Morphological, physicochemical, and viscoelastic properties of sonicated corn starch

Green fabrication of hierarchical pore starch with controllable pore size and shape based on different amylose-amylopectin ratios

Porous starch (PS) was widely prepared for its large effective surface area, pore volume, and superior hydrophilic property, but its application is limited by enzyme and chemical use. In this study, a novel method to prepare PS with controllable hierarchical pores through ultrasound-ethanol precipitation and different amylose-amylopectin ratios is proposed. As shown in porous morphology and parameters, there were macropores, mesopores and micropores in the formed PS. Moreover, we found that the content of amylose (AM) was negatively related with the total pore volume and pore diameter in PS. The different surface tensions created through ethanol evaporation and water migration during oven drying are the main mechanisms of forming pores with controllable sizes. Based on the molecular information and the long-/short-range orders reflected by crystalline pattern, lamellas, and single-/double-helices, we conclude that AM is easier to form V-type inclusion complexes with ethanol. More single helix of V-amylose was transformed from B-type polymorph after ethanol exchange, which had significantly broadened dLozentz in PS. The TG spectra proved that the novel PS has the stable thermodynamic property. Overall, the finding of an objective regular between AM and pore sizes of PS in this study may support the other work related to PS.

Physicochemical and rheological properties of ultrasonic-assisted pregelatinized rice flour

This study evaluated the physical and rheological properties of whole rice flour treated for different sonication times (0-15 min). Ultrasonication reduces the particle size of rice flour and improves its solubility. Viscosity tests using RVA and steady shear showed a notable decrease in the viscosity of the rehydrated pregelatinized rice flour. Although no unusual patterns were observed in the XRD analysis, the FT-IR and microstructure morphology findings suggest that ultrasonication led to structural changes in the rice flour. Overall, the study indicates that ultrasonication is a practical and clean method for producing plant-based drinks from rice flour, which could expand its limited applications in the beverage industry.

Heat moisture treatment and ultrasound-induced hydrothermal wheat starch modification: Techno-functional, microstructural and quality 3D printed characteristics

In this study, the effect of hydrothermal process, ultrasound and combined freezing-ultrasound process on the physical and structural characteristics of wheat starch (Triticum aestivum) was investigated. Two heat-moisture treatments for 2 h (HMT2) and 4 h (HMT4), high-intensity, high-frequency ultrasound under two treatment times (10 to 20 min) (UT10 and UT20) as pre-treatment and sonication after freezing as post-treatment (FUT) on wheat starch suspension was applied. The modifications of starch crystallinity, chemical bonds of starch treated, morphology, thermal, swelling, pasting, and physicochemical characteristics were evaluated. Finally, the starches treated under these conditions were used as ink for a 3D printer, and the characteristics of the printed product were evaluated. The results demonstrate that heat-moisture modified starch increased swelling and size of granules and lowered syneresis values. Sonication promoted molecular depolymerization and reduction of starch swelling and crystallinity. Combined treatment (Sonication and freezing) showed higher peak apparent viscosity during gelatinization and pasting, and the FUT starch-based hydrogels showed the best printability (better ability to stack layers on top of each other and build the desired 3D shape), indicating better reproducibility of this ink. These results showed that FUT is a suitable process for improving the synergy and properties of wheat starch-based hydrogels, which are suitable as inks for use in 3D printers.

Effects of plasma-activated water combined with ultrasonic treatment of corn starch on structural, thermal, physicochemical, functional, and pasting properties

In this study, corn starch was used as the raw material, and modified starch was prepared using a method combining plasma-activated water and ultrasound treatment (PUL). This method was compared with treatments using plasma-activated water (PAW) and ultrasound (UL) alone. The structure, thermal, physicochemical, pasting, and functional properties of the native and treated starches were evaluated. The results indicated that PAW and UL treatments did not alter the shape of the starch granules but caused some surface damage. The PUL treatment increased the starch gelatinization temperature and enthalpy (from 11.22 J/g to 13.13 J/g), as well as its relative crystallinity (increased by 0.51 %), gel hardness (increased by 16.19 %) compared to untreated starch, without inducing a crystalline transition. The PUL treatment resulted in a whitening of the samples. The dual treatment enhanced the thermal stability of the starch paste, which can be attributed to the synergistic effect between PAW and ultrasound (PAW can modify the starch structure at a molecular level, while ultrasound can further disrupt the granule weak crystalline structures, leading to improved thermal properties). Furthermore, FTIR results suggested significant changes in the functional groups related to the water-binding capacity of starch, and the order of the double-helical structure was disrupted. The findings of this study suggest that PUL treatment is a promising new green modification technique for improving the starch structure and enhancing starch properties. However, further research is needed to tailor the approach based on the specific properties of the raw material.

Ultrasonication: An Efficient Alternative for the Physical Modification of Starches, Flours and Grains

Ultrasonic (USC) treatments have been applied to starches, flours and grains to modify their physicochemical properties and improve their industrial applicability. The extent of the modification caused by USC treatment depends on the treatment conditions and the natural characteristics of the treated matter. Cavitation leads to structural damage and fragmentation and partial depolymerization of starch components. The amorphous regions are more susceptible to being disrupted by ultrasonication, while the crystalline regions require extended USC exposure to be affected. The increased surface area in USC-treated samples has a higher interaction with water, resulting in modification of the swelling power, solubility, apparent viscosity, pasting properties and gel rheological and textural properties. Starch digestibility has been reported to be modified by ultrasonication to different extents depending on the power applied. The most important treatment variables leading to more pronounced modifications in USC treatments are the botanical origin of the treated matter, USC power, time, concentration and temperature. The interaction between these factors also has a significant impact on the damage caused by the treatment. The molecular rearrangement and destruction of starch structures occur simultaneously during the USC treatment and the final properties of the modified matrix will depend on the array of treatment parameters. This review summarizes the known effects of ultrasonic treatments in modifying starches, flours and grains.

