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Dysphagia, a widely suffered disease mainly by seniors, causes food swallowing-related issues such as choking, aspiration, aspiration pneumonia, and even death. Designing special diets such as thickened fluids (e.g. water, milk, soups, and juices) is an essential means of managing swallowing problems for people with dysphagia. This review discusses intrinsic influencing factors (e.g. surface tension, viscosity, yield stress, and the cohesion of fluid food boluses) and external influencing factors (e.g. temperature, fluid volume, saliva secretion, and body posture) that influence the swallowing behaviors (e.g. oropharyngeal flow velocity, residual amount, and aspiration risk) of thickened fluids. Subsequently, computer models assessing the swallowing features of thickened fluids (Newtonian/non-Newtonian) are highlighted, including mesh-based methods (e.g. finite element method (FEM)) and mesh-free methods (e.g. smooth particle hydrodynamics (SPH) and moving particle semi-implicit (MPS)). Also, current challenges and prospects of computer modeling in the development of dysphagia fluid foods are proposed. The swallowing behaviors of thickened fluids are closely linked to intrinsic and external factors. Increasing the viscosity and cohesiveness can slow the flow of the swallowed fluid bolus and suppress fluid splashing, thus providing more response time for the nerve system and muscles to reduce choking and aspiration risks. Such information is vital for establishing mesh-based and mesh-free computer models used to inspect the swallowing process of thickened fluids. These computer models are potentially useful for developing dysphagia foods, especially thickened fluids, with tailored swallowing performance. [ABSTRACT FROM AUTHOR]

In practical scenarios, destabilizing the physical attributes of natural polymers such as gelatin and starch occurs readily when exposed to specific moisture levels and heat. In this context, this work was carried out to assess the impact of PVA addition (up to 13 wt%) on the structure and physical properties of a 6:4 (w/w) gelatin/starch blend. The inclusion of PVA unfolded the molecular chains of gelatin and starch, thereby disrupting gelatin α-helices and impeding biopolymer crystallization. This facilitated hydrogen-bonding interaction between PVA and the two biopolymers, enhancing the stability of the molecular network structure. Rheological results indicate that composites (added with 4 % or 7 % PVA) with good compatibility exhibited excellent mechanical properties and deformation resistance. The addition of PVA elevated the gelling temperature (T gel) of the composites from 41.31 °C to 80.33 °C; the tensile strength and elongation at break were increased from 2.89 MPa to 3.40 MPa and 341.62 % to 367.56 %, respectively; and the thermal stability was also apparently improved, signifying the effective enhancement of the physical properties of gelatin/starch-based composites and the broadening of their application scope. This work could provide insights into the development of biodegradable natural/synthetic polymer composites with application-beneficial characteristics. [Display omitted] [ABSTRACT FROM AUTHOR]

Understanding the intricate relationships between the fine structure of xanthan on the assembly of konjac glucomannan (KGM) and xanthan is crucial for developing KGM/xanthan synergistic interaction gels. A combination of micro-differential scanning calorimetry, rheometry and atomic force microscopy were employed to explore the assembly process of KGM and xanthan with varying fine structures. Xanthan possessing standard acetyl (4.57%) and high pyruvate group contents (6.49%)(SA/HP) exhibited type-A and type-B bindings when interacting with KGM through cooling process. Decreasing these group contents effectively reduced type-B binding. Additionally, removal of pyruvate groups to 5.53% amplified type-A binding and gel strength from 258 Pa to 653 Pa, thanks to the improved helical structure forming ability of xanthan. Decreasing acetyl groups also intensified type-A interaction and gel strength from 258 Pa to 872 Pa. This stemmed from the formation of more stable assembly structure of xanthan and KGM, compared to the helical structure of deacetylated xanthan. These findings hold promise for the rational design of KGM/xanthan systems for versatile applications. [Display omitted] • Decreasing acetyl and pyruvate group contents enhanced type-A binding. • Decreasing acetyl and pyruvate group contents eliminated type-B binding. • Self-aggregation of xanthan occurred in KGM-SA/VLP and KGM-LA/LP. • The extensive binding of xanthan and KGM improved the gel hardness. [ABSTRACT FROM AUTHOR]

This work explored the pivotal role of λ-carrageenan in fortifying the gel structure, consequently enhancing gel-related attributes within an acid-induced soy protein isolate/λ-carrageenan system (SPI/Car). The model system was prepared by subjecting a thermally treated mixture of these two biopolymers to acidification. Small-angle X-ray scattering (SAXS) and chemical force analysis unveiled the profound influence of hydrogen bonding and electrostatic interactions in the formation of the intricate network architecture of SPI/Car gels. Remarkably, λ-carrageenan interacted with the hydrophilic groups on the surface of agglomerated SPI particles, effectively composing the fundamental framework of SPI/Car gels. Simultaneously, λ-carrageenan emerged as a linchpin through hydrogen bonding, establishing pivotal crosslinking connections. The introduction of λ-carrageenan resulted in a reduction in SPI particle size, the dispersion of previously formed aggregates, and a subtle blurring of the SPI particles. It also significantly heightened the prevalence of hydrogen bonding and electrostatic interactions, ultimately giving rise to a robust yet somewhat coarse gel structure, as evidenced by confocal laser scanning microscopy (CLSM). These profound structural alterations underpinned the enhancement of water-holding capacity (WHC) and gel hardness in SPI/Car gels. These findings hold promise for the rational design and application of SPI-based systems in the production of processed vegetarian and vegan foods. [Display omitted] • Adding λ-carrageenan enhanced gel structure of SPI/carrageenan system. • More λ-carrageenan reduced SPI particle size and loosened SPI aggregates. • More λ-carrageenan caused formation of a coarse and crude gel structure. • Adding λ-carrageenan enhanced water holding capacity of SPI/Car gels. • Adding λ-carrageenan improved gel hardness of SPI/Car gels. [ABSTRACT FROM AUTHOR]

