Starch gelatinization using sodium silicate: FTIR, DSC, XRPD, and NMR studies

Characterization of Nano- and Microstructures of Native Potato Starch as Affected by Physical, Chemical, and Biological Treatments

Modifying starch allows for improvements in its properties to enable improved uses in food matrices, bioplastics, and encapsulating agents. In this research, four varieties of native potato starch were modified by acid treatment, enzymatic treatment, and ethanol precipitation, and their physicochemical, structural, thermal, and techno-functional characteristics were analyzed. According to FT-IR analysis, no influence of the modified starches on the chemical groups was observed, and by scanning electron microscopy (SEM), spherical and oval shapes were observed in the acid and enzymatic treatments, with particle sizes between 27 and 36 μm. In particular, the ethanolic precipitation treatment yielded a different morphology with a particle size between 10.9 and 476.3 nm, resulting in a significant decrease in gelatinization temperature (DSC) and more pronounced crystallites (XRD). On the other hand, the enzymatic treatment showed higher values for z-potential (ζ), and the acid treatment showed lower mass loss (TGA). Acid and ethanolic treatments affected the dough properties compared to native starches. The techno-functional properties showed a decrease in the water absorption index, an increase in the water solubility index, and varied swelling power behaviors. In conclusion, the modification of potato starches through acid, enzymatic, and ethanolic precipitation treatments alters their physicochemical properties, such as swelling capacity, viscosity, and thermal stability. This in turn affects their molecular structure, modifying morphology and the ability to form gels, which expands their applications in the food industry to improve textures, stabilize emulsions, and thicken products. Furthermore, these modifications also open new opportunities for the development of bioplastics by improving the biodegradability and mechanical properties of starch-based plastic materials.

Characterization of Polylactic Acid Biocomposites Filled with Native Starch Granules from Dioscorea remotiflora Tubers

Biocomposites were fabricated utilizing polylactic acid (PLA) combined with native starch sourced from mountain's yam (Dioscorea remotiflora Knuth), an underexplored tuber variety. Different starch compositions (7.5, 15.0, 22.5, and 30.0 wt.%) were blended with PLA in a batch mixer at 160 °C to produce PLA/starch biocomposites. The biocomposites were characterized by analyzing their morphology, particle size distribution, thermal, X-ray diffraction (XDR), mechanical, and dynamic mechanical (DMA) properties, water absorption behavior, and color. The results showed that the amylose content of Dioscorea remotiflora starch was 48.43 ± 1.4%, which corresponds to a high-amylose starch (>30% of amylose). Particle size analysis showed large z-average particle diameters (Dz0) of the starch granules (30.59 ± 3.44 μm). Scanning electron microscopy (SEM) images showed oval-shaped granules evenly distributed throughout the structure of the biocomposite, without observable agglomeration or damage to its structure. XDR and DMA analyses revealed an increase in the crystallinity of the biocomposites as the proportion of the starch increased. The tensile modulus (E) underwent a reduction, whereas the flexural modulus (Eflex) increased with the amount of starch incorporated. The biocomposites with the highest Eflex were those with a starch content of 22.5 wt.%, which increased by 8.7% compared to the neat PLA. The water absorption of the biocomposites demonstrated a higher uptake capacity as the starch content increased. The rate of water absorption in the biocomposites followed the principles of Fick's Law. The novelty of this work lies in its offering an alternative for the use of high-amylose mountain's yam starch to produce low-cost bioplastics for different applications.

Development of a Sustainable Biobased Flame-Retardant Microcapsule and Its Flame-Retarding Mechanism on Asphalt Combustion

To develop an efficient, sustainable, and eco-friendly biobased flame-retardant microcapsule suitable for the working environments of tunnel asphalt pavement and reveal its flame-retarding mechanism on asphalt combustion, microencapsulated amylopectin (MAMP) was first prepared using an in situ polymerization method. Changes in the basic properties of amylopectin (AMP) and its compatibility with asphalt after microencapsulation were studied. Then, the flame retarding efficiency and improvement effects of MAMP on the flame retardancy of asphalt were investigated. Results show that melamine formaldehyde (MF) resin is evenly coated on the AMP surface without changing the chemical composition of AMP, increasing the thermal stability of AMP and the compatibility between AMP and asphalt. MAMP reacts with ammonium polyphosphate (APP) to release a number of incombustible gases to delay asphalt combustion at early stages and subsequently dehydrates to form a stable starch-based charring layer to suppress heat and mass transfer during asphalt combustion, improving the fire safety of asphalt materials. The added 3% MAMP can reduce the total enthalpy value of all exothermic peaks of the 10% APP-modified asphalt by 43.6%. As a carbonization agent, MAMP produces a charring layer with higher heat capacity during asphalt combustion, exerting an excellent inhibition effect on heat release. This study provides a reference for the application of biobased materials in flame-retarded asphalt pavements.

