Infrared spectroscopy as a tool to characterise starch ordered structure—a joint FTIR–ATR, NMR, XRD and DSC study

Enhanced flocculation performance and coal slurry water by using starch-based flocculant with rich charges and its flocculation mechanism

A cationic starch-based flocculant as an efficient and environmentally friendly flocculant is designed for the improvement of flocculation performance of coal slurry water by the method of combining grafting and etherification. Structure and properties of the obtained samples are characterized by XRD, FTIR, NMR, and TG. Effects of grafting conditions and etherification conditions on intrinsic viscosity and cationic degree are investigated. The flocculation performance of grafted etherified starch (GE-St) is studied, and compared to cationic polyacrylamide (CPAM) and anionic polyacrylamide (APAM) flocculants, the final turbidities are 417 NTU for APAM, 20.6 NTU for CPAM and 59.1 NTU for GE-St demonstrating that the flocculation performance of grafted and etherified starch (GE-St) is slightly weaker than that of CPAM and significantly better than APAM. It can be supposed that GE-St is an effective flocculant for coal slurry water. The flocculation process of coal slurry water was analyzed by zeta potential analysis, extended DLVO theory calculation and microscopic images of flocs indicating that designing the molecular structure with rich charges and moderate molecular weight through grafting and etherification is beneficial for flocculation. The possible flocculation mechanism can be proposed that fine particles are agglomerated and settled by the flocculant GE-St through charge neutralization, adsorption bridging and sweeping, which is attributed to the matching of flocculant structure and mineral surface.

Curcumin Microcapsule Formulations for Prolong Persistence in the Photodynamic Inactivation of Aedes aegypti Larvae

Background: Viral diseases including dengue, zika, chikungunya, and yellow fever remain a significant public health challenge, primarily due to the increasing resistance of these vectors, the Aedes aegypti mosquito, to conventional control methods. Objectives: Herein, a microencapsulated curcumin formulation was developed and characterized using spray-drying technology, with D-mannitol and starch as encapsulating agents. After microencapsulation, photolarvicidal tablet formulations (Formulated Curcumin Tablets-FCT) were prepared, varying the proportions of starch and pectin: FCT1 (60% starch), FCT2 (35% pectin and 25% starch), and FCT3 (42.5% pectin and 17.5% starch), while maintaining 10% curcumin and 30% D-mannitol in all formulations. The main goal was to enhance the stability and efficacy of curcumin as a photolarvicidal agent. Methods: The formulation was characterized by UV-Vis spectroscopy, confocal microscopy, thermal analysis (TG and DSC), scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR), and photodegradation assays under fluorescent light. Results: The photodynamic inactivation (PDI) of Ae. aegypti larvae was evaluated under white, fluorescent light exposure, and the formulation exhibited a significantly enhanced larvicidal activity compared to free curcumin, with a 57-fold reduction in LC50 (LC50-24h = 0.27 mg/L). Additionally, the most effective formulation, FCT2, maintained its residual activity for 27 days, reinforcing that curcumin microencapsulation, combined with PDI, can extend vector control. Release studies under different pH conditions confirmed a controlled release mechanism, favoring environmental stability. Conclusions: The results indicate that microencapsulated curcumin has great potential as a sustainable photoinsecticidal agent, offering stability, efficacy, and a promising alternative for managing Ae. aegypti larval populations.

Effects of the addition of cassava starch and the size of water clusters on physicochemical and cooking properties of rice noodles

It is meaningful to explore the addition of additives and the structural characteristics of water on the quality of rice noodles. Herein, the effects of the addition of cassava starch and the size of water clusters on physicochemical and cooking properties of rice noodles were systematically studied. The addition of 25 % cassava starch effectively enhanced the swelling performance and textural properties of rice noodles. In comparison to non-activated water with large water clusters (LW), activated water with small water clusters (SW) significantly affected the interaction between water and starch molecules. Compared with LW-RN-25CS (rice noodles made with LW and 25 % cassava starch), SW-RN-25CS (rice noodles made with SW and 25 % cassava starch) presented better textural properties, including hardness, springiness, and adhesiveness. The rehydration time of SW-RN-25CS decreased from 12.31 ± 0.25 min (LW-RN-25CS) to 10.92 ± 0.46 min. This study provides reliable strategy and technology to produce high-quality rice noodles.

Effect of high hydrostatic pressure on the multi-scale structure and digestive properties of Lonicera caerulea berry polyphenol-wheat starch complex

Polyphenols increase resistant starch (RS) content and stabilize postprandial blood glucose levels. This study examined the effects of high hydrostatic pressure (HHP) technology on the multi-scale structure and digestibility of the Lonicera caerulea berry polyphenol-wheat starch (LPWS) complex in vitro and in vivo. The results showed that 200, 400, and 600 MPa HHP treatments promoted starch gelatinization, destroyed the grain structure of wheat starch (WS), significantly increased the particle size (P < 0.05), significantly increased the RS content by 1.60, 2.33, and 2.60 times (P < 0.05), and decreased the crystallinity and molecular weight. Under HHP, Lonicera caerulea berry polyphenols (LCBP) and WS formed A + V complex and the two interacted with each other through hydrogen bonding, leading to a further reduction in the gelatinization enthalpy (ΔH). The amount of glucose released by internal digestion in mice decreased significantly from 10.28 mmol/L to 8.87 mmol/L at 180 min (P < 0.05). Complex digestives appeared dense, which reduced WS digestion. This study provides a theoretical basis for the research and development of functional starch with stable postprandial blood glucose levels, and its use as a functional food ingredient.

Highly sensitive ratiometric fluorescence detection of dibutyl phthalate in liquor and water using bio-based fluorescent molecularly imprinted polymers

A novel fluorescent molecularly imprinted polymer (DBP-FMIPs) was designed and prepared for the selective detection of dibutyl phthalate (DBP) in food samples. This was achieved using inclusion complexes formed between short amylose and DBP as precursors, with tetrafluoroterephthalonitrile, which possesses an electron-donor-acceptor type dipolar structure within a compact benzene backbone, serving as a crosslinking agent and fluorescent readout signal. DBP-FMIPs exhibit excellent fluorescence stability and high selectivity, with a response time of less than 3 min for DBP. Based on the blue-green fluorescence emitted by DBP-FMIPs (λem = 500 nm), this material provided the response signal, while the red-emitting carbon dots(R-CDs, λem = 680 nm) were used as an internal reference, constructing a ratiometric fluorescence probe (R-CDs/DBP-FMIPs). The fluorescence intensity ratio (I500/I680)0/(I500/I680) exhibited a linear response to DBP within a concentration range of 0.020-20 mg L-1, with a detection limit as low as 4.5 μg L-1, and its fluorescence color shifted from blue to red. The fluorescent probe was successfully applied for detecting DBP in liquor and drinking water samples, achieving recoveries of 88-107 % and a relative standard deviation of 1.1-6.4 %. This preparation method can also be adapted for synthesizing FMIPs targeting other hydrophobic compounds. Additionally, the developed ratiometric fluorescence probe shows great potential for the selective and visual detection of phthalates in complex samples.

Effects of rolling on eating quality, starch structure, and water distribution in cooked indica rice dough

BACKGROUND

Given the composition of rice and its lack of gluten proteins, rice flour fails to form a cohesive and elastic dough when mixed directly with water. Consequently, many rice products rely on rice sheets (RS) made by rolling cooked rice dough. Limited research exists on how the rolling process impacts the properties and structure of cooked indica rice dough.

