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The synergistic interaction gels (SIGs) can be created by blending konjac glucomannan (KGM) and κ-carrageenan, and have been applied to modify and improve the rheological and texture properties of food system. However, the assembly behaviors between them are still unclear. This work revealed that the presence of KGM promoted phase transition of nearby κ-carrageenan molecules probably by contributing to entropy increment. Subsequently, the rest of κ-carrageenan transformed into helical structure, assembled into a series of laterally arranged trigonal units and formed a three-dimensional network. In KGM/κ-carrageenan SIGs, the size of high density domains (Ξ) in aggregates and the distance of these high density domains (ξ) were narrowed firstly and then enlarged as increasing of KGM content. These nano-scale structure features were responsible for the relative higher gel strength for KGM/κ-carrageenan SIGs with proportion ratios of 1:9 (K1C9) and 3:7 (K3C7). This study serves to facilitate the design and production of SIGs with the requisite performance characteristics., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Understanding the interplay among salt ions, anthocyanin and starch within food matrices under thermal conditions is important for the development of starch-based foods with demanded quality attributes. However, how salt ions presence influences the microstructure and properties of starch/anthocyanin binary system remains largely unclear. Herein, indica rice starch (IRS) and rice anthocyanin (RA) were used to construct an IRS-RA binary system, with thermal treatment under different concentrations of Na + (10-40 mM) and types of salt ions (Na + and Ca 2+ ). The incorporation of salt ions induced the formation of a porous gel matrix, and destroyed the hydrogen bond between starch and anthocyanin through electrostatic interactions, reducing the storage modulus and radius of gyration of the binary system, and increasing the relative crystallinity (from 1.08 % to 1.51 % (20 mM Na + ) and 1.69 % (20 mM Ca + )) of the IRS-RA binary system at 90 °C. Also, the DPPH radical scavenging ability of the binary system at 90 °C was enhanced upon incorporating salt ions (0.93 for Na + condition and 0.94 for Ca 2+ condition at 20 mM ion concentration). It is noteworthy that Ca 2+ inclusion had more significant effects than the case for Na + presence, presumably due to the increased charge density., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Gels derived from single networks of natural polymers (biopolymers) typically exhibit limited physical properties and thus have seen constrained applications in areas like food and medicine. In contrast, gels founded on a synergy of multiple biopolymers, specifically polysaccharides and proteins, with intricate interpenetrating polymer network (IPN) structures, represent a promising avenue for the creation of novel gel materials with significantly enhanced properties and combined advantages. This review begins with the scrutiny of newly devised IPN gels formed through a medley of polysaccharides and/or proteins, alongside an introduction of their practical applications in the realm of food, medicine, and environmentally friendly solutions. Finally, based on the fact that the IPN gelation process and mechanism are driven by different inducing factors entwined with a diverse amalgamation of polysaccharides and proteins, our survey underscores the potency of physical, chemical, and enzymatic triggers in orchestrating the construction of crosslinked networks within these biomacromolecules. In these mixed systems, each specific inducer aligns with distinct polysaccharides and proteins, culminating in the generation of semi-IPN or fully-IPN gels through the intricate interpenetration between single networks and polymer chains or between two networks, respectively. The resultant IPN gels stand as paragons of excellence, characterized by their homogeneity, dense network structures, superior textural properties (e.g., hardness, elasticity, adhesion, cohesion, and chewability), outstanding water-holding capacity, and heightened thermal stability, along with guaranteed biosafety (e.g., nontoxicity and biocompatibility) and biodegradability. Therefore, a judicious selection of polymer combinations allows for the development of IPN gels with customized functional properties, adept at meeting precise application requirements., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Dongling Qiao reports financial support was provided by National Natural Science Foundation of China. Dongling Qiao reports financial support was provided by Key Research and Development Project of Hubei Province. Fengwei Xie reports financial support was provided by Engineering and Physical Sciences Research Council. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

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., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

