Kinetics and Thermodynamics of Thermal Degradation of Different Starches and Estimation the OH Group and H2O Content on the Surface by TG/DTG-DTA

Improving the behavior of thermoplastic starch with the addition of gum Arabic: Antibacterial, mechanical properties and biodegradability

The incorporation of different amounts of Gum Arabic (GA) in thermoplastic starch (TPS) obtained by extrusion and subsequent thermocompression has been studied. The sheets have been characterized by means of XRD, FTIR, TGA, moisture content, SEM, mechanical properties, antimicrobial activity and biodegradability via composting. The FTIR analysis of the sheets shows the presence of ester groups, while the TGA shows the presence of new processes and a residue much higher than expected is obtained. No changes in crystallinity are observed by XRD. The inclusion of GA confers antimicrobial properties to thermoplastic starch against the Gram + and Gram - bacteria studied even at the smaller concentrations. For a low GA content (0.5 and 1 g GA/100 g TPS) a homogeneous material is observed by SEM, as well as an important increase in tensile strength, modulus and deformation at break, which are very interesting properties facing the applicability of this material in single use plastics which are in contact with food or other consumable goods. At higher contents of GA, hollows and cracks appear in the material, compromising the mechanical properties. In all cases, the inclusion of GA delays the biodegradation process in soil, which can be related to its antibacterial capacity and especially in case of GA concentrations of 2 and 5 g/100 g of TPS with lower humidity of these TPS sheets.

Effect of endogenous protein and lipid removal on the physicochemical and digestion properties of sand rice (Agriophyllum squarrosum) flour

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

Insight into the dynamic molecular mechanism underlying the endogenous polyphenols inhibiting the in vitro starch digestion of highland barley noodles

Highland barley is a type of grain with slow-digesting characteristics. It is worth exploring the impact of non-starch components on starch digestion. In this study, four varieties of highland barley were used to investigate the impacts of endogenous polyphenols (EP) on the relationship between starch structure, physicochemical properties, and the time course digestibility of highland barley noodles. The results showed that EP removal decreased the proportion of long-chain amylopectin and disrupted the crystalline structure, while increasing the short-range ordered structure in the residue. Significant correlations indicated that these structural changes make starch more susceptible to thermal degradation and digestion, causing a 12.60%-52.00% increase in rapidly digestible starch (RDS) and a 12.70%-25.22% decrease in resistant starch (RS). These results revealed the internal factors that affect the slow digestion characteristics of highland barley noodles from the perspective of EP and provide important reference values for a slow digestion diet.

Expanded porous-starch matrix as an alternative to porous starch granule: Present status, challenges, and future prospects

Exposing the hydrated-soft-starch matrix of intact grain or reconstituted flour dough to a high-temperature-short-time (HTST) leads to rapid vapor generation that facilitates high-pressure build-up in its elastic matrix linked to large deformation and expansion. The expanded starch matrix at high temperatures dries up quickly by flash vaporization of water, which causes loss of its structural flexibility and imparts a porous and rigid structure of the expanded porous starch matrix (EPSM). EPSM, with abundant pores in its construction, offers adsorptive effectiveness, solubility, swelling ability, mechanical strength, and thermal stability. It can be a sustainable and easy-to-construct alternative to porous starch (PS) in food and pharmaceutical applications. This review is a comparative study of PS and EPSM on their preparation methods, structure, and physicochemical properties, finding compatibility and addressing challenges in recommending EPSM as an alternative to PS in adsorbing, dispersing, stabilizing, and delivering active ingredients in a controlled and efficient way.

Effects of Tremella fuciformis Mushroom Polysaccharides on Structure, Pasting, and Thermal Properties of Chinese Chestnuts (Castanea henryi) Starch Granules under Different Freeze-Thaw Cycles

The purpose of this study was to investigate the effect of Tremella fuciformis polysaccharides on the physicochemical properties of freeze-thawed cone chestnut starch. Various aspects, including water content, crystallinity, particle size, gelatinization, retrogradation, thermal properties, rheological properties, and texture, were examined. The results revealed that moderate freezing and thawing processes increased the retrogradation of starch; particle size, viscosity, shear type, hinning degree, and hardness decreased. After adding Tremella fuciformis polysaccharide, the particle size, relative crystallinity, and gelatinization temperature decreased, which showed solid characteristics. Consequently, the inclusion of Tremella fuciformis polysaccharide effectively countered dehydration caused by freezing and thawing, reduced viscosity, and prevented the retrogradation of frozen-thawed chestnut starch. Moreover, Tremella fuciformis polysaccharide played a significant role in enhancing the stability of the frozen-thawed chestnut starch. These findings highlight the potential benefits of incorporating Tremella fuciformis polysaccharides in starch-based products subjected to freeze-thaw cycles.

