhanced properties were achieved. Films produced with ozonated cassava starch presented higher tensile strength, Young's modulus and lower elongation. The water vapour permeation and the oxygen permeation were increased by increasing the ozonation time. Moreover, ozone processing resulted in films with a more hydrophilic surface and lower solubility after 24 h. Possible explanations and applications were discussed. In conclusion, the ozone processing showed to be a good alternative for starch based packaging production. • Ozone processing change both starch molecules size and charge. • Ozonation resulted in film with enhanced mechanical properties. • A good alternative for packaging was developed. [ABSTRACT FROM AUTHOR]

Starch molecular structural effects in duckweed (Lemna minor and Landoltia punctata) controlling in vitro enzymatic degradation kinetics was studied. The molecular size distributions of fully-branched starches and the chain length distributions (CLDs) of enzymatically debranched duckweed starches were obtained using size-exclusion-chromatography (SEC). The CLDs of both debranched amylose and amylopectin were fitted with models using biologically-meaningful parameters. While there were no significant correlations between amylose content and starch degradation rate, the total amounts of amylose with shorter chain length negatively correlated with undigested starch content, and the amount of amylopectin long chains negatively correlated with the degradation rate coefficient. This provides new knowledge for the utilization of duckweed starches in bioethanol production. Unlabelled Image [ABSTRACT FROM AUTHOR]

Non-glutinous rice is always less sticky than glutinous rice. By soaking two non-glutinous rice (Jingmi and Xianmi) with different concentrations of NaOH solution, the stickiness of cooked non-glutinous rice is significantly increased, which is closely associated with the removal of surface proteins of these treated rice grains. By investigating starch leaching characteristics and the molecular structure of leached starch, we find: (i) total solids and amylopectin amount in the leached materials increase by raising NaOH concentration; (ii) the molecular size and chain-length distributions (CLDs) of leached starch significantly differ between samples with different soaking treatments; (iii) a strong correlation between stickiness of cooked rice and total amount of leached amylopectin is established. (iv) molecular causes for the increased stickiness of alkali-soaked rice are put forward to explain the above observations. This study could broaden the applications of non-glutinous rice by altering its stickiness attribute with alkali soaking. • NaOH soaking significantly increases the stickiness of non-glutinous rice. • Surface protein is significantly reduced by alkali soaking. • Total solids and amylopectin amount in the leachate increased by NaOH soaking. • Molecular structure of leached starch shows no large variation between soaked rice. • Leached amylopectin amount might be the main reason for the increased stickiness. [ABSTRACT FROM AUTHOR]

Abstract Starch molecular structure, in terms of chain-length distribution (CLD) and molecular size, are important structural features regarding to "(starch) structure-property" relations for starch-based foods. In this study, amylopectin CLDs from fluorophore-assisted carbohydrate electrophoresis (FACE) are parameterized by a biosynthesis-based model, amylose CLDs and molecular sizes of amylose and amylopectin are measured by size-exclusion chromatography (SEC), and statistically meaningful relationships are established between starch CLDs, starch molecular size, and amylose content using rice starches with a wide range of amylose content. This shows that amylopectin molecular size is increased by increasing the proportion of short amylopectin chains with degree of polymerization (DP) 6–32 and decreasing the percentage of long amylopectin chains with DP 63–100. On the other hand, molecular sizes of both branched amylopectin and amylose molecules are negatively correlated with amylose content, suggesting that high-amylose rice tends to have smaller amylopectin and amylose molecular sizes. These relations are rationalized in terms of chain-length effects on the production of branched amylopectin and amylose molecules between different rice cultivars, which could provide new insights regarding to starch "structure-property" relations. [ABSTRACT FROM AUTHOR]