Effect of ultrasound geometry on the production efficiency of damaged starch: Determining rheology parameters, and non-isothermal reaction kinetics

Present study investigates the effects of probe size geometry on thermodynamic kinetics, rheology, and microstructure of wheat and tapioca starch. Ultrasound treatment using different probe diameters (20 mm and 100 mm) significantly influenced the gelatinization process. Results showed reduced enthalpy (ΔH) and Gibbs energy (ΔG), indicating enhanced gelatinization efficiency. According to the results, using a 20 mm and 100 mm probe leads to a reduction of 52.7 % and 68.6 % in reaction enthalpy for wheat starch compared to native starch, respectively. Microstructure analysis revealed structural changes, with ultrasound treatment leading to granular fractures and a sheet-like structure with air bubbles. The rheological behavior of the starches is found to exhibit shear thinning behavior, with the Casson model providing the best fit for the experimental data. Moreover, rheology modeling using Herschel-Bulkley and power law models showed increased viscosity and shear stress in larger probes. Numerical simulation data demonstrated that probe size influenced ultrasonic pressure, sound pressure level, and thermal power dissipation density, affecting fluid motion and velocity field components. Moreover, the maximum dissipated power decreases from 8.43 to 0.655 mW/m3 with an increase in probe diameter from 20 to 100 mm. The average yield shear stress values are calculated as 3.36 and 3.14 for wheat and tapioca starches, respectively. The larger probe diameter leads to greater entropy increases, with tapioca starch showing a 4.72 % increase and wheat starch a 4.97 % increase, compared to 2.56 % and 3.11 %, respectively, with the smaller probe. Additionally, the Keller-Miksis model provided insights into bubble dynamics, revealing increased pressure and temperature with higher pressure amplitudes.

Effect of curdlan addition and thermal sterilization on the structural and properties of rice starch gel

This study delves into the effects of curdlan integration and thermal sterilization on the rheological properties, structure, and quality attributes of concentrated rice starch gel. Acting as a heat-set polysaccharide, curdlan established a dual-network gel structure with rice starch gel, displaying strong interactions with rice starch, as confirmed by confocal laser scanning microscopy and Fourier-transform infrared spectroscopy. The addition of curdlan expedited the gel formation of rice starch, yielding a denser gel structure. Consequently, this enhanced G', solid-like behavior, textural properties, and cooking quality while reducing frequency-dependence. Given the cooling-induced gelation behavior of pure rice starch, thermal treatment disrupted inter-chain hydrogen bonding, compromising the structural integrity of the gel. This disruption manifested in a softer texture and diminished mechanical properties and cooking quality. Notably, this decline in mechanical properties and cooking quality of rice starch gel was markedly ameliorated with the incorporation of curdlan, particularly at a content of ≥1.0 %. Compared with pure RS, 1.0 % CD inclusion showed a reduction in cooking breakage rate by 30.69 % and an increase in hardness by 38.04 %. This work provides valuable insights for the advancement of fresh starch gel-based foods that exhibit exceptional quality and an extended shelf life.

Ultrasound-assisted starch hydrolyzing by alpha-amylase: Implementation of computational fluid dynamics, acoustic field determination, and rheology modeling

The study aimed to optimize the ultrasonic-assisted modification (UAM) of corn and potato starch by assessing the influence of ultrasound geometry, power, and frequency on the fluid flow for sonicated starch to achieve porous starch with a higher degree of hydrolyzing by α-amylase. This assessment was conducted through mathematical modeling and 3D computational fluid dynamics (CFD) simulations. The ultrasonic pressure field is determined by the solution of the non-linear Westervelt equation in the frequency domain. Then, the obtained field is utilized to simulate the dissipated power and flow field characteristics. According to the results obtained from the Rapid Visco Analyzer (RVA), it was observed that the peak and final viscosity of hydrolyzed sonicated starch were less than hydrolyzed native starch. This decrease in viscosity indicates a breakdown of the starch structure, leading to a more fluid-like consistency. The shear rate and shear stress data are used for rheology modeling. The fluid's viscosity is represented based on three models of Herschel-Bulkley, Casson, and Power law (Ostwald-de Waele). The magnitude of yield shear stress at low shear rates, the shear-thinning behavior, and the nearly Newtonian fluid nature at high shear rates are extracted from the viscosity models. The surfaces of the starch granules were analyzed using scanning electron microscopy (SEM) revealed that sonication treatments caused damage, cracks, and porosity on the surfaces of the starch granules which were prone to amylolytic enzymes. This indicates that the structural integrity of the granules was compromised and facilitated enzyme penetration. This study proposes that ultrasonication can be utilized to produce damaged starch, which is susceptible to hydrolysis by α-amylase. This approach holds the potential for reducing enzyme consumption in various industries.

Multi-scale ultrasound induced composite coacervates of whey protein and pullulan polysaccharide on emulsion forming and stabilizing mechanisms

A non-destructive technique known as multi-scale ultrasound (MSU) was employed to modify the emulsion consisting of glycosylated bovine whey protein (WP) and pullulan (Pu). To assess the effect on the structural and emulsifying properties of the WP-Pu, the formulated emulsion, was treated with divergent MSU at (single: 20 kHz, 40 kHz, and 60 kHz; dual: 20-40 kHz, 40-60 kHz, and 20-60 kHz; and tri: 20-40-60 kHz) frequency for a duration of 30 min. The tri-frequency, treated emulsion showed improved emulsifying stability compared to the control and MSU-treated single, and dual-frequency samples, as indicated by the particle size, structural morphology, and adsorbed protein. The molecular docking and numerous spectral analysis provided evidence that WP can undergo successful phenolation. This modified form of WP then interacts with Pu through various forces, including H-bonding and other mechanisms, resulting in the formation of a composite emulsion. The rheological properties revealed that both the control emulsion and the MSU-treated emulsion exhibited non-Newtonian pseudoplastic flow behavior. This behavior is characterized by shear thinning, where the viscosity decreases with increasing shear rate. The shear rates tested ranged from 1 to 300 1/s, additionally, the degree of crystallinity increased from 18.2° to 19.4°. Overall, the tri-frequency effect was most pronounced compared to single and dual-frequency. Ultrasonication, an emerging non-thermal technology, proves to be an efficient approach for the formulation of WP-Pu composites. These composites have significant potential for use in drug delivery systems and functional foods.

