A new way to improve physicochemical properties of potato starch

Effects of the Amylose/Amylopectin Ratio of Starch on Borax-Crosslinked Hydrogels

Herein, we simultaneously prepared borax-crosslinked starch-based hydrogels with enhanced mechanical properties and self-healing ability via a simple one-pot method. The focus of this work is to study the effects of the amylose/amylopectin ratio of starch on the grafting reactions and the performance of the resulting borax-crosslinked hydrogels. An increase in the amylose/ amylopectin ratio increased the gel fraction and grafting ratio but decreased the swelling ratio and pore diameter. Compared with hydrogels prepared from low-amylose starches, hydrogels prepared from high-amylose starches showed pronouncedly increased network strength, and the maximum storage modulus increased by 8.54 times because unbranched amylose offered more hydroxyl groups to form dynamic borate ester bonds with borate ions and intermolecular hydrogen bonds, leading to an enhanced crosslink density. In addition, all the hydrogels exhibited a uniformly interconnected network structure. Furthermore, owing to the dynamic borate ester bonds and hydrogen bonds, the hydrogel exhibited excellent recovery behavior under continuous step strain, and it also showed thermal responsiveness.

Biochar/Biopolymer Composites for Potential In Situ Groundwater Remediation

This study explores the use of pine wood biochar (BC) waste gasified at 950 °C as fillers in polymer matrices to create BC@biopolymer composites with perspectives in groundwater remediation. Four biochar samples underwent different sieving and grinding processes and were extensively characterized via UV-Vis, FTIR, and FESEM-EDS, highlighting the fact that that BCs are essentially graphitic in nature with a sponge-like morphology. The grinding process influences the particle size, reducing the specific surface area by about 30% (evaluated by BET). The adsorption performances of raw BC were validated via an adsorption isotherm using trichloroethylene (TCE) as a model contaminant. A selected BC sample was used to produce hydrophilic, stable polymer composites with chitosan (CS), alginate (ALG), potato starch (PST), and sodium carboxymethylcellulose (CMC) via a simple blending approach. Pilot sedimentation tests over 7 days in water identified BC@PST and BC@CMC as the most stable suspensions due to a combination of both hydrogen bonds and physical entrapment, as studied by FTIR. BC@CMC showed optimal distribution and retention properties without clogging in breakthrough tests. The study concludes that biopolymer-based biochar composites with improved stability in aqueous environments hold significant promise for addressing various groundwater pollution challenges.

Antioxidant Edible Films Derived from Belitung Taro Tubers (Xanthosoma sagittifolium) Incorporated with Moringa Leaf Extract (Moringa oleifera)

Edible films are thin films frequently manufactured using natural bioresources and are employed in food packaging to safeguard food quality. This research prepared edible films from renewable biomass consisting of Belitung taro tuber starch (Xanthosoma sagittifolium) and incorporated sorbitol as a plasticizer, carboxymethyl cellulose as a reinforcing agent, and moringa leaf extract (Moringa oleifera) as an antioxidant. The physicochemical characteristics of the resulting edible films were examined. The most favorable treatment was identified in an edible film containing 3% (v/v based on the total volume of 100 mL) of moringa leaf extract. This exhibited a tensile strength of 6.86 N/mm2, percent elongation of 73.71%, elasticity of 9.37×10-3 kgf/mm2, water absorption of 349.03%, solubility of 93.18%, and water vapor transmission speed of 3.18 g/h m2. Its shelf life was five days at ambient temperature. The edible film was found to have 135.074 ppm of half maximal inhibitory concentration (IC50) based on the antioxidant analysis of inhibition concentration (IC50) value measurements, and was classified as having moderate antioxidant activity. Additionally, the biodegradability assessment revealed that the edible films degraded within 14 days. Based on this data, it can be deduced that adding moringa leaf extract enhances the physicochemical and functional characteristics of the film. These edible films can be used as substitutes for nonrenewable and nonbiodegradable packaging materials.

Exploring the influence mechanism of water grinding on the gel properties of corn starch based on changes in its structure and properties

BACKGROUND

At present, most studies have focused on the preparation of modified starches by dry grinding. As an excellent starch plasticizer, water might enhance the action of grinding on the structure of starch granules, and water grinding might improve the gel properties of starch. Therefore, this article explored the influence mechanism of water grinding on the gel properties of corn starch based on the changes in its structure and properties.

