Improving the Three-Dimensional Printability of Potato Starch Loaded onto Food Ink

This study focuses on improving the 3D printability of pea protein with the help of food inks designed for jet-type 3D printers. Initially, the food ink base was formulated using nanocellulose-alginate with a gradient of native potato starch and its 3D printability was evaluated. The 3D-printed structures using only candidates for the food ink base formulated with or without potato starch exhibited dimensional accuracy exceeding 95% on both the X and Y axes. However, the accuracy of stacking on the Z-axis was significantly affected by the ink composition. Food ink with 1% potato starch closely matched the CAD design, with an accuracy of approximately 99% on the Z-axis. Potato starch enhanced the stacking of 3D-printed structures by improving the electrostatic repulsion, viscoelasticity, and thixotropic behavior of the food ink base. The 3D printability of pea protein was evaluated using the selected food ink base, showing a 46% improvement in dimensional accuracy on the Z-axis compared to the control group printed with a food ink base lacking potato starch. These findings suggest that starch can serve as an additive support for high-resolution 3D jet-type printing of food ink material.

Differences in the Chromogenic Effect of Corn Starch and Potato Starch on Paprika Red Pigment and Structural Characterisation

The present study aims to investigate the chromogenic effect and the interaction between starch-pigment complexes of corn starch (CS) and potato starch (PS) complexed with paprika red pigment. Compared to PS, CS showed 12.5 times higher adsorption capacity for paprika red pigment. Additionally, the a* value of CS-P (26.90 ± 0.23) was significantly higher than that of PS-P (22.45 ± 1.84), resulting in a corn starch-paprika red pigment complex (CS-P) with a more intense red colour. The addition of paprika red pigment significantly decreased the particle size and porosity of CS by 48.14 ± 5.29% and 17.01 ± 3.80%, respectively. Conversely, no significant impact on PS was observed. Additionally, the Fourier transform infrared (FT-IR) spectroscopy results revealed that the starch molecules and paprika red pigment were bound to each other through strong hydrogen bonds. X-diffraction (XRD) results indicated that the starch-paprika red pigment complexes have a V-shaped structure. Furthermore, the relative crystallinity of the complexes between starch and red pepper pigment showed an increasing trend, however, the relative crystallinity of CS increased significantly by 11.77 ± 0.99-49.21 ± 3.67%. Consequently, the CS-P colouring was good.

FTIR, 1H, and 13C NMR Characterization and Antibacterial Activity of the Combination of Euphorbia Honey and Potato Starch

AIM AND OBJECTIVE

In recent years, natural biopolymer (potato starch) hydrogels have been widely used in the field of wound dressing material. This study aimed to develop and characterize a novel antibacterial hydrogel made from potato starch and natural honey.

METHODS

The structure of the composite films was evaluated by Fourier transform infrared (FTIR) and 1H,13C nuclear magnetic resonance (NMR) spectroscopy, and the antibacterial activities were tested by agar diffusion method. FTIR analysis showed chemical interaction between the components of Euphorbia honey (EH) and potato starch hydrogel (PSH).

RESULTS

The 1H-13C NMR and FTIR analyses of EH/PSH confirmed their structure and showed the presence of glucose and hydrocarbon derivatives. After 24 h of incubation, the EH/PSH hydrogel showed good antibacterial activity against three bacterial strains (K.pneumonia, P.mirabilis, and P. aeruginosa) by producing clear inhibition zones of 12.33±1.88 mm, 15.33±0.94, and 10±0 mm, respectively. In addition, K. pneumonia, P. mirabilis, and P. aeruginosa were sensitive to the EH/SPH with a minimum inhibitory concentration (MIC) of 1 %.

CONCLUSION

These results suggest that EH-PS has potential as an alternative candidate to conventional antibiotics.

Microwaved-Assisted Synthesis of Starch-Based Biopolymer Membranes for Novel Green Electrochemical Energy Storage Devices

The investigated starch biopolymer membrane was found to be a sustainable alternative to currently reported and used separators due to its properties, which were evaluated using physicochemical characterization. The molecular dynamics of the biomembrane were analyzed using low-field nuclear magnetic resonance (LF NMR) as well as Raman and infrared spectroscopy, which proved that the chemical composition of the obtained membrane did not degrade during microwave-assisted polymerization. Easily and cheaply prepared through microwave-assisted polymerization, the starch membrane was successfully used as a biodegradable membrane separating the positive and negative electrodes in electric double-layer capacitors (EDLCs). The obtained results for the electrochemical characterization via cyclic voltammetry (CV), galvanostatic charge with potential limitation (GCPL), and electrochemical impedance spectroscopy (EIS) show a capacitance of 30 F g-1 and a resistance of 2 Ohms; moreover, the longevity of the EDLC during electrochemical floating exceeded more than 200 h or a cyclic ability of 50,000 cycles. Furthermore, due to the flexibility of the membrane, it can be easily used in novel, flexible energy storage systems. This proves that this novel biomembrane can be a significant step toward ecologically friendly energy storage devices and could be considered a cheaper alternative to currently used materials, which cannot easily biodegrade over time in comparison to biopolymers.

Effect of potato starch coating containing selected amino acids to prevent the formation of PhIP in pan-fried chicken breast

The effects of potato starch (PS) coating containing amino acids (AAs) on the formation of 2-amino-1-methyl-6-phenylimidazo [4,5-b] pyridine (PhIP) in chicken breasts were evaluated. PhIP is classified as a Group 2B carcinogen by the International Agency for Research on Cancer (IARC). The 5% (w/w) gelatinized PS coating solution was incorporated with tryptophan (Trp) or lysine (Lys) at 0.25%, 0.5%, and 0.75% (w/w of the coating solution) concentrations. Chicken breast cuts with the same dimensions (5 × 2 × 1.5 cm) were dipped in the PS coating solution for 15 min before frying. After frying the chicken at 195°C for 7.5 min on each side, PhIP levels, color, cooking loss, tenderness, and texture profile assay were evaluated. The average PhIP concentration was decreased from 92.62 ng/g for the control chicken breast without coating to 6.30 ng/g (0.25% Lys), 6.76 ng/g (0.5% Lys), and 11.98 ng/g (0.75% Lys), accounting for an 89%-92% reduction in PhIP levels compared to the controls. However, dipping in Trp-containing PS coating had a significantly lower (p < 0.05) PhIP reduction effect (34%-67%). There was no significant difference in cooking loss percentage, tenderness, texture profile parameters, and color parameters of PS-coated chicken. Triangle test results showed that consumers did not detect a significant difference in the PS-coated chicken breasts (p < 0.001). Overall, this study suggests that the application of PS-based coatings incorporated with AAs on chicken breast reduces the PhIP formation.

The interactions of model cationic drug with newly synthesized starch derivatives

Background and purpose

The aim of the work was to compare the interactions of three newly synthesized non-toxic starch derivatives, with varied anionic and non-ionic functional groups with methylene blue (MB) as a model cationic drug, and selection of starch derivative with highest affinity to the MB.

Experimental approach

The native potato starch (SN), modified via acetylation (SM1), esterification and crosslinking (SM2) and crosslinking (SM3), was evaluated in MB adsorption studies and assessed by FTIR, PXRD, and DSC.

Key results

The adsorption of MB on SM2 and SM3 matched the BET isotherm model, which confirmed physisorption on the low-porous surface. In the case of SM1, adsorption took place via electrostatic attraction between the heterogeneous adsorbent surface and the adsorbate, as demonstrated by the Freundlich plot. The FTIR confirmed vibrations assigned to N=C stretching bonds at 1600 cm-1 in the case of MB adsorbed on the SN and SM2. The most intense PXRD peaks belonged to SN and the least to SM2. In the DSC study, the thermal stability via ΔT was assessed, with SM2 of lowest ΔT value (179.8 °C).