RESULTS

This study investigated the effect of the number of rolling passes on the eating quality, starch structure, and water distribution of cooked fermented indica RS formed by dough. When the number of rolling passes reached six, the RS (RP-6) that was obtained exhibited the lowest cooking loss, the highest hardness, adhesiveness, and chewiness, and optimal stretchability. It also demonstrated the lowest water loss after freezing. Dense microstructures were observed on both the surface and cross-section of RP-6. More ordered starch crystal structures and double helix structures were formed. The relative peak area of tightly bound water significantly increased in RP-6, indicating a stronger bonding status between the starch and water molecules. However, excessive rolling passes (more than six) led to a partial disruption of the internal RS structure, resulting in a decline in eating quality.

CONCLUSION

The study demonstrated the importance of the rolling process in improving the performance of RS. It was found that a moderate number of rolling passes was conducive to producing excellent RS, providing a theoretical basis for the production of high-quality rice-based products such as rice noodles, dumplings, and cakes. © 2024 Society of Chemical Industry.

Development of Plasma-Treated Corn-Starch-Based Film Incorporated with Acerola and Grape Pomace Extract Possessing pH-Sensing Capability

This study explores the development of biodegradable starch-based films treated with dielectric barrier discharge (DBD) plasma and incorporated with acerola residue and grape pomace extracts. The primary aim was to enhance the films' physicochemical properties and introduce pH-sensing capabilities. Plasma treatment at 200 Hz for 20 min modified the films' amylose content (by 13.2%), solubility (by 13.3%), contact angle (by 12.7%), moisture content (by 14.2%), and surface morphology. The addition of the extracts changed the short-range ordered structure parameters of the films (by 111.4%), solubility (by 11.1%), moisture content (by 18.4%), and water vapor permeability (by 6.1%). The films with acerola residue and grape pomace extracts exhibited good colorimetric responses for pH indication. The films with acerola residue extract tended to intensify the yellowish color, while those with grape pomace extract showed more significant color changes varying from purple to green. Integrating natural pigments like anthocyanins from grape pomace and carotenoids from acerola improved the films' functional properties and provided a visual indication of food freshness through pH changes.

Functions of high glycemic index carbohydrates: Exploring the effect of amorphous rice starch digestibility on glycometabolism

The digestive characteristics of amorphous starch in cooked rice have rarely been studied from a metabolic perspective. This study explores the effects of cooked rice starch on glycometabolism in rats to explore the role of high glycemic index (GI) carbohydrates in the daily diet. Utilizing X-ray diffraction and Fourier transform infrared spectroscopy allowed the structure of amorphous starch to be probed, while rats were subjected to a long-term pre-prandial gavage intervention (glucose as a positive control and normal saline as a negative control) to assess the effects of high GI carbohydrates on glucose tolerance, insulin sensitivity, and markers of glucose metabolism in skeletal muscle (SIRT1, PGC-1α, GSK-3β, GLUT4). Results showed that high-GI carbohydrates significantly enhanced systemic insulin sensitivity, glucose tolerance, and skeletal muscle glucose metabolism. Waxy rice starch (WRS), containing a high amylopectin content (98.57 %), was found to be particularly effective due to its high rapidly digestible starch (RDS) content (66.01 %) and a GI of 102 after cooked into an amorphous state. Consequently, it can be concluded that a long-term moderate intake of amorphous rice starch induces the body to increase insulin sensitivity and improve glycometabolism. These findings emphasize the functional characteristics of high-GI starchy foods, offering a more profound understanding of carbohydrate-based diets.

Effect of grapefruit peel pectin on the structure, pasting characteristics, and in vitro digestibility of starch under different moisture content and temperature

This study aims to explore the effects of hydrothermal treatment (HT)-assisted grapefruit peel pectin on the physicochemical, morphological, thermal, and pasting characteristics and in vitro digestibility of corn starch under varying temperatures and moisture content. Morphological analysis revealed that pectin uniformly coated starch granules, forming protective layers and rearranging crystalline structures. Fourier transform infrared spectroscopy and 13C nuclear magnetic resonance confirmed alterations in molecular order, with increases in single-helix structures and reductions in double-helix structures. X-ray diffraction and differential scanning calorimetry highlighted significant reductions in crystallinity and changes in thermal properties, indicating compact structural arrangements. Pasting and in vitro digestibility results revealed HT-C/P@60/80 exhibiting the highest resistant starch content and the lowest rapidly digestible starch content. Molecular docking and dynamics simulations demonstrated that pectin binds to α-amylase, then potentially inhibiting its catalytic activity. These findings highlight the role of pectin in altering starch properties for better food applications.

Effects of microwave treatment on structural and functional properties of germinated corn starch

BACKGROUND

Measuring the germination index of corn, and gelatinization index, thermodynamic properties, long-range structure, short-range structure and particle morphology of corn starch, the study aimed to investigate the effects of different microwave (MW) treatment on the structural and functional properties of germinated corn starch.

RESULTS

The results indicated that after appropriate MW treatment, the germination indices (germination rate, germination potential, sprout length and sprout weight) of germinated corn starch were improved after 7 days of germination. In addition, MW treatment also affected the structure of germinated corn starch. MW treatment could reduce the relative crystallinity of starch, but did not change the crystal type and the peak position of each absorption peak in Fourier transform infrared spectra. In addition, rapid visco-analysis and differential scanning calorimetry results showed, respectively, that MW treatment decreased the peak viscosity of germinated corn starch and increased the gelatinization temperature. Finally, MW treatment made the starch surface become rough, destroyed the starch particle structure and produced random cracks and voids.

CONCLUSION

Overall, the present study proves that appropriate MW treatment is an effective measure for the modification of germinated corn starch, and provides a theoretical basis for the application of MW technology in germinated corn products. © 2024 Society of Chemical Industry.

Saturated fatty acids as guest compounds in the annealing of high-amylose starch: Insights into fatty acid chain length and structural conformation

This study explores the effect of fatty acid chain length in regulating the structural changes and physicochemical properties of high-amylose maize starch (HAMS) induced by annealing with fatty acid solution (AFAS). AFAS was found to effectively regulate the conformation of amylose molecular chains within starch granules. Annealing with fatty acids of shorter chain length, such as lauric acid, promoted the formation of both double and single helices within HAMS granules. The single-helix fraction increased (up to 4.5 %) after AFAS treatment. HAMS modified with lauric acid exhibited the highest crystallinity (24.1 %). The level of structural changes varied for HAMS with shorter amylose chain length. Fatty acids with shorter chain lengths, such as lauric acid and myristic acid, induced higher levels of resistant starch (up to 65 %) under in vitro simulated digestion conditions. Pearson analysis revealed a significant negative correlation (p < 0.05) between the resistant starch content of the modified starch and the fatty-acid chain length complexed during AFAS. These findings suggest that the chain length of fatty acids affects the enzyme resistance of the modified starches, with shorter fatty-acid chain lengths being more effective in inducing ordered structures.

Potential of Process-Induced Modification of Potato Starch to Modulate Starch Digestibility and Levels of Resistant Starch Type III

Starch digestibility and the content of resistant starch (RS) play a crucial role in human health, particularly in relation to glycemic responses, insulin sensitivity, fat oxidation, and satiety. This study investigates the impact of processing methods on potato starch digestibility and RS content, focusing on two modification techniques: autoclaving and high hydrostatic pressure (HHP), followed by retrogradation at different temperatures. The research employs a comprehensive approach to characterize structural changes in starch samples using X-ray diffraction (XRD), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, and scanning electron microscopy (SEM). In turn, semi-dynamic in vitro digestion experiments based on the INFOGEST protocol were conducted to assess starch digestibility, while RS content was evaluated through enzymatic digestion of the non-RS fraction. SEM, XRD, and FTIR measurements reveal thermal processing appreciably affected starch architectures while HHP had a marginal effect. Further, the FTIR 1045/1022R ratio was found to be correlated with RS content measurements while reducing rapidly digestible starch (RDS). The findings led to the stipulation that thermal processing facilitates amylose leaching and granular disruption. In turn, retrogradation enabled the deposition of the amylose onto the disrupted structures which delineated their subsequent liability to enzymatic digestion. Conversely, HHP had minimal effects on granular architectures and amylose leaching. Overall, this research provides valuable insights for processing starch-based food products with the goal of increasing RS content, which may have significant implications for the food industry and nutritional science.

