Controlling sodium chloride concentration modulates the supramolecular structure and sol features of wheat starch-acetylated starch binary matrix

The sol performance of wheat starch (WS) matrix incorporating acetylated starch (AS) is crucial for the processing and quality features of wheat products. From a supramolecular structure view, how regulating salt (sodium chloride) concentration modulates the sol features, e.g., pasting, zero-shear viscosity (ZSV) and thixotropy of WS-AS binary matrix was explored. Compared to the salt-free counterpart, the saline matrices exhibited a delayed pasting profile and a decreased viscoelasticity. Thereinto, the sol at 0.02 M NaCl exhibited the smallest ZSV (23,710 Pa·s) and the greatest in-shear recovery ratio (33.7 %). Such variations could be attributed to the weakened coil-helix, nematic-smectic and isotropy-anisotropy transitions from a side-chain liquid-crystalline perspective. Meanwhile, the correlation length (ξ) and radius of gyration (Rg) obtained from small angle X-ray scattering analysis were increased by 5.2 and 9.6 Å respectively, which disclosed a restrained entanglement and an enhanced chain mobility. These results would provide a reference for the design of fluid/semisolid products with optimized qualities.

Anionic starch-based hybrid cryogel-embedded ZnO nanoparticles: tuning the elasticity and pH-functionality of biocomposites with dicarboxylic acid units

Weakly anionic semi-interpenetrating polymer network (semi-IPN) biocomposites based on starch (ST)-incorporated poly(acrylamide-co-itaconic acid)/ZnO (ST-PAI/ZnO) were synthesized by a simple one-pot method via free radical aqueous polymerization. Hybrid biocomposites exhibited lower equilibrium swelling compared with neat copolymer gel. For both hydrogels and cryogels, swelling followed a decreasing order as copolymer PAI > starch-free PAI/ZnO > ST-PAI/ZnO gels. With the addition of 9% ST and ZnO, the swelling ratio of gels decreased from 898 to 68.3, resulting in a significant increase in elastic modulus. Compared with a fixed amount of ST, biocomposite cryogels exhibited significantly higher modulus than hydrogels. With the addition of 9% ST, the elastic modulus of cryogels reached 22.2 kPa while it was 2.7 kPa for the hydrogels. An equation expressing the effective cross-linking density of semi-IPNs presented by a cubic polynomial as a function of starch was obtained. As pH increased with the presence of dicarboxylic acid units, a gradual increase in swelling occurred at two different pH values. A gradually reproducible swelling change of semi-IPNs was depicted with pH ranging from 2.1 to 11.2. Biocomposite cryogels showed rapid swelling in a buffer solution of pH 11.2 and rapid shrinking in pH 2.1. Salt-induced swelling testing showed that the ability to reduce the degree of swelling and solubility of starch was Br- > Cl- > NO3- > SO42- for anions consistent with the Hofmeister series. Adsorption efficiency for the removal of methyl violet (MV) dye was analyzed using Langmuir, Freundlich, Dubinin-Radushkevich and Temkin isotherm models. The results confirmed that the Langmuir isotherm and pseudo-second-order model are suitable for describing MV adsorption on semi-IPN biocomposites. The synthesized biocomposites with good swelling/deswelling kinetics in different pH-buffer solutions, high saline absorbency, desirable adsorption efficiency, and acceptable pH-dependent swelling reversibility can be considered as smart hybrid materials for the adsorption of the dye in water purification tasks.

Understanding resistant-starch formation during drying high-amylose maize kernels