Conclusion

SM2 presented the best adsorption capacity, followed by SM3 and the weakest SM1. The interactions were confirmed in the adsorption studies and may reflect applications of the modified starches as drug carriers. In the FTIR study, a probable interaction between the OH- groups of SM2 and N+ of MB was revealed. The most amorphous structure was shown for SM2, which was correlated with the lowest thermal stability provided by the DSC study.

Effect of Addition of Cross-Linked Starch on the Properties of Degraded PBAT Poly(butylene adipate-co-terephthalate) Films

This work aimed to evaluate the properties of butylene adipate-co-terephthalate (PBAT) degraded after 1800 days of storage (DPBAT) by preparing blends (films) with crosslinked starch (Cm) through extrusion and thermocompression. Different ratios of DPBAT:Cm (70:30, 60:40, and 50:50 m/m) were prepared. The incorporation of Cm into DPBAT significantly changed the properties of the films by making them stiffer (increasing Young's modulus by up to 50%) and increasing the thermal resistance of DPBAT. The presence of crosslinked starch in the films made them less hydrophobic (with decreased contact angle and increased moisture content), but these parameters did not vary linearly with changes in the content of crosslinked starch in the blend (DPBAT:Cm). The microscopic images show an inhomogeneous distribution of Cm granules in the DPBAT matrix. Thus, the films prepared with PBAT show a significant decrease in their mechanical parameters and heat resistance after long-term storage. However, the preparation of blends of degraded DPBAT with crosslinked starch promoted changes in the properties of the films prepared by thermocompression, which could be useful for disposable packaging.

Ultra-Fast Impedimetric Immunoassay for Detection of Streptococcus agalactiae Using Carbon Electrode with Nanodiamonds Film

This publication presents the results of work on the development of a quick and cheap electrochemical immunosensor for the diagnosis of infections with the pathogen Streptococcus agalactiae. The research was carried out on the basis of the modification of the well-known glassy carbon (GC) electrodes. The surface of the GC (glassy carbon) electrode was covered with a film made of nanodiamonds, which increased the number of sites for the attachment of anti-Streptococcus agalactiae antibodies. The GC surface was activated with EDC/NHS (1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide/N-Hydroxysuccinimide). Determination of electrode characteristics after each modification step, performed using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS).

Insight into property, function, and digestion of potato starch modified by phenolic compounds with varying structures

Influences of structural characteristics of phenolic compounds on the properties of potato starch were investigated, and their effects on the quality, function, and digestion of potato starch noodles were further determined. All testing phenolic compounds (including protocatechuic acid [PA], naringin [NA], and tannic acid [TA]) exhibited the significant capability to modify the thermal properties, rheological properties, and enzymatic hydrolysis of potato starch. The high amount of hydroxyl groups, the presence of glycoside structure, appropriate molecular size, and steric hindrance were beneficial to enhance their effects on potato starch. In addition, by changing the microstructure of starch hydrocolloids, PA, NA, and TA could affect the color, texture properties, and cooking properties of potato starch noodles. Meanwhile, PA and TA could endow potato starch noodles with remarkable antioxidant activity. Furthermore, the in vitro digestion of potato starch noodles was obviously inhibited by phenolic compounds, especially for TA. All present results suggested that structural characteristics of phenolic compounds affected their interaction affinity and combination degree with potato starch molecules, so as to modify the properties of starch and affect the quality, function, and digestion of starchy foods, which showed the valuable applications in food and chemical industries. PRACTICAL APPLICATION: The property, function, and digestion characteristics of potato starch show the significant effects on the quality of potato starch products in food industry. In present study, the thermal properties, rheological properties, and enzymatic hydrolysis of potato starch were modified by different phenolic compounds (including protocatechuic acid, naringin, and tannic acid) in varying degrees, whereas the quality, antioxidant activity, and digestion characteristic of potato starch noodles were modified by phenolic compounds with different structures. All results showed the potential application and interaction regularities of phenolic compounds as natural additives for potato starch processing in food industry.

Potato Starch-Based Film Incorporated with Tea Polyphenols and Its Application in Fruit Packaging

Effects of tea polyphenols (TP) on the physical properties, barrier properties and functionality of potato starch-based film were determined, while the interaction mechanism between TP and starch in film and the application of this film in fruit packaging were further evaluated. TP exhibited different effects on the physical properties of potato starch-based film, including thickness (0.083 to 0.087 mm), moisture content (9.27% to 9.68%), color (ΔE value: 5.41 to 10.55), light transmittance (51% to 62%), tensile properties and thermal properties, and improved its barrier properties, including water vapor permeability (9.68 to 11.84 × 10^-11 g m^-1 s^-1 Pa^-1),oxygen permeability (1.25 to 2.78 × 10^-16 g m^-1 s^-1 Pa^-1) and antioxidant activity. According to the determination of wide-angle X-ray diffraction, Fourier transform infrared and scanning electron microscope, TP could interact with starch chains via hydrogen bonds to form non-crystal complexes, thus affecting the cross-linking among starch chains and further changing the microstructure of film. Furthermore, film incorporated with TP could improve the storage quality (including weight and texture) of blueberries, and inhibit the enzymatic browning of fresh-cut bananas during storage. All present results suggested that tea polyphenols had potential to enhance the properties and function of potato starch-based film, and the film exhibited the application prospect in fruit packaging and preservation.

Structural, Physicochemical and Digestive Property Changes of Potato Starch after Continuous and Repeated Dry Heat Modification and Its Comparative Study

To investigate the effects of repeated dry heat treatment (RDH) and continuous dry heat treatment (CDH) on the structure and physicochemical and digestive properties of potato starch, potato starch was treated continuously and repeatedly at 130 °C for 3-18 h. The results showed that the crystalline form of starch was consistent with the original type B. Still, its physicochemical properties, such as swelling power, transparency, peak viscosity (PV), final viscosity (FV), breakdown (BD) and thermal properties (To, Tp, Tc, ΔT), tended to decrease. At the same time, solubility and RS increased after dry heat treatment. Moreover, RDH-treated starches were higher than CDH-treated ones in terms of molecular weight, crystallinity, swelling power, transparency and final viscosity for the same treatment time. Still, there was no significant difference between the thermal properties of the two. Meanwhile, the resistant starch (RS) content showed a downward trend after the peak value of 9 h of CDH treatment and five cycles of RDH treatment with increasing treatment time and the number of cycles, indicating a decrease in the overall digestibility of the starch. Overall, RDH had a more significant effect on potato starch's structure and physicochemical properties than CDH.

Effects of different altitudes on the structure and properties of potato starch

The main element influencing the quality of potato starch is the environment. To investigate the effects of different altitude cultivation locations on the molecular structure and physicochemical properties of starch, two potato varieties, Jiusen No.1 B1 and Qingshu No.9 B2, were planted in three different altitude zones: A1 at low altitude (Chongzhou 450 m), A2 at middle altitude (Xichang 2800 m), and A3 at high altitude (Litang 3650 m). The results showed that the average volume, number, surface area diameter, average branched polymerization degree, crystallinity, and gelatinization temperature of two potato granules in high altitude areas were significantly lower than those in middle and low altitude areas were, and the gelatinization performance of potato starch was affected according to the correlation of starch structure characteristics. Potato starch with more short-branched chains and less long branched chains resulted in a lower gelatinization temperature in high altitude areas. The results showed that Jiusen No. 1 and Qingshu No. 9 were mainly affected by accumulated radiation and accumulated rainfall in Litang, a high altitude area, and by effective accumulated temperature in Xichang, a middle altitude area. This study quantified the influence of meteorological factors on the main starch quality of potato tubers. The results can be used as a theoretical basis for the scientific planting of high-quality potatoes.