Comprehensive quality evaluation of plant-based cheese analogues

BACKGROUND

In recent years, there has been an increasing demand for plant-based cheese analogues, however, the protein content of plant-based cheeses currently on the market is generally low and cannot meet the nutritional needs of consumers.

RESULTS

Based on the ideal value similarity method (TOPSIS) analysis the best recipe for plant-based cheese was 15% tapioca starch, 20% soy protein isolate, 7% gelatine as a quality enhancer and 15% coconut oil. The protein content of this plant-based cheese was170.1 g kg-1 , which was close to commercial dairy-based cheese and significantly higher than commercial plant-based cheese, The fat content was 114.7 g kg-1 , lower than that of commercial dairy-based cheese. The rheology properties show that the viscoelasticity of the plant-based cheese is higher than that of dairy-based cheese and commercial plant-based. The microstructure results show that the type and content of protein has a significant impact on its microstructure. The Fourier-transform infrared (FTIR) spectrum of the microstructure shows a characteristic value at 1700 cm-1 , because the starch was heated and leached to form a complex with lauric acid under the action of hydrogen bond. It can be inferred that in the interaction between plant-based cheese raw materials, fatty acids serve as a bridge between starch and protein.

COUCLUSION

This study described the formula of plant-based cheese and the interaction mechanism between the ingredients, providing a basis for the development of subsequent plant-based cheese related products. © 2023 Society of Chemical Industry.

Characterizing digestibility of potato starch with cations by SEM, X-ray, LF-NMR, FTIR

Cations can combine with starch and alter its physicochemical characteristics. The addition of cations may influence the in vitro digestion of potato starch. Scanning electron microscopy, X-ray diffraction, low-field nuclear magnetic resonance, and Fourier transform infrared spectroscopy were used to measure the microstructure, relative crystallinity, water distribution, and interaction of potato starch with cations and characterize its digestibility. The results showed that all cations decreased rapidly digestible starch (RDS) at a low concentration but increased the RDS with the addition of cations, especially trivalent cations. However, the resistant starch (RS) had the opposite trend. All cations increased the relative crystallinity of potato starch, except Ca²⁺. Fe³⁺, and Al³⁺ markedly decreased the mobility and hydrogen bonds in potato starch. In general, the addition of cations influenced the retrogradation of potato starch, resulting in a change in its digestibility.

Yam Bean (Pachyrhizus erosus L. Urban) Powder Improves Grass Carp Myofibrillar Protein Gel by Forming Disulfide Bonds, Hydrogen Bonds, and Proper Microstructure

This study aimed to analyze the impact of different additions (0-1.25%) of yam bean powder (YBP) on myofibrillar protein (MP) gel characteristics such as the structure, water-holding capacity (WHC), chemical interaction strength of grass carp MP, and texture. The results showed that the YBP exhibited a strong water absorption capacity and filled in the protein heat-induced polymerization gel network well, which enabled the gel network to capture and retain water effectively, resulting in MP gels containing YBP with excellent WHC and gel strength (0.75%). In addition, YBP induced the formation of hydrogen and disulfide bonds in proteins and inhibited the conversion of α-helices to β-sheets and β-turn structures, facilitating the formation of high-strength gel networks (p < 0.05). In conclusion, YBP can significantly improve the thermally induced gelling properties of grass carp MP. In particular, the addition of 0.75% YBP had the best effect in terms of filling the gel network of grass carp MP, resulting in the formation of a continuous and dense protein network, leading to the composite gel with the best WHC and texture.