Structural interactions and mechanisms of amylose and amylopectin binding with cyanidin-3-O-glucoside

In this study, the structural interactions between starch and cyanidin-3-O-glucosde (C3G) were evaluated using three different starches with an amylose content of 20 % (CS) and 60 % (HS) and amylopectin content of 99 % (WS). It also increased the fractal dimension Dm values of CS, HS and WS from 1.83, 1.56, and 2.80 to 1.96, 2.05, and 2.99, respectively, along with their scattering intensities. The interaction of C3G and starch was through non-covalent binding with an enthalpy value (∆H) in a range of -3.602 × 104 to -2.298 × 104 cal/mol. The hydrogen bond binding energies of C3G-amylose and C3G-amylopectin were 34.71 and 30.99 kcal/mol, respectively. The results of this study revealed the interactions of C3G with different types of starches and provided potential approaches to design anthocyanin-modified starches for health promoting food.

Multi-Scale Structures, Functional Properties, and Applications of Starch Modified by Dry Heat Treatment

Dry heat treatment (DHT) is considered a green technology to modify starch structure and functionality since it does not generate effluents and avoids the use of chemical compounds, however, there is still no comprehensive understanding of the effects and mechanisms on the multi-scale structure and their relationship with functionality. This paper reviewed and analyzed the effects of DHT on multi-scale starch structures and functional properties, compared the performance of continuous and repeated DHT, discussed a mechanism of starch dry heating, and summarized the applications of dry-heated starches. DHT evaporates water, accelerates the movement of starch molecules, and breaks hydrogen bonds, which changes the multi-scale structure. In turn, structural modifications promoted by DHT affect the hydration properties, thermal stability, slowly digestible/resistant starch formation, and glycemic index. The multi-scale structure and functional changes after DHT are strongly affected by the starch botanical source and process conditions. This review contributes to understanding the starch DHT modification and establishes a theoretical basis for advancing DHT applications in the starch industry.

High temperature and humidity storage alter starch properties of faba (Vicia faba) and adzuki beans (Vigna angularis) associated with hard-to-cook quality

Hard-to-cook (HTC) beans are characterised by extended cooking times. Although the changes in cell walls limiting hydration in HTC beans are widely investigated, the role of macro-molecules (starch and protein, which constitute >80 % of beans) are almost overlooked. This study investigates the structural changes in starch associated with the HTC quality in faba and adzuki beans stored at contrasting temperature and humidity regimes. Beans were stored at 4 °C (control) and 40 °C with relative humidity (RH) levels of 60 % and 80 %. Significant changes in starch properties were observed, particularly in beans stored at 40 °C and 80 % RH, with swelling power decreasing by 7 % and 12 % for faba and adzuki beans, respectively. Additionally, gelatinisation behaviour was negatively affected, with peak temperatures increasing for adzuki beans (from 66.64 °C to 68.46 °C) and enthalpy rising for faba beans (from 9.25 J/g to 10.64 J/g) along with an increase in relative crystallinity. Overall findings indicate that storage at elevated temperature (40 °C) under both moderate and high humidity conditions (60 % and 80 %) primarily or partially leads to developing HTC beans due to molecular rearrangement of starch at helical and crystalline levels.

Kinetics of Structural Changes in Starch Retrogradation Observed by Simultaneous SANS/FTIR-ATR Measurements

Because of the complicated hierarchical structure of starch, starch retrogradation is usually evaluated by combining several structural analysis methods covering various spatial scales. However, structural analyses are typically performed individually, making correlating the structural changes at different spatial scales challenging. Therefore, this study used a simultaneous measurement system comprising small-angle neutron scattering (SANS)/Fourier-transform infrared (FTIR)-attenuated total reflection (ATR) to record multiple structural changes in potato starch during retrogradation. In the SANS patterns, the shoulder-like peak became more pronounced with time. The peak intensity, I max, representing the amount of ordered semicrystalline structures, increased over time, revealing the orderly reassembly of starch on the nanoscale upon retrogradation. In the FTIR-ATR spectra, the ratio of absorptions (R 1042/1016) at 1,042 and 1,016 cm-1, indicating the short-range ordered structure in starch, increased during retrogradation. Therefore, the double-helix structures were reformed during retrogradation. The rate constant of the kinetic change for R 1042/1016 was larger than for I max; thus, changes in the short-range ordered structure of starch converged before the changes in the semicrystalline structure. These results suggest that the formation of double-helix structures of the amylopectin side chain and the structural change of its ordered arrangement could occur in stages during retrogradation.

Effects of different fatty acids on the structure, physicochemical properties, and in vitro digestibility of Chinese yam resistant starch-lipid complexes

Nine CYRS-FA complexes were prepared by resistant starch in Chinese yam (CYRS) and nine fatty acids (FAs) with different chain lengths and degrees of unsaturation. CYRS-myristic acid and CYRS-palmitic acid showed higher complexing index (CI) and relative crystallinity (RC); CYRS-myristic acid and CYRS-oleic acid exhibited lower estimated glycemic index (eGI). Chain lengths of FAs showed significantly positive correlations with CI and contact angle (CA), and yet, unsaturation degree of FAs was negative correlated with both CI and CA. The eGI exhibited positive relations with solubility, and negative correlations with CI and RC. Therefore, the results indicated that chain lengths and unsaturation degrees of FAs were key factors for complexation of the CYRS-FA complexes, which influenced the structural, physicochemical and digestive properties. The findings were expected to provide a theoretical foundation for the interactions between starch and lipids in food processing, and elevate the high-tech values of Chinese yam.

Resolving differences in digestion features of cooked rice and wheat noodles: A view from starch multiscale structure

The staple foods play an important role in providing energy in the human daily diet. Wheat is the main staple food in northern China, rice in southern China, and the different staple food patterns between the north and south result in health disparities. Therefore, analyzing the differences in the digestion of staple foods are particularly important for understanding the digestive energy supply of staple foods. The firmer gel network structure, thicker crystalline lamellae, more V-type crystallites, higher degree of helical structure, and short-range order in cooked rice impeded the diffusion of amylase on the starch surface and inhibited the amylase-starch binding, leading to a lower rate of enzymatic hydrolysis of starch molecular chains and significantly higher content of RS than wheat noodles (P < 0.05). The different processing methods of cooked rice and wheat noodles influenced the multiscale structure of starch and thus the rate of digestion.