Biocompatible Potato-Starch Electrolyte-Based Coplanar Gate-Type Artificial Synaptic Transistors on Paper Substrates

In this study, we propose the use of artificial synaptic transistors with coplanar-gate structures fabricated on paper substrates comprising biocompatible and low-cost potato-starch electrolyte and indium-gallium-zinc oxide (IGZO) channels. The electrical double layer (EDL) gating effect of potato-starch electrolytes enabled the emulation of biological synaptic plasticity. Frequency dependence measurements of capacitance using a metal-insulator-metal capacitor configuration showed a 1.27 μF/cm² at a frequency of 10 Hz. Therefore, strong capacitive coupling was confirmed within the potato-starch electrolyte/IGZO channel interface owing to EDL formation because of internal proton migration. An electrical characteristics evaluation of the potato-starch EDL transistors through transfer and output curve resulted in counterclockwise hysteresis caused by proton migration in the electrolyte; the hysteresis window linearly increased with maximum gate voltage. A synaptic functionality evaluation with single-spike excitatory post-synaptic current (EPSC), paired-pulse facilitation (PPF), and multi-spike EPSC resulted in mimicking short-term synaptic plasticity and signal transmission in the biological neural network. Further, channel conductance modulation by repetitive presynaptic stimuli, comprising potentiation and depression pulses, enabled stable modulation of synaptic weights, thereby validating the long-term plasticity. Finally, recognition simulations on the Modified National Institute of Standards and Technology (MNIST) handwritten digit database yielded a 92% recognition rate, thereby demonstrating the applicability of the proposed synaptic device to the neuromorphic system.

Effect of the Addition of Corn Husk Cellulose Nanocrystals in the Development of a Novel Edible Film

The cellulose from agroindustrial waste can be treated and converted into nanocrystals or nanofibers. It could be used to produce biodegradable and edible films, contributing to the circular economy and being environmentally friendly. This research aimed to develop an edible film elaborated with activated cellulose nanocrystals, native potato starch, and glycerin. The activated cellulose nanocrystals were obtained by basic/acid digestion and esterification with citric acid from corn husks. The starch was extracted from the native potato cultivated at 3500 m of altitude. Four film formulations were elaborated with potato starch (2.6 to 4.4%), cellulose nanocrystals (0.0 to 0.12%), and glycerin (3.0 to 4.2%), by thermoforming at 60 °C. It was observed that the cellulose nanocrystals reported an average size of 676.0 nm. The films mainly present hydroxyl, carbonyl, and carboxyl groups that stabilize the polymeric matrix. It was observed that the addition of cellulose nanocrystals in the films significantly increased (p-value < 0.05) water activity (0.409 to 0.447), whiteness index (96.92 to 97.27), and organic carbon content. In opposition to gelatinization temperature (156.7 to 150.1 °C), transparency (6.69 to 6.17), resistance to traction (22.29 to 14.33 N/mm), and solubility in acidic, basic, ethanol, and water media decreased. However, no significant differences were observed in the thermal decomposition of the films evaluated through TGA analysis. The addition of cellulose nanocrystals in the films gives it good mechanical and thermal resistance qualities, with low solubility, making it a potential food-coating material.

Physical, Chemical and Biochemical Modification Approaches of Potato (Peel) Constituents for Bio-Based Food Packaging Concepts: A Review

Potatoes are grown in large quantities and are mainly used as food or animal feed. Potato processing generates a large amount of side streams, which are currently low value by-products of the potato processing industry. The utilization of the potato peel side stream and other potato residues is also becoming increasingly important from a sustainability point of view. Individual constituents of potato peel or complete potato tubers can for instance be used for application in other products such as bio-based food packaging. Prior using constituents for specific applications, their properties and characteristics need to be known and understood. This article extensively reviews the scientific literature about physical, chemical, and biochemical modification of potato constituents. Besides short explanations about the modification techniques, extensive summaries of the results from scientific articles are outlined focusing on the main constituents of potatoes, namely potato starch and potato protein. The effects of the different modification techniques are qualitatively interpreted in tables to obtain a condensed overview about the influence of different modification techniques on the potato constituents. Overall, this article provides an up-to-date and comprehensive overview of the possibilities and implications of modifying potato components for potential further valorization in, e.g., bio-based food packaging.

An Insight into Pasting and Rheological Behavior of Potato Starch Pastes and Gels with Whole and Ground Chia Seeds

With regard to technological innovations, we applied chia (oilseeds) as a stabilizer additive in a normal and waxy potato starch sample to obtain stable starch-based gels during 20 days of storage. The aim of this study was to investigate the 5% w/w normal and waxy potato starch pastes (hot samples) and gels (cold samples) with the addition of 1% w/w whole and ground chia seeds properties as pasting and flow properties of pastes and textural properties of gels. The pasting process using a viscograph showed that normal and waxy potato starch with the addition of chia had a different pasting characteristic. The addition of chia seeds had a greater effect on the properties of normal potato starch than waxy potato starch. From a rheological point of view, starch pastes without chia were less theologically stable as they showed bigger areas of hysteresis loops. Minor changes in the hardness of gels were obtained in normal starch gels with chia seeds during 20 days of storing compared to the samples without chia seeds, whereas in the waxy starch gels, the effect was the opposite.

Physical and Enzymatic Hydrolysis Modifications of Potato Starch Granules

In this work, a valorization of the starch stemming from downgraded potatoes was approached through the preparation of starch nanoparticles using different physical methods, namely liquid and supercritical carbon dioxide, high energy ball milling (HEBM), and ultrasonication on the one hand and enzymatic hydrolysis on the other hand. Starch nanoparticles are beneficial as a reinforcement in food packaging technology as they enhance the mechanical and water vapor resistance of polymers. Also, starch nanoparticles are appropriate for medical applications as carriers for the delivery of bioactive or therapeutic agents. The obtained materials were characterized using X-ray diffraction as well as scanning and transmission electron microscopies (SEM and TEM), whereas the hydrolysates were analyzed using size exclusion chromatography coupled with pulsed amperometric detection (SEC-PAD). The acquired results revealed that the physical modification methods led to moderate alterations of the potato starch granules’ size and crystallinity. However, enzymatic hydrolysis conducted using Pullulanase enzyme followed by nanoprecipitation of the hydrolysates allowed us to obtain very tiny starch nanoparticles sized between 20 and 50 nm, much smaller than the native starch granules, which have an average size of 10 μm. The effects of enzyme concentration, temperature, and reaction medium pH on the extent of hydrolysis in terms of the polymer carbohydrates’ fractions were investigated. The most promising results were obtained with a Pullulanase enzyme concentration of 160 npun/g of starch, at a temperature of 60 °C in a pH 4 phosphate buffer solution resulting in the production of hydrolysates containing starch polymers with low molecular weights corresponding mainly to P-10, P-5, and fractions with molecular weights lower than P-5 Pullulan standards.

Effect of Long-Term Potato Starch Retention with Citric Acid on Its Properties

The present study aimed to determine changes in the properties of starch triggered by its long-lasting (1, 2, 4, 7, 10, or 14 days) retention with citric acid (5 g/100 g) at a temperature of 40 °C. The starch citrates obtained under laboratory conditions had a low degree of substitution, as confirmed via NMR and HPSEC analyses. The prolonging time of starch retention with citric acid at 40 °C contributed to its increased esterification degree (0.05–0.11 g/100 g), swelling power (30–38 g/g), and solubility in water (19–35%) as well as to decreased viscosity of the starch pastes. Starch heating with citric acid under the applied laboratory conditions did not affect the course of DSC thermal characteristics of starch pasting. The low-substituted starch citrates exhibited approximately 15% resistance to amylolysis.