Efficient removal of Hg0 in flue gas using a novel Sn-based porphyrin polymer

A Sn-based porphyrin polymer (TAPP(Sn)-FAC) synthesized in a mild condition was introduced for the Hg⁰ removal in flue gas. The properties characterization of materials revealed the two-dimensional sheet structure, an amorphous structure and high stability of TAPP(Sn)-FAC, and Sn was successfully incorporated into TAPP-FAC in the form of SnN. The removal performance of Hg⁰ under different conditions was investigated using a lab-scale fixed-bed reactor. TAPP(Sn)-FAC presented an excellent Hg⁰ removal efficiency from 100 °C to 250 °C, which can reach 8 mg/g of Hg⁰ capture capacity at 100 °C for 300 min. Besides, TAPP(Sn)-FAC had a strong sulfur and water resistance, and the presence of NO and O₂ had a facilitating effect for Hg⁰ removal. Moreover, the existence of Sn can enhance the Hg⁰ adsorption and oxidation capacity of TAPP(Sn)-FAC by promoting the electron transfer process. Furthermore, TAPP(Sn)-FAC presented an excellent chemical stability, which was a promising material in the Hg⁰ removal in flue gas.

pH-shifting alters textural, thermal, and microstructural properties of mung bean starch-flaxseed protein composite gels

The objective of this study was to investigate the effect of pH-shifting on the textural and microstructural properties of mung bean starch (MBS)-flaxseed protein (FP) composite gels. Results showed that different pH-shifting treatments caused changes in hydrogen bond interactions and secondary structures in composite gels, leading to the formation of loose or compact gel networks. The pH 2-shifting modified protein and starch molecules with shorter chains tended to form smaller intermolecular aggregates, resulting in the formation of a looser gel network. For pH 12-shifting treatment, conformational change of FP caused the unfolding of protein and the exposure of more hydrophobic groups, which enhanced the hydrogen bond and hydrophobic interactions between polymers, contributing to the formation of a compact gel network. Furthermore, pH 12-shifting improved the water-holding capacity (WHC), storage modulus, and strength of gels, while pH 2-treated gels exhibited lower WHC, hardness, and gumminess due to the degradation of MBS and denaturation of FP caused by extreme acid condition. These findings suggest that pH-shifting can alter the gel properties of bi-polymeric starch-protein composite systems by affecting the secondary structures of proteins and the hydrogen bonding between the polymers, and provide a promising way for a wide application of FP in soft gel-type food production.

Textural characterization of calcium salts-induced mung bean starch-flaxseed protein composite gels as dysphagia food

Effects of calcium gluconate (CG), calcium lactate (CL) and calcium dihydrogen phosphate (CDP) on the structural and functional properties of mung bean starch (MBS)-flaxseed protein (FP) composite gels were investigated to explore the feasibility of developing dysphagia food. The water-immobilizing, rheological and structural properties of MBS-FP composite gels adding different calcium salts (10, 30, and 50 mmol/L) were analyzed by low-field nuclear magnetic resonance measurement, rheological and textural analyses, fourier transform infrared spectroscopy, scanning electron microscopy and confocal laser scanning microscopy. Results showed that calcium salts imparted various soft gel properties to the composite gels by influencing the interactions between MBS and FP. Calcium salts could affect the conformation of amylose chains, accelerate the aggregation of FP molecules, and increase the cross-linking between starch and protein aggregates, resulting in the formation of large aggregates and a weak gel network. Consequently, calcium salts-induced composite gels showed lower viscoelastic moduli and gel strength than the control gel. In particular, different calcium salts had various impacts on the gel properties due to their diverse ability forming hydrogen bonds. Compared with CL and CDP, the gels containing CG presented the higher viscoelastic moduli and hardness, and possessed an irregular cellular network with the increased pore number and the decreased wall thickness. The gel containing 50 mmol/L CL had the highest water-holding capacity, in all the gels tested, by retaining more immobilized and mobile water in the compact gel network with larger cavities. The gels adding CDP presented lower hardness and gumminess due to the obvious lamellar structure within the network. International dysphagia diet standardization initiative (IDDSI) tests indicated that the gels adding CG and CL could be categorized into level 6 (soft and bite-sized) dysphagia diet, while the samples adding CDP could be classified into level 5 (minced and moist). These findings provide insights for the development of the novel soft gel-type dysphagia food.