Starches and proteins are two major types of biopolymer components, especially in many flour (starch)-based foods consumed worldwide, which provide energy and nutrition needed by the human body. In many such starch-based matrices (the main structural component of such foods), proteins and their interactions with starches greatly influence the matrix structure and properties. Studying the different roles played by proteins (endogenous and exogenous) in various starch-based food systems can provide a frame of reference for the design and production of improved starch-based food products with tailored properties and desirable nutritional functions. Significant efforts have recently been made to tailor the morphology, structure, and properties of many starch-based food systems, and thus to design various starch-based food products with satisfactory attributes. This review surveys the latest literature on starch-based matrices containing proteins. Discussed are the influences of proteins and their interactions with starches on the morphologies and structures (e.g. short- and long-range orders) of starch-based matrices, as well as on their pasting, thermal, rheological, textural, sensory, and digestive properties. Also, current understandings of structure–property links are presented, along with their implications on the production of various starchy foods (e.g. pastas, breads, cakes, and biscuits), including gluten-free versions. Proteins in many starchy food matrices can encapsulate the starch phase (or be adsorbed on its surfaces) on a micron scale, and thereby interact with starch chains via both non-covalent (e.g. hydrogen bonding, hydrophobic, and electrostatic) and covalent bonds (e.g. via Maillard reactions). These facts and protein features (e.g. hydration and gelation abilities) can play major roles in inhibiting starch retrogradation (the reassembly of cooked starch chains into ordered structures) and in regulating various other properties of such starch-based matrices, including viscosity, transition temperatures, moduli, hardness, sensory, digestibility, and shelf-life. Despite the fact that the current literature presents considerable information on the structure–property relationships of many different starch-based matrices and their applications in the processing of various starchy foods (e.g. pastas, noodles, and biscuits), it is still highly necessary to define more comprehensive correlations among starch–protein interactions, starch–protein matrix structures, and the resulting properties of such food products. [Display omitted] • Starch–protein interactions are affected by biopolymer type, proportion, and processing. • Proteins often inhibit starch gelatinization and restrict starch retrogradation. • Proteins affect the textural, sensory, and digestive properties of many starch-based foods. • Understandings that are instrumental to the development of high-quality, healthy foods are reviewed. [ABSTRACT FROM AUTHOR]

• Adding NaCl or CaCl 2 eliminated the type-B binding. • The presence of NaCl enhanced the type-A synergistic binding. • Type-A binding was improved by low concentration of CaCl 2. • Addition of excessive CaCl 2 reduced the type-A binding. Synergistic interaction gels could be formed by synergistic type-A and type-B bindings between konjac glucomannan (KGM) and xanthan during cooling. Adding salt ions significantly altered those bindings and thus the gel-related properties. The results showed that adding NaCl or CaCl 2 eliminated type-B binding due to an electrostatic shielding effect. Adding NaCl or CaCl 2 (3 and 6 mM) enhanced type-A binding by neutralizing the negative charge of COOH and reducing the electrostatic repulsion among xanthan chains, as evidenced by an increase in the onset temperature of exotherm peak, the formation of more parallel multiple filaments, and an increase in aggregation structures (>1.0 nm) and gel hardness. When CaCl 2 concentration was higher, Ca2+ bridged side-chain clusters into more complex structures, which would hardly participate in the formation of helical structures and weaken type-A binding. The results obtained are beneficial for the rational design and preparation of KGM/xanthan gels with synergistic interaction. [ABSTRACT FROM AUTHOR]

As an interdisciplinary manufacturing technique, microfluidics has attracted great attention in fields such as food structuring, chemical analysis, biomedicine, and biological testing. In particular, significant efforts have been recently made to design food structures via microfluidics, starting with its fundamental principles, thus contributing to developing next-generation, high-quality food products with satisfactory properties and attributes. This review first introduces the fundamental principles of microfluidic systems, and then focuses on their applications in the fabrication of different food structures, including emulsions (via shear-driven, spontaneous, or wettability-controlled emulsification), foams, microparticles (biopolymers-based and liposomes), and microgels (induced by temperature or ions). The upscaling strategies for microfluidic devices and challenges for application in the food industry are also reviewed. Despite such advances, it is still vital to further understand the flowing, droplet formation, and structuring of multi-component food matrices and the related developments of cost-effective microfluidic devices to meet practical requirements. [Display omitted] • Basic principles of microfluidics and its application in food structuring reviewed. • Microfluidic dimensionless numbers affect fluid flow regime and droplet formation. • Microfluidic system geometry affects fluid flow regime and droplet formation. • Microfluidics useful for structuration of emulsions, microparticles and microgels. [ABSTRACT FROM AUTHOR]

• CP2 starch had a lower ratio of starch branching enzyme to soluble starch synthase. • CP2 starch showed a higher proportion of long amylopectin chains. • CP2 starch showed increased crystallites and thickened lamellae. • CP2 starch showed increased resistance to enzyme digestion and hydrothermal effects. • CP2 starch showed increased paste stability under heating. This work inspects the supramolecular/molecular structures and digestion rate of potato starches (BEM, C7H, CP2 and CP4) as affected by starch biosynthetic enzymes. Among the starches, CP2 had a lower digestion rate with a higher paste heating stability. Regarding this, predominantly enzyme-sets (i) and (ii) were revealed to produce amylopectin chains. For CP2, the reduced activity ratio of starch-branching enzymes to soluble starch synthases allowed more long amylopectin chains (polymerization degree ≥ 34). Such molecular features tended to increase the crystallites and thicken the lamellae. With similar surface morphology and amylose content, the bulk density of chain packing in CP2 supramolecular structures could be increased. Then, there were an increase in the resistance of starch structures to hydrothermal effects, and a reduction in the enzyme hydrolysis rate. Also, the increased long amylopectin chains played roles in increasing the paste stability during heating with shearing and in reducing the digestion rate. [ABSTRACT FROM AUTHOR]