Dual Modification of Cassava Starch Using Physical Treatments for Production of Pickering Stabilizers

Cassava starch nanoparticles (SNP) were produced using the nanoprecipitation method after modification of starch granules using ultrasound (US) or heat-moisture treatment (HMT). To produce SNP, cassava starches were gelatinized (95 °C/30 min) and precipitated after cooling, using absolute ethanol. SNPs were isolated using centrifugation and lyophilized. The nanoparticles produced from native starch and starches modified using US or HMT, named NSNP, USNP and HSNP, respectively, were characterized in terms of their main physical or functional properties. The SNP showed cluster plate formats, which were smooth for particles produced from native starch (NSNP) and rough for particles from starch modified with US (USNP) or HMT (HSNP), with smaller size ranges presented by HSNP (~63-674 nm) than by USNP (~123-1300 nm) or NSNP (~25-1450 nm). SNP had low surface charge values and a V-type crystalline structure. FTIR and thermal analyses confirmed the reduction of crystallinity. The SNP produced after physical pretreatments (US, HMT) showed an improvement in lipophilicity, with their oil absorption capacity in decreasing order being HSNP > USNP > NSNP, which was confirmed by the significant increase in contact angles from ~68.4° (NSNP) to ~76° (USNP; HSNP). A concentration of SNP higher than 4% may be required to produce stability with 20% oil content. The emulsions produced with HSNP showed stability during the storage (7 days at 20 °C), whereas the emulsions prepared with NSNP exhibited phase separation after preparation. The results suggested that dual physical modifications could be used for the production of starch nanoparticles as stabilizers for Pickering emulsions with stable characteristics.

Investigation of ultrasound-assisted starch acetylation by single- and dual- frequency ultrasound based on rheology modelling, non-isothermal reaction kinetics, and flow/acoustic simulation

To achieve wheat starch acetylation (AC) with a high degree of substitution (DS), the acetylation process was carried out using various ultrasonication frequencies, including 25 kHz, 40 kHz, and 25 + 40 kHz. In the second step, wheat starch's ultrasound-assisted acetylation (UAA) is simulated using various approaches including the rheology models, non-isothermal reaction kinetics, and flow/acoustic modelling. The computational fluid dynamics (CFD) simulation solves the non-linear acoustic governing equation to determine the flow field and the amount of delivered ultrasound energy. The acetylated starch increased peak and final viscosity, with the highest values observed for the 25 + 40 kHz frequency than other single frequencies (25 kHz and 40 kHz). The viscosity of the starch is specified based on the experimental data using Herschel-Bulkley, power law, and Casson rheology models. According to differential scanning calorimetry (DSC) analysis, the gelatinization parameters and enthalpy of gelatinization (ΔHgel), were found to be lower in acetylated starches at the frequency of 25 + 40 kHz compared to those at frequencies of 25 kHz and 40 kHz, as well as native starches (NS). Moreover, the gelatinization process is examined by implementing the non-isothermal reaction kinetics to obtain the activation energy and reaction order. Based on the results obtained, implementing sonication at 25 kHz reduces the activation energy by 70.3 % compared to native starch. However, the same parameter is obtained to be 69.9 % and 67.1 % for the application of 40 and 25 + 40 kHz transducers, respectively. Additionally, during the sonication treatment, the yield shear stress increases between 24.1 and 31.8 %, based on the applied frequency. Morphology analysis determined by scanning electron microscopy (SEM) revealed that the surfaces and small granules underwent more damage in acetylated starches at frequencies of 25 kHz and 40 kHz. However, in acetylated starches at 25 + 40 kHz, the larger granules were more affected than the smaller ones.

Impact of ultrasound treatment on the physicochemical and rheological properties of acid hydrolyzed sorghum starch

The present study aimed to evaluate the influence of ultrasonication on the physicochemical properties of native and acid-hydrolyzed white sorghum starch. Sorghum starch exhibited improved freeze-thaw stability, solubility, swelling power, and paste clarity after mild sonication. Starches sonicated at 30 % amplitude for 10 and 20 min increased the peak viscosity to 249 and 240 BU, gel firmness to 140.23 and 131.62 (g), ΔH to 13.4 and 13.1 (J/g), crystallinity to 29.51 and 29.10 (%), double helix content to 1.11 and 1.07 and degree of ordered structures to 1.16 and 1.09. The sonicated dual-treated samples (sonicated-acid hydrolyzed) exhibited reduced swelling power, peak viscosity, gelatinization temperatures and gel firmness. In contrast, the solubility, paste clarity, ΔH, percentage of crystallinity, double helix content and degree of ordered structures improved. Ultrasonic treatment made cracks and holes in the granule surface, whereas dual-treated starches were more porous and rougher, with deep depressions. All sorghum starches displayed shear-thinning behavior (n < 1). The pseudoplastic behavior and consistency indices of the starch paste decreased with increasing sonication time and amplitude. The G' was always higher than G" and tanδ was <1 for all samples, indicating a more solid/elastic behavior. The increased sonication time and amplitude, as well as the dual-treatment, caused the gel to become more susceptible to shear forces, which resulted in a decrease in G' and G" and an increase in tanδ.