Study of Changes in Crystallinity and Functional Properties of Modified Sago Starch (Metroxylon sp.) Using Physical and Chemical Treatment

Sago starch has weaknesses such as low thermal stability and high syneresis. Modifications were made to improve the characteristics of native sago starch. In this study, sago starch was modified by autoclave-heating treatment (AHT), osmotic-pressure treatment (OPT), octenyl-succinic anhydride modification (OSA), and citric acid cross-linking (CA). This study aimed to examine the changes in chemical composition, crystallinity, and functional properties of the native sago starch after physical and chemical modifications. The results show that physical modification caused greater granule damage than chemical modification. All modification treatments did not alter the type of crystallinity but decreased the relative crystallinity of native starch. New functional groups were formed in chemically modified starches at a wavelength of 1700-1725 cm-1. The degree of order (DO) and degree of double helix (DD) of the modified starches were also not significantly different from the native sample, except for AHT and OPT, respectively. Physical modification decreased the swelling volume, while chemical modification increased its value and is inversely proportional to solubility. AHT and OPT starches have the best freeze-thaw stability among others, indicating that both starches have the potential to be applied in frozen food.

Synthesis of a Starchy Photosensitive Material for Additive Manufacturing of Composites Using Digital Light Processing

In this study, digital light processing (DLP) was used to achieve 3D-printed composite materials containing photosensitive resin blended with starch and hemp fibers. The synthesis of 3D-printed composites was performed without heating, according to various material combinations ranging from pure photosensitive resin to a mixture of three phases, including resin, starch, and hemp fibers, with the weight content for each reinforcing phase reaching up to a third of the formulation. The morphology, composition, and structure of the 3D-printed composites were assessed using infrared spectroscopy, laser granulometry, X-ray diffraction, and optical and scanning electron microscopy. In addition, thermal behavior and mechanical performance were studied using calorimetry, differential scanning calorimetry, and tensile testing combined with high-speed optical imaging. The results showed that the post-curing step is a leading factor for improving the mechanical performance of the 3D-printed composites. In addition, hemp fiber or starch did not alter the tensile strength. However, the largest reinforcing effect in terms of stiffness improvement was obtained with starch. Additionally, starchy composites demonstrated the strongest dependence of heat capacity on operating temperature.

Thermal and microwave synthesis of silica fume-based solid activator for the one-part geopolymerization of fly ash

This paper tests the development of a silica fume-based material, capable to be used as a solid activator for the one-part geopolymerization of fly ash. Through a simple procedure, a mixture of silica fume, an amorphous and silicon-rich by-product, sodium hydroxide and water, is converted, after a low-temperature treatment, to a new powder product mainly containing sodium silicate (Na₂SiO₃). Two different treatment methods are tested for the synthesis of the solid activator: heat and microwave treatment. Microwave processing is more sustainable and more efficient than thermal treatment, since purer products are produced with less energy consumption. The use of these low embodied energy products, as the only solid activator of fly ash, leads to geopolymers with comparable mechanical performance to those prepared with commercial products revealing their potential successful addition in the geopolymer market.

Insights into the gelatinization of potato starch by in situ 1H NMR

The gelatinization of potato starch and the effect of NaCl on starch gelatinization were monitored successfully in situ by 1H NMR spectroscopy. Variable temperature (VT) 1H NMR measurement, from 316 K to 340 K, was conducted on a suspension of potato starch and deuterium water as well as a mixture of potato starch, NaCl and deuterium water. The hydration level of starch was determined with the increase of temperature. In the presence of NaCl, the initial gelatinization temperature of potato starch was decreased from 331 to 328 K. Meanwhile, in situ 1H NMR spectroscopy as a function of time was also carried out to monitor the gelatinization with a time resolution of 90 s per spectrum. Furthermore, the effect of using different processing methods during gelatinization, including varying the temperature or time duration, was investigated in detail. It was confirmed that protons from different groups of starch showed different accessibility for water during hydration of starch granules. In comparison with temperature, gelatinization time as the major factor for reaching complete gelatinization was confirmed. We expect that this research, as a continuing effort to apply NMR spectroscopy for characterizing starch, will pave a new way in the structural elucidation of starch.