Interests in using high-amylose maize (HAM) flour and starch for low glycemic index foods continue to grow. The objective of this work was to understand resistant-starch formation during drying the HAM kernels. Freshly harvested HAM kernels with 28.2 % initial moisture were subjected to sun drying (~30 °C) or hot-air drying at 50 °C, 70 °C, 90 °C, or 110 °C. The enzymatic digestibility of HAM flour decreased from 63.6 % to 41.1 % as the drying temperature increased from 30 °C to 110 °C. The swelling power, solubility, and overall viscosity of HAM flours milled from kernels dried at 110 °C decreased, whereas the peak and conclusion gelatinization temperatures, enthalpy change, and relative crystallinity increased compared to those of flours from kernels dried at 30 °C, 50 °C, 70 °C, and 90 °C. Light microscopic and scanning electron microscopic images showed that starch granule aggregation in HAM flour increased with increasing drying-temperatures. The aggregates remained after 16 h enzymatic hydrolysis of cooked HAM flours. These results suggested that the increase of enzymatic resistance of HAM flour resulted from the formation of high temperature-resistant ordered structures in starch granules and the starch aggregates less accessible to enzymatic hydrolysis.

Preparation of starch-palmitic acid complexes by three different starches: A comparative study using the method of heating treatment and autoclaving treatment

Recent research emphasizes the growing importance of starch-lipid complexes due to their anti-digestibility ability, prompting a need to explore the impact of different starch sources and preparation methods on their properties. In this study, starch-palmitic acid (PA) complexes were prepared by three different starches including Tartary buckwheat starch (TBS), potato starch (PTS), and pea starch (PS) by heating treatment (HT) and autoclaving treatment (AT), respectively, and their physicochemical property and in vitro digestibility were systematically compared. The formation of the starch-PA complex was confirmed through various characterization techniques, including scanning electron microscopy, differential scanning calorimetry, Fourier transform infrared spectroscopy, and X-ray diffraction. Among the complexes, the PTS-PA complex exhibited the highest complexation index over 80 %, while the PS-PA complex had the lowest rapid digestible starch content (56.49-59.42 %). Additionally, the complexes prepared by AT exhibited higher resistant starch content (41.95-32.46 %) than those prepared by HT (31.42-32.49 %), while the complexes prepared by HT held better freeze-thaw stability and hydration ability than those prepared by AT. This study highlights the important role of starch sources in the physicochemical and digestibility properties of starch-lipid complex and the potential application of AT in the preparation of novel resistant starch.

New Insight into the Effects of Endogenous Protein and Lipids on the Enzymatic Digestion of Starch in Sorghum Flour

The effects of endogenous lipids and protein in sorghum flour on starch digestion were studied following the depletion of lipids and/or protein and after the reconstitution of separated fractions. The removal of protein or lipids moderately increases the digestibility of starch in raw (uncooked) sorghum flour to values close to those for purified starch. Rapid Visco Analyzer data (as a model for the cooking process) show that cooked sorghum flours with lipids have a lower starch digestibility than those without lipids after RVA processing, due to the formation of starch-lipid complexes as evidenced by their higher final viscosity and larger enthalpy changes. Additionally, the formation of a starch-lipid-protein ternary complex was identified in cooked sorghum flour, rather than in a reconstituted ternary mixture, according to the unique cooling stage viscosity peak and a greater enthalpy of lipid complexes. After heating, the sorghum flour showed a lower digestibility than the depleted flours and the reconstituted flours. The results indicate that the natural organization of components in sorghum flour is an important factor in facilitating the interactions between starch, lipids, and protein during RVA processing and, in turn, reducing the starch digestion.

A review of starch swelling behavior: Its mechanism, determination methods, influencing factors, and influence on food quality

Swelling behavior involves the process of starch granules absorbing enough water to swell and increase the viscosity of starch suspension under hydrothermal conditions, making it one of the important aspects in starch research. The changes that starch granules undergo during the swelling process are important factors in predicting their functional properties in food processing. However, the factors that affect starch swelling and how swelling, in turn, affects the texture and digestion characteristics of starch-based foods have not been systematically summarized. Compared to its long chains, the short chains of amylose easily interact with amylopectin chains to inhibit starch swelling. Generally, reducing the swelling of starch could increase the strength of the gel while limiting the accessibility of digestive enzymes to starch chains, resulting in a reduction in starch digestibility. This article aims to conduct a comprehensive review of the mechanism of starch swelling, its influencing factors, and the relationship between swelling and the pasting, gelling, and digestion characteristics of starch. The role of starch swelling in the edible quality and nutritional characteristics of starch-based foods is also discussed, and future research directions for starch swelling are proposed.