Same but different - pseudo-pectin in the charophytic alga Chlorokybus atmophyticus

All land-plant cell walls possess hemicelluloses, cellulose and anionic pectin. The walls of their cousins, the charophytic algae, exhibit some similarities to land plants' but also major differences. Charophyte 'pectins' are extractable by conventional land-plant methods, although they differ significantly in composition. Here, we explore 'pectins' of an early-diverging charophyte, Chlorokybus atmophyticus, characterising the anionic polysaccharides that may be comparable to 'pectins' in other streptophytes. Chlorokybus 'pectin' was anionic and upon acid hydrolysis gave GlcA, GalA and sulphate, plus neutral sugars (Ara≈Glc>Gal>Xyl); Rha was undetectable. Most Gal was the l-enantiomer. A relatively acid-resistant disaccharide was characterised as β-d-GlcA-(1→4)-l-Gal. Two Chlorokybus 'pectin' fractions, separable by anion-exchange chromatography, had similar sugar compositions but different sulphate-ester contents. No sugars were released from Chlorokybus 'pectin' by several endo-hydrolases [(1,5)-α-l-arabinanase, (1,4)-β-d-galactanase, (1,4)-β-d-xylanase, endo-polygalacturonase] and exo-hydrolases [α- and β-d-galactosidases, α-(1,6)-d-xylosidase]. 'Driselase', which hydrolyses most land-plant cell wall polysaccharides to mono- and disaccharides, released no sugars except traces of starch-derived Glc. Thus, the Ara, Gal, Xyl and GalA of Chlorokybus 'pectin' were not non-reducing termini with configurations familiar from land-plant polysaccharides (α-l-Araf, α- and β-d-Galp, α- and β-d-Xylp and α-d-GalpA), nor mid-chain residues of α-(1→5)-l-arabinan, β-(1→4)-d-galactan, β-(1→4)-d-xylan or α-(1→4)-d-galacturonan. In conclusion, Chlorokybus possesses anionic 'pectic' polysaccharides, possibly fulfilling pectic roles but differing fundamentally from land-plant pectin. Thus, the evolution of land-plant pectin since the last common ancestor of Chlorokybus and land plants is a long and meandering path involving loss of sulphate, most l-Gal and most d-GlcA; re-configuration of Ara, Xyl and GalA; and gain of Rha.

Effect of protein on the gelatinization behavior and digestibility of corn flour with different amylose contents

The effects of endogenous proteins on the gelatinization behavior and digestibility of waxy corn flour (WCF), normal corn flour (NCF) and high amylose corn flour (HCF) were systematically investigated. Microscopic characteristics showed that the proteins surrounded multiple starch granules, which led to an increase in the particle size of the corn flour, but no significant change in the relative crystallinity. Small angle x-ray scattering experiments during pasting revealed that the starch granules of NCF remained compact, while WCF and HCF were relatively loose. Carbon-13 nuclear magnetic resonance spectroscopy (13C NMR) showed that the proteins retained the helical structure of starch allowing NCF to have a higher Resistant starch(RS) content. The presence of protein led to a decrease in swelling power, viscosity, and in vitro digestibility of starch, and a noticeable increase in gelatinization temperature and thermal stability. RS increased most significantly in NCF from 3.86 % to 15.27 %. The effect of protein on the water activity of starch with different amylose contents after pasting was also inconsistent. This study will contribute to the understanding of the interaction between starch and protein in corn flours with different amylose contents and contribute to the development of corn flours.

Effect of soluble soybean polysaccharides on the short- and long-term retrogradation properties of instant rice

BACKGROUND

Rice starch retrogradation is prone to occur during instant rice storage, which contributes to reduced viscosity, poor sensory characteristics, and shortened shelf life. The purpose of this study was to explore the anti-retrogradation effect of soybean soluble polysaccharides (SSPS) on instant rice and the possible interaction between SSPS and high-moisture starch products.

RESULTS

We studied the effects of SSPS on the retrogradation of instant rice, using hardness as an index. The optimal amount of SSPS was 0.2%. Hardness, enthalpy, relative crystallinity, and full width at half maximum values were lower in the SSPS-treated group than in the control group (no SSPS) during storage. The weight loss rate of instant rice had the following trend: SSPS-treated group (0 day) < control group (0 day) < SSPS-treated group (28 days) < control group (28 days). The lower the weight loss rate, the lower was the material loss. Scanning electron microscopy results showed that the gaps between starch granules were less obvious in the control group than in the SSPS-treated group during storage. The SSPS-treated group presented a starch network with uniform chambers. SSPS might compete with starch molecules for water absorption, thereby improving water retention and limiting starch retrogradation.

