Characterization of phosphorylated cross-linked resistant starch by 31P nuclear magnetic resonance (31P NMR) spectroscopy

Crosslinking ability of hydrolyzed distarch phosphate and its stabilizing effect on rehydrated sea cucumber

Effective crosslinking among food constituents has the potential to enhance their overall quality. Distarch phosphate (DSP), a common food additive employed as a thickening agent, bears a pre-crosslinked oligosaccharide (PCO) moiety within its molecular structure. Once this moiety is released, its double reducing end has the potential to undergo crosslinking with amino-rich macromolecules through Maillard reaction. In this study, hydrolyzed distarch phosphate (HDSP) was synthesized, and spectroscopic analysis verified the presence of PCO within HDSP. Preliminary validation experiment showed that HDSP could crosslink chitosan to form a hydrogel and significant browning was also observed during the process. Furthermore, rehydrated sea cucumber (RSC) crosslinked with HDSP exhibited a more intact appearance, higher mechanical strength, better color profile, and increased water-holding capacity. This series of results have confirmed that HDSP is capable to crosslink amino-rich macromolecules and form more stable three-dimensional network.

Resistant starch and the gut microbiome: Exploring beneficial interactions and dietary impacts

The intricate relationship between resistant starch (RS) and the gut microbiome presents a dynamic frontier in nutrition science. This review synthesizes current understandings of how RS, an indigestible form of starch found naturally in certain foods and also enhanced through various modification methods, interacts with the gut microbiome. We particularly focus on how RS fermentation in the colon contributes to the production of beneficial volatile fatty acids (VFAs) such as butyrate, acetate, and propionate. These VFAs have been recognized for their vital roles in maintaining gut barrier integrity, modulating inflammation, and potentially influencing systemic health. Additionally, we discuss the dietary implications of consuming foods rich in RS, both in terms of gut health and broader metabolic outcomes. By consolidating these insights, we emphasize the significance of RS in the context of dietary strategies aimed at harnessing the gut microbiome's potential to impact human health.

Biodegradable Dextrin-Based Microgels for Slow Release of Dual Fertilizers for Sustainable Agriculture

In this research, we report dextrin-based biodegradable microgels (PDXE MGs) having phosphate-based cross-linking units for slow release of urea and a potential P source to improve fertilization. PDXE MGs (∼200 nm) are synthesized by cross-linking the lauroyl-functionalized dextrin chains with sodium tripolyphosphate. The developed PDXE MGs exhibit high loading (∼10%) and encapsulation efficiency (∼88%) for urea. It is observed that functionalization of PDXE MGs with lauroyl chains slows down the release of urea (90% in ∼24 days) as compared to nonfunctionalized microgels (PDX MGs) (99% in ∼17 days) in water. Further studies of the developed formulation display that Urea@PDXE MGs significantly boost maize seed germination and overall plant growth as compared to pure urea fertilizer. Moreover, analysis of maize leaves obtained from plants treated with Urea@PDXE MGs reveals 3.5 ± 0.3% nitrogen content and 90 ± 0.7 mg/g chlorophyll content. These values are significantly higher than 1.4 ± 0.6% nitrogen content and 48 ± 0.05 mg/g chlorophyll content obtained by using bare urea. Further, acid phosphatase activity in roots is reduced upon treatment with PDXE MGs and Urea@PDXE MGs, suggesting the availability of P upon degradation of PDXE MGs by the amylase enzyme in soil. These experimental results present the developed microgel-based biodegradable formulation with a slow release feature as a potential candidate to move toward sustainable agriculture practices.

Food LEGO: Building hollow cage and sheet superstructures from starch

The idea of building large structures from small building blocks has had a long history in the human imagination, from the beautifully intricate shells assembled from silica by unicellular algae to the Egyptian pyramids built from stone. Carrying this idea into the food industry has important implications. Here, we introduce a Pickering emulsion platform for building superstructures like hollow cages and sheets using starch granules as building blocks. In food, these superstructures occupy up to six times more space than their constituent parts, thereby delivering a viscosity greater by an order of magnitude than unstructured starch. To achieve this higher viscosity, they use an alternative superstructure mechanism as opposed to the classic swelling mechanism of individual particles. These super-thickeners may reduce calories, cut production costs, and stretch the global food supply, demonstrating how we can design the future by playing with our food.