Spent Coffee Grounds as Building Material for Non-Load-Bearing Structures

The gradual development of government policies for ecological transition in the modern construction sector leads researchers to explore new alternative and low environmental impact materials with a particular focus on bio-sourced materials. In this perspective, the mechanical, thermal insulation, and the sound absorption performances of a spent coffee grounds/potato starch bio-based composite were analyzed for potential application in buildings. Based on thermal conductivity and diffusivity tests, the coffee grounds waste biocomposite was characterized as an insulating material comparable with conventional thermal insulation materials of plant origin. Acoustical tests revealed absorption coefficients in the same range as other conventional materials used in building acoustical comfort. This bio-sourced material presented a sufficient compressive mechanical behavior for non-load-bearing structures and a sufficient mechanical capacity to be shaped into building bricks. Mechanical, thermal, and acoustic performances depend on the moisture environment. The groundwork was laid for an initial reflection on how this composite would behave in two opposite climates: the continental climate of Reims in France and the tropical climate of Belém in Brazil.

The Influence of Hydroponic Potato Plant Cultivation on Selected Properties of Starch Isolated from Its Tubers

Starch is a natural polysaccharide for which the technological quality depends on the genetic basis of the plant and the environmental conditions of the cultivation. Growing plants under cover without soil has many advantages for controlling the above-mentioned conditions. The present research focuses on determining the effect of under cover hydroponic potato cultivation on the physicochemical properties of accumulated potato starch (PS). The plants were grown in the hydroponic system, with (greenhouse, GH) and without recirculation nutrient solution (foil tunnel, FT). The reference sample was PS isolated from plants grown in a tunnel in containers filled with mineral soil (SO). The influence of the cultivation method on the elemental composition of the starch molecules was noted. The cultivation method also influenced the protein and amylose content of the PS. Considering the chromatic parameters, PS-GH and PS-FT were brighter and whiter, with a tinge of blue, than PS-SO. PS-SO was also characterized by the largest average diameters of granules, while PS-GH had the lowest crystallinity. PS-SO showed a better resistance to the combined action of elevated temperature and shear force. There was a slight variation in the gelatinization temperature values. Additionally, significant differences for enthalpy and the retrogradation ratio were observed. The cultivation method did not influence the glass transition and melting.

Effect of pre-swelling and freezing/thawing cycles on the structure of molecular, morphological, and functional properties of potato starch

This study aimed to investigate the effect of pre-swelling at 55°C for 1 hr followed by freezing-thawing cycles (PFTCs), and freezing-thawing cycles (FTCs) in the starch granules to improve the freeze-thaw stability and evaluate its impact on the molecular, morphological, and functional properties of potato starch (PS). FTCs at 1 cycle and 7 cycles were applied for both treated PS. Microscopical structure, thermal, molecular, and functional properties (i.e., swelling power, solubility, shear viscosity, and gel strength) were comprehensively analyzed. In terms of granule structures, treated PS by FTC showed a slightly affected on the surface of starch granules, while treating PS by PFTC showed an affected in the form of small cracks and holes in the outer surface of starch granules. The gelatinization enthalpy (∆H_gel ) values decreased in the treated PS compared with the native. Thus, decreasing was systemically increased with the number of applied cycles from 1- to 7-cycle. The viscosity of treated PS decreased systematically with molecular degradation or the physical modification, with remarkable reduction, particularly at a higher shear rate (150°C). Treated PS by FTC showed a clear difference (p ≤ .05) in gel values compared with the native at disintegration temperature 115°C. Finally, the degradation of the molecular properties showed significant differences between the native and treated PS either by the FTC or PFTC in molecular weight of starch and amylose without debranching and after debranching by pullulanase enzyme. PRACTICAL APPLICATIONS: Freezing is one of the standard preservation methods used for ready-to-eat products. When this type of food's exposed to more freeze-thaw cycles, the phase separation will be increased due to the increase in retrogradation of amylopectin. To avoid such changes during frozen storage, native potato starch (PS) was modified using both pre-swelling followed by freezing-thawing cycles (PFTCs) and freezing-thawing cycles (FTCs) at 1- and 7-cycle to enhance starch properties, such as swelling power, solubility, shear viscosity, and gel strength. The findings of this study might add to the theoretical understanding of modified PS and act as a guideline for modified starch manufacturing.

Inhibitory Effect of Ascorbic Acid on in vitro Enzymatic Digestion of Raw and Cooked Starches

Ascorbic acid, also known as vitamin C, was previously reported to inhibit the activity of pancreatic α-amylase, the primary digestive enzyme for starch. A major implication of such inhibition is a slowed rate of starch digestion into glucose, which thereby reduces postprandial hyperglycemia. The aim of this study was to explore the inhibitory effects of ascorbic acid at various concentrations on the in vitro digestion of high amylose maize starch (HAMS) and potato starch (PS) in both raw and cooked conditions. Resistant starch (RS) content, defined as the starch that remained after 4 h of simulated in vitro enzymatic digestion, was measured for the starch samples. Upon the addition of ascorbic acid, the RS contents increased in both raw and cooked starches. Cooking significantly reduced the RS contents as compared to raw starches, and less increase in RS was observed with the addition of ascorbic acid. The inhibitory effect of ascorbic acid on the digestion of raw starches showed a dose-dependent trend until it reached the maximum extent of inhibition. At the concentrations of 12.5 and 18.75 mg/mL, ascorbic acid exhibited the most potent inhibitory effect on the in vitro starch digestion in raw and cooked conditions, respectively. Overall, our results strongly indicate that ascorbic acid may function as a glycemic modulatory agent beyond other important functions, and its effects persist upon cooking with certain concentrations applied.

Physicochemical Properties and Digestion Resistance of Acetylated Starch Obtained from Annealed Starch

One of the examples of physical starch modifications is the retention of a starch suspension in water having a temperature slightly lower than the pasting temperature (annealing). The aim of this study was to investigate the effect of the annealing process performed at various temperatures as the first stage of starch modification. The annealed starch preparations were then esterified using acetic acid anhydride. Finally, the annealed and acetylated starch preparations were determined for their properties. The annealing of starch before acetylation triggered changes in the properties of the modified preparations. It contributed to a higher degree of starch substitution with acetic acid residues and to the increased swelling power of starch. Both these properties were also affected by the annealing temperature. The highest resistance to amylolysis was found in the case of the starch preparation annealed at 53.5 °C and acetylated. The double modification involving annealing and acetylation processes increased the onset and end pasting temperatures compared to the acetylation alone. Similar observations were made for the consistency coefficient and yield point.

The Impact of Fiber from Buckwheat Hulls Waste on the Pasting, Rheological and Textural Properties of Normal and Waxy Potato Starch Gels

The aim of this study was to investigate the impact of fiber from buckwheat hull waste (BH) on the pasting, rheological, and textural properties of 4% and 5% (w/w) pastes and gels based on the potato starches with different amylose/amylopectin contents. The starch and starch/fiber mixtures were characterized by pasting and flow measurements as well as by viscoelastic and textural analysis. The pasting properties showed a greater BH effect (0.2%) on the gelatinization of PS than WPS. The starch gels and starch fiber mixtures showed biopolymer gel behavior. In the WPS/BH pastes, a smaller increase in hardness was noted compared to PS/BH.

Changes in the multi-scale structure and physicochemical properties of starch during potato growth

BACKGROUND

Growth stage contributes critically to the physicochemical properties of starches, which make achieving desired functional properties by controlling the growth period possible. Thus, this study investigated the changes in multiscale structure and physicochemical properties of potatoes starches harvested at different growth stages.