RESULTS

The results showed that water grinding could make water enter the starch granules and hydrate the starch molecules, and the starch gelatinized after water grinding for 20 min. Thus, water enhanced the action of grinding on the structure of the starch granules. Under the plasticization and grinding action of water grinding, the mechanochemical effect of the starch granules occurred. When the starch was in the aggregation stage (7.5-10 min), the crystallinity of the starch increased, and the starch molecules rearranged into a more stable structure, which increased apparent viscosity (η), elastic modulus (G') and viscous modulus (G″) of the starch gels.

CONCLUSION

Therefore, appropriate water grinding (10 min) contributed to increasing the viscoelasticity of starch gels. This study provided a theoretical foundation for research on improving the properties of starch by mechanical modification in future. © 2023 Society of Chemical Industry.

Study of unripe and inferior banana flours pre-gelatinized by four different physical methods

This study aimed to prepare the pre-gelatinized banana flours and compare the effects of four physical treatment methods (autoclaving, microwave, ultrasound, and heat-moisture) on the digestive and structural characteristics of unripe and inferior banana flours. After the four physical treatments, the resistant starch (RS) content values of unripe and inferior banana flours were decreased from 96.85% (RS2) to 28.99-48.37% (RS2 + RS3), while C∞ and k values were increased from 5.90% and 0.039 min^-1 to 56.22-74.58% and 0.040-0.059 min^-1, respectively. The gelatinization enthalpy (ΔHg) and I_1047/1022 ratio (short-range ordered crystalline structures) were decreased from 15.19 J/g and 1.0139 to 12.01-13.72 J/g, 0.9275-0.9811, respectively. The relative crystallinity decreased from 36.25% to 21.69-26.30%, and the XRD patterns of ultrasound (UT) and heat-moisture (HMT) treatment flours maintained the C-type, but those samples pre-gelatinized by autoclave (AT) and microwave (MT) treatment were changed to C + V-type, and heat-moisture (HMT) treatment was changed to A-type. The surface of pre-gelatinized samples was rough, and MT and HMT showed large amorphous holes. The above changes in structure further confirmed the results of digestibility. According to the experimental results, UT was more suitable for processing unripe and inferior banana flours as UT had a higher RS content and thermal gelatinization temperatures, a lower degree and rate of hydrolysis, and a more crystalline structure. The study can provide a theoretical basis for developing and utilizing unripe and inferior banana flours.

Effects of Heat-Moisture Treatment on the Digestibility and Physicochemical Properties of Waxy and Normal Potato Starches

Heat-moisture treatment (HMT) is a safe, environmentally friendly starch modification method that reduces the digestibility of starch and changes its physicochemical properties while maintaining its granular state. Normal potato starch (NPS) and waxy potato starch (WPS) were subjected to HMT at different temperatures. Due to erosion by high-temperature water vapor, both starches developed indentations and cracks after HMT. Changes were not evident in the amylose content since the interaction between the starch molecules affected the complexation of amylose and iodine. HMT increased pasting temperature of NPS from 64.37 °C to 91.25 °C and WPS from 68.06 °C to 74.44 °C. The peak viscosity of NPS decreased from 504 BU to 105 BU and WPS decreased from 384 BU to 334 BU. The crystallinity of NPS decreased from 33.0% to 24.6% and WPS decreased from 35.4% to 29.5%. While the enthalpy values of the NPS declined from 15.74 (J/g) to 6.75 (J/g) and WPS declined from 14.68 (J/g) to 8.31 (J/g) at 120 °C. The solubility and swelling power of NPS decreased while that of WPS increased at 95 °C. Due to the lack of amylose in WPS, at the same HMT processing temperature, the reduction in peak viscosity of treated WPS compared to that of native starch was smaller than that of NPS. The resistant starch (RS) content of NPS after HMT at 120 °C was 73.0%. The slowly digestible starch (SDS) content of WPS after HMT at 110 °C was 37.6%.

Thermal properties of different types of starch: A review

Starch is present in high amount in various cereals, fruits and roots & tubers which finds major application in industry. Commercially, starch is rarely consumed or processed in its native form, thus modification of starch is widely used method for increasing its application and process stability. Due to the high demand for starch in industrial applications, researchers were driven to hunt for new sources of starch, including modification of starch through green processing. Thermal properties are significant reference parameters for evaluating the quality of starch when it comes to cooking and processing. Modification of starches affects the thermal properties, which are widely studied using Differential scanning calorimeter or Thermogravimetric analysis. It could lead to a better understanding of starch's thermal properties including factors influencing and expand its commercial applications as a thickener, extender, fat replacer, etc. in more depth. Therefore, the review presents the classification of starches, factors influencing the thermal properties, measurement methods and thermal properties of starch in its native and modified form. Further, this review concludes that extensive research on the thermal properties of new sources of starch, as well as modified starch, is required to boost thermal stability and extend industrial applications.