Production and characterization of starch-lignin based materials: A review

In their pristine state, starch and lignin are abundant and inexpensive natural polymers frequently considered green alternatives to oil-based and synthetic polymers. Despite their availability and owing to their physicochemical properties; starch and lignin are not often utilized in their pristine forms for high-performance applications. Generally, chemical and physical modifications transform them into starch- and lignin-based materials with broadened properties and functionality. In the last decade, the combination of starch and lignin for producing reinforced materials has gained significant attention. The reinforcing of starch matrices with lignin has received primary focus because of the enhanced water sensitivity, UV protection, and mechanical and thermal resistance that lignin introduces to starch-based materials. This review paper aims to assess starch-lignin materials' production and characterization technologies, highlighting their physicochemical properties, outcomes, challenges, and opportunities. First, this paper describes the current status, sources, and chemical modifications of lignin and starch. Next, the discussion is oriented toward starch-lignin materials and their production approaches, such as blends, composites, plasticized/crosslinked films, and coupled polymers. Special attention is given to the characterization methods of starch-lignin materials, focusing on their advantages, disadvantages, and expected outcomes. Finally, the challenges, opportunities, and future perspectives in developing starch-lignin materials, such as adhesives, coatings, films, and controlled delivery systems, are discussed.

A novel efficient wet process for preparing cross-linked starch: Impact of urea on cross-linking performance

Although wet processes are promising for preparing cross-linked starch, they are currently challenged by lower cross-linking efficiency and the requirement of large amounts of salts. Herein, an efficient and greener wet process was proposed, in which the cross-linking performance between sodium hexametaphosphate (SHMP) and starch was enhanced with the aid of urea. The maximum degree of substitution (DS) of the urea-phosphorylated cross-linked starch (UPCS) was 0.040 at 35 °C, while that of the conventional phosphorylated cross-linked starch (CPCS) was 0.031 at 45 °C. Compared with CPCS, the maximum DS of UPCS was elevated by 29.03 %, but its optimum cross-linking temperature was reduced by 10 °C, indicating that the cross-linking efficiency of this novel wet process was greatly improved by urea. The structural difference between UPCS and CPCS was confirmed by using a series of techniques including 31P NMR and 13C NMR. Zeta potential results suggested that urea may promote starch cross-linking by preventing the closure of active sites through hydrophobic interactions. Due to the structural reinforcement of starch by urea, UPCS showed better thermal stability, water resistance, acid and alkali resistance, and steady shear tolerance properties. This study provides a facile wet process for the fabrication and application of cross-linked starch materials.

Phosphorylation and citration of normal corn starch by dry heating with phytic acid and citric acid

Normal corn starch was subjected to dry heating in the presence of phytic acid (PA, 2 %, starch basis) and citric acid (CA, 5 % and 10 %) for modification. Dual treatment with PA and CA induced structural and physicochemical changes in normal corn starch. Phosphorus concentration, degree of substitution, FTIR, and ³¹P NMR analyses confirmed esterification of starch by dry heating with PA and CA. Both phosphorylation and citration by esterification with PA and CA were observed in PA + 5CA starch, but high CA concentration inhibited covalent interaction between PA and starch in PA + 10CA starch. The degree of phosphorylation and citration resulted in different physicochemical properties in starch treated with PA and CA. The treatment with only PA did not change the crystalline regions of PA starch, but CA treatment induced the disruption of the crystalline structure of PA + 5CA and PA + 10CA starch. PA starch showed high solubility (46.41 %) and transmittance (90.51 %), but dual treatment of PA and CA induced significant decrease in solubility (3.23 %) and transmittance (2.18 %) of PA + 10CA starch. CA treatment increased the fraction of resistant starch in non-cooked (72.44 %) and cooked PA + 10CA starch (42.76 %). Therefore, dual treatment with PA and CA had potential to control physicochemical and functional properties of starch by phosphorylation and citration of starch.