Composite Films Based on Linear Polyethyleneimine Polymer and Starch or Polysaccharides from DDGS: Synthesis, Characterization, and Antimicrobial Studies

Different films were synthesized from starch or polysaccharides extracted from distillers dried grains with soluble (DDGS) in combination with different percentages of linear polyethyleneimine (PEI) hydrochloride polymer to assess the mechanical and antimicrobial properties of the resulting composites. Moreover, a simple method for the extraction of the polysaccharide content from DDGS is reported. The materials obtained were characterized by ATR-FTIR, NMR, and XPS spectroscopy, swelling capacity, and by organic elemental analysis. In particular, the stability of the film prepared with only DDGS in copper ion solutions was improved by the incorporation of PEI. 13C HRMAS NMR studies evidenced the incorporation of the PEI polymer in the new films. Moreover, the release of PEI molecules from the films was studied by 1H NMR experiments in D2O to explain the antimicrobial properties of the PEI-based films against Staphylococcus aureus, with the DDGS-10% PEI films being the most active surface. Furthermore, the incorporation of copper ions into the different films enhanced their antimicrobial activity. Additionally, the starch-10% PEI film exhibited good swelling capacity in deionized water (~1500%), which decreased with the addition of salts (~250%). Instead, the DDGS-10% PEI film showed low swelling capacity in deionized water (~80%), with this capacity increasing with the addition of salts (~250%). The mechanical properties of the films improved considerably when 3% PEI was used.

Yield, physicochemical properties and in vitro digestibility of starch isolated from defatted meal made from microwaved tigernut (Cyperus esculentus L.) tubers

In this work, the effects of microwave treatment (MDT) of tigernut tubers at 540 W for 140, 180, 220, 240 s on the yield, physicochemical properties and in vitro digestibility of tigernut starch (TS) were firstly investigated. MDT significantly reduced the crystallinity and double helix structures of the starch, without altering its native A-type crystal structure. After microwaving for 140 s and 180 s, the extraction yield of TS was significantly increased from 14.92 % to 16.68 %, and a dense gel network structure was found by rheological analysis. In vitro digestion results indicated that the microwaved TS contained more content of rapidly digestible starch (RDS, 76.10 %-80.74 %) but lower slowly digestible starch (SDS, 2.85 %-5.78 %) and resistant starch (RS, 14.94 %-18.12 %); in other words, microwaving increased the in vitro digestibility of TS. This work elucidated the essential features of the response of tigernut starch to microwave treatment, and provided a basic understand of the digestibility of tigernut starch under microwave treatment, making it more suitable for industrial applications.

Solubility of cellulose derivatives is a limited indicator of their function on retarding starch digestion

Cellulose and its derivatives have been utilized as additives and functional fibers in food industries. The solubility has been traditionally used to categorize cellulose derivatives, whilst their complex effects within food matrix are less understood. In this study, insoluble forms i.e., cellulose and ethyl cellulose (EC), and soluble forms i.e., methylcellulose (MC) and sodium carboxymethylcellulose (Na-CMC) were selected to investigate the mechanisms by which the two groups of cellulose ingredients regulate in vitro digestibility of starch-based foods. In the Michaelis-Menton analysis, the addition of insoluble cellulose or EC as inhibitors tended to decrease the Vmax of α-amylase at a non-significant level compared to the value without inhibitors (p > 0.05). Starch-based matrix with insoluble cellulose or EC became less porous, but did not consistently resulting in an increased level of resistant starch content. Soluble MC and Na-CMC as inhibitors not only significantly reduced the Vmax (decreased from 1.0 to 0.8 and 0.9 mg/min, respectively) and kcat/Km (catalytic efficiency, decreased from 30.9 to 22.2 and 23.3, respectively) of α-amylase (p < 0.05), but the formed matrices had higher level of short-range ordering (R1047/1022). The soluble forms of cellulose derivatives resulted in higher level of resistant starch (up to 6 %), compared to insoluble cellulose. In summary, this study provides new insights into the complexity in the effects of cellulose derivatives on the digestion of food matrix, and suggests that solubility is a limited indicator of their function on retarding starch digestion. The structural changes in starch-based food matrix induced by cellulose derivatives should be considered in the development of functional foods with low glycemic index.

Influence of carboxyl content on the rheological properties and printability of oxidized starch for 3D printing applications

With the rapid development of 3D printing technology, the development of starch gels based on 3D printing with excellent printing properties has attracted great attention. This study successfully prepared four types of oxidized starch (OMS) with varying carboxyl group contents (0.203 %, 0.612 %, 1.043 %, and 1.278 %) by controlling the amount of sodium hypochlorite. Rheological analysis of these OMS gels revealed typical shear-thinning behavior and excellent structural recovery during heating shear across various concentrations. As the concentration of OMS increased, key parameters such as consistency index (K), storage modulus (G'), yield stress (τy), and flow stress (τf) also increased, signifying enhanced molecular chain entanglement and densification with reduced digestibility. Conversely, at a constant concentration, increasing carboxyl group content led to decreased K, G', τy, and τf values due to molecular chain degradation, resulting in diminished aggregation and increased network pore size. Notably, OMS gels demonstrated favorable printability within a specific range of G' (4314.0-6690.0 Pa), τy (1254.8-2697.5 Pa), and τf (822.3-2296.3 Pa). Meanwhile, oxidized starch (OMS2 and OMS3) gels exhibited exceptional printability, attributed to appropriate molecular chain length and carboxyl content, which promoted sufficient physical crosslinking. These findings provided theoretical insights and foundational data for developing 3D printable starch-based materials.

Effect of carboxymethyl cellulose and/or wheat gluten on the pasting, rheological and quality properties of wheat starch-based batter for deep-fried products

This study aimed to investigate the effects of the individual and synergistic addition of wheat gluten (WG) and carboxymethyl cellulose (CMC) on the wheat starch (WS)-based batter characteristics to determine the molecular basis of texture formation in the actual batter system. Results showed that adding WG and/or CMC significantly increased the viscosity of WS during pasting. The rheological behavior showed that the WG-treated and CMC-treated group had the highest and lowest viscoelasticity. The addition of WG-CMC helped the WS-based batter obtain moderate viscoelasticity. These outcomes could be attributed to the enhancement of hydrogen bonding. The microstructure suggested that the addition of WG-CMC increased the density and integrity of the gel network. Overall, CMC competed for the binding sites of WG on WS, reducing the increase in viscoelasticity caused by the interaction between WG and WS. This might alleviate the unwanted springiness of fried products.

Efficient flotation separation approach of apatite from calcite for phosphate up-grading using phosphorylated starch macromolecules as a selective depressant

Physico-chemical similarities of surface proprieties of calcite and apatite make their separation challenging. Effective flotation separation requires sustainable depressants to mitigate environmental consequences associated with traditional chemical reagents. Here, for the first time we explore the potential of phosphorylated starch (PS) derived from potato waste as a green and effective depressant. Starch was modified using a straightforward phosphorylation process, resulting in PS with a remarkable charge density exceeding 6000 mmol kg-1. The PS was then evaluated for its ability to depress apatite, enhancing the separation efficiency of apatite from calcite in phosphate rock beneficiation via reverse flotation. Micro-flotation experiments revealed PS's distinct depression effect on apatite while minimally impacting calcite. Floatability rates of apatite and calcite were 90.45 % and 92.68 %, respectively. Introducing 10 mg/g PS drastically reduced apatite recovery to <19 %, while calcite recovery remained at 78.80 %. The bench-scale flotation tests demonstrated an upgrading of the phosphate rock to 70,64 % Bone Phosphate of Lime (BPL) with a yield of 89,41 %. Mechanistic studies employing zeta potential (ZP), and wettability analysis elucidated the depression mechanism. Apatite retained hydrophilicity post-PS addition and conditioning with ester, while calcite-acquired hydrophobicity even in the presence of PS. Furthermore, PS exhibited substantial adsorption onto the apatite surface through chemical reactions involving the phosphate groups and the activated calcium sites on the apatite. Overall, PS stands out as a promising, eco-friendly, and remarkably efficient depressant for separating apatite from calcite through flotation.