RESULTS

The amylose and phosphate content varied over the growth period, with the ranges 2.756-2.998 g kg^-1 and 0.0058-0.0077 g kg^-1 , respectively. The starch granules were round or oval, and the size increased with growth. X-Ray diffraction indicated the B-type crystalline structure of samples. Time-dependent changes in crystallinity were observed. The weight-average molecular weight (M_w ) showed a tendency to decrease first and then increase, and presented the lowest M_w (1.105 × 10⁸  g mol^-1 ) at 35 days. A higher proportion of long chains were noted in starch from earlier harvested potatoes than that in later harvested ones. Differential scanning calorimetry revealed that starch gelatinization temperature decreased, and gelatinization enthalpy decreased from 16.39 to 14.89 J g^-1 . All samples possessed weak elastic gel-like structure, and starches harvested at early stage possessed highest viscosity and stronger gel behaviour. Resistant starch showed a decreasing trend on the whole, and presented highest value (10.69%) at earliest harvest time. Starch from the potatoes harvested at 35 days after tuberization exhibited excellent light transmittance (up to 62.47%).

CONCLUSION

Potato starches harvested at different growth period presented extremely different structures and physicochemical properties. The results will provide fundamental data in terms of changes of potato starch during growth which will affect the choice of harvest time. © 2021 Society of Chemical Industry.

Effect of Continuous and Discontinuous Microwave-Assisted Heating on Starch-Derived Dietary Fiber Production

Dietary fiber can be obtained by dextrinization, which occurs while heating starch in the presence of acids. During dextrinization, depolymerization, transglycosylation, and repolymerization occur, leading to structural changes responsible for increasing resistance to starch enzymatic digestion. The conventional dextrinization time can be decreased by using microwave-assisted heating. The main objective of this study was to obtain dietary fiber from acidified potato starch using continuous and discontinuous microwave-assisted heating and to investigate the structure and physicochemical properties of the resulting dextrins. Dextrins were characterized by water solubility, dextrose equivalent, and color parameters (L* a* b*). Total dietary fiber content was measured according to the AOAC 2009.01 method. Structural and morphological changes were determined by means of SEM, XRD, DSC, and GC-MS analyses. Microwave-assisted dextrinization of potato starch led to light yellow to brownish products with increased solubility in water and diminished crystallinity and gelatinization enthalpy. Dextrinization products contained glycosidic linkages and branched residues not present in native starch, indicative of its conversion into dietary fiber. Thus, microwave-assisted heating can induce structural changes in potato starch, originating products with a high level of dietary fiber content.

Analysis of the sol and gel structures of potato starch over a wide spatial scale

We analyzed edible potato starch and observed the interaction between its granular structure and water molecules. We studied the changes caused by gelatinization during heating and stirring using microscopy, micro-FT-IR spectroscopy, and X-ray scattering techniques. A wide range of spatial scales was revealed using these various techniques. The rate of gelatinization varied significantly and was dependent on the starch concentration. The process of adsorption of water on starch molecules was studied using the humidity-controlled FT-IR spectroscopy technique. Furthermore, by comparing the X-ray scattering profiles of dry and wet granules, the 9-nm repeat "cluster" structure was studied. A gradual collapse of the granules occurred during the processes of heating and stirring. A clustered smectic structure and a smectic-like structure were observed in the opaque gel after gelatinization. Upon further heating, a transparent gel was obtained after the melting of the cluster.

Effects of proanthocyanidins on the pasting, rheological and retrogradation properties of potato starch

BACKGROUND

Proanthocyanidins (PAS) were complexed with potato starch (PS) to prepare polyphenol-starch complexes. The pasting, rheological and retrogradation properties of the complexes were investigated.

RESULTS

The addition of PAS markedly affected the pasting, rheological and retrogradation properties of PS, especially at a concentration of 5% (w/w). Rapid viscosity analysis indicated that PAS significantly changed the viscosity, breakdown and setback value of PS. The rheological results showed that PAS decreased the flow behavior index and consistency coefficient, but increased the viscoelasticity of PS. Differential scanning calorimetry and X-ray diffraction indicated that PAS delayed the retrogradation of PS. Furthermore, scanning electron microscopy indicated that the morphologies of retrograded PS gels were greatly altered to a less compact structure with the presence of PAS. Moreover, Fourier transform infrared spectroscopy elucidated that PAS interacted with PS via a noncovalent interaction, and inhibited the retrogradation of PS.

CONCLUSIONS

The findings suggested that supplementing PS with PAS might be an effective and convenient method for modifying the physicochemical properties of PS. © 2021 Society of Chemical Industry.

Assessment of physicochemical and thermal properties of soluble dextrin fiber from potato starch for use in fruit mousses

BACKGROUND

Fruit mousses are products with a relatively low amount of dietary fiber in a single portion, but with additional portions of soluble fiber they may be good alternative to fiber-rich snacks as take-away food. In the present study, the properties of new soluble dextrin fiber (SDexF) from potato starch were assessed to establish whether it could be used to enrich fruit mousses. The properties of SDexF that can affect processing and storage stability of enriched mousses were studied and compared with those of native potato starch and semiproducts (resulting from various drying temperatures). The effect of the addition of SDexF on the pasting properties of mousse was also analyzed.

RESULTS

The application of food-grade hydrochloric and citric acids as catalysts in the dextrinization of food-grade potato starch allowed to SDexF to be obtained. Despite the differences in characteristics of the semiproducts, the final SDexF preparations were very similar in the meaning of solubility, dextrose equivalent (DE), retrogradation, and pasting properties. SDexF preparations were characterized by a significantly lower retrogradation tendency, peak viscosity, final viscosity, and gelatinization enthalpy in comparison with both native starch and semiproducts. Soluble dextrin fiber was successfully added to banana-apple mousse. The addition of SDexF to mousse did not cause any undesirable changes to the viscosity of the product, and surprisingly even resulted in mousse with lower viscosity. Turbidity and RVA studies revealed that SDexF was stable and retrogradation processes can be negligible during storage.

CONCLUSION

The SDexF obtained from potato starch can be a novel functional substance to increase the dietary fiber content of fruit or fruit and vegetable mousses. © 2020 Society of Chemical Industry.

Effect of Esterification Conditions on the Physicochemical Properties of Phosphorylated Potato Starch

The aim of this study was to evaluate the effect of the temperature (15 or 45 °C) and the duration (15–120 min) of the modification process on the selected physicochemical, thermal, and rheological properties of phosphorylated potato starch. The modified starches contained 93.6–98.2 mg P/100 g (dry weight basis, d.w.b.). Phosphorylation caused color changes with a total color difference between the starches below 0.55, but these changes were less than those that were recognizable by the human eye. The thermal analysis showed two opposite processes appearing during the modification: the loosening of the structure (dominant among starches obtained at 15 °C) and the strengthening of the structure (dominant among starches obtained at 45 °C). The higher phosphorylation temperature reduced native starch recovery from 140% to 87–116% and increased the hysteresis loop area from −169 to 1040. All of the pastes made from the modified starches showed a weaker tendency for retrogradation (during 21 days of storage) than native starches. The results of the regression analysis conducted between the properties of the starch pastes obtained at 45 °C indicated that the modification time appeared to be a better indicator of the rate of modification progress than the phosphorus content. The PCA (principal component analysis) results made it possible to distinguish starch phosphates obtained at 15 °C from those obtained at 45 °C and those from natural starch.

DMA Study of the Molecular Structure of Porcine Fat in-Water Emulsions Stabilised by Potato Starch

The aim of the study was to determine how the molecular structure of porcine fat-in-water type emulsions stabilised with potato starch affected their rheomechanical properties. Dynamic mechanical analysis (DMA) and instrumental analysis of the texture were the method used in experiments. Starch gels with concentrations corresponding to the water starch concentration of the examined emulsions were used as control systems. The analysis of the starch and starch-fat systems showed that the values characterising their rheomechanical and textural properties reflected the spatial reaction of the amylose matrix to dynamic mechanical interactions. Changes in their values resulted from conformational changes in the structure of segments and nodes of the lattice, conditioned by the concentration of starch and the presence of fat. As a result of these changes, starch-fat emulsions are distinguished by greater densities of network segments and nearly two times greater functionalities of nodes than starch gels. The instrumental analysis of the texture showed that the values of the texture parameters in the starch gels were greater than in the starch-fat emulsions. The high values of the correlation coefficients (R~0.9) between the texture determinants and the rheological parameters proved that there was a strong correlation between the textural properties of the tested systems and their rheomechanical properties.

