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Summary: In this study, pre‐gelatinized highland barley flour (PHBF), pre‐gelatinized sweet potato starch (PSPS), wheat gluten (WG), and egg white protein (EWP) were used to develop highland barley noodles. Their effects on noodle quality were analysed, and then noodle formula optimization was carried out based on them. Changes in quality characteristics and intermolecular structure were analysed to explore the underlying mechanism. PHBF, PSPS, WG, and EWP influence the quality characteristics of HB noodles from diverse angles. After formula optimization, noodles with improved cooking and textural properties were obtained, in which HBF accounts for 93.0% of the composite flour and can be categorised as low expected glycemic index (eGI) foods. The viscosity and elasticity of the dough both improved; a more stable protein structure and enhanced starch structure were formed; and increased intermolecular forces were observed, which would contribute to the enhanced protein cross‐linking, structural order, and textural properties of noodles. [ABSTRACT FROM AUTHOR]

In this study, glucan 1,4‐α‐maltotriohydrolase (AMTS) is used to modify corn starch granules to elucidate the structural and physical property changes following AMTS modification. The degree of hydrolysis (DH) of granular corn starch is modulated by adding various amounts of AMTS. Pore structures with more pores, deep channels, and cavities in starch granules with extended hydrolysis are observed by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). The short‐range ordered structure, lamellar structure, and crystalline structure are significantly enhanced under moderate AMTS modification, and then slightly decreased with further modification. These structural changes significantly improve oil and water absorption capacities, decrease solubility and swelling power, diminish pasting properties, and lower the digestibility of granular corn starch. When AMTS interferes with the starch system, the specific surface area of granular starch gradually increases with extended hydrolysis, with the maximum being almost 4.6‐fold that of native starch. All these results suggest AMTS hydrolysises of corn starch granules through an "inside‐out" pattern, preferential hydrolysis of the amorphous region, and subsequent alternate hydrolysis of the amorphous and crystalline regions. Overall, AMTS is a potential granular starch hydrolase for producing porous starch used as the carrier material in a variety of food applications. [ABSTRACT FROM AUTHOR]

Both the effects of enzymolysis condition on the microstructures and emulsifying property of enzymatic modified quinoa starch (EMQS) and the effects of emulsion formulation on the EMQS based emulsions were investigated. The emulsifying capacity (EC) and stability (ES) of EMQS were positive correlated with enzyme amount (0–2.4 % w/w starch). The particle sizes of EMQS decreased and its hydrophobicity increased with increasing enzyme amount (0–2.4 % w/w starch), which were the main reasons for the increasing emulsifying performance of EMQS. With the increasing starch concentration, the EC of the EMQS increased, the oil droplet size of the emulsion decreased. With the oil/water ratios ranging from 1:9 to 6:4, the emulsification index (EI) and oil droplet size of the emulsion increased. EMQS based emulsion had a relatively good stability in the pH range of 2–10. This study lays the foundation for the application of EMQS as a stable clean-label Pickering emulsifier. [ABSTRACT FROM AUTHOR]

The study investigated the effect of removing protein and/or lipid on the physicochemical characteristics and digestibility of sand rice flour (SRF). Morphological images showed that protein removal had a greater impact on exposing starch granules, while lipids acted as an adhesive. The treatment altered starch content in SRF samples, leading to increased starch crystallinity, denser semi-crystalline region, lower onset gelatinization temperature (T o), higher peak viscosity and gelatinization enthalpy (ΔH), where Protein removal showed a more pronounced effect on altering physicochemical properties compared to lipid removal. The research revealed a positive correlation between rapidly digestible starch (RDS), maximum degree of starch hydrolysis (C ∞), digestion rate constant (k) values and 1047/1022 cm−1 ratio, showing a strong connection between short-range structure and starch digestibility. The presence of endogenous proteins and lipids in SRF hinder digestion by restricting starch swelling and gelatinization, and physically obstructing enzyme-starch interaction. Lipids had a greater impact on starch digestibility than proteins, possibly due to their higher efficacy in reducing digestibility, higher lipid content with greater potential to form starch-lipid complexes. This study provides valuable insights into the interaction between starch and proteins/lipids in the sand rice seed matrix, enhancing its applicability in functional and nutritional food products. [ABSTRACT FROM AUTHOR]