Active bio-nanocomposites from litchi seed starch, tamarind kernel xyloglucan, and lignin nanoparticles to improve the shelf-life of banana (Musa acuminata)

Valorization of agricultural byproducts to biodegradable packaging films aids in reducing plastic dependency and addressing plastic perils. Herein, starch (LSS) from litchi seeds and xyloglucan (XG) from tamarind kernels were recovered, and composite films were developed. The XG addition strengthened the weak polymer networks of LSS and improved rheological, molecular, morphological, mechanical, and water vapor barrier properties. The incorporation of lignin nanoparticles (LNPs) into the LSS-XG network further increased the tensile strength (14.83 MPa), elastic modulus (0.41 GPa), and reduced surface wettability (80.07°), and water vapor permeability (5.63 ± 0.38 × 10-7 g m-1s-1Pa-1). The phenolic hydroxyls of LNPs imparted strong UV-shielding and free radical scavenging abilities to films. These attributes aided in preserving the quality of coated banana fruits with minimal weight loss and color change. Overall, this research highlights the potential transformation of underutilized abundant byproducts into sustainable active bio-nanocomposites for food packaging and shelf-life extension of fruits.

Microwave and Steam Processing: A Novel Approach to Modifying the Characteristics of Reconstituted Whole Wheat Flour and Dough

To reduce the adverse effects of bran on whole wheat flour products. In this study, seven reconstituted whole wheat flours were prepared and used to determine the effects of microwave and steam treatment on bran. We aimed to understand the effect of modification treatment on the properties of reconstituted whole wheat flour and dough. Treatment with whole wheat flour had a significant impact on the color, solubility, and swelling. As the cooking time increased, the initial temperature (To), peak temperature (Tp), and final temperature (Tc) of pasting and enthalpy (Hp) decreased. The combination of microwave and steam modification increased water absorption and stabilization time, leading to improved fermentation performance and cooking stability of the dough. The modified whole wheat flour and dough exhibited a significant decrease in crystallinity, possibly due to the degradation of the crystalline and amorphous regions of the starch granules during heat treatment. Upon modification treatment, the spiral β-turn structure was transformed into an irregular curled and β-sheet structure, and the β-sheet ratio increased significantly (p < 0.05). The modification of bran through microwave treatment (700 W for 30 s) followed by steam treatment (10 min) enhanced the processing performance of reconstituted whole wheat flour, offering substantial potential for the development of novel products and the optimization of industrial production efficiency.

Mechanism of starch multi-scale structural in determining the textural properties and formability of starch pearls

Starch pearls are widely used in bubble tea and desserts, yet the mechanistic understanding of the formation process of their textural properties remain unclear. To investigate the relationship between the multi-scale structure of starch and the textural properties of starch pearls, analyses of fine structure, crystal structure, rheological behavior, and textural profiling were conducted. The results showed that starch gels with a higher content of short-chain amylose (100 < X ≤ 1000) exhibited weaker formability during starch pearl preparation, leading to a lower flow behavior index (n*). This, in turn, positively influenced the hardness and resilience of the starch pearls. Cassava, potato, and yam starch pearls contained a large amount of long-chain amylopectin (24 < X ≤ 100) and long-chain amylose (5000 < X ≤ 20,000). The high proportion of long chains resulted in a weaker ordered structure, leading to increased peak viscosities and final viscosities and a higher consistency coefficient (k*). This structural feature enhanced the formability stability, viscosity, and chewability of starch pearls. Our findings reveal that variations in starch multi-scale structure significantly influence the textural quality and formability of starch pearls, providing valuable insights for optimizing starch selection and processing techniques in the food industry.

Underlying mechanism of electrospun starch-based nanofiber mats to adsorb the key off-odor compounds of oyster peptides

The solid-phase adsorption principles and fundamental mechanism of isobutyric acid, 1-octen-3-ol, and octanal (three key off-odor compounds of oyster peptides) were explored using electrospun octenyl succinylated starch-pullulan (OSS-PUL) nanofiber mat. The nanofiber mats had selective adsorption behaviors as indicated by the selective adsorption rates of isobutyric acid, 1-octen-3-ol, and octanal, which were 94.96%, 85.03%, and 65.36%. The contents of the II-type inclusion complexes (ICs) formed with the nanofiber mats by the three off-odor compounds mentioned above were significantly different. The mean fiber diameter of the octanal/nanofiber mat IC with the highest content of II-type IC was significantly decreased (p < 0.05). In contrast, the isobutyric acid/nanofiber mat IC did not significantly change. The findings suggested that nanofiber mats interacted most strongly with octanal and weakly with isobutyric acid. This study will provide the theoretical foundation for deodorizing aquatic products using electrospun starch-based nanofiber mats.

Autoclaved Starch: Structure and Functionality Relationship in a Matrix With the Same Contribution of Amylose and Amylopectin

The rational use of autoclaved starches in food applications is difficult because there is a lack of information on their structure-functionality relationship. The novelty of this research relies on disclosing such an association. Hylon V starch was autoclaved at 105, 120, and 135°C to investigate its crystalline and double-helical features and its relationship with functionality. In autoclaved Hylon V starch, interactions of amylopectin and amylose improved while the crystalline regions decreased. The degree of double helices (DD) decreased after autoclaving at 105°C and the degree of order (DO) increased after treatment at 120 and 135°C. The water solubility index (WSI) (4.63-6.38%) and swelling power (SP) (4.39-7.1 g/g) increased when the temperature increased. On the other hand, water (103.49-225.01%) and oil (61.91-94.53%) holding capacity (WHC and OHC, respectively) increased after autoclaving treatment, although the values decreased with the treatment intensity. The functional properties were affected when the structure changed as a function of the treatment temperatures. PCA analysis showed that WSI and SP of autoclaved Hylon V starch were associated with a high DD, with better compaction, and with stronger amylopectin-amylose interactions. WHC and OHC were associated with better crystallinity, stronger interactions of amylopectin and amylose, and heterogeneous double-helical crystallites. These findings are useful for understanding the structure-functionality relationship of autoclaved Hylon V starch and pave the way for future research regarding the effects of its incorporation on the properties of food matrices such as bread, yogurt, cakes, and pudding.

Digestive characteristics and structural changes of lotus seed starch-lotus seed protein blend system during in vitro digestion

This study analyzes the digestive characteristics, morphological changes, particle size distribution, and the evolution of crystalline and molecular structures of the lotus seed starch-lotus seed protein blend system (LS-LP) through simulated in vitro static and dynamic digestion experiments. The findings indicate that LS-LP, treated by high-pressure homogenization (HPH), exhibits a higher digestion rate and total digestibility compared to the physical mixture of lotus seed starch and protein (PM) and lotus seed starch (LS). Interestingly, scanning electron microscopy (SEM) observations reveal that during digestion, the structure of lotus seed protein (LP) changes, forming a physical barrier to LS, thereby partially slowing down the digestion process. Furthermore, the transformation in particle size distribution (PSD) from unimodal to bimodal, the progressive increase in crystallinity observed through X-ray diffraction (XRD) analysis, and the structural alterations in LP identified by Fourier Transform infrared spectroscopy (FTIR) provide additional confirmation of the structural changes of LS-LP during digestion. In summary, this study provides a new insight for the digestive characteristics and structural changes of LS-LP during in vitro digestion, and offers a scientific basis for further research on the impact of LS-LP digestion products on gut microbiota.

