Cross-linked Starch Research Articles

Preparation and Characterization of Carboxymethylated and Cross-Linked Enset Starch as a Disintegrant in Tablets

Starch and modified starches have been commonly employed as excipient in pharmaceutical industry. The use of non-modified or “native” starch, However, is mostly confined due to limitation in several physicochemical properties. Cross-linked sodium carboxymethyl starch which is also known as sodium starch glycolate is extensively used in fast dissolving tablets to disperse the drugs within short span of time. In this study, enset starch was carboxymethylated and subsequently cross-linked. Carboxymethyl enset starch (CMES) was obtained by reacting enset starch and monochloroacetic acid (MCA) in the presence of sodium hydroxide. CMESs having different degree of substitution (DS) were cross-linked at variousconcentrations (2.5, 5 and 10% w/w) of sodium hexametaphosphate (SHMP) to provide sodium starch glycolate of enset starch (SSG-E). The fourier transform infrared (FTIR) spectra confirmed the presence of carboxymethylated group in the modified starch granules with new band at 1608.52 cm-1. This dually modified enset starch (SSG-E) was evaluated as a potential disintegrant in paracetamol tablets in comparison with commercially available sodium starch glycolate, Disegel. Carboxymethylation was significantly influenced by reaction medium, reaction temperature and reaction time (p < 0.05). CMES with higher DS (0.437 ± 0.03) exhibited higher peak viscosity than CMES with lower DS (0.224 ± 0.01). Despite exhibiting greater swelling power, CMES showed significantly lower pasting viscosity compared to the native starch (p < 0.05). At 2.5% SHMP, the dually modified starch (SSG-E) exhibited significant increase in swelling but its rate of water-uptake was lower than that of Disegel. As the SHMP concentration wasincreased from 2.5 to 5%, the swelling power decreased significantly (p < 0.05). When the concentration was increased to 10% the swelling power increased significantly (p < 0.05). At 2.5% SHMP concentration SSG-E showed a viscosity comparable to that of CMES. As the concentration of SHMP increased to 5 and to 10% w/w, significant decrease in viscosity (p < 0.05) was observed. Compared to the native enset starch (NES), the solubility of SSG-E was more than 4-fold, but its viscosity was much lower than that of CMESs. The SSG-E exhibited lower moisture sorption than CMES but higher sorption than NES. SSG-E showed good flowability, superior swelling power and solubility than NES. The disintegration time (DT) of paracetamol tablets containing SSG-E as a disintegrant was comparable to those tablets with similar concentration of Disegel. At 4% SSG-E, paracetamol tablets exhibited DT less than 1 min.
 Keywords: carboxymethylation, degree of cross-linking, enset starch, paracetamol tablets, sodium starch glycolate

Formulation and Evaluation of Cyperus esculentus (Tiger Nut) Starch-Alginate Microbeads in the Oral Delivery of Ibuprofen

Microencapsulation is a technique employed in the development of controlled drug delivery systems. It is beneficial in reducing dosing frequency, ensuring targeted drug delivery, and improving drug bioavailability. The objective of this study was to evaluate the effectiveness of Cyperus esculentus starch and its derivative in the development of microbeads for sustained delivery of ibuprofen. Ibuprofen-loaded microbeads were prepared by ionotropic gelation using Cyperus esculentus starch and its derivative in combination with sodium alginate at concentrations of 1:1, 1:2, and 2:1 and calcium chloride solution as cross-linker. Morphology of the microbeads by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), and differential scanning calorimetry (DSC) were investigated. Entrapment efficiency, swelling capacity, mucoadhesion, and in vitro drug release were also evaluated. SEM showed that the microbeads were spherical to irregular in shape, FT-IR returned prominent peaks specific for ibuprofen and absence of new peaks, DSC revealed evidence of entrapment of ibuprofen in the microbeads, and entrapment efficiency ranged between 46.05 and 89.86%. Microbeads prepared with native and cross-linked starches showed better mucoadhesion, and those prepared with cross-linked starch blend exhibited highest swelling capacity. In vitro release was pH dependent, and increasing the concentration of cross-linked starch in the blend caused greater retardation of drug release (45.19%) than the formulations containing native starch-alginate blend or sodium alginate alone. The blend of cross-linked Cyperus esculentus starch and sodium alginate shows propensity to sustain ibuprofen release and could be exploited for targeted delivery especially to the lower GIT.