A novel lotus seed cross-linked resistant starch: Structural, physicochemical and digestive properties

The structural properties and physicochemical characteristics of lotus seed cross-linked resistant starches (LSCSs; LS-0CS, LS-1CS, LS-2CS, LS-4CS, LS-6CS, LS-8CS, LS-10CS, and LS-12CS) with different concentrations of cross-linking agents were investigated. The degrees of cross-linking of LSCSs increased along with the amount of cross-linking agent. The higher the degree of cross-linking, the greater the degree of LSCSs granule agglomeration. The occurrence of the cross-linking reaction was confirmed by the appearance of P = O at 1,250 cm^–1 as assessed by FT-IR, and the covalent bonds formed by the phosphate group in LSCSs were mainly composed of distarch monophosphate (DMSP) as determined by ³¹P NMR. As the crosslinking degree increased, the peak strength of DMSP in starch was stronger and the specific gravity of DMSP was larger. Among the samples, LS-12CS had the highest cross-linking degree, with a greater specific gravity of DMSP. Moreover, the solubility levels of LSCSs decreased and the thermal stability and anti-digestive properties improved as the cross-linking degree increased, which was correlated with the degree of agglomeration and DMSP in LSCSs. The RS content of LS-12CS was 48.95 ± 0.86%.

Preparation and structural properties of starch phosphate modified by alkaline phosphatase

In this study, a method for the synthesis of starch phosphate using the transferase properties of alkaline phosphatase was explored. Maize starch was treated with a pyrophosphate solution containing alkaline phosphatase and catalytic ions under pH 8 at 37 °C. The synthesis of starch phosphate was evaluated and compared with untreated and treated starch controls. The phosphorus content of the samples increased up to 8500% with the catalytic ion concentration, whereas the peak viscosity by up to 41.4% decreased. The crystallinity and enthalpy of the phosphorylated samples were reduced by up to 26.8% and 23.3%, respectively; however, no significant was observed by Fourier-transform infrared spectrometer. The roughness of the starch surface and the distribution of elemental phosphorus were observed by scanning electron microscopy and energy dispersive Spectrometry. X-ray photoelectron spectroscopy and time of flight secondary ion mass spectrometry results further indicated the grafting of the phosphate radical.

Distribution and Quantification of Diverse Functional Groups on Phosphorylated Nanocellulose Surfaces

Phosphorylated cellulose nanofiber (CNF) is attracting attention as a newly emerged CNF with high functionality. However, many structural aspects of phosphorylated CNF remain unclear. In this study, we investigated the chemical structures and distribution of ionic functional groups on the phosphorylated CNF surfaces via liquid-state nuclear magnetic resonance measurements of colloidal dispersion. In addition to the monophosphate group, polyphosphate groups and cross-linked phosphate groups were introduced in the phosphorylated CNFs. The proportion of polyphosphate groups increased as the phosphorylation time increased, reaching ∼30% of all phosphate groups. Only a small amount of cross-linked phosphate groups existed in the phosphorylated CNF after a prolonged reaction time. Furthermore, phosphorylation of cellulose using urea and phosphoric acid was found to be regioselective at the C2 and C6 positions. There existed no significant difference between the surface degrees of substitution at the C2 and C6 positions of the phosphorylated CNFs.

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.