Removal of Pb (II) and Zn (II) in the mineral beneficiation wastewater by using cross-linked carboxymethyl starch-g-methacrylic acid as an effective flocculant

The cross-linked carboxymethyl starch-g-methacrylic acid (CCMS-g-MAA) was prepared by using grafting and micro-cross-linking in the one-pot preparation process. CCMS-g-MAA presented high removal capacity of Pb (II) of 57.13 mg/g at pH = 4 and high removal capacity of Zn (II) of 51.41 mg/g at pH = 5 by using a sample dosage of 0.68 g/L. Characterization results of FTIR, TG, and XRD illustrate that methacrylic acid and sodium tri-metaphosphate were successfully introduced into the structure of carboxymethyl starch. SEM characterization presented that the sample particles were amorphous aggregates with surface voids, which was favorable for the adsorption of heavy metal ions from wastewater. Adsorption isotherm results indicated that Freundlich equation could be better used to describe the adsorption process of metal ions on CCMS-g-MAA. The adsorption kinetic results indicated that the pseudo-second-order model is more suitable to describe this removal process. XPS results indicated that metal ions interacted with functional groups on the surface of flocculant, especially carboxyl groups. The removal process may be purposed that metal ions were adsorbed by porous material, and then combined with surface functional groups of the flocculant via electrostatic interaction, chelation or ion exchange. Subsequently, metal ions were separated from the wastewater with flocs precipitated in the bottom of solution via bridging and patching. The obtained results illustrated that CCMS-g-MAA was an effective material for the treatment of wastewater containing polymetallic ions besides mineral beneficiation wastewater supported by its excellent regeneration.

Molecular morphology & interactions, functional properties, rheology and in vitro digestibility of ultrasonically modified pearl millet and sorghum starches

The present research investigated to study the effect of ultrasound treatment on isolated pearl millet starch (PMS) and sorghum starch (SS). Ultrasonication was applied to PMS and SS for 10, 15, and 20 min. Ultrasonically modified pearl millet and sorghum starches evaluated for their techno-functionality, pasting profile, morphology, in vitro starch digestibility, XRD, and molecular interactions. Ultrasound treatment increased water and oil absorption capacity, swelling power, and solubility with treatment time. For ultrasonicated PMS and SS, a significant increase (p < 0.05) in paste clarity (PC) (70.05 % and 67.23 %), freeze-thawing stability (FTS), gel consistency (GC) (25.05 mm and 32.95 mm), and in vitro starch digestibility were observed (57.70 g/100 g and 50.29 g/100 g), whereas no significant changes were recorded for the color values after the ultrasound treatment. Variations in pasting property were also observed in ultrasonicated starches with treatment duration. SEM images confirmed ultrasonication mainly forms pores and indentations on starch granule surface. FTIR spectra and X-ray diffractogram for ultrasonicated starches revealed a slight decrease in the peak intensity and A-type X-ray pattern with lower relative crystallinity (RC) than the native starches. G' > G″ value, indicating the elastic behavior and lower tan δ value, depicting viscous behavior and high gel strength.

Impact of long-term ultrasound treatment on structural and physicochemical properties of starches differing in granule size

Granule size is a critical parameter affecting starch processing properties. Ultrasound treatments of up to 22 h were applied on two starches differing in granule size (quinoa starch and maize starch). The two starches showed significantly different trends in both structural and physicochemical aspects affected by the ultrasound treatments. For the small granule starch (volume-weighted mean particle size of 1.79 μm), short-term ultrasonication caused an increase of swelling power. As the treatment time increased, the physicochemical properties were influenced by the degradation of amylopectin external chains. The X-ray diffraction results showed a decrease of relative crystallinity and changes of peak areas with long-term treatment. On the other hand, a balance between amylose leaching and surface damages was seen for the large granule starch (volume-weighted mean particle size of 18.3 μm). The effect of ultrasound modification on starches with different molecular and granular structures was discussed. A possible mechanism of the ultrasound effect was proposed.

Changes in physiochemical properties and in vitro digestion of corn starch prepared with heat-moisture treatment

To investigate the effect of heat-moisture treatment (HMT) on the physiochemical properties and in vitro digestibility of corn starch, the pasting behavior, viscoelasticity, thermal properties, long/short range structure, morphology and in vitro digestion of corn starch treated with different HMT conditions (HMT-20, 25, 30, 35 and 40 %) were characterized. Results indicated that after HMT, the pasting and disintegration behaviors of corn starch were affected and correlated with the moisture content. The dynamic viscoelasticity of corn starch was changed, and when glassy conditions were reached, the elastic properties decreased with increasing moisture while the viscous properties increased, especially for the HMT-40 %. The thermal stability of starch was improved by HMT, although the enthalpy of pasting (ΔH) was reduced. Additionally, the HMT processing also promoted the conversion of RDS to SDS and/or RS (SDS and RS increased to 39.80 % and 31.68 % for HMT-40 %, respectively), which might attribute to the rearrangement of free starch molecules. The present work provides a potential approach to make functional starches with healthy properties.

Starch Modification with Molecular Transformation, Physicochemical Characteristics, and Industrial Usability: A State-of-the-Art Review

Starch is a readily available and abundant source of biological raw materials and is widely used in the food, medical, and textile industries. However, native starch with insufficient functionality limits its utilization in the above applications; therefore, it is modified through various physical, chemical, enzymatic, genetic and multiple modifications. This review summarized the relationship between structural changes and functional properties of starch subjected to different modified methods, including hydrothermal treatment, microwave, pre-gelatinization, ball milling, ultrasonication, radiation, high hydrostatic pressure, supercritical CO₂, oxidation, etherification, esterification, acid hydrolysis, enzymatic modification, genetic modification, and their combined modifications. A better understanding of these features has the potential to lead to starch-based products with targeted structures and optimized properties for specific applications.