Abstract Using combined techniques and two comparisons (maize and cassava starches), this work concerns the multi-scale structure and digestion rate of water chestnut tuber starch. Among the starches, the water chestnut starch showed altered hierarchical structural features and a relatively low digestion rate. The underlying mechanism on the reduced digestion rate of water chestnut starch was discussed from a hierarchical structural view. Specifically, compared with maize starch, the water chestnut starch contained no pores on the granule surface, with the thickened crystalline lamellae, the increased lamella ordering, and the elevated content of crystallites. Such structural features probably increased the bulk density of molecule assembly in starch and thus could hinder the diffusion of enzyme molecules in starch matrixes. Consequently, the absorption of enzyme to the starch glucan chains could be retarded, resulting in a reduced enzyme hydrolysis rate of starch chains. The relatively large amylose molecules of water chestnut starch also tended to reduce the starch digestion rate, associated with the enhanced molecule interactions such as that between starch chains. In addition, the further reduction in the digestion rate of cassava starch could be also ascribed to the variations in the multi-scale structural features. Graphical abstract Image 1014 Highlights • Water chestnut starch showed thickened lamellae relative to maize or cassava starch. • Water chestnut starch exhibited a relatively high crystallinity level. • Water chestnut starch had an intermediate amylose molecule size. • Water chestnut starch showed a larger amylose size than maize starch. • Water chestnut starch displayed a relatively low digestion rate. [ABSTRACT FROM AUTHOR]

Highlights • Yam bean starch had relatively flawed lamellae and crystallites. • Yam bean starch had smaller molecule sizes than did potato starch. • Yam bean starch had fewer amylose and amylopectin long chains. • Yam bean starch was less resistant to hydrothermal effects and enzyme digestion. • Yam bean starch showed higher paste stabilities during heating and cooling. Abstract This work discloses the multi-scale structure and pasting/digestion behaviors of yam bean tuber starches (YB-GD and YB-SC). Compared to potato starch, YB starches exhibited varied pasting/digestion features that were understood from a multi-scale structural view. Especially, YB starches showed relatively polydisperse lamellae, less perfect crystallites, and fewer amylose molecules. These features should reduce the bulk density of starch chain packing, and could facilitate the water or enzyme diffusion in starch matrixes. Consistently, not only was starch's resistance to hydrothermal effects weakened (shown by reduced pasting temperature), but also the enzyme absorption to starch chains and the subsequent hydrolysis events were accelerated. Furthermore, YB starch molecules had more short chains, which played roles in reducing the paste viscosity along with the reduced granule size and in enhancing the paste stabilities during heating and cooling. Also, those molecular features tended to speed up the enzyme diffusion and digestion events. [ABSTRACT FROM AUTHOR]

Abstract This work concerns how crosslinker amount (N, N′ -methylene-bisacrylamide) affects the microstructural, absorbent and rheological features of one-step prepared starch-based superabsorbent polymers at a high starch concentration (0.27:1 w/w starch-water). The increased crosslinker amount evidently altered the microstructure and the absorbent and rheological features. Then, the variations in starch-based superabsorbent polymer properties were discussed from a microstructure viewpoint. Particularly, the higher crosslinker quantity rose the crosslinking density and the ratio (GR) of grafted anhydroglucose unit on starch backbone (from 27% to 52%), but short the average polyacrylamide (PAM) chain length (L PAM). These structural features suppressed the chain stretch within starch-based superabsorbent polymer fractal gels (confirmed by smaller R g value) and promoted the formation of smaller chain networks, thus weakening the water absorption to the starch-based superabsorbent polymer chain networks. Also, the increased GR and reduced L PAM , with lowered chain extension and elevated crosslinking density, probably decreased the flexibility and mobility of chain segments in starch-based superabsorbent polymer gel matrixes. This caused the enhanced robustness and storage modulus of the gels with reduced chain energy dissipation ability. Highlights • More crosslinker increased the ratio of anhydroglucose unit grafted. • More crosslinker reduced the average length of polyacrylamide chains. • More crosslinker reduced the size of mass fractal gels on nanoscale. • More crosslinker weakened the water absorbent capacity of starch-SAP. • More crosslinker enhanced the gel robustness of starch-SAP. [ABSTRACT FROM AUTHOR]

This work explores the influence of starch amylose/amylopectin ratio on the gel-related features of gelatin/starch system using small and large amplitude oscillation shear methods. The higher self-aggregation and self-entanglement ability of amylose reduced the miscibility of gelatin and starch, and increases zero-shear viscosity (ŋ 0) and reduces sol-gel transition temperature (T gel) by enhancing the difficulty of molecule movement and thus the difficulty of gel formation. The gelatin/amylopectin-rich system has higher gel hardness and wider linear viscoelastic region, which are related to the higher integrity and uniformity of network structure. The gelatin/amylose-rich system shows enhanced ability to resist deformation against external shear forces (suggested by higher storage and complex modulus) under small amplitude oscillatory shear (SAOS), which is ascribed to the larger rigidity and entanglement degree of amylose. At strain amplitude up to 50% (middle amplitude oscillatory shear, MAOS), gelatin/amylose-rich system exhibits reduced structure recovery ability (reflected by larger semi-minor axis of ellipse, and lower strain amplitude for inflexion of elastic stress) under MAOS, but enhances restructuring capacity at strains of 500% and 1000% (large amplitude oscillatory shear, LAOS) (indicated by occurrence of secondary loop) than gelatin/amylopectin-rich system. Those seemingly contradictory phenomena are correlated with the preference of hydrogen bond forming ability among amylose rather than with gelatin. This weakens interactions between amylose and gelatin and thus inhibits recovery of bulk structure under MAOS, but is favor for the formation of amylose aggregations, which is helpful for the local structure restructuring and thus enhances structure restructuring capacity under LAOS. The results help us comprehensively understand the gel-related properties of gelatin/starch system and are valuable for rational design of gelatin/starch systems with improved gel-related features. [Display omitted] • Higher amylose content reduces compatibility of gelatin and starch. • Higher amylose content decreases gel hardness of gelatin/starch composite. • Amylose-rich system exhibits higher G ′ in SAOS than amylopectin-rich one. • Amylopectin-rich system has higher structural resilience in MAOS than amylose-rich one. • Amylose-rich system has stronger restructuring in LAOS than amylopectin-rich one. [ABSTRACT FROM AUTHOR]