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 %)., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Kudzu is usually consumed at different growth years, yet the influences of growth years on its multi-scale structures and physicochemical features have not been fully disclosed. In this study, those influences occurred on kudzu starches (KS2, KS10, KS30 and KS50, isolated using precipitation method) were investigated. The granules size, crystallinity, short-range ordered structure, amylose content, intermediate and longer amylose chains reduced but the average thickness of crystalline lamella increased as the rise of growth years. KS2 had lower content of defective crystal structure and higher content of near-perfect crystal structure. Those signified that bulk density of molecules packing into starch substrate was higher for KS2, which was not beneficial for water molecules and enzymes entering into starch granules and thus elevated pasting temperature and reduced digestion rate. Besides, reduced proportions of defective ordered structures and enhanced lipid-amylose complex also reduced digestion rate. Both the peak and breakdown viscosity were in order of KS2 > KS10 > KS30 ≈ KS50. And KS2, KS10, and KS30 exhibited enhanced retrogradation tendency during cooling than KS50 as evidenced by the relative higher setback viscosity. Those results are favor for rational screen and usage of kudzu starch resources with different growth years for food applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

For the development of innovative foods and nutritional fortification, research into food gel is essential. As two types of rich natural gel material, both legume proteins and polysaccharides have high nutritional value and excellent application potential, attracting wide attention worldwide. Research has focused on combining legume proteins with polysaccharides to form hybrid hydrogels as their combinations show improved texture and water retention compared to single legume protein or single polysaccharide gels, and these properties can be tailored for specific applications. This article reviews hydrogels of common legume proteins and discusses heat induction, pH induction, salt ion induction, and enzyme-induced assembly of legume protein/polysaccharide mixtures. The applications of these hydrogels in fat replacement, satiety enhancement, and delivery of bioactive ingredients are discussed. Challenges for future work are also highlighted., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Cold-chain cooked rice is an instant food consumed worldwide. Through inspecting rice structural alterations during digestion, this work discloses how microwave reheating tailors the starch digestibility of cooked rice following cold storage. The cold storage allowed approximately 2% of B-type (not V-type) starch crystallites, more nanoscale and short-range orders, and smaller pores in the rice matrix. These changes retarded the hydrolysis of structural domains (e.g., amorphous regions and short-range orders) during digestion, which increased the content of slowly digestible starch to about 38.16%. Then, microwave reheating partially disrupted the B-type crystallites and nanoscale orders, but unaffected the contents of V-type crystallites and short-range orders. Even with such structural disruptions, the resistant starch content was apparently increased to approximately 30.06%, as the structural domains became less susceptible to the digestion. Additionally, for the rice samples, the percentage of V-type crystallites could be largely increased from ca. 3% to 13%-14% during digestion., (Copyright © 2022 Elsevier B.V. All rights reserved.)

To tailor the properties and enhance the applicability of starch, various ways of starch modification have been practiced. Among them, physical modification methods (micronization, nonthermal plasma, high-pressure, ultrasonication, pulsed electric field, and γ-irradiation) are highly potential for starch modification considering its safety, environmentally friendliness, and cost-effectiveness, without generating chemical wastes. Thus, this article provides an overview of the recent advances in nonthermal physical modification of starch and summarizes the resulting changes in the multi-level structures and physicochemical properties. While the effect of these techniques highly depends on starch type and treatment condition, they generally lead to the destruction of starch granules, the degradation of molecules, decreases in crystallinity, gelatinization temperatures, and viscosity, increases in solubility and swelling power, and an increase or decrease in digestibility, to different extents. The advantages and shortcomings of these techniques in starch processing are compared, and the knowledge gap in this area is commented on., (Copyright © 2022. Published by Elsevier B.V.)

Cold-chain cooked rice is a widely-consumed instant food. While the quality of cooked rice as affected by processing has been widely studied, it remains largely unexplored how concurrent cold-chain conditions (e.g., refrigeration time with specific water contents) tailor the structure and starch digestibility of cooked rice. Here, as shown by combined techniques (e.g., scanning electron microscopy and small angle X-ray scattering), the cold storage (1 to 3 days) of cooked rice at 1.1:1 w/w water-to-rice ratio increased the uniformity of the rice matrix, strengthened the nonperiodic structure, and allowed more B-type starch crystallites and short-range orders. This induced an increase in the slowly digestible starch (SDS) content (from ca. 33.7% to 38.5%) as the refrigeration time rose. In contrast, for cooked rice with 1.5:1 w/w water-to-rice ratio, the cold storage (mainly 1 day) strengthened the matrix uniformity and the nonperiodic structure, and eventually increased the resistant starch (RS) content from ca. 10.3% to 17.7%. The present data could facilitate the design of cold-chain cooked rice with tailored starch digestibility., (Copyright © 2021 Elsevier B.V. All rights reserved.)