Synergistic impact of heat-ultrasound treatment on the properties and digestibility of Sagittaria sagittifolia L. starch-phenolic acid complexes

The current research investigated the multi-scale structural interactions between arrowhead starch (AS) and phenolic acids, such as ferulic acid (FA) and gallic acid (GA) to identify the mechanism of anti-digestion effects of starch. AS suspensions containing 10 % (w/w) GA or FA were subjected to physical mixing (PM) followed by heat treatment at 70 °C for 20 min (HT) and a synergistic heat-ultrasound treatment (HUT) for 20 min using a dual-frequency 20/40 KHz system. The synergistic HUT significantly (p < 0.05) increased the dispersion of phenolic acids in the amylose cavity, with GA showing a higher complexation index than FA. XRD analysis showed a typical V-type pattern for GA, indicating the formation of an inclusion complex, while peak intensities decreased for FA following HT and HUT. FTIR revealed sharper peaks possibly of amide bands in the ASGA-HUT sample compared to that of ASFA-HUT. Additionally, the emergence of cracks, fissures, and ruptures was more pronounced in the HUT-treated GA and FA complexes. Raman spectroscopy provided further insight into the structural attributes and compositional changes within the sample matrix. The synergistic application of HUT led to increased particle size in the form of complex aggregates, ultimately improving the digestion resistance of the starch-phenolic acid complexes.

Physicochemical, structural, and rheological characteristics of corn starch after thermal-ultrasound processing

Thermal-ultrasound treatment is a green technology that can significantly alter the structural and functional properties of starches. This research extend the effect of at different temperatures (25 °C, 45 °C, and 65 °C) and times (30 and 60 min) on the physicochemical, structural, and rheological properties of corn starch was studied. Amylose content, solubility, swelling power, and the least gelling content increased with increasing temperature and time. Starch treated at 45 °C for 30 min had the lowest syneresis among all treatments. Thermal-ultrasound treatment at 25 °C and 65 °C for 60 min caused increasing paste clarity. Microscopic observations demonstrated that the starch granules were agglomerated at 65 °C. Although the crystallinity of samples decreased from 35.42% to 8.94%, the storage modulus was more than the loss modulus during the frequency sweep test. Pasting properties showed that pasting temperatures shifted to higher values after treatment. Nonetheless, the maximum viscosity decreased, and the final viscosity of the treated samples demonstrated that short-term retrogradation could deteriorate. Results showed that thermal-ultrasound is a viable technique for starch modification compared to conventional thermal and ultrasound treatments.

Modification of the microstructure of tef [Eragrostis tef (Zucc.) Trotter] flour ultrasonicated at different temperatures. Impact on its techno-functional and rheological properties

Tef flour comes from a nutritionally-rich ancient grain gaining increasing interest in gluten-free market. Gluten-free sources are modified by different means to improve their functionality. Ultrasound treatment (US) alters flours' structure and leads to physically modified flours with a wider application range. The aim of the present work was to evaluate the impact of US treatments of moderate treatment time, 10 min, and high concentration of the aqueous flour dispersion, 25%, on the microstructural, starch damage, apparent amylose content, techno-functional, pasting and rheological properties of two tef flour varieties, white and brown. Temperature was varied (20, 40, 45, 50, and 55 °C) to modulate the impact of sonication. US treatments led to general particle fragmentation which markedly increased starch damage and lightness (L*) values. Apparent amylose content was higher after ultrasonication, as consequence of molecular fragmentation due to cavitation. Increased starch granules' exposed area led to enhanced interaction with water, promoting the water absorption index (WAI) and swelling power (SP) of treated flours. Pasting properties showed increased pasting temperatures as well as decreased viscometric profiles with lower breakdown viscosities, indicative of starch rearrangement improved by increasing temperature. Rheological properties indicated higher consistency in gels after US treatments, with improved ability to withstand stress and lower values of tan(δ)1 reflecting a higher solid-like behavior and higher strength of the gel. Temperature was found to be a crucial variable during US treatments, showing an improved degree of modification at higher temperatures in ultrasonicated tef flours, following the same trend in both varieties.

Impact of Solubilized Substances on the Techno-Functional, Pasting and Rheological Properties of Ultrasound-Modified Rice, Tef, Corn and Quinoa Flours

The modification of flours by ultrasound (US) treatments requires excess water to suspend the sample to be treated, which must be removed after treatment to recover the ultrasonicated flour. The aim of this study was to determine the influence that the water removal method has on the final characteristics of US-treated gluten-free flours (rice, brown tef, corn and quinoa). US treatment parameters were constant, and two water removal methods were studied: freeze-drying and centrifugation + drying. The elimination of water by centrifugation resulted in the loss of solubilized compounds from the treated flours, which led to important differences between the final characteristics of US-treated flours. Ultrasonication resulted in the reduction of flours' particle size and modification of their color parameters. Techno-functional properties were modified by US treatment, where the water removal method was more influential in whole grain samples (brown tef and quinoa). Few differences were found in thermal properties among pairs of US-treated samples, indicative that the effect caused to starch was mainly attributed to ultrasonication conditions than to the drying method. The water removal method markedly influenced the pasting properties of US-treated flours, resulting in lower profiles when freeze-drying was applied and higher profiles when flours were retrieved by centrifugation. Gels made with tef, corn and quinoa presented reduced tan(δ)₁ values after sonication, while gels made with rice did not show any modification. The water removal method is a decisive step in US treatments, defining the final characteristics of the treated matter, and having a great influence in the modification attributed to ultrasonication.

Developing Self-Assembled Starch Nanoparticles in Starch Nanocomposite Films

Starch nanoparticles (SNPs) are synthesized by different precipitation techniques using corn starch, and SNP films are prepared by the evaporation casting method. The morphological study is investigated by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The distribution and sizes of precipitated SNPs after synthesizing are discovered by these methods as well. The crystallinity of the SNPs is studied by the X-ray diffractometry (XRD) method that demonstrates reduction compared to neat starch granules, and it is changed from A-style to V_H-style after precipitation. The chemical bonding of different SNPs after the nanoprecipitation is analyzed by Fourier transform infrared spectroscopy (FT-IR). Thermogravimetric analysis (TGA) demonstrates the decomposition of starch nanoparticles and the starch matrix that is related to the depolymerization of carbon chains in the range of 260 to 350 °C. The mechanical properties of the SNP films versus the temperature changing are discovered by dynamic mechanical analysis (DMA). The water contact angles of SNP films are measured using a goniometer, and the results showed the hydrophobic surfaces of the prepared films. Our study indicates that SNPs have a promising impact on the properties of corn starch films, which would be useful in biodegradable packaging material.