Optimizing Printability of Rice Protein-Based Formulations Using Extrusion-Based 3D Food Printing

The purpose of this study was to investigate the application of an innovative extrusion-based 3D food printing (3DFOODP) technique in developing rice protein-starch (RP-S) gel-based products. The effects of 3DFOODP conditions were examined, which included variations in the concentrations of rice protein (RP) and corn starch (S) (15, 17.5, and 20 wt.%), nozzle size (0.8, 1.5, and 2.5 mm), printing temperature (40°C, 60°C, and 80°C), and ingredient flow speed (5.7, 6.3, and 6.9 mL/min). A hollow cylindrical model was chosen as a test object to determine the printability of RP-S gels. The best 3D printability was achieved using an RP concentration of 17.5% and an S concentration of 15% at 60°C printing temperature with a nozzle size of 1.5 mm, and ingredient flow speed of 6.3 mL/min. With increasing the RP concentration, a rise in apparent viscosity, loss, and storage moduli was observed. The recovery test showed the gels' rapid and reversible response. The freeze-dried 3D-printed RP-S gels showed a porous granular structure, depending on the printing temperature. No chemical interactions between the RP and S were observed as analyzed by FTIR. Overall, RP, in combination with S, provides a new opportunity for the 3DFOODP and their utilization by the alternative protein industry.

Octenyl succinic anhydride starch enhanced 3D printability of corn starch-based emulsion-filled gels incorporating egg yolk

This work investigated the effect of octenyl succinic anhydride starch (OSAS) on the 3D printing performance of corn starch-based emulsion-filled gels containing egg yolk. The influence of OSA-S concentration on emulsion droplet size, ζ-potential and stability, as well as the printing performance, rheological properties and microstructure of gel were discussed. The results indicated that the addition of OSA-S significantly improved the accuracy of the printed objects, with the best accuracy of the models printed using OSA-1.6 and OSA-2.0 inks. Emulsion tests showed that increasing the OSA-S content reduced the droplet size, increased its ζ-potential, and enhanced the stability of the emulsion. Rheological analyses showed that the energy storage modulus, loss modulus, and apparent viscosity of the gels were slightly enhanced with increasing OSA-S content. Microstructural analysis showed that OSA-S increased the density of the gel microstructural network. In addition, the addition of OSA-S enhanced the thermal stability of the gels and facilitated the transition of water molecule states from free water to bound water. The melting temperature of the gel gradually increased from 135.72 °C to 147.52 °C with the increase of OSA content. This study aims to develop promising 3D printing ink to facilitate its industrial applications.

The Properties of Damaged Starch Granules: The Relationship Between Granule Structure and Water-Starch Polymer Interactions

The morphology of wheat starch granules with different damaged starch (DS) content was analyzed using a particle size analyzer and scanning electron microscopy (SEM); the granular structure was studied using FT-IR spectroscopy and X-ray diffraction (XRD); and the granule-water interaction was evaluated by thermogravimetric analysis (TGA) and dynamic vapor sorption (DVS). The increase in the level of DS shifted the population of B-type granules towards larger particle diameters and shifted the population of A-type granules towards smaller particle diameters. The appearance of the surface of the starch-damaged granules was rough and flaky (SEM images). Crystallinity reductions were related to higher mechanical damage levels of the granular structure (FT-IR and XRD). Higher DS increased the liquid-water absorption capacity of the granules. Higher DS was associated with increments in less-bound water proportions and reductions in more strongly bound water proportions and related to reductions in the evaporation temperature of these water populations (TGA analyses). Concerning DVS data, the results suggested that the driving force for water-monolayer attachment to the starch granules decreased as DS increased. Therefore, it was suggested that the changes in granule structure led to a weaker water-starch polymer chain interactions due to the increase in DS. The results contribute to a better understanding of the influence of mechanical damage on the starch granular structure, which could be related to the rheological and thermal behavior of starch-based systems with different DS.

Structural evolution of maize starches with different amylose content during pasting and gelation as evidenced by Rapid Visco Analyser

This study examined multi-scale structural alterations of maize starches varying in amylose content during pasting and gelation, using Rapid Visco Analyser (RVA). At 50 °C, starch granules maintained their morphology with low viscosity. As the temperature increased to 95 °C, helical and crystal structures were destroyed, leading to granule swelling, distortion and porosity, as identified by Wide Angle X-ray Scattering and Fourier Transforms Infrared measurements at 90% moisture. This resulted in increased viscosity and the formation of a loose gel network structure. Subsequently, maintaining the temperature at 95 °C caused a decrease in viscosity as most granules disappeared, forming a reorganized flaky gel structure with larger pores. As the temperature decreased, gel porosity reduced. In high amylose content starch, the viscosity remained low and granules were partially gelatinized since the heating temperature was below the gelatinization temperature. This study is the first to detail starch multilevel structural dynamics during RVA gelatinization.

Optimization of ultrasound-assisted extraction of mango cotyledon starch: Physicochemical, structural, thermal and functional properties

Mango (Mangifera indica L.) seed, a byproduct of mango pulp and juice processing, is recognized for its abundant starch content. The advancement of the modern food industry has prompted a shift away from traditional starch extraction methods due to their environmental impact and low efficiency. The study aimed to optimize the ultrasound-assisted extraction process of starch from the cotyledons of mango seeds, employing response surface methodology with a customized optimal design and an optimal-I optimality criterion. We investigated the effects of cotyledon/water ratio, time, power, and sonication frequency on maximizing starch extraction yield. We explored the impact of ultrasound on structural, morphological, functional, and pasting properties. The maximum starch extraction yield was 50.74%. This yield was about 82.4% higher than that of conventional wet extraction. Ultrasound-assisted extraction increased starch purity and amylose content; it reduced granule size while enhancing all starch pasting properties without affecting starch's chemical structure and morphological, thermal, and functional properties. The mango cotyledon starch can be classified as medium to normal amylose content starches, exhibiting A-type polymorphs, fast-swelling, and capable of forming strong, firm, low-sticky gels. These results demonstrate the potential applications of mango residue and ultrasound technology in the food and pharmaceutical industry.

Mechanism of multiscale structural reassembly controlled by molecular chains during amylase digestion of wheat starch

The digestive characteristics of wheat starch (WS) are closely related to its structure. However, the mechanisms underlying the multiscale structural evolution and reassembly controlled by molecular chains during digestion are poorly understood. To address this issue, amylopectin of wheat starch (APWS) and amylose of wheat starch (AMWS) were separated and digested in vitro. After digestion, chains in WS with a degree of polymerization (DP) < 12 or DP > 37 were degraded, the double-helix content decreased from 58.65 % to 48.77 %, and many particles were degraded. For APWS, the DP > 36 chains increased, the B-type crystallinity increased to 9.55 %, and the particles were transformed into new aggregated structures. For AMWS, the number of 18 < DP < 270 chains was increased, the double-helix content increased from 19.78 % to 37.92 %, the B-type crystallinity increased from 6.65 % to 19.40 %, and a dense granular structure was formed. Overall, our study confirmed that WS, APWS, and AMWS had distinct multiscale structural reassembly mechanisms during in vitro digestion. The DP > 36 chains in APWS and 18 < DP < 270 chains in AMWS were the primary contributors to the formation of enzyme-resistant multiscale structures. This study can serve as a theoretical basis for designing the WS multiscale structure using molecular chains to improve its nutritional value.