Temperature Profile in Starch during Irradiation. Indirect Effects in Starch by Radiation-Induced Heating

Present research deals with exposure of granular starch to the accelerated electron of 5.5 MeV energy in order to examine: (i) the temperature evolution in starch within an irradiation process and (ii) the indirect effects generated in starch by radiation-induced heating. The temperature evolution in potato and corn starches within the irradiation process was investigated by placing two different sensors inside each starch batch and recording the temperature simultaneously. Each starch batch was sampled into distinct location sectors of different absorbed radiation levels. The output effects in each sample were analyzed through physicochemical properties such as moisture content, acidity and color attributes. The outcomes showed that a starch temperature profile had different major stages: (i) heating during irradiation, (ii) post-irradiation heating, up to the maximum temperature is reached, and (iii) cooling to the room temperature. A material constant with signification of a relaxation time was identified by modeling the temperature evolution. Changes of the investigated properties were induced both by irradiation and radiation-induced heating, depending on the starch type and the batch sectors. Changes in the irradiated batch sectors were explained by irradiation and radiation-induced heating whereas changes in the sector of non-irradiated starch were attributed only to the heating.

Synthesis and Characterization of Novel Hybrid Flocculants Based on Potato Starch Copolymers with Hollow Carbon Spheres

Novel carbon nanofiller-based starch-g-polyacrylamide hybrid flocculation materials (St-PAM-CS) were in situ prepared using potato starch (St), acrylamide (AM), and hollow mesoporous carbon spheres (CSs; diameters of 300–400 nm). Structures of different St-PAM-CS systems were characterized by Fourier transform infrared (FTIR) spectroscopy, X-Ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), laser scanning microscopy (LSM), and particle size analysis. The flocculation tests were evaluated by removing high turbidity kaolin suspension—initial absorbance 1.84. The effect of the St to AM molar ratio, doses, and content of CSs in hybrids on flocculation efficiency were examined. Satisfactory flocculation efficiency was obtained for all hybrids with 1 wt.% of the CS component. The highest reduction of the kaolin suspension absorbance (to 0.06) was observed for a 3 mL dose of the starch hybrid with the highest AM content. Additionally, St-PAM-CS showed a reduction in the sludge volume in time. The hybrids reached better flocculation efficiency in relation to the reference systems without CSs. The proposed flocculation mechanism (considering bridging, patching, and formation of hydrogen bonds) has been confirmed by the recorded results.

Different Reactivity of Raw Starch from Diverse Potato Genotypes

Potato starch is one of the most important renewable sources for industrial manufacturing of organic compounds. Currently, it is produced from mixed potato varieties that often are harvested from different fields. Meanwhile, tuber starches of various potato breeds differ in their crystallinity, granule morphology, and other physical and chemical parameters. We studied the reactions of raw potato starches of different origins to chemical and biochemical reactions typically used for industrial starch modification. The results clearly demonstrate that there is a significant difference in the reactivity of the starches of different potato genotypes. While the main products of the transformations are the same, their preparative yields differ significantly. Thus, tuber starch of certain potato varieties may be more suitable for specific industrial purposes. Starch reactivity may potentially be a phenotypical trait for potato breeding to obtain potato starches for various industrial applications.

The molecular structure, morphology, and physicochemical property and digestibility of potato starch after repeated and continuous heat-moisture treatment

The multiscale structural, physicochemical, and digestible properties of potato starch before and after heat-moisture treatment were investigated, and further compared between repeated heat-moisture treatment (RHMT) and continuous heat-moisture treatment (CHMT). After heat-moisture treatment, there appeared partial disruption and pits on the starch granules, and the birefringence edges of HMT starch particles became blurred. Besides, the molecular weight of samples conspicuously decreased after two kinds of treatments. The crystal type of HMT starches transformed from B-type to C-type according to X-ray analysis. A decrease in the solubility and swelling power in high temperatures were identified. The pasting temperature, the gelatinization transition temperature (T_o , T_p , T_c ), and the slowly digestible starch (SDS) content of HMT starches were significantly higher than native potato starch, while the peak viscosity, the trough viscosity, the final viscosity, the breakdown, and the gelatinization enthalpy (ΔH) of RHMT and CHMT potato starches decreased compared to the native. RHMT potato starches displayed significantly higher relative crystallinity degree and gelatinization transition temperatures. The cooling process of RHMT in which the linkage between the recombinant amylose/amylopectin was enhanced compared with CHMT, which contributed to that RHMT potato starches exhibited greater advantages in practical applications. PRACTICAL APPLICATION: The described RHMT and CHMT starches provide new ideas for the study of modified starch. Furthermore, this study revealed the mechanism of heat-moisture processing provided some instructions to the application of RHMT potato starch.

Biodegradable Starch/Chitosan Foam via Microwave Assisted Preparation: Morphology and Performance Properties

The effects of chitosan (CTS) as the reinforcing phase on the properties of potato starch (PS)-based foams were studied in this work. The formic acid solutions of CTS and PS were uniformly mixed in a particular ratio by blending and then placed in a mold made of polytetrafluoroethylene for microwave treatment to form starch foam. The results showed that the molecular weight and concentration of CTS could effectively improve the density and compressive properties of starch-based foams. Furthermore, orthogonal experiments were designed, and the results showed that when the molecular weight of CTS in foams is 4.4 × 10⁵, the mass fraction is 4 wt%, and the mass ratio of CTS–PS is 3/4.2; the compressive strength of foams is the highest at approximately 1.077 mPa. Furthermore, Fourier transform infrared spectroscopy analysis demonstrated the interaction between starch and CTS, which confirmed that the compatibility between CTS and PS is excellent.

Molecular Dispersion of Starch as a Crucial Parameter during Size-Exclusion Chromatography

Starch, α-polyglucan consisting of a large number of anhydroglucose units joined by α-1,4- and α-1,6-glycosidic bonds, seems to be characterized by a simple structure when compared to other natural polymers. Nevertheless, starches of various botanical origins have different physicochemical properties that are related to the differences in molecular and supramolecular structure of this polymer. In terms of the functional value of starch, the behavior of its macromolecules in solution is the most important result of its structural features. Extremely high molecular mass is the fundamental structural property of starch. Water, considered simply as a solvent for solubilization, does not provide molecular dispersion of starch without its degradation. The objectives of this study are to characterize the suitability of a new aqueous media (urea/NaOH) for enhancing the dispersion of native corn and potato starches and its effect on the consequent size-exclusion chromatography (SEC) analysis. The results were referred to other aqueous base solvents used for dispersing starch (NaOH and KOH). The samples were separated using SEC with triple detection and phosphate buffer (pH 8.0) with urea as the eluent. The characteristics of tested normal and waxy starches were compared. The results revealed that urea/NaOH did not degrade starch during the dispersion process. The recovery of starches, however, was not higher than 42%. These results prove that while the urea/NaOH solvent allows to obtain cold-water-soluble starch, the degree of disintegration of the intramolecular interactions of amylopectin chains is still insufficient.