Effect of ultrasound on the physical properties and processing of major biopolymers-a review

Designing and developing modern techniques to facilitate the extraction and modification of functional properties of biopolymers are key motivations among researchers. As a low-cost, sustainable, non-toxic, and fast process, ultrasound has been considered a method to improve the processing of carbohydrate and protein-based biopolymers such as cellulose, chitin, starch, alginate, carrageenan, gelatine, and guar gum. A better understanding of the complex physicochemical behavior of biopolymers under ultrasonication may fortify the eminence of this technology in advanced-level applications. This review summarizes the recent advances in biopolymer processing and the effect of ultrasound on the physical properties of the selected biopolymers. A major focus will be given to the mechanisms of action and their impact on the properties and extraction. At the end, some possible suggestions are highlighted which need future investigation for amending the physical properties of biopolymers using ultrasonication.

Modification of corn starch by thermal-ultrasound treatment in presence of Arabic gum

This research extends the effects of a thermal-ultrasound treatment (at 25, 45, and 65 °C for 30 and 60 min) on the physicochemical, structural, and pasting properties of corn starch in presence of Arabic gum. Treated samples had lower leached amylose compared with corn starch, but it was non-significant (p < 0.05). In comparison to alone corn starch and a combination of Arabic gum, thermal-ultrasound treatment increased the swelling power and solubility of samples. Treatment significantly (p < 0.05) decreased the syneresis of treated starch gels, especially at a temperature of < 45 °C, but paste clarity was increased at the higher temperature (65 °C). The enthalpy of treated samples was in the range 15.20-16.37 J/g. Sonication at 65 °C for 60 min had the most destructive effect on corn starch granules, but at 30 min granules were swollen only. FT-IR spectra of samples confirmed the physical modification of thermal-ultrasound treatment. The relative crystallinity index of samples changed in the range 21.88-35.42-% and decreased with rising time and temperature. Sonication at 45 °C for 30 and 60 min produced starch-gum mixtures with different pasting properties. Thermal-ultrasound treatment in presence of gum can be a viable technique to modify starches with different functionality.

Effect of ultrasonic cavitation on the formation of soy protein isolate - rice starch complexes, and the characterization and prediction of interaction sites using molecular techniques

Protein-carbohydrate interactions occur naturally in glycoproteins which are highly stable in nature and are involved in various food complexes and can enhance the quality and functional properties of foods. In the current study, we characterized the protein-carbohydrate complex formed between commercial soy protein isolate and rice starch using different treatments namely heat treatment alone, ultrasound treatment alone, combination of ultrasound and heat treatment and mixing alone. The structural data obtained using circular dichroism indicated that during the complex formation, the α-helix values were reduced by a maximum of 67% compared to soy protein isolate alone. The crystalline nature of the complexes formed by ultrasound treatment preserved the techno-functional properties as compared to complexes formed by heat treatments. The FTIR analysis of the complexes formed indicated the formation of glycosidic bond. Molecular docking analysis revealed the interaction between the complexes occurred due to hydrogen bonds which make the proteins more stable in nature thus enhancing their denaturation temperature. Glutamine, Proline and Arginine present in the D subunit of 7S 3AUP interacts with the starch molecule. The obtained results suggest that sonication combined with heat treatment led to higher interaction between the soy proteins isolate and rice starch.

Optimization of the Sustainable Production of Resistant Starch in Rice Bran and Evaluation of Its Physicochemical and Technological Properties

In this study, the optimization of ultrasound (US) (850 kHz, 120 W) processing parameters (temperature, time, and power) for the enhanced production of resistant starch (RS) in rice bran (RB) matrixes was performed. The effect of US cavitation at different temperatures on the morphology, physicochemical properties, and mechanical performance of RS was evaluated. Ultrasonication at 40−70 °C temperatures affected the chemical structure, reduced the crystallinity of RS from 23.85% to between 18.37 and 4.43%, and increased the mechanical and thermal stability of RS pastes, indicating a higher tendency to retrograde. US treatment significantly (p < 0.05) improved the oil (OAC) and water (WAC) absorption capacities, swelling power (SP), solubility (WS), and reduced the least-gelation concentration (LGC). The mathematical evaluation of the data indicated a significant effect (p < 0.05) of the US parameters on the production of RS. The largest increment of RS (13.46 g/100 g dw) was achieved with US cavitation at 1.8 W/cm2 power, 40.2 °C temperature, and 18 min of processing time. The developed method and technology bring low-temperature US processing of rice milling waste to create a new sustainable food system based on modified rice bran biopolymers.

Ultrasound Treatment Enhanced Semidry-Milled Rice Flour Properties and Gluten-Free Rice Bread Quality

The structural and functional properties of physical modified rice flour, including ultrasound treated rice flour (US), microwave treated rice flour (MW) and hydrothermal treated rice flour (HT) were investigated with wet-milled rice flour (WF) used as a positive control. The results showed the presence of small dents and pores on the rice flour granules of US and MW while more fragments and cracks were showed in HT. XRD and FTIR revealed that moderate ultrasonic treatment promoted the orderly arrangement of starch while hydrothermal treatment destroyed the crystalline structure of rice flour. In addition, the significant decrease of gelatinization enthalpy and the narrowing gelatinization temperature were observed in US. Compared to that of SF, adding physical modified rice flour led to a batter with higher viscoelasticity and lower tan δ. However, the batter added HT exhibited highest G' and G″ values and lowest tan δ, which led to a harder texture of bread. Texture analysis demonstrated that physical modified rice flour (except HT) reduced the hardness, cohesion, and gumminess of rice bread. Especially, the specific volume of bread with US increased by 15.6% and the hardness decreased by 17.6%. This study suggested that ultrasound treatment of rice flour could improve texture properties and appearance of rice bread.