Poria cocos (Schw.) Wolf is a well-known edible and medicinal fungus. The polysaccharide in the sclerotium of P. cocos was extracted and prepared into carboxymethyl pachymaran (CMP). Three different degradation treatments including high temperature (HT), high pressure (HP) and gamma irradiation (GI) were used to process CMP. The changes in physicochemical properties and antioxidant activities of CMP were then comparatively investigated. We found that the molecular weights of HT-CMP, HP-CMP, and GI-CMP decreased from 787.9 kDa to 429.8, 569.5 and 6.0 kDa, respectively. Degradation treatments had no effect on the main chains of →3-β-D-Glcp-(1 → while changed the branched sugar residues. The polysaccharide chains of CMP were depolymerized after high pressure and gamma irradiation treatments. The three degradation methods improved the stability of CMP solution while decreased the thermal stability of CMP. In addition, we found that the GI-CMP with lowest molecular weight had the best antioxidant activity. Our results suggest that gamma irradiation treatment could degrade CMP as functional foods with strong antioxidant activity. • CMP was degraded by high temperature, high pressure and irradiation treatments. • Degradation reduced the viscosity, molecular weight and particle size of CMP. • Degradation treatments only changed the branched sugar residues of CMP. • High pressure and irradiation treatments depolymerized the chain structure of CMP. • Antioxidant activities of CMP increased after high temperature and irradiation treatments. [ABSTRACT FROM AUTHOR]

Poly (β-L-malic acid) (PMLA) is attracting industrial interest for its potential application in medicine and other industries, whose functions primarily depend upon its molecular size and chemical structure. Up to now, the fractionation and characterization of PMLA produced by Aureobasidium spp. were still unclear. In this study, the product from A. melanogenum ipe-1 was effectively fractionated using 300 and 50 kDa membranes. During the filtration, the mechanisms of membrane fouling were illegible since the PMLA can both reject and permeate the membrane, while the main fouling mechanism varied between standard blocking and complete blocking during the diafiltration. After fractionation, 14.0, 8.4 and 77.6 % of the PMLAs with M w s of 75,134, 21,344 and 10,056 Da were distributed in the 300 kDa retentate after diafiltrating, 50 kDa retentate after diafiltrating, and the 50 kDa permeate, respectively. The M w /M n s of the PMLAs were 4.12, 1.92, and 1.12 in the three fractions. Based on characteristic spectra of NMR, HPLC and FTIR, the product was not usual L-malic acid monomers, but glucose-terminated PMLA. The glucose was located at the terminal hydroxyl of PMLA. These results would serve as a valuable guide for process design and practical operation in subsequent industrial application. • PMLA was effectively fractionated using 300 and 50 kDa membranes. • A higher PMLA M w of 75,134 Da was obtained. • Glucose-terminated PMLA was produced by A. melanogenum ipe-1. • The glucose was located at the terminal hydroxyl of PMLA [ABSTRACT FROM AUTHOR]

In this work, xanthan gum-based composites were successfully graft-modified by amantadine (XG-Fe3+/AM) with higher adsorption capacity and selectivity on recycling cationic dye (methylene blue, MB) from aqueous solution. The adsorption equilibrium of MB could be achieved approximately within 5 min when the initial concentration was 100 mg/L, and the maximum adsorption capacity was up to 565 mg/g. After 5 desorption-regeneration cycles, the removal rate of XG-Fe3+/AM for MB could still be as high as 95 % with slight decrement. Additionally, the effects of pH, contact time, temperature and initial dye concentration on the adsorption performance of MB were systematically examined. Furthermore, the adsorbent was characterized by FT-IR, BET and XPS analysis. In mixed anionic and cationic dyes, the adsorption selectivity of XG-Fe3+/AM on MB in the mixture of MB and methyl orange (MO) reached up to 99.69 %. Molecular dynamics simulation revealed that the trend of adsorption energy for dyes was in good agreement of the experimental order of adsorption capacities and molecular sizes among seven anionic and cationic dyes based on molecular matching effect and electrostatic interaction. Therefore, XG-Fe3+/AM is an eco-friendly, facile-synthesis and high-selectivity adsorbent, which remove cationic dyes in multi-component systems through electrostatic interaction and molecular matching effect. [Display omitted] • A facile-preparation xanthan gum adsorbent was studied to recover MB selectively. • The adsorption equilibrium of MB could be achieved within 5 min. • The adsorption selectivity on MB in the mixture of MB and MO can reach up to 99.69 %. • The adsorption capacity on MB could be up to 565 mg/g. • The selective mechanism has been well studied by molecular dynamics. [ABSTRACT FROM AUTHOR]