Properties of extruded cross-linked waxy maize starches and their effects on extruded oat flour

The objectives of this study were to study the extrusion of cross-linked waxy maize starches (CLWMS) with different cross-linking levels and their function as a secondary ingredient in extruded oat flour (OF) formulations. CLWMS (18 %) and OF (82 %) were hydrated to 20 % moisture content and subjected to twin-screw extrusion at the screw speed of 350 rpm. Low cross-linking level of CLWMS (0.05 % sodium trimetaphosphate/sodium tripolyphosphate) in OF formulation increased the void fraction and reduced the breaking strength of extrudates. The low cross-linked starch was more resistant to breakdown and had a higher pasting viscosity than the unmodified starch. Higher cross-linking levels of CLWMS restricted swelling of starch granule and increased the resistant starch level of OF formulation but had very poor structural and textural properties. Varying the level of cross-linking offers an alternative way to manipulate the structural, textural and nutritional properties of extrudates in snack and cereal applications.

Production and Properties of Starch Citrates-Current Research.

Starch modification by chemical reaction is widely used to improve the properties of native starch. Modified by citric acid, starch is characterized by specific properties resulting from the presence of citrate residues and as a result of cross-linking starch. The chemicals used for preparing starch citrates are safe for human health and the natural environment compared to the harsh chemicals used for conventional modifications. Starch citrates are traditionally produced by heating starch–citric acid mixtures in semi-dry conditions or by a heat moisture treatment. The conditions of the modification process (roasting temperature, heating time, citric acid dose) and the botanic source or genotype of starch determine the degree of substitution and the properties of the obtained preparations. Changes of starch properties occurring during esterification lead to reduced relative crystallinity, resulting in a decrease in the affinity for water, the gelatinization parameters, and the viscosity of starch citrate. However, one of the most important outcome of the modification is the formation of resistant starch (RS), which has increased resistance to the action of amylolytic enzymes. Currently, new methods for producing starch citrates with improved functional and rheological properties while maintaining the highest possible content of resistant starch are being sought. The article presents an overview of recent studies on the production, properties. And applicability of starch citrates with special attention paid to their role as preparations of resistant starch (RS). The use of citric acid for modification of starch is better for the technology process, while using cross-linking is better than simply using esterification.

Effect of the epichlorohydrin grafting of starch on its pyrolysis behavior and mechanism

Crosslinking is a common method for preparing biomass-based carbon materials. Corn starch grafted with epichlorohydrin was prepared and then stabilized and carbonized to obtain starch-based near-spherical carbon materials. The pyrolysis of corn starch under the influence of epichlorohydrin was analyzed by TG-MS, and the micro-morphology and crystal structure of the near-spherical carbon materials were characterized by SEM and XRD. The surface chemical evolution of the starch before and after pyrolysis was characterized by in-situ FTIR. The modified starch pyrolysis and the cross-linking reactions between epichlorohydrin and starch were investigated. Results indicate that for the modified starch the temperature at which the weight loss rate is a maximum is lowered so that the pyrolysis is relatively mild, and the destruction of the basic skeleton is reduced and the carbon yield greatly increased compared with pristine starch. The cross-linked starch tends to transform to aromatic structures in pyrolysis, the carbonization degree of the hydrolysate is improved, and the yield of the final product is increased compared to the non-crosslinked material. During pyrolysis, epichlorohydrin cross-links with starch to form a network structure, which stabilizes the starch skeleton, thus reducing the production of volatile small molecules.