Methods for characterizing the structure of starch in relation to its applications: a comprehensive review

Starch is a major part of the human diet and an important material for industrial utilization. The structure of starch granules is the subject of intensive research because it determines functionality, and hence suitability for specific applications. Starch granules are made up of a hierarchy of complex structural elements, from lamellae and amorphous regions to blocklets, growth rings and granules, which increase in scale from nanometers to microns. The complexity of these native structures changes with the processing of starch-rich ingredients into foods and other products. This review aims to provide a comprehensive review of analytical methods developed to characterize structure of starch granules, and their applications in analyzing the changes in starch structure as a result of processing, with particular consideration of the poorly understood short-range ordered structures in amorphous regions of granules.

Effect of natural deep eutectic solvents on thermal stability, syneresis, and viscoelastic properties of high amylose starch

This work aimed to use natural deep eutectic solvents to modify the thermal, textural, freeze-thaw, and rheological properties of high amylose rice starch. Three different natural deep eutectic solvents (NADES) composed of sugar and organic acids were applied to modify the properties of starch dispersion. In presence of NADES, the onset temperature of starch was decreased, in comparison with starch in aqueous and glycerol medium. During thermal decomposition, starch with the aqueous and glycerol systems showed two-step weight losses whereas with NADES starch showed single-stage weight losses or decomposition. Moreover, negligible syneresis was observed for starch-NADES dispersion after 3rd cycle of the freeze-thaw process. The flow behavior of starch-NADES dispersion follows Herschel-Bulkley models as R² (0.996 ≤ R² ≤ 0.999) are higher than the Mizrahi-Berk model. The flow behavior index (n) of starch-NADES dispersion was closer to 1, indicated a nearly Newtonian fluid. The loss modulus (G″) value of starch-NADES dispersions was markedly higher than the corresponding storage modulus (G') value and thus materials behaved like viscoelastic liquid. The present study manifested a green way to modify the properties of the high amylose starch to improve the processing stability.

Foldable/Expandable Gastro-retentive Films Based on Starch and Chitosan as a Carrier For Prolonged Release of Resveratrol

BACKGROUND

Resveratrol exerts a number of therapeutic effects, notably anti-inflammatory, antioxidant and anti-cancer activities which are beneficial for the treatment of gastric diseases. However, the efficacy of resveratrol is severely limited due to the poor aqueous solubility and rapid metabolism following oral administration. As a result, foldable/expandable devices based on natural polymers merging with solid dispersion technology have been developed to increase the solubility, prolong the gastric residence time, and provide a controlled release therapy of resveratrol.

OBJECTIVES

This research aimed to invent foldable/expandable films based on natural polymers, including starch and chitosan, for stomach-specific delivery and prolonged release of resveratrol.

METHODS

The films were prepared by solvent casting using either rice, tapioca, corn starch or pre-gelatinized corn starch combined with chitosan in different weight to weight ratios. Glycerol was included as a plasticizer. Resveratrol solid dispersions (Res-SD) prepared by solvent evaporation and employing PVP-K30 as a hydrophilic polymer were loaded into the polymeric film, which was subsequently folded prior to insertion in a hard gelatin capsule.

RESULTS

The solid dispersions improved the solubility of resveratrol by a factor of 500. All Res-SD loaded film formulations completely unfolded in simulated gastric fluid at 37oC within 10 min. Fluid absorption by the films was influenced by the ratio of amylose and amylopectin in the starch granules, with tapioca starch formulations displaying the highest fluid uptake. Films prepared from pre-gelatinized corn starch and chitosan resulted in highly efficient delivery of resveratrol, with more than 80%of the content released over a period of 12 hrs. Furthermore, the released polyphenol exhibited cytotoxic activity against human gastric adenocarcinoma cells and anti-inflammatory effects against lipopolysaccharide-stimulated murine, macrophage-like cells.

CONCLUSIONS

These findings demonstrate the potential of foldable/expandable films based on natural polymers as a promising stomach-specific carrier for improving the treatment of gastric disorders.