Impact of low-frequency ultrasound technology on physical, chemical and technological properties of cereals and pseudocereals

Cereals (CE) and pseudocereals (PSCE) play a pivotal role in nourishing the human population. Low-frequency ultrasound (LFUS) modifies the structure of CE and PSCE macromolecules such as starch and proteins, often improving their technological, functional and bioactive properties. Hence, it is employed for enhancing the traditional processes utilized for the preparation of CE- and PSCE-based foods as well as for the upcycling of their by-products. We report recent advances in LFUS treatments for hydration, germination, extraction of bioactive compounds from by-products, and fortification of CEs and PSCE, including kinetic modelling and underlying action mechanisms. Meta-analyses of LFUS influence on compounds extraction and starch gelatinization are also presented. LFUS enhances hydration rate and time lag phase of CE and PSCE, essential for germination, extraction, fermentation and cooking. The germination is improved by increasing hydration, releasing promoters and eliminating inhibitors. Furthermore, LFUS boosts the extraction of phenolic compounds, polysaccharides and other food components; modifies starch structure, affecting pasting properties; causes partial denaturation of proteins, improving their interfacial properties and their peptides availability. Overall, LFUS has an outstanding potential to improve transformation processes and functionalities of CE and PSCE.

Nonthermal physical modification of starch: An overview of recent research into structure and property alterations

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.

Ultrasound based modification and structural-functional analysis of corn and cassava starch

In this study, the starch molecules were modified with ultrasonication at two different time intervals by using starch molecules from corn and cassava. This research aimed to examine the effect of the high power ultrasound of 40 kHz voltage and frequency with short time duration on structural and physical properties of corn and cassava starch. Morphology of ultrasonically treated starch granules was observed by scanning electron microscopy (SEM), FTIR, differential scanning calorimetry (DSC), and X-ray diffraction (XRD) and compared with untreated samples. After the ultrasound treatment groove and notch appeared on the surface of the starch granules. The results showed that gelatinization temperature did not change with ultrasound treatments, but enthalpy value decreased from 13.15 ± 0.25 J/g to 11.5 ± 0.29 J/g and 12.65 ± 0.32 J/g to 10.32 ± 0.26 J/g for sonicated corn and cassava starches, respectively. The XRD results revealed a slight decreased in the crystallinity degree (CD) of sonicated corn (25.3,25.1) and cassava starch (21.0,21.4) as compared to native corn (25.6%) and cassava starch (22.2%). This study suggests that non-thermal processing techniques have the potential to modify the starch from different sources and their applications due to starch's versatility, low cost, and comfort of use after processing with altered physicochemical properties.

Structural and physicochemical characterization of modified starch from arrowhead tuber (Sagittaria sagittifolia L.) using tri-frequency power ultrasound

Sagittaria sagittifolia L. is a well-known plant, belongs to the Alismataceae family. Sonication can improve the functional properties of starch; hence, the aim of this study was to develop ultrasonically modified arrowhead starch (UMAS) using a sophisticated and eco-friendly tri-frequency power ultrasound (20/40/60 kHz) method at 300, 600, and 900 W for 15 and 30 min. Significant (p < 0.05) increases in swelling power, solubility, and water and oil holding capacities were achieved. FTIR spectroscopy corroborated the ordered, amorphous, and hydrated crystals of the sonicated samples. Increases in sonication frequency and power led to significant (p < 0.05) increases in onset gelatinization temperatures. Scanning electron microscopic analysis of sonicated samples showed superficial cracks and roughness on starch granules appeared in a sonication power-dependent manner compared with that of untreated sample. Overall, the ultrasonically-treated samples showed improved physicochemical properties, which could be useful for industrial applications.

Understanding the aggregation structure, digestive and rheological properties of corn, potato, and pea starches modified by ultrasonic frequency

Corn starch (CS), potato starch (PtS), and pea starch (PS) were modified by ultrasonic frequency (codes as UFCS, UFPtS and UFPS), and changes in aggregation structure, digestibility and rheology were investigated. For UFCS, the apparent amylose content and gelatinization enthalpy (∆H) decreased, while the R1047/1022 values and relative crystallinity (RC) increased under lower ultrasonic frequencies (20 kHz and 25 kHz). For UFPtS, the apparent amylose content, R1047/1022 values and RC increased, while the ∆H decreased under a higher ultrasonic frequency (28 kHz). For UFPS, the apparent amylose content, R1047/1022 values, RC, ∆H decreased at 20 kHz, 25 kHz and 28 kHz. Cracks were observed on the surface of UFCS, UFPtS and UFPS. These aggregation structure changes increased the resistant starch content to 31.11% (20 kHz) and 26.45% (25 kHz) for UFCS and to 39.68% (28 kHz) for UFPtS, but decreased the resistant starch content to 18.46% (28 kHz) for UFPS. Consistency coefficient, storage modulus, and loss modulus of UFCS, UFPtS and UFPS increased, while the flow behavior index and damping factor decreased. Results indicated that CS, PtS and PS had diverse digestion and rheology behaviors after ultrasonic frequency modification, which fulfilled different demands in starch-based products.