Saltiness perception in gel-based food systems (gels and emulsion-filled gels)

Reducing salt in food without compromising its quality is a huge challenge. Some review articles have been recently published on saltiness perception in some colloidal systems such as emulsions. However, no published reviews are available on saltiness perceptions of gel-based matrices, even though salt release and perception in these systems have been extensively studied. This article reviews the recent advances in salt perception in gel-based systems and provides a detailed analysis of the main factors affecting salt release. Strategies to enhance saltiness perception in gels and emulsion-filled gels are also reviewed. Saltiness perception can be improved through addition of biopolymers (proteins and polysaccharides) due to their ability to modulate texture and/or to adhere to or penetrate through the mucosal membrane on the tongue to prolong sodium retention. The composition of the product and the distribution of salt within the matrix are the two main factors affecting the perception of salty taste. Food structure re-design can lead to control the level of interaction between the salt and other components and change the structure, which in turn affects the mobility and release of the salt. The change of ingredients/matrix can affect the texture of the product, highlighting the importance of sensory evaluation.

Effect of Ecotype and Starch Isolation Methods on the Physicochemical, Functional, and Structural Properties of Ethiopian Potato (Plectranthus edulis) Starch

The Ethiopian potato (Plectranthus edulis) is an annual tuber crop indigenous to Ethiopia. The crop is underutilized and not much studied despite its high yield of starch, which has a good potential to contribute to the effort in meeting the quickly growing demand for starch. In this study, the effects of the ecotype and isolation methods on the physicochemical, functional, structural, and crystalline properties of starches were evaluated. Starches were isolated from two Ethiopian potato ecotypes (Loffo and Chanqua) using distilled water (DW), 0.01% sodium metabisulphite (SMS), and 1M sodium chloride (NaCl) in the isolation media. The results showed that the lowest starch yield was obtained from Chanqua using DW (97.4%), while the maximum was from Loffo using SMS (99.3%). The L* (lightness) and whiteness values of the starches obtained from Loffo were higher than those of Chanqua starches, with NaCl and SMS extractants yielding the highest values. The bulk density, water activity (aw), pH, proximate composition (moisture content, protein, ash, fat, crude fiber, and carbohydrate contents), and techno-functional properties were established. The majority of these parameters varied depending on both the isolation method and the ecotype. The crystallinity pattern of all starches showed B-type diffraction, with differences in diffraction peak intensities between all starches. FTIR tests showed structural changes as a function of the ecotype and isolation procedure used. The Loffo ecotype exhibited considerably better results, and the SMS isolation method was found to be the most effective way to acquire the highest starch quality in most of the characteristics evaluated.

Graphene as a nano-delivery vehicle in agriculture - current knowledge and future prospects

Graphene has triggered enormous interest in, and exploration of, its applications in diverse areas of science and technology due to its unique properties. While graphene has displayed great potential as a nano-delivery system for drugs and biomolecules in biomedicine, its application as a nanocarrier in agriculture has only begun to be explored. Conventional fertilizers and agricultural delivery systems have a number of disadvantages, such as: fast release of the active ingredient, low delivery efficiency, rapid degradation and low stability that often leads to their over-application and consequent environmental problems. Advanced nano fertilizers with high carrier efficiency and slow and controlled release are now considered the gold standard for promoting agricultural sustainability while protecting the environment. Graphene's attractive properties include large surface area, chemical stability, mechanical stability, tunable surface chemistry and low toxicity making it a promising material on which to base agricultural delivery systems. Recent research has demonstrated considerable success in the use of graphene for agricultural applications, including its utilization as a delivery vehicle for plant nutrients and crop protection agents, as well as in post-harvest management of crops. This review, therefore, presents a comprehensive overview of the current status of graphene-based nanocarriers in agriculture. Additionally, the review outlines the surface functionalization methods used for effective molecular delivery, various strategies for nano-vehicle design and the underlying features necessary for a graphene-based agro-delivery system. Finally, the review discusses directions for further research in optimization of graphene-based nanocarriers.