From Corn Starch to Nanostructured Magnetic Laser-Induced Graphene Nanocomposite

Laser-Induced Graphene (LIG) is a 3D, conductive, porous material with a high surface area, produced by laser irradiation of synthetic polymers with high thermal stability. Recently, the focus has shifted toward sustainable bioderived and biodegradable precursors, such as lignocellulosic materials. Despite starch being an abundant and cost-effective biopolymer, direct laser scribing on starch-derived precursors has not yet been explored. This study demonstrates that corn starch bioplastic (SP) can be converted into LIG through iron-catalyzed laser-induced pyrolysis, using Fe(NO₃)₃ as an additive. The impact of iron additive concentration on LIG formation and on its properties is investigated, with only certain concentrations yielding reliable and reproducible results. The investigation of LIG's crystal structure reveals magnetic and non-magnetic iron phases: γ-Fe₂O₃, Fe₃C, and Fe(C). The LIG nanocomposite exhibits soft magnetic properties, with a coercive field of Hc ≈ 200 Oe and a saturation magnetization of Ms ≈ 67 emu g⁻¹. The SP substrate degrades almost entirely in soil within 12 days and is unaffected by the addition of Fe(NO₃)₃, allowing for material compostability in line with circular economy principles. Consequently, SP stands out as a promising "green" precursor for magnetic LIG, paving the way for sustainable applications in environmental remediation.

Effects of hydrocolloids on the structure and physicochemical properties of triticale starch during fermentation

The regulation of the structure and properties of new starch varieties has been a necessary step in the development of promising products. This study investigated the effects of 1 % xanthan gum (XG) and hydroxypropyl methylcellulose (HPMC) on the physicochemical properties and structure of triticale starch during fermentation. Frequency scanning and rapid viscosity analyzer results showed that the addition of XG or HPMC during fermentation resulted in the reduced loss factor (tanθ) and the increased peak viscosity, indicating that the network gel strength is enhanced. X-ray diffraction and attenuated total reflectance Fourier transform infrared spectroscopy experimental results revealed that adding XG or HPMC in the triticale starch during fermentation increased relative crystallinity (2.7 % and 5.27 %, respectively) and short-range order. Combined with microstructure and thermal analysis, the encapsulation effect of XG or HPMC on triticale starch increased the thermal stability of triticale starch during fermentation, which was specifically reflected by higher residue content (26.69 % and 19.13 %, respectively). This study can provide a theoretical basis for the effect of hydrocolloids on the texture and digestibility of triticale starch fermented products.

Wheat MYOSIN-RESEMBLING CHLOROPLAST PROTEIN controls B-type starch granule initiation timing during endosperm development

Molecular factors that contribute to the diverse spatial and temporal patterns of starch granule initiation between species and organs are poorly understood. Wheat (Triticum sp.) endosperm contains both large A-type granules initiated during early grain development and small B-type granules that initiate about 10 to 15 days later. Here, we identify that the MYOSIN-RESEMBLING CHLOROPLAST PROTEIN (MRC) is required for the correct timing of B-type granule initiation in wheat endosperm during grain development. MRC is expressed in the endosperm exclusively in early grain development, before B-type granule initiation. We isolated three independent TILLING mutants of tetraploid wheat (Triticum turgidum cv. 'Kronos') with premature stop or missense mutations in the A-genome homeolog, which we showed to be the only active homeolog in tetraploid wheat due to a disruption of the B-genome homeolog. The mrc mutants had significantly smaller A-type granules and a higher relative volume of B-type granules in the endosperm than the wild type. Whereas B-type granules initiated 15 to 20 days post-anthesis (dpa) in the wild type, they appeared as early as 10 dpa in the mrc-1 mutant. These results suggest a temporal role for MRC in repressing B-type granule initiation, providing insight into how the distinct biochemical mechanisms that control A- and B-type granule initiation are regulated. This role of MRC in the wheat endosperm is distinct from the previously described role of Arabidopsis (Arabidopsis thaliana) MRC in promoting granule initiation in leaves, providing an example of functional diversification among granule initiation proteins.

A comparison of the physicochemical properties, digestibility, and expression patterns of starch-related genes of two supersweet corn hybrids (F1) and their parents

The quality difference of corn largely depends on parental selection. Herein, the structure, digestive characteristics, and expression patterns of starch-related genes of two supersweet maize hybrids and their parents were studied. The structural analysis revealed that the starch of supersweet corn is round or oval, and the particles are smaller compared to those of normal corn. Hybridization changed the grain morphology, crystal, and helical structure of starch. Parents had a significantly different influence on supersweet corn. Notably, hybridization improved the setback value and digestibility of Shantian1500F1 and Shantian2000F1 compared to that of the parents. ZmBEI, ZmPHOH, and ZmAGPL2 genes had a consistent high expression throughout the whole grain formation phase. The results of this study expand our understanding of the breeding of supersweet corn hybrids and the effect of parents on the new strand. These results provide a useful reference for further breeding and studies of supersweet corn for starch production in corn.

Relationship between internal structure and in vitro digestibility of A- and B-type wheat starch revealed by chemical surface gelatinization

In this study, the properties of remaining starch granules obtained with different degrees of exfoliation were explored by removing the outer layers of A- and B-type wheat starch (AWS and BWS) granules with chemical surface gelatinization. SEM images revealed significant morphological variations with increasing exfoliation. CLSM and amylose content analysis indicated a predominance of lipid complexes in the outer granule layers, particularly in BWS. The structural characteristics of AWS and BWS were analyzed using PLM, XRD, FT-IR and DSC, verifying the conclusion of the alternation of starch crystalline and amorphous zone. And the amorphous regions are proportionally higher in the inner starch layer. Moreover, raw AWS and BWS granules were more easily digested from the outside in, with the RS content decreasing from 80.65 % to 66.92 % and 49.06 % to 45.01 %, respectively. The RS content of cooked WS were affected by the internally structures, particularly lipid content (11.46 % - 19.09 %) in BWS outer layers and amylose content (13.59 % - 19.43 %) in the inner layers. These results revealed the internal radial structural differences and digestibility patterns of AWS and BWS granules.

Sugar inclusion influences the expansion characteristics of corn starch extrudates

Corn starch-based direct expanded products incorporated with 2% and 10% (w/w) sugar (fructose, glucose, sucrose, and xylose) were produced using a 20 mm co-rotating twin-screw extruder. The pasting and thermal properties of raw corn starch-sugar mixes were analyzed before extrusion processing. The independent variables for extrusion processing included two sugar inclusion levels (2% and 10% w/w) and two screw speeds (150 and 250 rpm). The extrudates were characterized by their initial expansion ratio (IER), expansion ratio (ER), and shrinkage. ER values were high for fructose at 2% and 150 rpm and 10% glucose and sucrose extrudates at 250 rpm. The extrudates with 2% sucrose inclusion shrunk significantly higher than the control. Fourier transform infrared (FTIR) spectroscopy of the extruded blends did not indicate the presence of any new covalent bond formed between starch and sugar post-extrusion. The interactions between sugar concentration and screw speed significantly influenced extrudate expansion characteristics. Due to their thermal and plasticizing properties, sugar inclusion (glucose, fructose, sucrose, and xylose) enhanced the extrudate expansion by altering their melt viscosity. PRACTICAL APPLICATION: The findings of this study can improve the expansion characteristics of high-fiber-based extruded snacks. Ingredients high in fiber generally hinder the starch transformation during extrusion and negatively impact the expansion properties. The presence of sugar at low concentrations can improve melt properties during extrusion processing and, in turn, significantly improve the textural properties of snacks.

Modulation of retrogradation properties by removal and retention of starch granule-associated lipids: A case study on buckwheat and wheat starches

The objective of this research was to investigate the influence of starch granule-associated lipids (SGALs) on retrogradation properties of buckwheat and wheat starches. According to the results, the removal of SGALs led to remarkable increase in the retrogradation enthalpy change of all starches and the strength of starch gels, as well as the density and short-range ordered structure of starch aggregates. The strength of starch gel experienced a rise from 3139.39 g to 3718.18 g in Tartary buckwheat, 2924.12 g to 3551.13 g in common buckwheat, and 1887.55 g to 2555.24 g in wheat, respectively. The removal of SGALs contributed to a decrease in the thermal stability of starches and an augmentation of amylose leaching during gelatinization process, which would strengthen the hydrogen bond interaction between starch molecules during cooling process, and promoting the rearrangement of the order structure of starch molecules. In general, these results indicated that the retention of SGALs could limit amylose leaching, then inhibited rearrangement and recrystallization of dissolved starch molecules, and ultimately delayed the short-term and long-term retrogradation process. This work further supplemented theoretical knowledge about SGALs in buckwheat and wheat starches, also provided a new perspective for regulating the physicochemical properties of starches.