Starch is a polysaccharide with varying amylose-to-amylopectin ratios as a function of its biological sources. It is characterized by low shear stress resistance, poor aqueous/organic solubility and gastrointestinal digestibility which limit its ease of processing and functionality display as an oral drug delivery vehicle. Modulation of starch composition through genetic engineering primarily alters amylose-to-amylopectin ratio. Greater molecular properties changes require chemical and enzymatic modifications of starch. Acetylation reduces water solubility and enzymatic digestibility of starch. Carboxymethylation turns starch acid-insoluble and aggregative at low pHs. The summative effects are sustaining drug release in the upper gut. Acid-insoluble carboxymethylated starch can be aminated to provide an ionic character essential for hydrogel formation which further reduces its drug release. Ionic starch can coacervate with oppositely charged starch, non-starch polyelectrolyte or drug into insoluble, controlled-release complexes. Enzymatically debranched and resistant starch has a small molecular size which confers chain aggregation into a helical hydrogel network that traps the drug molecules, protecting them from biodegradation. The modified starch has been used to modulate the intestinal/colon-specific or controlled systemic delivery of oral small molecule drugs and macromolecular therapeutics. This review highlights synthesis aspects of starch and starch derivatives, and their outcomes and challenges of applications in oral drug delivery. [ABSTRACT FROM AUTHOR]

In this study, rice starch-protein hydrolysate (WPH-S) complexes with high resistant starch (RS) content were prepared by heat-moisture treatment (HMT) and annealing (ANN). The effects of different hydrothermal treatments on the structure and thermal stability of the WPH-S complexes and their relationship with starch digestibility were further discussed. The results showed that RS contents of ANN-WPH-S complexes (35.09–40.26 g/100 g) were higher than that of HMT-WPH-S complexes (24.15–38.74 g/100 g). Under hydrothermal treatments, WPH decreased the hydrolysis kinetic constant (k) of starch form 4.07 × 10−2–4.63 × 10−2 min−1 to 3.29 × 10−2–3.67 × 10−2 min−1. HMT and ANN promoted hydrogen bonding between WPH and starch molecules, thus increasing the molecular size of starch. In addition, the shear stability of WPH-S mixture was improved with the hysteresis loop area decreased after HMT/ANN treatments, resulting in a more stable structure. Most importantly, the hydrothermal treatment made the scatterers of WPH-S complexes denser and the surface smoother. Especially after ANN treatment, the WPH 60 -S complex formed a denser aggregate structure, which hindered the in vitro digestion of starch to a certain extent. These results enrich our understanding of the regulation of starch digestion by protein hydrolysates under different hydrothermal treatments and have guiding significance for the development of foods with a low glycemic index. [Display omitted] • The resistant starch contents of ANN-WPH-S was higher than that of HMT-WPH-S. • HMT and ANN promoted hydrogen bonding between WPH and starch. • WPH decreased the hydrolysis kinetic constant of starch after HMT and ANN. • Hydrothermal treatment promoted compactness of the WPH-S structure, especially ANN. [ABSTRACT FROM AUTHOR]

Dextrans enzymatic synthesis by immobilized Enterococcus faecalis Esawy dextransucrase was studied. Different parameters, such as: enzyme protein concentration (EPC), substrate concentration (SC), temperature and reaction time were evaluated. EPC played a fundamental role in controlling dextran molecular size with 0.1% dextran in reaction mixture. Dextran 38,397 and 125,471 Da were yielded at EPC 4.78 and 5.78 mg, respectively. Proper dextrans (73,378 and 117,521 Da) demanded in pharmaceutical applications were achieved at 6% and 12% sucrose concentrations and at 4.78 and 5.78 mg EPC, respectively. Optimum temperature for conversion of glucose to dextran was 30 °C (73% and 80% at 5.78 and 4.78 mg EPC, respectively). Varieties of maltooligosaccharides (MOS) were yielded by synergistic cooperation between sucrose and maltose. Six MOS and three dextrans samples in vitro have prebiotic effect on Lactobacillus casei with degree of variation. Two samples of MOS with different degree of polymerization (DP) and three samples of dextran with different molecular weight (MW) reported different fibrinolytic activity. [ABSTRACT FROM AUTHOR]