CONCLUSION

The results showed that adding SSPS to instant rice could effectively inhibit starch retrogradation, because the interaction of SSPS and amylopectin side chains inhibited the crosslinking of starch molecules through hydrogen bonds, which hindered the formation of ordered structures. It was helpful to understand the anti-retrogradation mechanism of SSPS during the storage of instant rice, and provided the basis for the industrial production of high-water-content starch foods. © 2023 Society of Chemical Industry.

A more efficient synthesis and properties of saturated and unsaturated starch esters

This work presents a series of starch esters synthesized via 1,5,7-triazabicyclo[4.4.0]-dec-5-ene (TBD) catalyzed transesterifications in dimethyl sulfoxide (DMSO). The reaction was performed with saturated and unsaturated fatty acids (8, 11, and 18 carbon atoms). The degree of substitution (DS) was raised by purging the reaction flask with nitrogen instead of simply performing the reaction under a nitrogen atmosphere. The increase of DS was most obvious for long-chain fatty acids, as an almost complete DS was observed for starch stearate (2.8) and starch oleate (2.7). The products were characterized by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and X-ray diffraction. Starch esters from unsaturated fatty acids have a lower T_g than their saturated analogues. Moreover, contact angle and moisture uptake measurements showed increased hydrophobicity for all starch esters in comparison to pristine starch. Our results show a more efficient method for synthesizing a biobased material that steers into the direction of a material that could replace conventional plastics.

Influence of Starch on the Structure–Properties Relationship in Polyethylene Glycol/Polycaprolactone Diol Polyurethanes

Improvements in the antithrombogenicity activity of biomaterials for cardiovascular applications are necessary to meet the demand for vascular grafts in the world. Zwitterionic compounds tend to be used due to their anti-fouling properties, which reduce platelet adhesions and protein absorptions. Therefore, in this research, potato starch (AL-N) and zwitterionic starch (AL-Z) (obtained by Williamson etherification) were included as fillers in polyurethane (PU) matrices from polycaprolactone diol (PCL), polyethylene glycol (PEG), pentaerythritol (PE) and isophorone diisocyanate (IPDI) in order to study their effect in terms of their physicochemical, mechanical and thermal properties. We conducted our evaluation using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), contact angle analysis, swelling behavior, thermogravimetric analysis (TGA), tensile/strain analysis, scanning electron microscopy equipped with energy dispersive X-ray spectroscopy (SEM-EDS), dynamic mechanic analysis (DMA), differential scanning calorimetry (DSC), and X-ray diffraction (XRD). The results showed that AL-N and AL-Z modified these properties, where AL-N improved tensile strength, and AL-Z increased the hydrophilicity of polyurethanes matrices; additionally, AL-N had interactions with the soft segments, and AL-Z had interactions with the hard segments. Finally, both fillers reduced the degree of crystallinity and did not affect the thermal stability of polyurethanes.

Flame Retardancy and Thermal Degradation Behaviors of Thiol-Ene Composites Containing a Novel Phosphorus and Silicon-Containing Flame Retardant

In this article, a novel phosphorus and silicon-containing flame retardant (DOPO-V-PA) was synthesized via condensation reaction and then added into thiol-ene (TE) to prepare a flame-retardant composite. The results of cone calorimeter measurement demonstrated that, compared with pure TE, 22.7% and 53.2% reduction of TE/DOPO-V-PA (thiol-ene/9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide-vinyltrimethoxysilane-phenyltrimethoxysilane-(3-aminopropyl)trimethoxysilane copolymer) was found for the peak heat release rate (PHRR) and total heat release (THR), respectively. The thermal degradation of TE composites was investigated by the TGA measurement under non-isothermal conditions, and kinetic parameters were both calculated by the Kissinger and Flynn-Wall-Ozawa methods. It was indicated that the activation energies of TE at conversions exceeding 50% were enhanced by the incorporation of DOPO-V-PA for the whole conversion range.