The excessive water sensitivity of hydroxypropyl methylcellulose (HPMC) films prevent them from being used extensively. In order to overcome this limitation, superhydrophobic HPMC films were meticulously crafted through the utilization of a composite of polydimethylsiloxane (PDMS) and ball-milled rice starch, corn starch, or potato starch (RS/CS/PS) for the coating process. Initially possessing hydrophilic properties, the HPMC Film (CA = 49.3 ± 1.8°) underwent a transformative hydrophobic conversion upon the application of PDMS, resulting in a static contact angle measuring up to 103.4 ± 2.0°. Notably, the synergistic combination of PDMS-coated HPMC with ball-milled starch demonstrated exceptional superhydrophobic attributes. Particularly, the treated HPMC-based film, specifically the HP-CS-2 h film, showcased an impressive contact angle of 170.5° alongside a minimal sliding angle of 5.2°. The impact of diverse starch types and the ball milling treatment on the PDMS/starch coatings and HPMC film was thoroughly examined using scanning electron microscopy (SEM), wide-angle X-ray diffraction (WAXS), and particle size analysis. These studies demonstrated that the low surface energy and roughness required for the creation of superhydrophobic HPMC-based films were imparted by the hierarchical structure formed by the application of PDMS/ball-milled starch. Polydimethylsiloxane (PubChem CID: 24764); Hydroxypropyl methylcellulose (PubChem CID: 671); Ethyl acetate (PubChem CID: 8857). [Display omitted] [ABSTRACT FROM AUTHOR]

A small granule starch from sand rice (Agriophyllum squarrosum) was subjected to heat‐moisture treatment (HMT) at different moisture contents (MCs,15%–30%). With MC≤20%, a higher MC resulted in increases in the starch orders (i.e., short‐range and crystalline structure) with unchanged granule morphology. Nonetheless, a further elevated MC (>20%) gradually destroyed the granule morphology and starch orders. Also, HMT gradually vanished the lamellar structure as MC increased during HMT. These structural evolutions in HMT‐modified starch resulted in greater thermal stability, higher pasting temperature, lower pasting viscosity and weakened digestibility. Particularly, HMT applied directly in sand rice starch at 20% MC obtained the highest amount of SDS and RS (23.6%), which was 2.2‐fold higher than that of native starch. Therefore, the small granule sand rice starch can be modulated by HMT through controlled MC to expand their application range in food production. [ABSTRACT FROM AUTHOR]

Quinoa starch was developed as a new kind of Pickering emulsifier by enzymatic modification. The morphological structure, crystalline structure, lamellar structure, fractal structure, particle size distribution, contact angle, emulsion index (EI), and emulsion micromorphology were studied to explore the relationship between structure characteristics, hydrophilic property, and emulsifying properties of enzymatically modified (EM) quinoa starches. With the increasing enzymatic hydrolysis time in the test range of 0–9 h, particle size of EM quinoa starch decreased, and the broken starch and contact angle of EM quinoa starch increased; the EI value of emulsions with EM quinoa starch increased, and the oil droplet size of emulsions with EM quinoa starch decreased. It suggested that both the smallest particle size and the closest extent of the contact angle to 90° derived the best emulsifying property of EM-9. The EM quinoa starch had higher emulsifying capacity at higher oil volume fraction (Φ) (50%) than at lower Φ (20%), proving that the EM starch has potential to be used as Pickering emulsifiers in higher oil products, such as salad dressing. [ABSTRACT FROM AUTHOR]

[Display omitted] • Critical melting with freeze–thaw (CMFT) can be used as a clean-label way to prepare porous starch. • Partial weakening of structure before FT is critical for porous starch formation. • Freezing rates determined the pore-forming characteristics of starch. • CMFT-prepared porous starch had more ordered double-helical structures. • CMFT significantly increased the thermostability and water/oil absorption of starch. In this work, critical melting (CM) combined with freeze-thawing treatment (FT, freezing at −20 ℃ and −80 ℃, respectively) was used to prepare porous starch. The results showed that CM combined with the slow freezing rate (−20 ℃) can prepare porous starch with characteristics of grooves and cavities, while combined with the rapid freezing rate (−80 ℃) can prepare with holes and channels, especially after repeating FT cycles. Compared with the native counterpart, the specific surface area, pore volume, and average diameter of CMFT-prepared porous starch were significantly increased to 4.07 m2/g, 7.29 cm3/g × 10−3, and 3.57 nm, respectively. CMFT significantly increased the thermal stability of starch, in which the To, Tp, and Tc significantly increased from 63.32, 69.62, and 72.90 (native) to ∼69, 72, and 76 °C, respectively. CMFT significantly increased water and oil absorption of porous starch from 91.20 % and 72.00 % (native) up to ∼163 % and 94 %, respectively. Moreover, CMFT-prepared porous starch had a more ordered double-helical structure, which showed in the significantly increased relative crystallinity, semi-crystalline lamellae structure, and the proportion of the double helix structure of starch. The synergistic effect of melting combined with ice recrystallization can be used as an effective way to prepare structure-stabilized porous starch. [ABSTRACT FROM AUTHOR]