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., (Copyright © 2021 Elsevier B.V. All rights reserved.)

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., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Colored brown rice shows better health benefits than polished rice, and there is great interest in the design of demanded cooking manners for brown rice. This investigation concerns how the change of cooking mode can slow starch digestion of colored brown rice by inspecting mainly starch structural changes during cooking. Compared to cooking Mode 1, the soaking of Mode 2, at higher temperature, probably enhanced water diffusion into rice matrices, thus strengthening starch lamellae without apparently altering rice morphology and ordered structures such as starch polymorphs and helices. The followed heating of Mode 2, with reduced time, more sufficiently disrupted rice structures, causing less prominent nonperiodic molecular organizations. At the final cooking stage, the braising of Mode 2, having faster temperature reduction for prolonged time, leading to similar rice morphology, reduced molecular orders (e.g., helices) and probably denser amorphous regions of nonperiodic organizations. Such features tended to increase packing density of molecular chains (mainly starch) in rice matrices, thus slowing the enzyme diffusion in rice matrices and associated binding and catalysis events. In this way, a reduced starch digestion rate and increased resistant starch (RS) and slowly digestible starch (SDS) were seen for the rice following Mode 2 cooking., (Copyright © 2020 Elsevier B.V. All rights reserved.)

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., (Copyright © 2019. Published by Elsevier B.V.)

This work concerns the multi-scale structures and digestion behaviors of indica rice starches with apparent amylose contents (AACs) of ca. 14%-24%. A higher AAC not always allowed a lower digestion rate (k), different from previous findings that starches containing more amylose normally show slowed digestion. Here, the proportion of stable molecular orders (melting temperature above ca. 73 °C) and AAC synergistically governed starch digestion rate. With a similar AAC, a higher amount of stable orders (R h/l , ratio of enthalpy of stable orders to that of the rest) led to a lower k. Also, with a similar R h/l , a larger AAC caused a lower k. Consistently, JPZ starch had almost the highest AAC and R h/l , showing the lowest k. Regarding this, amylose and stable orders played roles in increasing the bulk density of starch structure matrices, and eventually slow the diffusion, absorption and catalysis events of digestion enzymes within the matrices., (Copyright © 2019 Elsevier B.V. All rights reserved.)

From a supramolecular structure viewpoint, we concern how concurrent microwave and heat moisture treatment (M/HMT) tailors the pasting and digestion features of indica rice starch (IRS) and waxy rice starch (WRS), using combined analytical methods such as scanning electron microscopy and small-angle X-ray scattering. The results confirm that, for the starches (especially IRS), M/HMT led to a concave granule surface, weakened alignment of helices in lamellae, loosened packing of chains in amorphous regions, and somewhat disrupted crystallites. Consequently, the susceptibility of starch structures to hydrothermal effects was insignificantly altered, as reflected by unchanged pasting temperature; the enzyme absorption/hydrolysis could be properly accelerated, as affirmed by a modestly increased digestion rate and slightly reduced enzymatic resistance. Also, compared to WRS, IRS had more amylose with relatively long branches, which probably contributed to starch chain interactions during M/HMT. This tended to reduce the paste viscosity related to the swelling degree of starch granules, and increase the paste stabilities during heating and cooling related to the robustness of swelled granules and the reorganization of glucan chains., (Copyright © 2019 Elsevier B.V. All rights reserved.)

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., (Copyright © 2019. Published by Elsevier B.V.)

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., (Copyright © 2018 Elsevier B.V. All rights reserved.)

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., (Copyright © 2017 Elsevier B.V. All rights reserved.)

This work concerned the effects of amylose/amylopectin ratio on the structure and thermal stability of propionylated starches with high degree of substitution (DS). Four starches with different amylose content were used to obtain propionylated starches. Acylation partly disrupted granule morphology of native starches, and the imperfection and porous structures of starch granule were intensified along with the increased amylose content. It was noted that the crystalline structure of starch was destroyed and thus intense acylation occurred in both amorphous and crystalline regions. The acylated starch with high-amylose content displayed more ordered region compared to low-amylose starch. Acylation enhanced the thermal stability of starch, and this effect became more evident as the amylose content increased. Thus, the amylose/amylopectin ratio has been confirmed capable of affecting the structure and thermal behaviors of hydrophobic propionylated starch, which is of value for the design of starchy materials with tailored thermal stability., (Copyright © 2017 Elsevier B.V. All rights reserved.)