Starch as the Flame Retardant for Electrolytes in Lithium-Ion Cells

The main purpose of this work is to illustrate the flame retardant properties of corn starch that is used as an additive to the classic electrolytes in lithium-ion cells. The advantages of using natural biomass include the increased biodegradability of the cell, compliance with the slogan of green chemistry, as well as the widespread availability and easy isolation of this ingredient. Due to the non-Newtonian properties of starch, it increases work safety and prevents the occurrence of thermal runaway as a shear-thinning fluid in the event of a collision. Thus, its use may, in the future, prevent explosions that affect electric cars with lithium-ion batteries without significantly degrading the electrochemical parameters of the cell. In the manuscript, the viscosity test, flash point measurements, the SET (self-extinguishing time) test and conductivity measurements were performed, in addition to the determination of electrochemical impedance spectroscopy (EIS) for the anode system. Additionally, the kinetic and thermodynamic parameters, for both flow and conductivity, were determined for a deeper analysis; this constitutes the scientific novelty of this study. Through mathematical analysis, it was shown that the optimal amount of added starch is 5%. This is supported primarily by the determined kinetic and thermodynamic parameters and the fact that the system did not gel during heating.

Characterization of Cassava Starch and Its Structural Changes Resulting of Thermal Stress by Functionally-Enhanced Derivative Spectroscopy (FEDS)

Starch is one of the biopolymers that has been recognized as promising for its application as an eco-friendly substitute for conventional polymers due to its biodegradable nature, low cost, and considerable abundance from renewable vegetal-type resources. In particular, the use of cassava starch as raw material in the manufacture of packaging materials has increased in recent years. Consequently, the analytical study of the quality and features of starch and its derivatives throughout their entire life cycle have gained importance, with non-destructive sample methods being of particular interest. Among these, spectroscopic methods stand out. The aim of this study was evaluated using spectroscopic techniques (i.e., mid-infrared spectroscopy (MIRS) and functional-enhanced derivative spectroscopy (FEDS)) for the monitoring of the effect of the thermal stress of starch in conjunction with computational tools such as density-functional theory (DFT). It is concluded that the FEDS technique in conjunction with DFT calculations can be a useful tool for the high-precision spectral analysis of polymers subjected to small thermal perturbations. In addition, it is demonstrated that small changes produced by thermal stress can be monitored by infrared spectroscopy in conjunction with FEDS at wavenumber range between 3800 and 3000 cm−1, which would allow for the implementation of spectral techniques instead of thermal techniques for out-lab evaluations and for the study of the thermal stress of biomaterials.

Influence of Home Composting on Tensile Properties of Commercial Biodegradable Plastic Films

In recent years biodegradable plastic films have been increasingly used for various purposes, most often as grocery bags and for collecting bio-waste. Typically, the biodegradation of these films should take place in industrial compost facilities where the biodegradation process occurs under controlled conditions. Nevertheless, many of these films are often disposed of in home composting bins, so the aim of this study was to examine the course of biodegradation of compostable plastic films under uncontrolled conditions in garden composting sites during a period of four months. Mechanical properties were tested on seven different commercially available biodegradable films and bags that were placed in a garden composting bin from February to May. Both tensile properties and tensile-impact strength showed some unexpected results in terms of increase of the properties after the first, second, and third month for some films and bags. The same unpredictability was seen in FTIR and TG analyses.

Starch Nanoparticles for Enhancement of Oral Bioavailability of a Newly Synthesized Thienopyrimidine Derivative with Anti-Proliferative Activity Against Pancreatic Cancer

Purpose

This research aimed to improve water solubility and oral bioavailability of a newly synthesized thienopyrimidine derivative (TPD) with anti-pancreatic cancer activity by loading on starch nanoparticles (SNPs).

Methods

TPD was synthesized, purified and its ADME behavior was predicted using Swiss ADME software. A UV spectroscopy method was developed and validated to measure TPD concentration at various dosage forms. SNPs loaded with TPD (SNPs-TPD) were prepared, characterized for particle size, polydispersity index, zeta potential, transmission electron microscopy, Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), entrapment efficiency, in-vitro release, and in-vivo animal study.

Results

The Swiss ADME results showed that TPD can be administered orally; however, it has low oral bioavailability (0.55) and poor water solubility. The significant regression coefficient of the calibration curve (r² = 0.9995), the precision (%RSD < 0.5%) and the accuracy (99.46−101.72%) confirmed the efficacy of the developed UV method. SNPs-TPD had a spherical monodispersed (PDI= 0.12) shape, nanoparticle size (22.98 ± 4.23) and good stability (−21 ± 4.72 mV). Moreover, FT-IR and DSC revealed changes in the physicochemical structure of starch resulting in SNPs formation. The entrapment efficiency was 97% ± 0.45%, and the in-vitro release showed that the SNPs enhanced the solubility of the TPD. The in-vivo animal study and histopathology showed that SNPs enhanced the oral bioavailability of TPD against solid Ehrlich carcinoma.