Starch modification through its combination with other molecules: Gums, mucilages, polyphenols and salts

Apart from its non-toxicity, biocompatibility and biodegradability, starch has demonstrated eminent functional characteristics, e.g., forming well-defined gels/films, stabilizing emulsions/foams, and thickening/texturizing foods, which make it a promising hydrocolloid for various food purposes. Nonetheless, because of the ever-increasing range of its applications, modification of starch via chemical and physical methods for expanding its capabilities is unavoidable. The probable detrimental impacts of chemical modification on human health have encouraged scientists to develop potent physical approaches for starch modification. In this category, in recent years, starch combination with other molecules (i.e., gums, mucilages, salts, polyphenols) has been an interesting platform for developing modified starches with unique attributes where the characteristics of the fabricated starch could be finely tuned via adjusting the reaction parameters, type of molecules reacting with starch and the concentration of the reactants. The modification of starch characteristics upon its complexation with gums, mucilages, salts, and polyphenols as common ingredients in food formulations is comprehensively overviewed in this study. Besides their potent impact on physicochemical, and techno-functional attributes, starch modification via complexation could also remarkably customize the digestibility of starch and provide new products with less digestibility.

Climate-Nutrient-Crop Model: Novel Insights into Grain-Based Food Quality

Mineral nutrients spatiotemporally participate in the biosynthesis and accumulation of storage biopolymers, which directly determines the harvested grain yield and quality. Optimizing fertilizer nutrient availability improves the grain yield, but quality aspects are often underestimated. We hypothesize that extensive mineral nutrients have significant effects on the biosynthesis, content, and composition of storage proteins, ultimately determining physicochemical properties and food quality, particularly in the context of climate change. To investigate this, we hierarchized 16 plant mineral nutrients and developed a novel climate-nutrient-crop model to address the fundamental question of the roles of protein and starch in grain-based food quality. Finally, we recommend increasing the added value of mineral nutrients as a socioeconomic strategy to enhance agro-food profitability, promote environmental sustainability, and improve climate resilience.

Influence of accelerating storage of foxtail millet on the edible and cooking quality of its porridge: An insight into the structural alteration of the in-situ protein and starch and physicochemical properties

This study aimed to elucidate the effect of the accelerating storage (40 °C, 10 weeks) of foxtail millet on the edible and cooking quality of its porridge. The structural alteration of the in-situ protein and starch in foxtail millet, as well as the physicochemical properties were investigated. Both the homogeneity and palatability of millet porridge were significantly improved after 8-week storage of millet, while its proximate compositions remained unchanged. Meanwhile, the accelerating storage increased the water absorption and swelling of millet by 20 % and 22 %, respectively. The morphological studies (using the SEM, CLSM and TEM) revealed that the starch granules in the stored millet became easier to swell and melt, leading to better gelatinization with a higher coverage extension in protein bodies. FTIR results showed that the protein hydrogen bonds in the stored millet became stronger and the starch ordered degree was reduced. Compared to the native foxtail millet, the peak, trough, final, and setback viscosity of the stored sample increased by 27 %, 76 %, 115 % and 143 %, respectively, while the onset, peak, and conclusion temperature increased by 0.80, 1.10 and 0.80 °C, respectively. Besides, the G' and G″ of the stored foxtail millet were significantly higher than its native counterpart.

Starch granular size and multi-scale structure determine population patterns in bivariate flow cytometry sorting

Bivariate flow cytometry (FC) sorting with forward scatter (FSC) and side scatter (SSC) is a recently established novel technique to separate starch granules. However, the forming mechanism of starch FC-dependent population patterns (i.e. the number of subgroups (NS) and FSC/SSC-dependent distribution patterns) remain partly elusive. For this, the correlation of granular size and multi-scale structure of native starches and FC-dependent population patterns was investigated through employing a wide range of native starches originating from different species involving cereal-, pulse-, and tuber crops. Results showed NS was pertinent with particle size, amylose content (AC), amylopectin chains length distribution, lamellar structure, short-range ordered structure. The distinct NS was determined by impacts of native starch FSC / SSC-dependent distribution patterns. Specifically, starch granular size significantly correlated with both FSC and SSC-dependent distribution patterns. The proportion of chains with DP 6-12 was the intra-molecular decisive factor to influence short-range ordered structure, finally leading to FSC-dependent distribution patterns. By contrast, AC was another intra-molecular index to determine SSC-dependent distribution patterns through affecting lamellar structure and short-range ordered structure.