Starch chemical modifications applied to drug delivery systems: From fundamentals to FDA-approved raw materials

Starch derivatives are versatile compounds that are widely used in the pharmaceutical industry. This article reviews the advances in the research on hydrophilic and hydrophobic starch derivatives used to develop drug delivery systems over the last ten years, specifically microparticles, nanoparticles, nanocrystals, hydrogels, and scaffolds using these materials. The fundamentals of drug delivery systems, regulatory aspects, and chemical modifications are also discussed, along with the synthesis of starch derivatives via oxidation, etherification, acid hydrolysis, esterification, and cross-linking. The chemical modification of starch as a means to overcome the challenges in obtaining solid dosage forms is also reviewed. In particular, dialdehyde starches are potential derivatives for direct drug attachment; carboxymethyl starches are used for drug encapsulation and release, giving rise to pH-sensitive devices through electrostatic interactions; and starch nanocrystals have high potential as hydrogel fillers to improve mechanical properties and control drug release through hydrophilic interactions. Starch esterification with alginate and acidic drugs could be very useful for site-specific, controlled release. Starch cross-linking with other biopolymers such as xanthan gum is promising for obtaining novel polyelectrolyte hydrogels with improved functional properties. Surface modification of starch nanoparticles by cross-linking and esterification reactions is a potential approach to obtain novel, smart solid dosages.

The relationship between rheological and textural properties of shrimp surimi adding starch and 3D printability based on principal component analysis

The three-dimensional (3D) printing properties of pure shrimp surimi are poor and require improvement via the addition of other materials. The effects of the different amounts of potato starch, corn starch, tapioca starch, and cross-linked starch (CLS) (0%, 3%, 6%, or 9%, respectively) on the 3D printing properties and material properties of white shrimp (Litopenaeus vannamei) surimi were evaluated in the present study. The results showed that the apparent viscosity, G', and G'' of the samples were increased by adding 6% CLS, making it easy to extrude the sample from the nozzle and resulting in an improvement in the printing accuracy. In addition, after adding 6% CLS, the hardness, adhesiveness, and springiness of the sample were increased, which assist with maintaining the shape of the printed material and improve the printing stability of the sample. Moreover, the water holding capacity of shrimp surimi increased as a result of the addition of 6% CLS. In summary, 6% CLS can improve the material properties of shrimp surimi and make it more suitable for 3D printing.

Gel growth of aqueous konjac glucomannan solution containing sodium trimetaphosphate dialyzed with dilute sodium hydroxide

The growth rate of the hydrogel of the aqueous konjac glucomannan (KGM) solution containing sodium trimetaphosphate (STMP) dialyzed with aqueous NaOH was investigated in a rectangular cell. The growth rate of the KGM-STMP gel depended on both the KGM and STMP concentrations in addition to the NaOH concentration. The initial growth rate of the KGM-STMP gel was closely related to the diffusion of NaOH into the KGM-STMP solution, leading to the ring-opening reaction of STMP and the deacetylation of KGM at the interface. The time course of the gelation of the KGM-STMP solution was analyzed on the basis of the moving boundary picture theory by introducing the characteristic length to express the consumption of NaOH in the gel layer accompanying the decomposition of STMP. Dynamic mechanical measurements were performed to compare the gelation of the KGM-STMP solution mixed homogeneously with dilute NaOH and the gel dynamics by the dialysis method.

Intrinsic Apyrase-Like Activity of Cerium-Based Metal-Organic Frameworks (MOFs): Dephosphorylation of Adenosine Tri- and Diphosphate

Apyrase is an important family of extracellular enzymes that catalyse the hydrolysis of high-energy phosphate bonds (HEPBs) in ATP and ADP, thereby modulating many physiological processes and driving life activities. Herein, we report an unexpected discovery that cerium-based metal-organic frameworks (Ce-MOFs) of UiO-66(Ce) have intrinsic apyrase-like activity for ATP/ADP-related physiological processes. The abundant Ce^III /Ce^IV couple sites of Ce-MOFs endow them with the ability to selectively catalyse the hydrolysis of HEPBs of ATP and ADP under physiological conditions. Compared to natural enzymes, they could resist extreme pH and temperature, and present a broad range of working conditions. Based on this finding, a significant inhibitory effect on ADP-induced platelet aggregation was observed upon exposing the platelet-rich plasma (PRP) to the biomimetic UiO-66(Ce) films, prefiguring their wide application potentials in medicine and biotechnology.