Effect of hydrocolloids on normal and waxy maize starches cross-linked with epichlorohydrin

Research was conducted to test the hypothesis that the surface charge on maize starch granules cross-linked with POCl3 affects how hydrocolloids (HC) interact with them. Normal (NMS) and waxy maize (WMS) starches were cross-linked with epichlorohydrin (ECH) to 2 extents. The products were heated in water or one of 9 HC solutions, and the pasting and paste properties and the rheological attributes of the produced gels were determined and compared to those of POCl3 cross-linked NMS and WMS. Results confirm the hypothesis that the ability of HC to alter early events in the pasting process is an important factor in their effects in altering the properties of starch pastes, as all HC used appeared to have an effect on granule swelling of heated slurries of both native and cross-linked starches. Differences in the effect produced by the different HC on the pasting and paste properties of POCl3 and ECH cross-linked products of both NMS and WMS appeared primarily to be in degree and unrelated to whether the cross-linked starch had a negative surface charge. Two mechanisms are proposed for the influence of HC on granule swelling: 1) strengthening of granules via interactions with HC molecules, and 2) inhibition of water penetration and, therefore, granule swelling by plugging of granule micro- and mesopores by those hydrated HC molecules that are too large to enter them. Rheological properties of the produced gels determined before and after cold storage also had both similarities and differences in effects produced by addition of a HC.

PENGARUH KONSENTRASI STPP DAN LAMA PERENDAMAN TERHADAP KARAKTERISTIK PATI KIMPUL TERMODIFIKASI IKATAN SILANG

Kimpul is one type of tubers that is high in carbohydrate content so it canbe used as a source of starch. Natural starch generally still has severaldisadvantages. One of method that can be done to overcome theseweaknesses is by modifying cross-linked starch. The objectives of thisstudy are: 1) to know the effect of STPP concentration on chemical andphysical characteristics of modified kimpul starch; 2) to know the effect ofsoaking time on chemical and physical characteristics of modified kimpulstarch; 3) to determine the best combination treatment between STPPconcentration and soaking time on the chemical and physicalcharacteristics of modified kimpul starches. This is an experimentalresearch with Randomized Block Design. The factors studied were theconcentration of sodium trypolyphosphate (1, 2 and 3%) and soaking time(60 and 90 minutes). The variables tested were moisture content, starchcontent, amylose content and calcium oxalate content, brightness, swellingpower, sollubility and its amylographic properties. The results showedthat both STPP concentration factors and soaking time affected themodified chemical and physical characteristics of kimpul starchcrosslinking methods. The chemical and physical characteristics of crossbonded modified kimpul starch increased with STPP concentration andsoaking time used. Modified kimpul starch using 3% STPP concentrationand 90 minutes soaking time had moisture content, starch content, amylosecontent, calcium oxalate content, brightness and high swelling power. Thebest modified kimpul starch is modified kimpul starch using 2% STPPconcentration and 60 minutes soaking time. It has a water content of7,88%, starch content of 63,13%, amylose content of 17,28%, oxalatecontent of 15,84 ppm, swelling power 15,79 g/g, sollubility 11,55%,brightness of 44.13, initial gelatinization temperature of 78,75oC, peakviscosity of 5152.5 cP, hot paste viscosity of 2310,4 cP, breakdownviscosity of 2815 cP, setback viscosity of 1563 cP and cold paste viscosityof 3873,5 cP

Synthesis and adsorption properties of cross-linked carboxymethyl starch (CMS)

Cross-linked carboxymethyl starch CMS was synthesized with cross-linked starch as raw material, sodium chloroacetate as etherification agent and sodium hydroxide as catalyst, and the structure of the product was characterized by FTIR, SEM and XRD. The optimum synthesis conditions of CMS were m (CSt): m (MCA) = 5:3, NaOH dosage 12 ml, reaction temperature 55 °C and reaction time 3 h. When the concentration of copper ion in the simulated water sample was 25 mg/L and the dosage of CMS was 2 g/L, the removal rate of copper ion was 96.0%, and the adsorption capacity of CMS was 15.4 mg/g.