The sol-gel performance of wheat starch (WS) is of great importance for the processing and quality management of flour-based products. Herein, how acetylated starch (AS) inclusion modulates those properties of wheat starch-based system was understood using different techniques, e.g., rheological analysis and X-ray diffraction (XRD). Compared with WS alone, the resultant WS-AS binary system exhibited lower setback viscosity (corresponding to inhibited starch retrogradation as verified by XRD), zero-shear viscosity, moduli, and gel strength, accompanied by a suppressed sol-gel transition. Also, from thixotropy tests, the binary system with AS (WS-8%AS) presented the weakest thixotropy in hysteresis loop and a greater in-shear recovery property (as indicated by the three interval thixotropy test (3-ITT)), and the systems containing 6%–8% AS were proved to show good sol-gel properties. The property improvement could be related to the inhibited retrogradation, according to correlation analysis. In addition, the gel freeze-thaw stability of WS-AS systems was reduced as compared to WS, probably related to phase separations. The present information would facilitate the design of wheat starch-based matrices with regulated quality attributes. [Display omitted] • Incorporating acetylated starch reduced modulus, viscosity and thixotropy of binary sol. • Incorporating acetylated starch lowered hardness, chewiness and strength of binary gel. • Incorporating acetylated starch delayed the sol-gel transition of binary system. • Phase separations probably occurred in the wheat starch-acetylated starch binary system. • Including 6%–8% acetylated starch improved the performance of wheat starch-based system. [ABSTRACT FROM AUTHOR]

The surface hydrophobicity of starch-based films could be regulated using a two-step surface modification method. Such modification was realized by grafting with alkanols of different chain lengths (hexanol, dodecanol and octadecanol) on the surface of starch-based films. The grafting of alkanol increased the mobility of glycerol as the plasticizer within the film surface. Also, this grafting increased the mass ratio of carbon to oxygen on the film surface but reduced the mass ratio of carbon to nitrogen. Under the same reaction conditions, there were fewer dodecyl chains grafted onto the film surface than hexyl or octadecyl chains. Furthermore, the results revealed that the surface hydrophobicity of starch-based films could be enhanced by simply increasing the alkyl chain length. Also, fewer alkyl chains tended to reduce the surface hydrophobicity of the films. These results are valuable for the rational design of starch-based materials with demanded hydrophobic properties. [ABSTRACT FROM AUTHOR]

From a microstructural view, the focus of this work was on the water absorption rate of starch-based superabsorbent polymers (starch-SAPs) prepared under high starch concentration (0.27:1 w/w starch:water). The effects of starch amylose/amylopectin ratio were disclosed. The increase in amylopectin reduced the amount ( C PAM ) of polyacrylamide (PAM) in starch-SAPs but increased the ratio of starch carbons grafted with PAM, which eventually decreased the average length ( L PAM ) of PAM chains. The shorter PAM chains could reduce starch-SAP chain flexibility, thus inducing larger mass fractal gels in swollen starch-SAPs. In general, the increases in C PAM and L PAM were preferable for a higher water absorbent capacity ( WAC ), whereas the denser fractal gels reduced WAC . Interestingly, all starch-SAPs had a dual-phase absorption process with the first stage showing a higher rate than the second phase ( k 1 > k 2 ). The shorter PAM chains caused increases in k 1 and k 2 . [ABSTRACT FROM AUTHOR]

With synchrotron small/wide-angle X-ray scattering (SAXS/WAXS), we revealed that post-harvest hydration at ambient conditions can further alter the starch crystalline structure. The hydration process induced the alignment of starch helices into crystalline lamellae, irrespective of the starch type (A- or B-). In this process, non-crystalline helices were probably packed with water molecules to form new crystal units, thereby enhancing the overall concentration of starch crystallinity. In particular, a fraction of the monoclinic crystal units of the A-type starches encapsulated water molecules during hydration, leading to the outward movement of starch helices. Such movement resulted in the transformation of monoclinic units into hexagonal units, which was associated with the B-type crystallites. Hence, the hydration under ambient conditions could enhance the B-polymorphic features for both A-type and B-type starches. The new knowledge obtained here may guide the design of biopolymer-based liquid crystal materials with controlled lattice regularity and demanded features. [ABSTRACT FROM AUTHOR]

The practical characteristics (rheological, hydrophobic, and mechanical) of biopolymer matrix are essential for its application in food. This work discloses how zein incorporation alters these characteristics of agar/konjac glucomannan (KGM) based matrix. The zein particles formed non-intensive interactions with hydrophilic agar/KGM molecules and thus weakened the chain entanglements in the agar/KGM/zein (AKZ) ternary solutions, which allowed reductions in the zero-shear viscosity (from 4800 to 600 mPa s), sol-gel transition point (T gel , from 39 to 35 °C) and storage modulus (from about 16000 to ∼1000 Pa) of the resulting AKZ ternary gels. Also, such effects tended to enhance the agar aggregation (zein content: <12%) and the zein crystalline structure (zein content: >12%), reducing the dissolution rate and swelling ability of the acquired AKZ films (dehydrated gels) but increasing their T g (ca. 10 °C higher). The tensile strength and elongation at break of the composite films reached ca. 70–80 MPa and ca. 5%–7%, respectively. The results here may facilitate the development of agar/KGM-based composites (solution, gel or film) with desirable performance. [Display omitted] • Zein inclusion reduced chain entanglements and viscosity of agar/KGM solution. • Zein inclusion reduced the sol-gel transition point of resultant AKZ ternary solution. • Zein inclusion enhanced the crystallinity of resultant AKZ ternary film. • Zein inclusion reduced the dissolution rate and swelling of AKZ ternary film. • Zein inclusion could increase the elongation of resultant AKZ ternary film. [ABSTRACT FROM AUTHOR]

This work concerns how the multi-scale supramolecular structure of starch relates to its digestion rate from a view of structural heterogeneity. The untreated granule starch displayed a dual-phase digestion pattern, ascribed to two digestible fractions within the heterogeneous multi-scale structure of starch, which had prominently different digestion rates. Not only amorphous starch but also part of molecular orders (crystallites with flaws) were digested at a same rate k 1 at the first phase; densely-assembled starch including orders with fewer flaws was digested at a rather slow rate k 2 ( ca . 2/5 of k 1 ) at the second phase. When alkali altered the heterogeneous supramolecular structure of starch, the digestion behaviors were also changed. The 0.1% (w/v) alkali solution slightly disrupted the starch multi-scale structure, which reduced the molecular orders, disrupted the lamellae, weakened the molecular organization within growth rings, and enlarged the granule pores. Then, part of resistant starch was transformed into slowly-digestible fraction with a digestion rate close to k 2 . In contrast, when stronger (0.5% w/v) alkali was used, the starch multi-scale structure was more apparently disrupted, causing even granule swelling. This structural change resulted in a triple-phase digestion with three different digestion rates. Moreover, especially with stronger alkali, along with the structural disruption, some orders with a higher thermal stability emerged and reduced the accessibility of starch molecules to the enzyme. In this case, the digestion rate decreased with the treatment time. [ABSTRACT FROM AUTHOR]