Structural changes of A-, B- and C-type starches of corn, potato and pea as influenced by sonication temperature and their relationships with digestibility

The effect of sonication temperature on the structures and digestion behaviour of corn starch (CS, A-type), potato starch (PtS, B-type), and pea starch (PS, C-type) was investigated. For CS, sonication temperature resulted in a rough surface, decreased apparent amylose content, gelatinization enthalpy and gelatinization degree, increased short-range orders, long-range orders, retrogradation degree and resistant starch content. For PtS, sonication temperature led to a coarser surface with scratches, increased apparent amylose content and gelatinization degree, decreased short-range orders, long-range orders, gelatinization enthalpy, retrogradation degree, and resistant starch content. For PS, sonication temperature showed partial disintegration on surface, increased gelatinization degree, decreased apparent amylose content, short-range orders, long-range orders, gelatinization enthalpy, retrogradation degree and resistant starch content. This study suggested that starch digestion features could be controlled by the crystalline pattern of starch used and the extent of sonication temperature, and thus were of value for rational control of starch digestion features.

Changes in structural, digestive, and rheological properties of corn, potato, and pea starches as influenced by different ultrasonic treatments

Ultrasound was widely used in starch modification, whereas there was no review focusing on the effects of different ultrasonic treatments on A-, B- and C-type starches. In this study, the effects of ultrasonic power (UP, 100-600 W) and ultrasonic time (UT, 5-35 min) on structural, digestibility and rheology of corn starch (CS), potato starch (PtS), and pea starch (PS) were investigated. As a result, UP and UT decreased the apparent amylose content of CS and PS, while increased the apparent amylose content of PtS. UP and UT enhanced R1047/1022 values of CS, whereas those of PtS and PS were decreased. Moreover, UP and UT decreased the gelatinization enthalpy of CS, PtS and PS. In vitro digestion revealed that UP and UT decreased the resistant starch content of PtS and PS, but increased the resistant starch content of CS. Rheological tests indicated that UP and UT decreased the flow behavior index of CS, PtS and PS pastes, and caused an increase in storage modulus and loss modulus. Results revealed that ultrasonic treatment represented a promising technology to obtain CS, PtS and PS with tailored digestibility and rheology, which allowed the texture and glycemic response of starch-based products to be adjusted.

Isothermal and temperature-cycling retrogradation of high-amylose corn starch: Impact of sonication on its structural and retrogradation properties

In this study, the effects of sonication and temperature-cycled storage on the structural properties and resistant starch content of high-amylose corn starch were investigated. Sonication induced a partial depolymerization of the molecular structures of amylopectin and amylose. Sonication treatment induced the appropriate structural changes for retrogradation. Although the relative crystallinity of sonicated starch was lower than that of non-sonicated starch, sonicated starch after retrogradation showed much higher relative crystallinity than non-sonicated starch. Regardless of sonication treatment, temperature-cycled storage resulted in a higher degree of retrogradation than isothermal storage, but the rate of retrogradation was greater in sonicated starch than in non-sonicated starch, as supported by retrogradation enthalpy, the Avrami constant, and relative crystallinity. The highly developed crystalline structure in sonicated starches due to retrogradation was reflected by the large amount of resistant starch.

The assisting effects of ultrasound on the multiscale characteristics of heat-moisture treated starch from Agriophyllum squarrosum seeds

Present study was aimed to characterize the effects of heat-moisture treatments supported by ultrasound on structural, physicochemical and digestive properties of the starch from Agriophyllum squarrosum seeds. The starch sample was subjected to heat-moisture (120°C, 25% moisture) for different durations with assisting by pre- or post-treatment of ultrasound (20 Hz, 300 W, 20 min). A. squarrosum starch exhibited the original A-type of crystalline structure after all treatments. All modified starches had lower amylose content, amylopectin molecular weight, swelling power and solubility, and higher resistant starch content than the native starch. Heat-moisture treatments and dual modifications of heat-moisture and ultrasound increased the gelatinization temperature of starch granules and significantly (p ≤ 0.05) reduced the viscosity of starch paste. Pretreatment of ultrasound enhanced the effects of heat-moisture on the viscosity properties while post-treatment of ultrasound weakened which on the gelatinization temperature, by regulating the changes of double helix structure and short-range ordered structure in starch granules tested by Fourier-transform infrared spectrometer. Scanning electron microscopy unveiled that A. squarrosum starch pretreated by ultrasound became more susceptible to heat moisture in morphology. This work was very important for the deep excavation of the characteristics of A. squarrosum starch and the effective application of ultrasound in starch modifications.

Impact of thermo-sonication on quality indices of starch-based sauces

In this study, ultrasonication, a physical, relatively cheap, and environmentally benign technology, was investigated to characterize its effect on functional properties of rice starch and rice starch-based sauces. Temperature-assisted ultrasound treatment improved the granular swelling power, fat and water absorption capacities, and thermal properties of rice starch, signifying its suitability in the formulation of starch-based sauces. Rheological characterization of the formulated sauces revealed a shear-thinning flow behavior, well described by the Ostwald de Waele model, while viscoelastic properties showed the existence of a weak gel. Results indicated that ultrasonication significantly enhanced the pseudoplastic behavior of starch-based sauces. Additionally, textural analysis showed that textural attributes (stickiness, stringiness, and work of adhesion) were also improved with ultrasonication. Moreover, enhanced freeze/thaw stability was also achieved with ultrasound-treated starch-based sauces. Overall, the results from this study show that ultrasound-treated starches can be used in the formulation of sauces and potentially other food products, which meets the requirements for clean label and minimally processed foods.

Impact of ultrasonic treatment on rice starch and grain functional properties: A review

As a green, nonthermal, and innovative technology, ultrasonication generates acoustic cavitation in an aqueous medium, developing physical forces that affect the starch chemistry and rice grain characteristics. This review describes the current information on the effect of ultrasonication on the morphological, textural, and physicochemical properties of rice starch and grain. In a biphasic system, ultrasonication introduced fissures and cracks, which facilitated higher uptake of water and altered the rice starch characteristics impacting textural properties. In wholegrain rice, ultrasonic treatment stimulated the production of health-related metabolites, facilitated the higher uptake of micronutrient fortificants, and enhanced the palatability by softening the rice texture. This review provides insights into the future direction on the utilization of ultrasonication for the applications towards the improvement of rice functional properties.