Thermoplastic starch nanocomposites: sources, production and applications - a review

The development of materials based on thermoplastic starch (TPS) is an excellent alternative to replace or reduce the use of petroleum-derived polymers. The abundance, renewable origin, biodegradability, biocompatibility, and low cost of starch are among the advantages related to the application of TPS compared to other thermoplastic biopolymers. However, through the literature review, it was possible to observe the need to improve some properties, to allow TPS to replace commonly used polyolefins. The studies reviewed achieved these modifications were achieved by using plasticizers, adjusting processing conditions, and incorporating fillers. In this sense, the addition of nanofillers proved to be the main modification strategy due to the large number of available nanofillers and the low charge concentration required for such improvement. The improvement can be seen in thermal, mechanical, electrical, optical, magnetic, antimicrobial, barrier, biocompatibility, cytotoxicity, solubility, and swelling properties. These modification strategies, the reviewed studies described the development of a wide range of materials. These are products with great potential for targeting different applications. Thus, this review addresses a wide range of essential aspects in developing of this type of nanocomposite. Covering from starch sources, processing routes, characterization methods, the properties of the obtained nanocomposites, to the various applications. Therefore, this review will provide an overview for everyone interested in working with TPS nanocomposites. Through a comprehensive review of the subject, which in most studies is done in a way directed to a specific area of study.

Cross-Linking of Centrifugally Spun Starch/Polyvinyl Alcohol (ST/PVA) Composite Ultrafine Fibers and Antibacterial Activity Loaded with Ag Nanoparticles

In this research, centrifugally spun ultrafine composite starch/polyvinyl alcohol (ST/PVA) fibers with high water stability were prepared by cross-linking with a mixture of glutaraldehyde and formic acid in the form of vapor phase. The effect of cross-linking temperature combined with time on the water stability, crystal structure, and thermal properties of fibers was investigated to obtain the optimum parameters. On this basis, we further prepared Ag-loaded ST/PVA fibers with different contents of nano silver. The structure and properties of Ag-loaded fibers, which cross-linked under the optimum parameters, were analyzed. As a result, the Ag-loaded fibers exhibited excellent water stability and mechanical properties and possessed inhibition zone diameters of 3 and 2 mm to Escherichia coli and Staphylococcus. aureus, respectively. The antibacterial property of the Ag-loaded ST/PVA fibers provided a new route for developing less costly antibacterial fiber materials in the future.

Impacts of Hydrothermal Treatments on the Morphology, Structural Characteristics, and In Vitro Digestibility of Water Caltrop Starch

The influence of hydrothermal treatments on the structural properties and digestibility of water caltrop starch was investigated. Scanning electron microscopy (SEM) showed some small dents on the surface of starch granules for samples treated with heat moisture treatment (HMT), but not for samples treated with annealing (ANN) which generally showed smoother surfaces. The gelatinization temperature of starch was generally increased by hydrothermal treatments, accompanied by a trend of decreasing breakdown viscosity. These results implied the improvement of thermal and shearing stability, particularly for HMT in comparison to ANN. After being cooked, the native and ANN-modified water caltrop starch granules were essentially burst or destroyed. On the other hand, the margin of starch granules modified by HMT and dual hydrothermal treatments remained clear with some channels inside the starch granules. X-ray diffraction revealed that the crystalline pattern of water caltrop starch changed from the CA-type to the A-type and the relative crystallinity reduced with increasing moisture levels of HMT. Results of ANN-modified water caltrop starch were mostly similar to those of the native one. Moreover, water caltrop starch modified with HMT20 and dual modification contained a pronouncedly higher resistant starch content. These results suggested that HMT, ANN, and dual modification effectively modified the functional properties of water caltrop starch.

Preparation and characterization of corn flours with variable starch digestion

Several grains such as wheat, rice, corn, oat, barley and rye are cultivated throughout the world. They are converted to variety of food products using a multitude of processing technologies to quench the growing organoleptic demands and consumers' preferences. Among them, corn, ranking third in wide consumption, is cost-effective and has long-term storability. Herein, ready-to-eat corn flours with variable starch digestion have been developed by processing at high temperature with shear using a twin screw continuous processor. The influence of processing temperature (121, 145 and 160°C) and moisture (25, 30 and 35%) has been studied. Results suggest both processing temperature and moisture modulate the rapidly digestible starch (RDS), slowly digestible starch (SDS) and resistant starch (RS) amounts of the flours. The presence or absence of oil in the flour further controls the starch digestion. The outcome is deemed to be helpful to design and develop healthy and palatable functional food products in addition to furthering the current market share for corn and other grains.