The effects of starch cross-linking, stabilization and pre-gelatinization at reducing gluten-free bread staling

Gluten-free breads are characterized by a rapid staling and short shelf-life, therefore increasing bread waste. To reduce staling, physically and/or chemically modified starches were incorporated at 10 and 20% levels in gluten-free breads. Di-starch phosphate (DP), acetylated di-starch adipate (ADA), and pregelatinized acetylated di-starch phosphate (PADP) were used. All modified starches at 10% of replacement and 20% ADA starch decreased crumb hardness and increased cohesiveness not only on the same day of baking but also after 7-days of storage. Conversely, breads with 20% PADP starch, with a lower specific volume, due to greater dough viscoelastic behavior, showed harder and less cohesive crumbs. Moisture loss ranged from day 0–7 from 6.4 to 11.0%, being especially significant in low-volume breads. Calorimetry results denoted a lower propensity of ADA and PADP starches to retrograde (amylopectin retrogradation) compared to DP, due to the dual cross-linking/acetylation modification. Among all starches, ADA was the most promising starch for reducing and delaying hardness and loss of cohesiveness in breads, with hardness (20% ADA) at day 7 similar to control at day 1.

Trial of Available Energy Evaluation of Highly Cross-linked Starch and Modified Cellulose Based on Breath H2 Excretion

Background: The energy value of a substance is essential in nutritional labeling. However, the available energy of newly developed highly cross-linked phosphate starch (HCPS-N) and modified cellulose (MC) are unknown. Objective: To evaluate the available energy of HCPS-N and MC, an indirect and simple method which was applied as an indicator of the fermentability based on the breath hydrogen excretion, was used. Methods: HCPS-N was made from tapioca starch by polymerization in the presence of 0.5% phosphoric acid. MC was made from microcrystalline cellulose, maltodextrin, and karaya gum to attain a highly stable suspension. The present study was carried out using a within-subject, repeatedmeasures design. Blood was collected at 30 min intervals for 3 h after the ingestion of 30 g of a test substance. The end-respiratory gas was collected for 14 h after ingestion of 5 g of a test substance to evaluate the available energy. Results and Discussion: Plasma glucose and insulin levels did not elevate after the ingestion of HCPS-N, although they increased significantly after glucose ingestion. In the experiments to evaluate the available energy, breath hydrogen excretion after ingesting HCPS-N did not increase distinctly during the experiment. Breath hydrogen excretion after preceding HCPS-P (0 kcal) ingestion was also markedly smaller compared with the peak value at 4 h after FOS ingestion. For the ingestion of MC, breath hydrogen excretion increased scarcely, and the basal level remained until the end of the experiment. Conclusion: The available energies were evaluated to be 0 kcal/g for HCPS-N and 1 kcal/g for MC in healthy humans.

Highly Cross-linked Starch and Modified Cellulose as Dietary Fibers, and their Acclimation Effect on Hydrogen Excretion in Rats

Background: Highly cross-linked phosphate starch (HCPS) and modified cellulose (MC) were newly developed and modified dietary fiber materials to prevent lifestyle-related diseases. Objective: We investigated the physiological property of HCPS and MC to be a dietary fiber. Methods: HCPS was made from tapioca starch by polymerization in the presence of 0.5% phosphoric acid, and MC was made from cellulose, maltodextrin and karaya gum by high-speed mixing. In the present study, rats were raised on a diet containing 10% or 15% HCPS, or 10% MC for four weeks, and physical effects such as growth, organ weights, blood biomedical parameters, fecal weight, and hydrogen excretion were recorded. Results: Growth was normal among all groups, and there was no significant difference in total body weight gain. Some organ weights including the adipose tissues differed slightly among groups, but no difference based on diet composition was observed. Blood biomedical parameters were normal and not significantly different among groups. Cecum tissue and content weights were significantly greater in the 15% HCPS, 10% MC, and 10% fructooligosaccharide (FOS) groups than in the control group, and fecal weight was significantly increased in the 10% and 15% HCPS, and 10% MC groups compared with the control group. Hydrogen excretion over 24 h was negligible when HCPS was administered orally to rats non-acclimatized to HCPS but increased significantly in rats acclimatized to 10% HCPS diet for one week. Conclusion: We conclude that both HCPS and MC could be suitable for use as low energy bulking materials.