Effect of slow biodegradable substrate addition on biofilm structure and reactor performance in two MBBRs filled with different support media

In this study, two moving-bed biofilm reactors (MBBR₁ and MBBR₂) filled with different size of carrier media (Kaldnes K₁ and Kaldnes K₁ micro, respectively) were subjected to soluble (sugar and sodium acetate (Ac)) substrate and mixture of soluble and particulate (particulate potato starch (PS)) substrate in a very high organic loading rate (12 kgCOD/m³·d) at different temperatures (26 and 15°C, in MBBR₁ and MBBR₂, respectively). The effects of carrier type and substrate on biofilm structure and reactor performance have been studied. Starch was removed by adsorption at the biofilm surface and hydrolyzed which caused substrate gradient in MBBR₁, however, hydrolyzed uniformly within biofilm in MBBR₂. The biofilm of MBBR₁ was irregular due to filamentous structure growth due to the substrate gradient, while, it was regular in MBBR₂ due to uniform distribution of substrate. The performance of both MBBRs in ammonium, COD and TN removal decreased significantly when the amount of small particles in the reactor increased owing to feeding by starch, which led to biomass density decline. The type of media affected the quantity and distribution of attached biomass, which in turn influenced the activity of specific microbial functional groups in the biofilm. The biofilm in MBBR₂ was thicker and consequently nitrogen removal by denitrification was much higher. The lower temperature did not affect negatively the reactor performance in MBBR₂.

Properties of Potato Starch Roasted with Apple Distillery Wastewater

This study aimed to produce starch esters by roasting potato starch with apple distillery wastewater at various temperatures and aimed to determine the effects of esterification conditions on selected properties of the modified preparations. Apple distillery wastewater was concentrated, mixed with starch (30 g of dry matter per 100 g of starch), dried, and roasted at temperatures of 110, 130 or 150 °C for 3 h. The resulting preparations were rinsed 30 times with a 60% ethanol solution, dried, and disintegrated. After that, the following analyses were performed: content of substituted acids (after alkaline de-esterification) with high performance liquid chromatography (HPLC); thermal characteristics with differential scanning calorimetry (DSC); swelling power and solubility in water at 80 °C; color changes with a colorimeter; rheology of the pastes based on the plotted flow curves; and the pastes’ resistance to amyloglucosidase. Starch treatments with apple distillery wastewater at 130 and 150 °C caused significant changes to its properties when compared to the control samples of native starch and starch roasted without wastewater, including: a lower temperature and heat of pasting, lower swelling power and solubility in water, darker color, higher resistance to amyloglucosidase, and the formation of pastes with a lower viscosity.

Effect of the Esterification of Starch with a Mixture of Carboxylic Acids from Yarrowia lipolitica Fermentation Broth on Its Selected Properties

Potato starch was esterified with carboxylic acids contained in the fermentation broth from Yarrowia lipolitica yeast production. Various acid concentrations and various roasting temperatures were used to determine effects of process conditions on ester properties, including the number of acid residues attached to starch chains, starch susceptibility to amylolysis, and thermal characteristics of starch phase transitions. Study results demonstrated the effect of both the composition and the dose of the fermentation broth and of roasting temperature of starch on the number of acid residues attached to starch chains. Citric acid was more susceptible to esterification with starch (DS = 5.65%) compared to the α-ketoglutaric acid (DS = 0.12%). In the case of the latter, a higher degree of substitution was determined in the esters produced at higher roasting temperatures. The lowest digestibility (RS = 20%) was demonstrated for the starch esters with the highest degree of substitution with citric acid, whereas all starch esters showed decreased values of the thermal characteristics of pasting.

Surface Morphology Formation of Edible Holographic Marker on Potato Starch with Gelatin or Agar Thin Coatings

Edible films and coatings based on biopolymers to protect and extend the shelf life of food and medicine can be functionalized, by applying a holographic marker on the coating surface for marking products or sensing storage conditions. In this work, holographic markers were prepared on the surface of thin biopolymer coatings based on starch, gelatin, agar and also starch/gelatin and starch/agar blends by the nanoimprint method from a film-forming solution. The morphology of the surface of holographic markers using optical microscopy in reflection mode was examined, as well as the reasons for its formation using an analysis of the flow curves of film-forming solutions. It was found that the surface morphology of the marker strongly depends on the composition, consistency index of film-forming solution and miscibility of the components. It was shown that the starch/agar film-forming solution at the ratio of 70/30 wt.% has a low consistency index value of 21.38 Pa·s^0.88, compared to 64.56 Pa·s^0.67 for pure starch at a drying temperature of 30 °C, and the components are well compatible. Thus, an isotropic morphology of the holographic marker surface was formed and the value of diffraction efficiency of 3% was achieved, compared to 1.5% for the marker made of pure starch. Coatings without holographic markers were analyzed by tensile strength and water contact angle, and their properties are highly dependent on their composition.

Pasting, thermo, and Mixolab thermomechanical properties of potato starch-wheat gluten composite systems

This research investigated the viscosity, thermal, thermomechanical, and microstructural properties of potato starch-wheat gluten composite systems with different starch/gluten ratios under mechanical shear and heating conditions. Results showed that the peak, trough, and final viscosities increased with the increase in potato starch fraction. The breakdown and setback values of samples decreased with increasing gluten content, and the endothermic enthalpy showed a similar variation trend. The gelatinization temperature of the samples increased significantly as the gluten proportion increased. Morphological observation showed that the gluten protein was wrapped around potato starch granules and the starch granules have a diluting effect on gluten network. Moreover, gluten formed a water diffusion barrier out of the starch granules, this barrier effect and the competitive hydration between starch and gluten could primarily explain the delayed gelatinization temperatures.

Influence of anionic, neutral, and cationic polysaccharides on the in vitro digestibility of raw and gelatinized potato starch

BACKGROUND

Polysaccharides have been expected to have a suppressive effect on starch digestibility by blending. The objective of this study was to investigate the effects of anionic (xanthan gum), neutral (guar gum), and cationic (chitosan) polysaccharides on the in vitro digestibility of raw and gelatinized starch using six potato cultivars differing in phosphorus content.

RESULTS

By comparing the starch digestibility between potato cultivars, a significant difference was observed for the raw starches, and 'Benimaru', which is a potato cultivar containing a higher proportion of short-chain amylopectin and the lowest phosphorus content in starch, showed a distinctly faster rate of starch hydrolysis. The added polysaccharides decreased the extent of digestion of both raw and gelatinized starches. No significant correlation between phosphorus content and the extent of starch digestion was observed in mixed systems, whereas significant correlations were noted between the extent of starch digestion and Rapid Visco Analyser parameters. The extent of raw and gelatinized starch digestion negatively correlated with pasting temperature, initial viscosity before heating, and peak viscosity (P < 0.01).

CONCLUSION

The added polysaccharides were observed to decrease the starch digestibility, and their suppressive effects were mainly dependent on the increase of viscosity rather than chemical interactions. A combination of potato cultivar and type of polysaccharide was proved to be important for nutritional value of potato starch. © 2020 Society of Chemical Industry.

Physicochemical and Digestion Properties of Potato Starch Were Modified by Complexing with Grape Seed Proanthocyanidins

Dietary intake of potato starch could induce a dramatic increase in blood glucose and is positively associated with chronic metabolic diseases (type II diabetes, cardiovascular disease, etc.). Grape seed proanthocyanidins (GSP) are known to decrease starch digestion by inhibiting digestive enzymes or changing the physicochemical properties of starch. In the present study, GSP were complexed with potato starch to prepare polyphenol-starch complexes. The physiochemical properties and digestibility of complexes were investigated by in vitro digestion model, X-ray diffraction, differential scanning calorimetry, rapid visco analyzer, Fourier transform infrared spectroscopy as well as texture profile analysis. Results indicated that the peak viscosity, breakdown, trough, and setback of the complexes disappeared, replaced by a special continuous increase in paste viscosity. The complexes showed a lower final viscosity and higher thermal stability with the increasing binding amount of GSP. GSP decreased the hardness of the complexes' gel significantly. FT-IR indicated that GSP might interact with potato starch through noncovalent forces. Additionally, the complexes also showed a higher content of slowly digestible starch and resistant starch than that of the native starch. Thus, we inferred that the addition of GSP could modify the digestibility of potato starch and be an optional way to modify the starch with lower digestion.