Highlights • Effect of PEF on structural properties of starches type A, B, and C investigated. • Polarized light microscopy, XRD, ATR-FTIR, SSNMR, SAXS, GPC used. • Effect of PEF on structure and in vitro digestibility of starch patterns revealed. Abstract Effect of pulsed electric field (PEF) on the structural properties of representative starches with different crystalline type, wheat starch for type A, potato starch for type B, and pea starch for type C, were investigated with polarized light microscopy (PLM), X-ray diffractometry (XRD), attenuated total internal reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, solid-state nuclear magnetic resonance (SSNMR) spectroscopy, small-angle X-ray scattering (SAXS), and gel permeation chromatography (GPC) to understand whether PEF could be applied directly in starchy foods. The results showed that PEF could change the structure of all three types of starch, especially potato starch; the birefringence, represented by Maltese cross in polarized microscopic observation changed slightly; XRD and SSNMR spectra demonstrated PEF did not change the crystalline type of starch granules. However, relative crystallinity variations happened at some points of electric field intensity (EFI). Increasing with the EFI, a bigger variation of R 1045/1022 happened in potato starch than in wheat starch and pea starch, as illustrated by ATR-FTIR. Significant influences of PEF on the scatter structure and fractal dimension of self-similar structures were observed for wheat starch and potato starch, but not for pea starch. The GPC suggested that molecular weight distribution changed for all the three starches. And in vitro tests showed that PEF changed significantly (P < 0.05) the digestibility of starches, especially wheat starch and potato starch. [ABSTRACT FROM AUTHOR]

Highlights • Smaller granules had the fewest lamellar structure. • The fractal structure of SPS showed the lowest compactness. • The fractal structure of SCS showed the highest compactness. • SPS had the highest total double helix content. • LCS showed a new diffractive peak at 24.3°, and SPS showed a new 13C peak at 64 ppm. Abstract Large-, medium-, and small-sized granules were separated from cassava and potato starches. Fourier transform infrared spectroscopy, wide angle X-ray diffraction, small angle X-ray scattering, nuclear magnetic resonance and scanning electron microscope were used to investigate the supramolecular structures of cassava and potato starch fractions. The crystallinity of small-sized potato starch (SPS) was lower than that of its counterparts, while crystallinities of all cassava fractions were similar. The contents of lamellar structure of small-sized granules were the smallest, while those of their counterparts were similar. The lamellar repeat distance was similar for the starch fractions. Self-similar structure of SPS showed mass fractal with the lowest compactness, while that of small-sized corn starch showed surface fractal with the largest compactness. The NMR test revealed that SPS had the highest total double helix content, while its counterparts showed similar values. Moreover, a new 13C peak at 64 ppm was observed for SPS. [ABSTRACT FROM AUTHOR]

In this study, rice starch (RS) was mixed with varying amounts of rice protein (RP; 0 % to 16 %) to explore the effects of protein on the gelatinization and retrogradation of starch during storage. The increased RP addition decreased the viscosity and gelatinization enthalpy of the mixtures but caused an upward trend in the gelatinization temperature, indicating that protein hampers the process of starch gelatinization. Furthermore, RP addition reduced gel hardness, decreased retrogradation enthalpy and crystallization rate constant, but increased Avrami exponent upon RS retrogradation. RP addition also facilitated the mobility of water molecules, weakened the conversion from bound water to free water in the gels, and moderately increased the uniformity and thickness of gel shape. In summary, RP had a dose-dependent effect on the gelatinization and retrogradation behavior of RS, although the anti-retrogradation concentration effect strongly weakened at protein levels exceeding 12 %. It is noteworthy, that excessive RP addition resulted in disulfide bond formation, which increased gel strength and network structure but reduced the ability of RP to facilitate water molecule mobility and restrict water migration, ultimately reducing its anti-retrogradation capability. This phenomenon can be partially attributed to spontaneous protein-protein interaction caused by excessive protein addition, replacing the starch-protein interaction. [ABSTRACT FROM AUTHOR]