Preparation and characterization of octenyl succinylated starch microgels via a water-in-oil (W/O) inverse microemulsion process for loading and releasing epigallocatechin gallate

Corn starch (CS), octenyl succinic anhydride modified corn starch (OSCS) and shells (OSC_s) microgels have been prepared using water-in-oil (W/O) inverse microemulsions for loading and releasing of epigallocatechin gallate (EGCG). The structural and morphological properties of CS, OSCS, and OSC_s microgels were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), Transmission electron microscopy (TEM), and Thermogravimetric analysis (TGA). The strong hydrogen bonds between starch molecules in the W/O system and interplay between hydroxyl groups of EGCG and oxygen atoms of starch microgels were formed. OSC_s microgel showed low average particle size and weak thermal stability with an irregular shape and a typical V-type crystalline structure. Encapsulation efficiency (EE) and clearance rate of 2,2-diphenyl-1-picrylhydrazyl (DPPH) for EGCG were ranged between 41.78 and 63.89% and 75.53-85.37%, respectively, when absorbed into OSCS and OSC_s microgels, the values which were higher than that of CS microgel. Further, OS starch microgels (particularly OSC_s) modulated the slow release of EGCG into simulated gastrointestinal tract conditions and therefore could be proposed as an encapsulating agent for loading polyphenols.

The effect of pre and post-ultrasonication on the aggregation structure and physicochemical characteristics of tapioca starch containing sucrose, isomalt and maltodextrin

The present research investigated the aggregation behaviors of different levels (4, 8 and 12%) of incorporation of sucrose, isomalt and maltodextrin to pre or post- ultrasonication (400 W, 10 min at 60 °C) by fourier transform infrared spectroscopy (FTIR), microstructure by scanning electron microscopy (SEM), water absorption, pasting by rapid visco analysis (RVA), and thermal by differential scanning calorimetry (DSC). FTIR results showed that the aggregation process between polyol and starch after ultrasonication is more effective than before ultrasonication owning to more hydroxyl groups of polyols are engaged with the hydrogen bonds of starch which is more pronounced peaks at 1500-1750 cm^-1, 1700-2700 cm^-1 and 3000-3700 cm^-1. These findings are in line with the results from SEM analysis. The spots, deformations and cross-linking created by the polyols were more significant after ultrasound assisted pregelatinizion. Impact intensity of polyol on starch granule was reduced in the following order: isomalt > sucrose > maltodextrin. RVA profiles showed that through the incorporation of polyols after sonication, were higher in samples pregelatinized in comparison with those before sonication.

Microscopic and spectroscopic characterization of rice and corn starch

Starch granules from rice and corn were isolated, and their molecular mechanism on interaction with α-amylase was characterized through biochemical test, microscopic imaging, and spectroscopic measurements. The micro-scale structure of starch granules were observed under an optical microscope and their average size was in the range 1-100 μm. The surface topological structures of starch with micro-holes due to the effect of α- amylase were also visualized under scanning electron microscope. The crystallinity was confirmed by X-ray diffraction patterns as well as second-harmonic generation microscopy. The change in chemical bonds before and after hydrolysis of the starch granules by α- amylase was determined by Fourier transform infrared spectroscopy. Combination of microscopy and spectroscopy techniques relates structural and chemical features that explain starch enzymatic hydrolysis which will provide a valid basis for future studies in food science and insights into the energy transformation dynamics.

Fabrication and Characterization of Starch Nanohydrogels via Reverse Emulsification and Internal Gelation

Biopolymer-based nanohydrogels have great potential for various applications, including in food, nutraceutical, and pharmaceutical industries. Herein, starch nanohydrogels were prepared for the first time via reverse emulsification coupled with internal gelation. The effects of starch type (normal corn, potato, and pea starches), amylose content, and gelation time on the structural, morphological, and physicochemical properties of starch nanohydrogels were investigated. The diameter of starch nanohydrogel particles was around 100 nm after 12 h of retrogradation time. The relative crystallinity and thermal properties of starch nanohydrogels increased gradually with an increasing amylose content and gelation time. The swelling behavior of starch nanohydrogels was dependent upon the amylose content, and the swelling ratios were between 2.0 and 14.0, with the pea starch nanogels exhibiting the lowest values and the potato starch nanogels exhibiting the highest values.

Starch-metal complexes and metal compounds

Recently, metal derivatives of starch evoked considerable interest. Such metal derivatives can take a form of starch compounds bearing metal atoms and metal carrying moieties either covalently bound or complexed. Starch metal complexes may have a character of either Werner, inclusion, sorption or capillary complexes. In this publication, preparation, structure, properties and numerous current and potential applications of those compounds as well as benefits resulting from the application and formation of the complexes are presented. © 2017 Society of Chemical Industry.