Combined with rheology and micro-DSC methods, atomic force microscopy was applied to explore the synergistic binding ways of KGM and xanthan with high pyruvate group content at a total polymer concentration of 0.5% when mixed in ratios of 9:1 (K9X1) to 1:9 (K1X9). Upon cooling, Type A and B, corresponding to the peak Ⅰ (40-25 °C) and Ⅱ (55-40 °C) on G ′ curves respectively, were evidenced for KGM/xanthan composites. Type A binding was associated with the interactions of KGM and helical structures of xanthan and was mainly responsible for the building up of three-dimensional network for K5X5, K4X6, K3X7, K2X8 and K1X9 (with no remarkable flow after inversion). The maximum Type A binding occurred at K4X6, K3X7, and K2X8 samples with the relatively higher proportions of thick bundles (1.5–2.5 nm), enthalpy value, G ′ values and gel hardness. Type B binding was related to the interactions involving KGM and disordered xanthan molecules, and was positively related to the pyruvate group content and negatively correlated with the cation concentration and xanthan content. This work is helpful in comprehensively understanding the binding ways of KGM and xanthan with high pyruvate group content and are valuable for the exploration of binding ways between food hydrocolloids. [Display omitted] • AFM was used to explore the synergistic binding of KGM and xanthan. • Type A and B binding were evidenced for KGM/xanthan solution upon cooling. • Type A was associated with the interaction of KGM and helix of xanthan. • The maximum Type A binding occurred at K4X6, K3X7, and K2X8. • Type B was related to the interaction of KGM and disordered xanthan molecules. [ABSTRACT FROM AUTHOR]

The properties (e.g., viscosity, sol-gel transition, and mechanical characteristics) of polysaccharides are crucial for their food applications. This work discloses how xanthan gum (XG) incorporation tailors the performance of an agar/konjac glucomannan (KGM) system. As reflected by rheological and thermal analyses, an increasing content of XG added could strengthen the chain entanglement in the resulting ternary solution with strong KGM-XG binding (an exothermic event). For example, a ternary system with a 16% XG content (AKX-16%) showed simultaneous increases in the zero-shear viscosity (about 5.5 times that of the binary counterpart AK), sol-gel transition point (about 48 °C; 10 °C higher than that of AK), and gel hardness (about 2300 g; 450 g higher than AK). Moreover, the AKX-16% composite showed lower crystallinity and enhanced hydrogen bonding and tensile strength (74 MPa) resulting from gel dehydration. Additionally, increasing the XG content showed a negligible effect on the morphology of the composite matrix, suggesting the excellent compatibility between these different polysaccharides. [Display omitted] • Xanthan inclusion (16% for instance) strengthened chain entanglements of agar/KGM system. • Xanthan inclusion increased the zero-shear viscosity of agar/KGM-based system. • Xanthan inclusion increased the sol-gel transition point of agar/KGM-based system. • Xanthan inclusion increased the gel hardness of agar/KGM-based system. • Xanthan inclusion enhanced the tensile strength of agar/KGM-based composite. [ABSTRACT FROM AUTHOR]

To enhance the effectiveness of fertilizers, a novel double-coated slow-release fertilizer was developed using ethyl cellulose (EC) as inner coating and starch-based superabsorbent polymer (starch-SAP) as outer coating. For starch-SAPs synthesized by a twin-roll mixer using starches from three botanical origins, a reduced grid size and an increased fractal gel size on nano-scale (i.e., increased stretch of 3D network) contributed to increasing the water absorbing capacity with a reduced absorbing rate and thus improving the slow-release property of fertilizer. The fertilizer particles coated with starch-SAP displayed well slow-release behaviors. In soil, compared to urea particles without and with EC coating, the particles further coated with starch-SAP showed reduced nitrogen release rate, and in particular, those with potato starch-SAP coating exhibited a steady release behavior for a period longer than 96 h. Therefore, this work has demonstrated the potential of this new slow-release fertilizer system for improving the effectiveness of fertilizers. [ABSTRACT FROM AUTHOR]

Combined analytical techniques were used to explore the effects of alkali treatment on the multi-scale structure and digestion behavior of starches with different amylose/amylopectin ratios. Alkali treatment disrupted the amorphous matrix, and partial lamellae and crystallites, which weakened starch molecular packing and eventually enhanced the susceptibility of starch to alkali. Stronger alkali treatment (0.5% w/w) made this effect more prominent and even transformed the dual-phase digestion of starch into a triple-phase pattern. Compared with high-amylose starch, regular maize starch, which possesses some unique structure characteristics typically as pores and crystallite weak points, showed evident changes of hierarchical structure and in digestion rate. Thus, alkali treatment has been demonstrated as a simple method to modulate starch hierarchical structure and thus to realize the rational development of starch-based food products with desired digestibility. [ABSTRACT FROM AUTHOR]

Starch/agar systems are highly potential for versatile applications such as packaging and biomedical materials. Here, how combined factors affect the features of a starch/agar binary system were explored. An increase of starch amylose/amylopectin ratio from 0/100 to 50/50 increased the sol-gel transition temperature and gel hardness of the aqueous starch/agar mixture. An increased agar content (mainly from 30% to 70%) allowed increases in both the tensile strength (reaching 50–60 MPa) and elongation at break of the starch/agar binary films. This phenomenon should be related to the strengthened crystalline structure and the weakened hydrogen bonding between starch chains (reflected by infrared spectroscopy). Furthermore, a higher relative humidity (from 30% to 70%) allowed enhanced chain interactions and probably nanoscale molecular order but weakened the crystalline structure, leading to reduced tensile strength and increased elongation at break. This work could facilitate the design of starch/agar binary systems with improved sol-gel and mechanical performance. [ABSTRACT FROM AUTHOR]