Resistant Starch Contents of Starch Isolated from Black Longan Seeds

A large quantity of longan fruits (Dimocarpus longan Lour.) produced annually are processed into many products, one of which is black longan, from which the dried, dark-brown meat has been used medicinally in traditional medicine, while the starch-containing seeds are discarded. In this study, starch samples (BLGSs) were isolated from seeds of black longan fruits prepared using varied conditions. The in vitro digestibility was determined in comparison with those extracted from fresh (FLGS) and dried (DLGS) seeds. Scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC), and Fourier transform infrared (FTIR) spectroscopy were employed to evaluate the starch properties. The results showed that the yields of FLGS, DLGS, and BLGSs were 20%, 23%, and 16-22% w/w, respectively. SEM images showed starch granules of mixed shapes, with sizes up to 15 µm in all samples. XRD patterns confirmed an A-type crystallinity for FLGS and DLGS, with strong refraction peaks at 2θ = 15°, 17°, 18°, and 23°, while BLGSs also showed detectable peaks at 2θ = 10° and 21°, which suggested V-type structures. Thermal properties corroborated the changes by showing increases in peak gelatinization temperature (Tp) and enthalpy energy (ΔH) in BLGSs. The paste viscosity of BLGSs (5% w/w) decreased by 20-58% from that of FLGS. The FTIR peak ratio at 1045/1022 and 1022/995 cm-1 also indicated an increase in ordered structure in BLGSs compared to FLGS. The significant increase in the amounts of slowly digestible starch (SDS) and resistant starch (RS) in BLGSs compared to FLGS, especially at a prolonged incubation time of 20 (4.2×) and 30 days (4.1×), was proposed to be due to the heat-induced formation of starch inclusion with other components inside the seed during the black longan production process. Thus, black longan seed could be a new source of starch, with increased RS content, for potential use in the food and related industries.

Physicochemical properties of heat-moisture treated, sodium stearate complexed starch: The effect of sodium stearate concentration

Amylose‑sodium stearate (SS) complexes (2, 5 and 8%) in heat-moisture treated potato starch (HPS) were evaluated for their physicochemical properties. Based on the DSC thermograms, the amylose - SS complexes were successfully formed with high thermal stability, indicated by a melt temperature (T_peak) of ≥ 112 °C for type I and ≥125 °C for type II complexes. Addition of 2% SS resulted in a single endothermal peak of the complexes, while 5 and 8% led to the formation of type I and II complexes with much higher enthalpy (ΔH) values. The XRD curve confirmed that the complexes were successfully formed. The pasting temperature increased from 66 °C for native to 91 °C for HPS145 complexed starch with 5% SS. Furthermore, the swelling power could be largely decreased, and the granular structure preserved. In addition, the inclusion complexation with SS on (HPS) succesfully improved the cook stabiliy.

Physicochemical properties of heat-moisture treated, stearic acid complexed starch: The effect of complexation time and temperature

Starch modification has been extensively studied to alter its physicochemical properties based on human needs. Lowering the digestion rate of starch is one of the interests in food science research, since when it is nutritionally improved, it can reduce the risk of human chronic diseases. In this study, heat-moisture treatment (HMT) followed by inclusion complexation with stearic acid at various temperatures and times was applied to improve the functional properties of starch. Thermal analysis suggested the formation of type I and type II complexes after complexation at 90 °C, indicated by a endothermal peak at 107 and 122 °C, respectively, while native starch after complexation only resulted in type I complexes. The formation of crystalline complexes was also confirmed by XRD showing peaks at 2θ = 13.1° and 20.1°. Furthermore, the modified starch displayed a higher pasting temperature, considerably less swelling and significantly lower viscosity behavior. This implied that the starch granules were thermally and mechanically more stable. The granular appearance of the modified starch was confirmed with light microscopy that presented more intact granules and less ruptured granules, even after heating to 90 °C. This study offers a way to upgrade the nutritional properties of starch.

Polyurethane Coatings Based on Renewable White Dextrins and Isocyanate Trimers

The polyurethane industry is strongly dependent on fossil-based polyols and polyisocyanates. Developing novel sustainable polyols from valuable biobased building blocks is a first step toward strong and durable development. The synthesis and properties of PU films based on pristine and acylated white dextrins (AVEDEX W80) as polyol and an aliphatic, low-viscosity, solvent-free triisocyanate based on hexamethylene diisocyanate (trimer-Desmodur N3300) as crosslinker is reported. After optimizing several conditions, such as the reaction time, reaction temperature, amount of solvent, isocyanate index, and amount per surface area, it is possible to obtain smooth PU films with good thermal properties.