Conclusion

SNPs-TPD were superior in drug solubility and oral bioavailability than those obtained from TPD suspension.

Effect of cellulose and starch fatty acid esters addition on microstructure and physical properties of arabinoxylan films

Arabinoxylan (AX) and cellulose were extracted from wheat straw, whereas starch was extracted from potato peel. Thereafter, cellulose and starch were esterified with lauric, myristic, palmitic and stearic acids to prepare corresponding cellulose (CFAs) and starch fatty acid esters (SFAs) with DS 2.1-2.8. XRD study revealed remarkable loss of crystallinity in cellulose and starch due to fatty acid esterification. The addition of palmitate and stearate esters of cellulose and starch to AX formed laminar film microstructures which limited water vapor permeability whereas films prepared by blending AX with laurate and myristate esters of starch and cellulose were less effective as water vapor barrier due to their non-layer microstructures. The laminar structures also resulted significant reduction in mechanical strength of the composite films. Furthermore, all AX-CFAs and AX-SFAs films were thermally more stable than native composite films. These films might be used to produce industrially useful coating material for food products.

Effect of oil pomaces on thermal properties of model dough and gluten network studied by thermogravimetry and differential scanning calorimetry

Thermal analyses were used to determine thermal properties and transitions in model dough and gluten network induced by five oil pomaces obtained from seeds of black seed, pumpkin, hemp, milk thistle and primrose. The model dough was supplemented with 3%, 6% and 9% of the pomaces. Analysis of TGA parameters of supplemented model dough and gluten showed that both objects were thermally stable. However, analysis of difference TGA thermograms indicated that samples supplemented with pomaces differ in thermal behaviour. The differences were confirmed by DSC results. In the case of model dough, supplementation caused appearance of two endothermic peaks at ca. 295 and 340 °C and significant increase in transition enthalpy. Modified gluten thermograms showed one exothermic peak at 280 °C which enthalpy changed slightly with increase in pomace content. The present results indicated that model dough is characterized by more ordered structure comparing to control and gluten samples.

Physicochemical properties of raw starches and their impact on electrochemical activity - Biomolecule-based anode material

Starch is a modern and prospective biodegradable material, which could improve lithium-ion batteries by making them safer and thus increasing the energy density and capacity of the cells. The main aim of this study was to research the influence of the physical and chemical properties of different botanical origin starches on their electrochemical properties. The investigation was carried out by examining the colloid stability of starches in water solution at room temperature, and the size of particles, which gave really good stability results. Moreover, the vibrations and the functional groups structure were described by Fourier Transform Infrared Spectroscopy (FTIR). The surface properties were characterized by determining the specific surface area, pore diameter and volume diameter. The structures of the granules were determined by scanning electron microscope (SEM) measurement. The results of the electrochemical investigations showed good cyclic reversibility and stability. The research was aimed at improving and modifying current lithium-ion cells using biodegradable material as an active anode material, which is connected with the currently well-known "Green Chemistry".

Synthesis of Titanium Dioxide via Surfactant-Assisted Microwave Method for Photocatalytic and Dye-Sensitized Solar Cells Applications

In this study, titania nanoparticles were obtained using the microwave-assisted technique. Moreover, different surfactants (PEG (Mn = 400), Pluronic P123 and Triton X−100) were used during the synthesis in order to determine their impact on the crystallinity and morphology of the final products. Subsequently, techniques such as XRD, SEM and TEM (performed in high contrast and high-resolution mode), diffuse reflectance spectroscopy (DRS), low temperature N2 sorption (BET model), FTIR and TGA were carried out. Based on the crystallinity analysis of the obtained materials, it was established that the addition of surfactants results in greater (PEG and Triton X−100) or smaller (Pluronic P123) average crystallite size. The main purpose of this study was to use the synthesized nanomaterials in the photodegradation process (in the UV light range) of the model organic pollutants – phenol (20 mg/L) and etodolac (15 mg/L). Furthermore, it was also pointed out that the dye-sensitized solar cells can be a second application for the synthesized titania nanomaterials. The photo-oxidation and photovoltaic tests have shown that the titanium dioxide obtained using the surfactant-assisted microwave method is characterized not only by better photodegradation efficiency of phenol and etodolac, but also by higher photocurrent density compared to the reference titania samples—the pristine TiO2 and commercial P25.