The effect rules of MgCl2 and NaCl on the properties of potato starch: The inflection point phenomenon

The effects of MgCl₂ and NaCl concentrations on potato starch were analysed. With an increase in MgCl₂ and NaCl concentrations from 0 to 4 mol/L, the gelatinisation properties, crystalline properties, and sedimentation rate of potato starch all showed a trend of rising first and then falling (or falling first and then rising). The inflection points of the effect trends were observed at 0.5 mol/L. This inflection point phenomenon was further analysed. At higher salt concentrations, starch granules were found to absorb external ions. These ions enhance the hydration of starch molecules and promote starch gelatinisation. When NaCl and MgCl₂ concentrations were increased from 0 to 4 mol/L, the starch hydration strength increased 52.09 and 65.41 times, respectively. At lower salt concentrations, the ions that naturally exist in starch granules seep out of the granules. The exudation of these ions may cause a certain degree of damage to the native structure of starch granules.

High-amylose maize starch: Structure, properties, modifications and industrial applications

High-amylose maize refers to a special type of maize cultivar with a 50 %-90 % amylose content of the total starch. High-amylose maize starch (HAMS) is of interest because it possesses unique functionalities and provides many health benefits for humans. Therefore, many high-amylose maize varieties have been developed via mutation or transgenic breeding approaches. From the literature reviewed, the fine structure of HAMS is different from the waxy and normal corn starches, influencing its gelatinization, retrogradation, solubility, swelling power, freeze-thaw stability, transparency, pasting and rheological properties, and even in vitro digestion. HAMS has undergone physical, chemical, and enzymatical modifications to enhance its characteristics and thereby broaden its possible uses. HAMS has also been used for the benefit of increasing resistant starch levels in food products. This review summarizes the recent developments in our understanding of the extraction and chemical composition, structure, physicochemical properties, digestibility, modifications, and industrial applications of HAMS.

Particle Agglomeration of Acid-Modified Tapioca Starches: Characterization and Use as Direct Compression Fillers in Tablets

Acid-modified tapioca starches (AMTSs) possessed good compressibility but showed poor particle flowability for preparing tablets by the direct compression method. The aims of this work were to prepare and characterize AMTS agglomerates using polyvinylpyrrolidone (PVP) as an agglomerating agent. The dilution potential and stability studies of the AMTS agglomerates were investigated. The results showed that particle enlargement of TS and AMTS could be achieved via agglomeration using PVP. The thermal behavior and molecular interaction of the agglomerates were revealed using DSC and FTIR spectroscopy, respectively. An increase in PVP concentrations resulted in greater particle strength of the TS agglomerates and a higher acid concentration for modification enhanced the strength of the AMTS agglomerates. All agglomerates presented good particle flowability. Moreover, the AMTS agglomerates provided higher compressibility hardness than the TS agglomerates. The addition of PVP could extend the disintegration time and slow drug dissolution from the agglomerate tablets. The humidity of the storage conditions influenced the thickness and hardness of the AMTS agglomerate tablets, and good physical and chemical stability of the tablets was obtained under ambient conditions and in the refrigerator. Furthermore, the AMTS agglomerates displayed good carrying capacity and possessed desirable characteristics for use in direct compression tablets.

Multi-functional SiO32--releasing hydrogel with bioinspired mechanical properties and biodegradability for vascularized skeletal muscle regeneration

Vascularized skeletal muscle regeneration remains a great medical need but significant challenge. Biomaterial strategies that can facilitate the regeneration of muscle fibers and blood vessels are unavailable. Herein, we report...