The limited and unstable interactions between potato starch (PS) and xanthan gum (XG) by simple mixing (SM) lead it difficult to induce substantial changes in starchy products. Structural unwinding and rearrangement of PS and XG by critical melting and freeze-thawing (CMFT) were used to promote PS/XG synergism, and the physicochemical, functionalities, and structural properties were investigated. Compared to "Native" and SM, CMFT promoted the formation of large clusters with a rough granular surface and wrapped by a matrix composed of released soluble starches and XG (SEM), thus making the composite more compact to thermal processes, such as the significantly decreased WSI and SP, and increased the melting temperatures. The enhanced synergism of PS/XG after CMFT effectively decreased the breakdown viscosity from ~3600 (Native) to ~300 mPa·s and increased the final viscosity from ~2800 (Native) to ~4800. CMFT significantly increased the functional properties of PS/XG composite, including water/oil absorptions and resistant starch content. CMFT caused the partial melting and loss of large packaged structures in starch (XRD, FTIR, and NMR), and the melting and the loss of crystalline structure controlled at approximately 20 % and 30 %, respectively, are the most effective for promoting PS/XG interaction. • Critical melting and freeze-thawing (CMFT) enhanced potato starch/xanthan gum (PS/XG) interaction. • Starch melting and crystalline loss controlled at ~20 % and 30 %, respectively, are the most effective. • Soluble starches released by CMFT are beneficial to promote PS/XG interchain entanglement. • CMFT increased the functional properties of starch with decreased digestibility. • CMFT effectively raised the thermal, heating, and shear stability of starch. [ABSTRACT FROM AUTHOR]

The effect of an interchain entanglement on the enhancement of starch and hydrocolloid synergism and their changes in structural and functional properties was investigated. Potato starch (PS) and xanthan gum (XG) were taken as research materials, and critical melting at the onset melting temperature of starch combined with freeze-thawing (CMFT) was used to promote interchain entanglement of PS/XG. The work suggested that CMFT effectively stabilized the aqueous mixture system of PS/XG, showing no phase separation in the water phase system, even after 12 h of storage. The PS/XG composite prepared by CMFT had significantly improved stability against acid, salt, and shear stress during the thermal process DSC demonstrated that CMFT raised the T o of composite to ∼67 from 62.79 °C for native PS. RVA suggested that when pasted in distilled water, acid, and salt solution media, the breakdown viscosity of PS/XG composite declined to ∼380, 660, and 240 from 3615, 1541, and 1114 mPa s for native PS, respectively. CMFT significantly affected the apparent dropping properties of the starch paste, displaying a shorter and more cohesive paste drop against gravity. CMFT effectively improved the gelling properties of starch, with significant improvement in apparent surface adhesion properties and texture of gels, as well as freeze-thawing stability. [Display omitted] •Critical melting and freeze-thawing (CMFT) enhanced potato starch/xanthan gum (PS/XG) synergism. •Release of soluble starches by CMFT effectively promotes interchain entanglement with XG. •Partial melting of the ordered crystalline structure is beneficial to promoting PS/XG interaction. •CMFT significantly improved the pasting and gelling properties of starch. •CMFT effectively raised the thermal, acid, salt, and shear stability of starch paste. [ABSTRACT FROM AUTHOR]

Porous starch is one of the widely used multifunctional materials in food and pharmaceutical industries. This work was carried out to prepare porous starch by a novel clean-label method of critical melting (CM) and freeze-thawing (FT) treatment. Porous starch prepared by CMFT showed observable grooves and holes on the surface, channels and cavities inside the granule. Repeated FT after CM promoted the formation of porous structures, in which freezing rates showed different effects on the pore-forming properties of starch granules. Compared to the native counterpart, porous starch prepared by CMFT showed significantly increased thermal stability as shown by water solubility, swelling power, DSC, and RVA. CMFT treatment significantly increased water and oil absorption of porous starch from 85 to 75% (native) up to about 160 and 100%, respectively. Moreover, CMFT prepared porous starch showed the appearance of a visible diffraction peak at 20°, indicating a more ordered double-helical structure in starch granules. The synergistic effect of CM combined with FT could be used to prepare porous starch with "clean-label". [Display omitted] • Critical melting with freeze-thawing could be used for porous starch preparation. • The prepared porous starch has an increased thermostability. • Treatment significantly increased the water and oil absorption of porous starch. • Melting energy and ice crystals recrystallization are critical for porous structure formation. • Reassociation of leached soluble starches during treatment raised thermostability of starch. [ABSTRACT FROM AUTHOR]