The practical features (e.g., sol-gel, mechanical and hydrophobic) of biopolymer systems are crucial for their materials applications. This work reveals how polyvinyl alcohol (PVA) inclusion affects the practical features of agar/konjac glucomannan (KGM) system. From rheological analysis, incorporating PVA (especially 6%) enhanced the chain entanglements of resulted ternary solution (A 70 K 24 P 6) with stabilized sol-gel transition point. Such effect not only increased the zero-shear viscosity (ca. 1.5 times that of agar/KGM counterpart) and structural recovery degree of A 70 K 24 P 6 solution, but also caused reduced crystallites and simultaneously increased tensile strength, elongation at break and hydrophobicity for A 70 K 24 P 6 film from solution dehydration. This ternary film exhibited a tensile strength of ca. 105 MPa, an elongation at break of ca. 20%, and a water contact angle of ca. 97.6°. Additionally, incorporating PVA almost unaffected the morphology of film fracture surface. These results are valuable for the design of agar/KGM systems with improved practical features. [ABSTRACT FROM AUTHOR]

From a microstructural point of view, this work concerns how deacetylation improves the practical characteristics of deacetylated-konjac glucomannan/agar (DK/A) composite films. As disclosed by infrared spectroscopy and X-ray diffraction, the deacetylation of konjac glucomannan (KGM) enhanced the chain interactions in DK/A composites and suppressed the realignment of agar molecules into crystallites. The enhanced associations between acetyl-free regions of KGM and agar reduced the exposure of OH groups and thus increased the hydrophobicity of the composites. Besides, the partial removal of acetyl groups allowed shortened distances between chains; consequently, denser composite matrices emerged with lower water vapor permeability and higher tensile strength. Also, the KGM deacetylation increased the matrix flexibility and elongation at break for DK/A composites, associated with the hindered rearrangement of agar chains. Thus, altering the deacetylation degree of KGM may be an effective way to design KGM-based composites with improved hydrophobicity and mechanical performance. [ABSTRACT FROM AUTHOR]

Encapsulation systems have gained significant interest in designing innovative foods, as they allow for the protection and delivery of food ingredients that have health benefits but are unstable during processing, storage and in the upper gastrointestinal tract. Starch is widely available, cheap, biodegradable, edible, and easy to be modified, thus highly suitable for the development of encapsulants. Much efforts have been made to fabricate various types of porous starch and starch particles using different techniques (e.g. enzymatic hydrolysis, aggregation, emulsification, electrohydrodynamic process, supercritical fluid process, and post-processing drying). Such starch-based systems can load, protect, and deliver various food ingredients (e.g. fatty acids, phenolic compounds, carotenoids, flavors, essential oils, irons, vitamins, probiotics, bacteriocins, co-enzymes, and caffeine), exhibiting great potentials in developing foods with tailored flavor, nutrition, sensory properties, and shelf-life. This review surveys recent advances in different aspects of starch-based encapsulation systems including their forms, manufacturing techniques, and applications in foods. [Display omitted] • Recent progress in the types, fabrication and applications of starch-based encapsulation systems discussed • Starch modification improves amphiphilicity, film-forming and emulsifiability. • Starch can be fabricated into porous starch or particles for encapsulation. • Starch can encapsulate fatty acids, antioxidant, flavors, probiotics, etc. • The flavor, nutrition, sensory properties and shelf-life of foods improved [ABSTRACT FROM AUTHOR]

The sol performance of wheat starch (WS) matrix incorporating acetylated starch (AS) is crucial for the processing and quality features of wheat products. From a supramolecular structure view, how regulating salt (sodium chloride) concentration modulates the sol features, e.g., pasting, zero-shear viscosity (ZSV) and thixotropy of WS-AS binary matrix was explored. Compared to the salt-free counterpart, the saline matrices exhibited a delayed pasting profile and a decreased viscoelasticity. Thereinto, the sol at 0.02 M NaCl exhibited the smallest ZSV (23,710 Pa·s) and the greatest in-shear recovery ratio (33.7 %). Such variations could be attributed to the weakened coil-helix, nematic-smectic and isotropy-anisotropy transitions from a side-chain liquid-crystalline perspective. Meanwhile, the correlation length (ξ) and radius of gyration (R g) obtained from small angle X-ray scattering analysis were increased by 5.2 and 9.6 Å respectively, which disclosed a restrained entanglement and an enhanced chain mobility. These results would provide a reference for the design of fluid/semisolid products with optimized qualities. [Display omitted] [ABSTRACT FROM AUTHOR]

Recently, we reported the effect of mild alkaline treatment on the structure and enzymatic hydrolysis of waxy maize starch. Here, we have used extended- q small-angle neutron scattering (SANS) to examine the extent to which this treatment causes structural changes on even greater length scales — to yield a complete picture from the nanometre to micron — including on the lamellar distribution and larger-scale structural features of the same starch. For this A-type polymorph starch containing mostly amylopectin, we found the changes caused by NaOH solution treatment (0.1% or 0.5% (w/v)) were confined mainly to double helices and crystallites, whereas the lamellar and supramolecular structures were conserved. Although the overall lamellar ordering was reduced in the 0.5% (w/v) alkaline treatment for 6 days, further treatment until 12 days could restore the overall lamellar ordering. Despite changes in starch double helical order and crystallites, there were minimal changes at larger length scales (e.g. , blocklets and growth rings). This combination of methods reveals the extent of structural changes occurring as a result of mild alkaline treatment of waxy maize starch; it also provides insight into the rational design of granular starch products with varied functionality via hydrolytic control. Image 1 ✓ Extended- q SANS detects larger-scale structural changes of waxy maize starch ✓ Mild alkaline treatment mainly changes starch double helices and crystallites ✓ Lamellar and supramolecular structures were conserved during the alkaline treatment ✓ There were minimal changes at larger scales (e.g. , blocklets and growth rings) ✓ The mechanism of mild alkaline treatment of waxy maize starch is revealed [ABSTRACT FROM AUTHOR]