Characterization of underutilized root starches from eight varieties of ramie (Boehmeria nivea) grown in China

Ramie root is an underutilized starch source. In this study, eight ramie varieties were investigated for starch properties. Starch content ranged from 18.6% to 50.1% in dry root. Starches from different varieties showed similar morphology including ellipsoidal, spherical and truncated granules with size D[4,3] from 10.1 to 14.1 μm. Starch had amylose content from 20.8% to 28.5%. All ramie varieties had B-type starches with relative crystallinity from 24.8% to 27.1%, ordered degree from 0.724 to 0.897 and lamellar thickness from 9.1 to 9.6 nm. Starches had gelatinization peak temperature from 70.5 to 73.8 °C and enthalpy from 14.9 to 15.8 J/g. Starches had swelling power and water solubility from 27.9 to 31.9 g/g and from 11.7% to 15.5%, respectively, at 95 °C, and exhibited different pasting properties with breakdown viscosity from 36 to 377 mPa s and setback viscosities from 1295 to 1863 mPa s. Starch pastes exhibited pseudoplastic behavior and different rheological properties. Native, gelatinized and retrograded starches had resistant starch from 81.7% to 83.9%, from 1.7% to 5.1% and from 5.6% to 13.3%, respectively. The eight varieties were divided into 3 groups according to starch properties. This study is helpful for selecting suitable ramie variety as starch source.

Preparation and characterization of native and autoclaving-cooling treated Pinellia ternate starch and its impact on gut microbiota

The aim of this study was to investigate and compare the structural and physicochemical properties of native Banxia starch (BXS) and autoclaving-cooling treated Banxia starch (CTBXS) and its related impacts on production of short chain fatty acids (SCFAs) and human gut microbiota by in vitro fecal fermentation. BXS had semicircle to spherical granules, whereas CTBXS exhibited block-shape. According to XRD and TGA, BXS had a C-type crystalline pattern, while CTBXS had a B-type crystalline pattern. CTBXS had better thermal stability than BXS. In addition, BXS exhibited significantly higher solubility and swelling power than CTBXS, and CTBXS had higher content of SDS than BXS. Moreover, BXS and CTBXS could change the composition and abundance of gut microbiota, could also promote the production of SCFAs. This study is beneficial to well understand the in vitro digestion and fecal fermentation behaviors of BXS and CTBXS, and can be developed as a potential functional food with the aim of improving colonic health.

Study of cassava starch degradation using sonication process in aqueous sodium chloride

BACKGROUND

Starch degradation is an important process that can increase starch utilization in some industrial applications. In many polysaccharide compounds, the addition of salt is an alternative method to enhance the structural degradation of starch by sonication. This study aimed to investigate the effect of sonication in aqueous NaCl solution on the structural degradation of cassava starch.

RESULTS

This method produces reducing sugar which its amount is relatively smaller than the amount of total dissolved solid product. The maximum total reducing sugar (TRS) was 0.365 ± 0.005 kg m^-3 (or about 7.3 mg g^-1 ) that resulted by S50 for 60 min reaction. The increase of sonication amplitude was in line with the increase of granule defect in SEM image. X-ray diffraction (XRD) showed that the degradation process was characterized by rupturing of the amorphous region.

CONCLUSION

The structural alteration and the increase in NaCl weight suggest that this process may become a useful method for starch modification. © 2020 Society of Chemical Industry.

Influence of protein type, content and polymerization on in vitro starch digestibility of sorghum noodles

The impacts of protein type, content and polymerization on in vitro starch digestibility of cooked sorghum noodles were investigated. Results showed that addition of exogenous proteins decreased the starch hydrolysis rate. The noodles added wheat protein (WP) exhibited the highest amount of resistant starch, followed by whey protein isolate (WPI) and egg white protein (EWP). In each group, the hydrolysis kinetic parameters were the lowest when protein addition amounts were 5% WP, 3% EWP and 3% WPI, respectively. These changes were ascribed to the interactions of starch-proteins and protein-proteins, as proved by the enhancement of protein polymerization and starch short-range structure. The increase of protein polymerization degree induced by disulfide cross-links reduced the starch digestion rate of noodles. Additionally, the confocal laser scanning microscope observations demonstrated that the strengthening of protein network had a positive effect on decreasing starch digestibility by preventing the accessibility of enzymes to starch.