Starch phosphorylation and the in vivo regulation of starch metabolism and characteristics

Starch is the most significant carbon and energy reserve in plants and is also a sustainable feedstock for many industrial applications. Substantial research effort has been devoted to enhancing the yield and quality of starch. Over the past century, starch phosphorylation has aroused increasing interest as the only naturally occurring covalent modification in starch. Many studies have investigated the role of phosphorylation in starch metabolism and its impact on the starch granule. In this review, the two key enzymes involved in starch phosphorylation and their catalytic mechanisms are described at the molecular level; the vital roles of phosphorylation in starch degradation and biosynthesis are illuminated in detail; and the multiple influences of phosphorylation on starch composition, granule structure and physicochemical properties are discussed. This review systematically summarizes the importance of phosphorylation in starch metabolism, and describes the advanced methods used to precisely measure phosphate and increase the level of starch phosphorylation.

Derivatization approaches and applications of pullulan

Pullulan (PUL), a linear exo-polysaccharide, is useful in industries as diverse as food, cosmetics and pharmaceuticals. PUL presents many favorable characteristics, such as renewable origin, biocompatibility, stability, hydrophilic nature, and availability of reactive sites for chemical modification. With an inherent affinity to asialoglycoprotein receptors, PUL can be used for targeted drug delivery to the liver. Besides, these primary properties have been combined with modern synthetic approaches for developing multifunctional biomaterials. This is evident from numerous studies on approaches, such as hydrophobic modification, cross-linking, grafting and transformation as a polyelectrolyte. In this review, we have discussed up-to-date advances on chemical modifications and emerging applications of PUL in targeted theranostics and tissue engineering. Besides, we offer an overview of its applications in food, cosmetics and environment remediation.

Physicochemical and morphological properties of resistant starch type 4 prepared under ultrasound and conventional conditions and their in-vitro and in-vivo digestibilities

In the present work, cross-linked resistant starch (RS4) was prepared under sonication and conventional conditions at various levels of pH (9-12) and cross-linker concentration (sodium trimetaphosphate/sodium tripolyphosphate 99:1, 5-15%). It was found that phosphorous and resistant starch content was generally increased by increasing the cross-linker concentration, pH and application of sonication. The damage to the surface of sonicated granules was revealed by scanning electron micrographs. The presence of cross-linked phosphorous groups was demonstrated by FT-IR results through the appearance of a new peak at wave numbers of 1248-1252 cm^-1 that was more conspicuous in sonicated cross-linked samples. Sonicated cross-linked starches showed higher gelatinization temperatures and lower degrees of crystallinity, while no changes was detected in terms of A-type crystalline pattern. The development of viscosity was diminished prominently by the extreme cross-linking reactions in both sonicated and conventional cross-linked starches. The least glycemic index value was obtained for sonicated cross-linked starches which was negatively correlated to their higher RS content measured in-vitro. These results provide novel information on the preparation of cross-linked resistant starch under sonication conditions.

In Vitro Digestibility of Nanoporous Wheat Starch Aerogels

This study reports the in vitro digestibility of starch aerogels for the first time. The relative crystallinities of the wheat starch aerogels (WSAs) produced at gelatinization temperatures of 120 °C (WSA-120C), 130 °C (WSA-130C), and 120 °C with the addition of sodium metaphosphate (STMP) (WSA-STMP) and xerogel were similar. However, WSA-120C showed the highest amylose-lipid complex content. The addition of STMP created some cross-linked starch with a phosphorus content of 0.023%. Resistant starch (RS) contents of WSA-STMP (33.5%) and xerogel (26.9%) were higher than the other samples when they were uncooked prior to digestion. Nevertheless, the RS contents of WSA-STMP and xerogel decreased drastically with cooking. RS contents of WSA-120C and WSA-130C were stable with cooking and provided 4.5- and 3.0-fold increases in the RS content, respectively. WSA is a promising functional food ingredient with a high RS content, even after cooking.