Although gelatin-based composite gels have been widely used in the food and pharmaceutical industries, further research is needed to improve gel strength. This work reported the microstructure and gel properties of gelatin-based composite gels containing different contents of κ-carrageenan (CGN) or konjac glucomannan (KGM). The rheological and textural results revealed that the gelling temperature, melting temperature, strength (from 1.68 to 4.13 times), toughness, and chewiness of the composite gel were positively correlated with the addition of CGN. The microscopy and infrared spectroscopy showed that gelatin and CGN molecules could be clustered in helices by electrostatic interactions and hydrogen bonding to form excellent gel networks with outstanding gelation properties. However, gelatin and KGM could either be compatible with or separated from each other. At a low KGM content, the gelatin-based composite gel was porous and had a dense gel structure. When the KGM content was 0.3%, the composite gel showed greater ordering degree. Thus, the addition of the proper amount of CGN to gelatin led to composite gels with better strength, toughness, and chewiness, whereas the addition of KGM generated gels being easy to chew and swallow. [Display omitted] • Addition of κ-carrageenan enhanced strength, toughness, and chewiness of gelatin-based gel. • Addition of κ-carrageenan promoted gel formation and suppressed gel disruption. • Phase separation occurred for gelatin-based gel with >0.3% konjac glucomannan. [ABSTRACT FROM AUTHOR]

Synergistic interaction gels (SIGs) hold immense promise for applications in 3D printing, colonic drug delivery, and sustained release. The amalgamation of xanthan and tamarind gum (TMG) gives rise to SIGs through molecular interaction; however, the intricacies of their assembly behaviors remain elusive. This work elucidates that in xanthan-rich systems, the predominant formation of xanthan aggregations shapes network assembly structure, with TMG clusters adhering to them. Conversely, in TMG-rich systems, TMG clusters actively participate in creating a "sea-island" assembly structure enveloped by xanthan aggregations. Higher concentration of TMG contributes to augmenting the association extent of TMG and xanthan. The heightened binding between TMG and xanthan correlates with an increase in chain distance in scatters and the compactness of scatter arrangement. These favor the development of micro-structures with a relatively larger mesh size and the enhancement of gel hardness. This study serves to facilitate the design and production of SIGs-based artificial gel foods with the requisite performance characteristics, such as artificial sea cucumber and porcine back fat. [Display omitted] • Xanthan aggregation shapes network structure in xanthan-rich system. • "Sea-island" structure is formed in tamarind gum (TMG)-rich system. • Higher TMG content increases association extent of xanthan and TMG. • Higher association extent causes higher gel hardness of TMG/xanthan SIGs. [ABSTRACT FROM AUTHOR]

The differences in the self-assembly process between cold-set (CCS) and heat-set (CHS) curdlan gels were investigated using micro-differential scanning calorimetry, atomic force microscopy, and small-angle X-ray diffraction. The results indicate that the triple-helix structure of curdlan dissociated into single helices in its suspension state (C-SUS) at 65 °C. Upon cooling to around 38 °C, these single helices assembled into long, thick fibers with a height of up to 11.50 nm, contributing to the gel structure of CCS. Heating C-SUS from 65 °C to 90 °C caused the single helices to transform into triple helices due to hydrophobic interactions. Subsequent cooling to 25 °C, led to the formation of short, thick bundles with a height of up to 8.78 nm, forming the network structure of CHS gel. As a consequence, CHS gels exhibited higher hardness and elasticity but lower fatigue resistance. This is attributed to an increased degree of physical cross-linking, as evidenced by a reduction in the size (Ξ) and spacing (ξ) of high-density domains within the gel structure, and a simpler mechanism of energy dissipation through alignment of the molecular chain segment. These findings are valuable for the design and development of curdlan-based gels with tailored mechanical properties. [Display omitted] • Single and triple helixes are main building blocks for cold- and heat-set curdlan gel, respectively. • Single helix assembled into long and thick fibers in cold-set curdlan gel. • Triple helix associated into short and thick bundles in heat-set curdlan gel. • High-density domain was smaller and packed more densely in heat-set curdlan gel. • Heat-set gel exhibited higher gel strength and elasticity, but weak fatigue resistance. [ABSTRACT FROM AUTHOR]

Synergistic interaction gels (SIGs) have become attractive in food industry due to their ability to modify rheology features, realize safe swallowing and apply as fat simulants. Locust bean gum (LBG) and xanthan give rise to SIG, however, their assembly process remain elusive. This work demonstrated that, in xanthan-rich system, xanthan chains transformed into helical structure and aggregated into thick bundles upon cooling. Subsequently they bound with LBG clusters, constructing a xanthan-like 3D gel network. However, in LBG-rich system, LBG chains gradually dissociated from clusters and associated into helical structure during cooling ("dissociation-association" process), forming an LBG-like "sea-island" structure. With further cooling, LBG continued to undergo "dissociation-association" process, along with specifically binding by xanthan chains (helical structure or thick bundles), generating thick grid contour lines and larger sparse gel network. The enthalpy change values indicated that with the decrease of xanthan content, synergistic binding extent was increased and then decreased, reaching the maximum at LBG: xanthan ratio of 7:3. This was responsible for the increment of G ′, gel hardness, and capacity to accumulate energy for the weak shear-induced structure for LBG/xanthan SIGs. This study serves to facilitate the design and production of SIGs with the requisite performance characteristics. [Display omitted] • "3D" network structure was generated in xanthan-rich system. • Sparse network with larger grid was formed in LBG-rich system. • Ratio of 7:3 (LBG: xanthan) was a well-defined stoichiometry for synergistic bind. • Higher association extent caused higher gel strength of LBG/xanthan SIGs. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ions enhanced DPPH radical scavenging capacity of RA/BRA composite system. • Metal ions restrict the interaction between RA and BRA. • Ca2+ showed more detrimental behavior to the stability of BRA/RA composite system than Na+ at the same concentration. Thermal processing with salt ions is widely used for the production of food products (such as whole grain food) containing protein and anthocyanin. To date, it is largely unexplored how salt ion presence during thermal processing regulates the practical performance of protein/anthocyanin binary system. Here, rice albumin (RA) and black rice anthocyanins (BRA) were used to prepare RA/BRA composite systems as a function of temperature (60–100 °C) and NaCl concentration (10–40 mM) or CaCl 2 concentration (20 mM). It was revealed that the spontaneous complexing reaction between RA and BRA was driven by hydrophobic interactions and hydrogen bonds and becomes easier and more favorable at a higher temperature (≤90 °C), excessive temperature (100 °C), however, may result in the degradation of BRA. Moreover, the salt ion presence during thermal processing may bind with RA and BRA, respectively, which could restrict the interaction between BRA and RA. Additionally, the inclusion of Na+ or Ca2+ at 20 mM endowed the binary system with strengthened DPPH radical scavenging capacity (0.95 for Na+ and 0.99 for Ca2+). Notably, Ca2+ performed a greater impact on the stability of the system than Na+. [ABSTRACT FROM AUTHOR]