[Display omitted] • Partial gelatinization and freeze-thawing significantly modified the properties of waxy maize starch. • The addition of xanthan gum enhanced these effects of physical treatments. • Treatments affected inner structure and chain arrangement of starch. • Treatments improved the pasting properties and produced a short and cohesive paste. • Treatments increased the gelling ability and stability to freeze-thawing cycles. To improve the pasting and gelling behaviors of waxy maize starch, an aqueous dispersion with or without xanthan gum was subjected to partial gelatinization (5 ℃ above the onset melting temperature of starch) and freeze-thawing treatment. After the treatments, starch granules were slightly deformed, with partial loss of birefringence, and tended to aggregate. The relative crystallinity and thermal stability of waxy maize starch crystals decreased by the treatments. These changes indicated that the treatment affected the inner structure and chain arrangement of the granules. The treated waxy maize starches, however, showed a higher overall pasting viscosity with shorter and more cohesive pastes than that of the native starch. The treated starches formed rigid gels with increased stability against freeze-thawing. The addition of small amounts of xanthan gum enhanced the effects of the treatments. [ABSTRACT FROM AUTHOR]

Critical melting pretreatment for granular swelling and soluble starch release was performed before freeze-thawing (FT) to enhance the effect of FT treatment on structure modification of potato starch. The critical melting temperature applied was based on the onset melting temperature (T o) of the native potato starch. After pretreatment, the effect of multiple FT cycles on the morphology, structure, and functionality was investigated. The pretreatment effectively induced granular swelling and partial disruption of the crystalline structure by increasing the volume of water molecules inside the granules. The pasting pattern changed obviously after treatments with the significantly increased final viscosity (up to 5000 from 2900 mPa s) and decreased breakdown (1/5th of native starch). Soluble starch released due to the both critical melting and FT treatments had a strong tendency to reassociate outside the granules, which effectively raised the thermal stability of starch granules. Moreover, increased water (∼109–∼164%) and oil (∼56–∼64%) absorption of starch at room temperature were observed. The synergistic effect of the combination of critical melting pretreatment and mechanical force of ice crystals effectively modified the properties of potato starch, suggesting a useful clean-label method for starch modification. [Display omitted] • Pretreatment enhanced modification effect of freeze-thawing on potato starch (PS). • Critical melting pretreatment applied is based on onset melting temperature of PS. • The combined treatment changed the morphology, structure, and functionality of PS. • Thermal stability of PS granules raised significantly after the combined treatment. • Partial disruption of chain arrangement and soluble starch release plays a key role. [ABSTRACT FROM AUTHOR]

An aqueous suspension of native potato starch (PS)/xanthan gum (XG) mixture was subjected to physical treatments, including critical melting (mild heating, MH; partial gelatinization, PG) and freeze-thawing (FT) treatments. The Physical treatments significantly changed the morphology, pasting, and structural characteristics of potato starch compared with the simple aqueous blending of PS and XG. Microscopy revealed that the starch granules partially melted and some of the melted granules aggregated into a cluster after critical melting and FT treatment. The overall intensity of X-ray diffraction peaks and relative crystallinity also decreased obviously after treatment, indicating partial disruption of the starch inner structure. Both XG addition and physical treatment decreased the solubility index, swelling power, and water holding capacity of starch after physical treatments. Moreover, the final viscosity (from 2988 to about 5000 mPa s) and shear stability (from 3542 to about 200 mPa s) of starch paste were substantially increased by the physical treatments. The critical melting caused the leaching of soluble starch, which induced the formation of starch/XG aggregate matrix attached to the surface of starch granules during FT treatment, contributing to the starch property modification. While the formation of these matrices might also be the reason for the increased thickness of the starch semi-crystalline lamellar structure. [Display omitted] • Critical melting and freeze-thawing treatments with xanthan gum (XG) effectively modified potato starch. • Treatments significantly changed the morphology, pasting and structural characteristics of starch. • Formation of soluble starch/XG matrix during treatments stabilized the starch granules against heating. • Treatments raised the final viscosity and shear stability of starch pastes. • Intensity of X-ray diffraction peaks and relative crystallinity decreased obviously after treatments. [ABSTRACT FROM AUTHOR]