Physicochemical properties of a new starch from ramie (Boehmeria nivea) root

A new starch was isolated from ramie root, and its physicochemical properties were investigated. Ramie dry root contained 45.9% starch. Starch had truncated, ellipsoidal, and spherical granule shapes with size from 7 to 30 μm and D[4,3] about 14.1 μm. Starch contained 38.9% apparent amylose content and 22.4% true amylose content, exhibited B-type crystallinity, and had 26.6% relative crystallinity, 0.82 ordered degree, and 9.2 nm lamellar thickness. Starch had 71.8 °C gelatinization peak temperature and 15.6 J/g gelatinization enthalpy, and exhibited 31.4 g/g swelling power and 17.1% water solubility at 95 °C. Starch had peak, hot, breakdown, final, and setback viscosities at 3048, 2768, 279, 4165, and 1397 mPa s, respectively, and showed peak time at 4.36 min and pasting temperature at 75.0 °C. The native, gelatinized, and retrograded starches contained 15.1%, 94.0%, and 86.5% rapidly digestible starch and 83.3%, 4.0%, and 10.7% resistant starch, respectively. Compared with potato and rice starches, ramie starch was somewhat similar to potato starch but significantly different from rice starch in starch component, crystalline structure, and functional properties. Therefore, ramie starch exhibited the potential to be used as a thickening agent, resistant-digesting food additive, and alternative to potato starch in food and nonfood industries.

Effects of potassium sulfate on swelling, gelatinizing and pasting properties of three rice starches from different sources

This study evaluates the effects of potassium sulfate (K₂SO₄) on the swelling, gelatinization, and pasting properties of indica rice starch (IRS), japonica rice starch (JRS), and waxy rice starch (WRS). As a result, the gelatinization temperatures (T_p), swelling capacities, and pasting viscosities of rice starches in water followed the order of WRS > JRS > IRS, showing positive correlations to amylopectin content and molecular weight. At K₂SO₄ concentration of 0.05-0.6 M, T_p increased by 10-13 ℃ due to a more compact structure of starch granules resulting from increased interactions of starch chains with K⁺. However, the swelling capacity decreased with increasing K₂SO₄ concentration and followed the order of WRS < JRS < IRS, which decreased sharply from 27.3 to 2.5 g/g for WRS. K₂SO₄ dramatically reduced the pasting viscosity of starch pastes due to the decreased swelling capacity. This study provides the scientific basis for rice starch processing with K₂SO₄.

Sodium dodecyl sulfate improves the properties of bio-based wood adhesive derived from micronized starch: Microstructure and rheological behaviors

Enhancing the performance of starch-based wood adhesive is vitally important for its practical applications. Accordingly, we designed the use of micronized starch (MS) to prepare micronized starch-based wood adhesive (MSWA) by incorporating 0, 2, 4 and 6% (w/w, dry basis starch) sodium dodecyl sulfate (SDS). The results showed that 2% SDS exhibited remarkable improvement in shear strength and viscosity of MSWA. The grafted reaction was demonstrated by ¹H NMR and the steady shear results indicated that the adhesive possessed a pseudoplastic behavior under yield stress conditions. Besides, dynamic rheological measurements were applied to evaluate the structure of MSWA under varying frequencies, temperatures and constant stain. The transmission electron microscopy (TEM), Zeta potential and surface tension indicated that SDS could improve the surficial properties. Meanwhile, the microstructure of adhesive films and fracture surfaces of glued wood veneers by scanning electron microscopy (SEM) demonstrated that the migration of SDS led to the formation of surfactant layer. Furthermore, element analysis revealed the distribution of S/N in latex slices. The results of this study provide the detailed information about the influence of SDS on the rheological properties and microstructures of MSWA, which may facilitate the preparation of high performance bio-based adhesive for wood applications.