This study explored how microwave reheating (to about 73 °C at different power levels) affects the microstructure and digestion characteristics of cooked rice with different water contents (1.1 and 1.5 times that of rice in weight). Irrespective of water content, mainly the V-type crystallites remained after microwaving reheating, with slight changes in other multi-scale structural features. Only at a relatively high water content (1.5) and with a power level high enough could short-range order be reduced. Such microwave reheating increased the digestion resistance of cooked rice. At a water content of 1.1 times, increasing the microwave power led to a decreased rapid digestible starch (RDS) content and an increased resistant starch (RS) content. With a higher water content (1.5), the enhancement of digestion resistance with higher microwave power was less significant but still, a reduced slowly digestible starch (SDS) content and a higher RS content were observed. [Display omitted] • Cooked rice with high water contents were microwaved at different power levels. • V-type crystallites remained after microwaving reheating. • Microwave reheating increased the digestion resistance of cooked rice. • Rice with 110% water content had increased RS content with reduced RDS content. • Rice with 150% water content had increased RS content with reduced SDS content. [ABSTRACT FROM AUTHOR]

This work concerns how starch-protein interplay affects the multi-scale structures (e.g., short- and long-range orders, nanoscale structure and morphology) of starch undergoing thermal processing (pasting) involving heating and cooling at high water content. An indica rice starch (IRS) and three proteins (whey protein isolate, WPI; soy protein isolate, SPI; casein, CS) were used. By inspecting rheological profiles of mixed systems before and after adding chemicals, IRS-WPI and IRS-CS showed mainly hydrophobic molecular interaction; and IRS-SPI exhibited hydrophobic, hydrogen bonding and electrostatic interactions. The RVA results revealed that, with starch and proteins as controls, starch-globular protein (WPI or SPI) interplay accelerated the swelling of starch granules (faster viscosity increase at initial pasting stage), and reduced the paste stability during heating (higher breakdown) and during cooling (higher setback); however, the starch-casein interactions resulted in opposed effects. Moreover, starch-protein interactions varied the multi-scale chain reassembly of starch into different structures during cooling. Observed could be fewer short- and long-range starch orders, and larger nonperiod structure (or colloidal clusters) on the nanoscale. On even larger scale to micron, IRS-globular protein molecules generated larger grids (with reduced number) in the gel network, and IRS-casein formed a more continuous gel network with less prominent tunnel-like features. • Starch-globular protein interaction accelerated starch's water uptake during heating. • Starch-casein interaction stabilized swollen granules and paste stability during heating. • Starch-protein interaction reduced the amount of ordered structures during cooling. • Starch-protein interaction allowed larger or more nanostructures during cooling. • Starch-casein formed a more continuous matrix in the gel network on micron scale. [ABSTRACT FROM AUTHOR]

[Display omitted] • Edible oil alters the microstructure of cooked brown rice. • Edible oil ameliorates the texture properties of cooked brown rice. • Edible oil incorporation reduces the starch digestibility of brown rice. • The effect of edible oil on the brown rice varies in edible oil type. While brown rice (BR) has numerous nutritional properties, the consumption potential of which is seriously restricted since the poor cooking quality and undesirable flavor. Here, edible oils (pork lard and corn oil, 1–5 wt%) were incorporated during the cooking of BR following heat moisture treatment. Incorporating corn oil rather than lard significantly ameliorated the texture properties (e.g. hardness, cohesiveness, and chewiness) and sensory properties of cooked BR. Both lard- and corn oil-incorporated cooked BR showed obvious structural changes accompanied by the formation of amylose-lipid complexes during cooking. It was confirmed that the incorporation of lard and corn oil allowed a higher degree of short-range molecular order, more V-type starch crystallites, and elevated nano-structural arrangements. Additionally, a decreased hardness (from 559.04 g to 424.18 g and 385.91 g, respectively) and enriched resistant starch (RS) were also observed, the highest RS content (15.95 % and 16.32 %, respectively) was observed when 1 wt% of lard and corn oil were incorporated. [ABSTRACT FROM AUTHOR]

Synergistic interaction gels (SIGs) formed by mixing konjac glucomannan (KGM) and xanthan at an appropriate ratio have gained increased interest due to its inherent versatility. However, their mechanical properties were not high enough to meet the needs of practical applications. This work demonstrated that freeze-thaw treatment (FT) significantly improved their mechanical properties, and the underlying mechanisms were proposed. Relative lower frozen temperature (−40 °C or −80 °C) and more freeze-thaw cycles reduced the pore size, decreased the average size of orderings (crystalline structure) and increased the ordering content (at −40 °C or under third cycle at −80 °C, except for KGM/xanthan SIGs with a ratio of KGM to xanthan at 2:8) for KGM/xanthan SIGs. Those undoubtedly increased the crosslinking density and improved the gel structure, which was responsible for the increment of G ' (at 25–30 °C) and gel hardness, and reduction of water holding capacity. Freeze-thaw treatment with −15 °C did not increase the ordering contents and gel hardness, but enhanced the G ' (at 25–30 °C). It is possible that freezing at −15 °C enhanced gel structure rigidity by increasing the molecular entanglement via squeezing of ice crystals and rearrangement of molecular chains. Those results are helpful to rational design and production of KGM/xanthan SIGs with physical methods. [Display omitted] • Freeze-thaw treatment improved mechanical properties of KGM/xanthan gels. • Pore structure was altered significantly after freeze-thaw treatment. • Frozen at −40 or −80 °C decreased average size of ordering structure. • Treatment of two/three freeze-thaw cycles decreased average size of ordering structure. • Frozen at −40 or −80 °C (three cycles) increased contents of nano-scale ordering structure. [ABSTRACT FROM AUTHOR]