Potato Starch Hydrogels Produced by High Hydrostatic Pressure (HHP): A First Approach

Starch-based hydrogels have received considerable interest due to their safe nature, biodegradability and biocompatibility. The aim of this study was to verify the possibility of producing natural hydrogels based on potato starch by high hydrostatic pressure (HHP), identifying suitable processing conditions allowing to obtain stable hydrogels, as well as to characterize structural and mechanical properties of these products. Sieved (small size granules and medium size granules) and unsieved potato starch samples were used to prepare aqueous suspensions of different concentrations (10-30% w/w) which were processed at 600 MPa for 15 min at different temperatures (25, 40 and 50 °C). Products obtained were characterized by different techniques (light and polarized microscopy, Fourier transform infrared spectroscopy (FTIR), rheology and differential scanning calorimetry (DSC)). Results obtained so far demonstrated that potato starch suspensions (20% starch-water concentration (w/w)) with granules mean size smaller than 25 µm treated at 600 MPa for 15 min and 50 °C showed a complete gelatinization and gel-like appearance. Potato HHP hydrogels were characterized by high viscosity, shear-thinning behavior and a highly structured profile (G' >> G''). Moreover, their FTIR spectra, similarly to FTIR profiles of thermal gels, presented three absorption bands in the characteristic starch-gel region (950-1200 cm-1), whose intensity increased with decreasing the particle size and increasing the processing temperature. In conclusion, potato starch hydrogels produced by HHP in well-defined processing conditions exhibited excellent mechanical properties, which can be tailored according to the requirements of the different applications envisaged.

Revisiting Mechanisms Underlying Digestion of Starches

The factors that determine the digestion rate of starches were revealed using different forms of starches and a mixture of α-amylase and amyloglucosidase. Gelatinized starch samples with a degree of gelatinization (DG) from 12.2 to 100% for potato starch and from 7.1 to 100% for lotus seed starch were obtained. With an increasing DG, the short- and long-range molecular orders of both starches were disrupted progressively. The first-order digestion rate constant (k) of both starches increased with an increasing DG, although the positive linear relationships between DG and k differed (R² = 0.87 for potato starch, and R² = 0.74 for lotus seed starch). The mean fluorescence intensity showed a positive linear correlation with DG, which was strong for potato starch (R² = 0.99) and relatively weaker for lotus seed starch (R² = 0.54). These results indicated that DG is a major determinant for the digestion rate of potato starch and lotus seed starch and that the access/binding of enzymes to starch was the main rate-limiting factor for digestion of starches.

Synthetized Potato Starch-A New Eco Sizing Agent for Cotton Yarns

The objective of this research was to verify the feasibility of the use of newly synthesized biopolymer materials for sizing cotton yarns based on the basic principles of chemical modification. Research included acid hydrolysis of potato starch up to controlled molar masses together with graft-polymerization and methacrylic acid onto hydrolyzed starch to improve hydrophilicity and solubility, to increase the capability of film forming, to increase adhesive potential and to avoid retrogradation phenomena. Research objectives were primarily focused on finding an appropriate, environmentally-friendly and productive sizing agent for cotton yarns via the analysis and systematization of a large number of synthesis methods in conjunction with the characterization and properties of graft-copolymers. The research results showed that potassium persulfate initiator was most efficient in grafting of methacrylic acid onto hydrolyzed starch, while azobisisobutyronitrile (AIBIN) initiator was most efficient in grafting of acrylic acid (AC). FTIR analysis confirmed that new and efficient products for sizing cotton yarns from synthetized potato starch were obtained. Research on rheological properties of copolymers shows a higher viscosity of grafted products indicating the good stability of potential starches. Ecological improvements have been established through high desizing degree as well as improvements in physical-mechanical properties of yarn, abrasion resistance and decrease in yarn surface hairiness were noticed. The use of new derivatives of potato starch, especially of hydrolyzed starch grafted with methacrylic acid (MAA), potassium persulfate (KPS) as initiator, was confirmed. Anova statistical analysis determined the influence of the entire sizing process on individual yarn parameters.

Understanding the Properties of Starch in Potatoes (Solanum tuberosum var. Agria) after Being Treated with Pulsed Electric Field Processing

The purpose of this study was to investigate the properties of starch in potatoes (Solanum tuberosum cv. Agria) after being treated with pulsed electric fields (PEF). Potatoes were treated at 50 and 150 kJ/kg specific energies with various electric field strengths of 0, 0.5, 0.7, 0.9 and 1.1 kV/cm. Distilled water was used as the processing medium. Starches were isolated from potato tissue and from the PEF processing medium. To assess the starch properties, various methods were used, i.e., the birefringence capability using a polarised light microscopy, gelatinisation behaviour using hot-stage light microscopy and differential scanning calorimetry (DSC), thermal stability using thermogravimetry (TGA), enzyme susceptibility towards α-amylase and the extent of starch hydrolysis under in vitro simulated human digestion conditions. The findings showed that PEF did not change the properties of starch inside the potatoes, but it narrowed the temperature range of gelatinisation and reduced the digestibility of starch collected in the processing medium. Therefore, this study confirms that, when used as a processing aid for potato, PEF does not result in detrimental effects on the properties of potato starch.

Hollow selenium nanoparticles from potato extract and investigation of its biological properties and developmental toxicity in zebrafish embryos

A facile synthesis of hollow selenium nanoparticles (hSeNPs) was prepared using potato starch as a reducing and capping agent. The morphological and structural characters of the hSeNPs were characterised by ultraviolet-visible spectroscopy (UV), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDX) and zeta potential analyser. The optical characteristics of hSeNPs were confirmed by UV. The presence of various functional groups in the hSeNPs suspension was confirmed by FTIR. The SEM results suggested that the synthesised hSeNPs were uniformly distributed and circular in shape with a hollow. The average size of the hSeNPs was found to be around 115 nm. The EDX analysis also confirmed the presence of hSeNPs in the sample. The zebrafish embryos were treated with hSeNPs of various concentrations ranging from 10 to 50 µg/ml. Abnormalities such as improper heartbeat, embryo sac oedema, ocular oedema and head oedema were noted at higher concentrations (30-50 µg/ml). A concentration-dependent antioxidant activity of hSeNPs was observed. The hSeNPs showed good antibacterial activity against gram-positive Bacillus subtilis and gram-negative Escherichia coli. The results of this study indicate that potato extract reduces the toxicity of hSeNPs and lower concentrations of hSeNPs could be used for various biomedical applications in near future.

Preparation and partial characterization of films made with dual-modified (acetylation and crosslinking) potato starch

BACKGROUND

Starch is an alternative material for the production of biodegradable plastics; however, native starches have drawbacks due to their hydrophilic nature. Chemical modifications such as acetylation and crosslinking are used to broaden the potential end-uses of starch. Dual modification of starches increases their functionality compared to that of starches with similar single modifications. In this study, a dual-modified potato starch (acetylated and crosslinked) was used to produce films by casting.

RESULTS

Changes in the arrangement of the amylopectin double helices of dual-modified starch were evident from X-ray diffraction patterns, pasting profiles and thermal properties. The degree of substitution for acetyl groups was low (0.058 ± 0.006) because crosslinking dominated acetylation. Modified starch film had higher elongation percentage (82.81%) than its native counterpart (57.4%), but lower tensile strength (3.51 MPa for native and 2.17 MPa for dual-modified) and lower crystallinity in fresh and stored films. The sorption isotherms indicated that the dual modification decreased the number of reactive sites for binding water, resulting in a reduction in the monolayer value and a decrease in the solubility and water vapor permeability.

CONCLUSIONS

Dual modification of starch may be a feasible option for improving the properties of biodegradable starch films. © 2018 Society of Chemical Industry.