Influence of gelatinized octenyl succinic anhydride-modified waxy adlay seed starch on the properties of astaxanthin-loaded emulsions: Emulsion properties, stability and in vitro digestion properties

Octenyl succinic anhydride (OSA)-modified starch is a commonly used food emulsifier and its emulsifying properties are positively correlated with the degree of substitution (DS). However, the maximum concentration of OSA in starch approved by the FDA and the China National Food Safety Standards is 3%. This study aims to enhance the emulsifying properties of OSA-modified waxy adlay seed starch by gelatinization under a limited DS and investigate its use in preparing delivery systems. The gelatinized OSA starch exhibited a more flexible macromolecular structure and better emulsifying activity (20.19 m2/g). The gelatinized OSA starch-stabilized astaxanthin-loaded emulsions showed high retention of astaxanthin (>50%) and long-term stability (56 days). In vitro digestion, the emulsion system showed a protective effect on astaxanthin, and the bioaccessibility of astaxanthin was increased to 16.32%. This study indicated that gelatinization could enhance the emulsifying properties of OSA starch, and this starch-stabilized emulsion was an effective system for astaxanthin.

Structural characterization and functional properties of resistant dextrins prepared from different starch sources

The molecular structures of different starch sources differ, and the structure of the prepared resistant dextrin is affected. Seven types of starches (corn, wheat, pea, mung bean, tapioca, sweet potato, and potato) were used to prepare resistant dextrins under identical conditions. The physicochemical properties, molecular structure, micromorphology, glucose dialysis retardation index (GDRI), and cholesterol-binding capacity of different starch-resistant dextrins were analyzed and compared. The results revealed that the starch source exerted a greater effect on the structure of the resistant dextrins, and this was primarily attributed to the difference in the content of amylose and amylopectin. Both high amylose and high amylopectin may be the sources of highly resistant dextrins. The microscopic morphology of resistant dextrins were fragmentary, and the original form of starches was completely lost. Additionally, pea resistant dextrin exhibited higher GDRI values and stronger cholesterol-binding capacity compared to other samples.

Research on the quantitative relationship of the viscosity reduction effect of large-ring cyclodextrin on potato starch during gelatinization process and mechanism analysis

Starch is extensively used across various fields due to its renewable properties and cost-effectiveness. Nonetheless, the high viscosity that arises from gelatinization poses challenges in the industrial usage of starch at high concentrations. Thus, it's crucial to explore techniques to lower the viscosity during gelatinization. In this study, large-ring cyclodextrins (LR-CDs) were synthesized from potato starch (PS) by using 4-α-glucanotransferase and then added to PS to alleviate the increased viscosity during gelatinization. The results from rapid viscosity analyzer (RVA) demonstrated that the inclusion of 5 % (w/w) LR-CDs markedly reduced the peak viscosity (PV) and final viscosity (FV) of PS by 49.85 % and 28.17 %. In addition, there was a quantitative relationship between PV and LR-CDs. The equation was fitted as y = 2530.73×e-x/2.48+1832.79, which provided a basis for the regulation of PS viscosity. The mechanism of LR-CDs reducing the viscosity of PS was also studied. The results showed that the addition of LR-CDs inhibited the gelatinization of PS by enhancing orderliness and limiting water absorption, resulting in a decrease in viscosity. This study provides a novel method for reducing the viscosity of starch, which is helpful for increasing its concentration and reducing energy consumption in industrial applications.

Study on the Mechanism of Effect of Protein on Starch Digestibility in Fermented Barley

Previous studies have shown that fermented barley has a lower digestion rate. However, it remains unclear whether the antidigestibility of starch in fermented barley is affected by other nonstarch components. In this paper, the removal of protein, lipid, and β-glucan improved the hydrolysis rate of starch and the protein showed the greatest effect. Subsequently, the inhibitory mechanism of protein on starch digestion was elucidated from the perspective of starch physicochemical properties and structural changes. The removal of protein increased the swelling power of starch from 10.09 to 11.14%. The short-range molecular ordered structure and the helical structure content decreased. The removal of protein reduced the coating and particle size of the starch particles, making the Maltese cross more dispersed. In summary, protein in fermented barley enhanced the ordered structure of starch by forming a physical barrier around starch and prevented the expansion of starch, which inhibited the hydrolysis of starch.

Structural features of rice starch-protein system: Influence of retrogradation time and quick-freezing temperature

This work investigated the effect of retrogradation time (0 h, 2 h, 4 h, 6 h, 8 h) and freezing temperature (-20 °C, -32 °C, -80 °C) on the muti-scale structures of the rice starch-protein system of quick-frozen wet rice noodles. The Relative crystallinity and porosity of the rice starch-protein system increased with increasing retrogradation time. However, while longer retrogradation does lead to an improvement in relative crystallinity, it also results in significant damage to the microstructure. When the retrogradation time was 6 h, the microstructure of the rice starch-protein system was less damaged and the quality was better. The mass fractal dimension and relative crystallinity of the rice starch-protein system exhibited an increase as the freezing temperature was decreased from -20 to -80 °C. Additionally, the retrogradation degree of starch decreased, the size of ice crystals decreased, and the disruption of microforms was reduced. The muti-scale structures of the rice starch-protein systems were similar when quick-frozen at temperatures of -32 and -80 °C. Therefore, the optimal treatment method for practical production is to quick-freeze at -32 °C and age for 6 h to obtain high-quality quick-frozen wet rice noodles.

Modifying Cassava Starch via Extrusion with Phosphate, Erythorbate and Nitrite: Phosphorylation, Hydrolysis and Plasticization

Extrusion processing of plasticized cassava starch, a prominent industrial crop, with chemical additives offers a thermo-mechanical approach to modify starch structures through physical and chemical interactions. This research investigates the interaction and morphology of thermoplastic cassava starch (TPS) blended with tetrasodium pyrophosphate (Na4P2O7), sodium tripolyphosphate (Na5P3O10), sodium hexametaphosphate (Na6(PO3)6), sodium erythorbate (C6H7O6Na), and sodium nitrite (NaNO2) via twin-screw extrusion. The effects of these additives on the chemical structure, thermal profile, water absorption, and solubility of the TPS were examined. The high temperature and shearing forces within the extruder disrupted hydrogen bonding at α-(1-4) and α-(1-6) glycosidic linkages within anhydroglucose units. Na4P2O7, Na5P3O10 and Na6(PO3)6 induced starch phosphorylation, while 1H NMR and ATR-FTIR analyses revealed that C6H7O6Na and NaNO2 caused starch hydrolysis. These additives hindered starch recrystallization, resulting in higher amorphous fractions that subsequently influenced the thermal properties and stability of the extruded TPS. Furthermore, the type and content of the added modifier influenced the water absorption and solubility of the TPS due to varying levels of interaction. These modified starch materials exhibited enhanced antimicrobial properties against Escherichia coli and Staphylococcus aureus in polyester blends fabricated via extrusion, with nitrite demonstrating the most potent antimicrobial efficacy. These findings suggest that starch modification via either phosphorylation or acid hydrolysis impacts the thermal properties, morphology, and hydrophilicity of extruded cassava TPS.