Preparation and characterization of C-phycocyanin coated with STMP/STPP cross-linked starches from different botanical sources

This work aimed to use sodium trimetaphosphate/sodium tripolyphosphate cross-linked potato, banana, corn, cassava, and breadfruit starches as wall materials for C-phycocyanin encapsulation, characterize them and evaluate their in vivo pharmacological effects in an inflammation model. The cross-linked starches were successfully obtained, characterized, and submitted to C-phycocyanin encapsulation by freeze-drying. The characterization of cross-linked starches-C-phycocyanin composites by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetry, and differential scanning calorimetry demonstrated that the C-phycocyanin was encapsulated between amorphous chains of cross-linked starches. Among the five preparations, the cross-linked potato starch presented the highest phosphorous content (0.084%), substitution degree (0.004), water uptake capacity (0.88 g g−1), and C-phycocyanin encapsulation efficiency (67.58%), thus was tested in vivo. The cross-linked potato starch-C-phycocyanin prolonged the antihyperalgesic effects attributed to C-phycocyanin, evaluated by complete Freund's adjuvant (CFA) model. Starch cross-linking promoted the formation of a hydrogel network in swollen state entrapping C-phycocyanin, thus, acting as a barrier to its release to the medium and promoting long-lasting in vivo effects. The combination of chemical modification of starches followed by physical treatment presented itself as a useful tool for the development of pharmaceutical formulations.

Hydroxyethyl starch nanocapsules by multiple nanoemulsions for carrying and controlled release of lapachol

In the present work, an alternative to synthesized nanocapsules in which the lipophilic core was a multiple nanoemulsification forming a complex system constituted of various phases was studied. A primary emulsion (O/W) was poured into another lipophilic solvent, forming a multiple nanoemulsion (O/W/O) able to provide the encapsulation of lapachol, a lipophilic drug. The synthesized nanocapsules were well characterized and the results demonstrate a core-shell morphology, based on the polyurethane formation that exists in the cross-linked starch shell. Furthermore, these systems have moderate stability, with particle size measuring up to 274 nm. The nanocapsules containing lapachol encapsulated 73% of the drug initially added. This demonstrates success in the synthetic route adopted, evidenced by the efficiency of incorporation of the lapachol, in addition of providing a controlled release, reaching 51.4% in 24 h. This behavior shows that the polymeric shell influences the drug release profile and it is in accordance with the kinetic model proposed by Peppas.

Injectable hydrogel wound dressing based on strontium ion cross-linked starch

Severe skin wounds cause great problems and sufferings to patients. In this study, an injectable wound dressing based on strontium ion cross-linked starch hydrogel (SSH) was developed and evaluated. The good inject-ability of SSH made it easy to be delivered onto the wound surface. The good tissue adhesiveness of SSH ensured a firm protection of the wound. Besides, SSH supported the proliferation of NIH/3T3 fibroblasts and facilitated the migration of human umbilical vein endothelial cells (HUVECs). Importantly, SSH exhibited strong antibacterial effects on Staphylococcus aureus (S. aureus), which could prevent wound infection. These results demonstrate that SSH is a promising wound dressing material for promoting wound healing.

Effect of cross-linking on physico-chemical, thermal, pasting, in vitro digestibility and film forming properties of Faba bean (Vicia faba L.) starch

Faba bean starch was crosslinked (CL) at different levels (1, 3 & 5%) using sodium trimetaphosphate and studied for physicochemical, thermal, pasting and in vitro digestibility characteristics. Further, films were prepared from these starches and characterized for moisture content, thickness, water solubility, opacity, water vapor permeability (WVP) and mechanical properties. Amylose content, swelling power and solubility decreased after modification. CL resulted in decrease in peak viscosity (PV) whereas pasting temperature increased; CL (5%) showed the lowest PV (6474 mPa.s). Steady shear properties showed flow behavior index values <1 for starch pastes, indicating pseudoplastic and shear-thinning behavior. Thermal properties of CL starches showed higher transition temperatures and enthalpy of gelatinization (ΔHgel) as compared to native starch. ΔHgel values of CL starches ranged from 10.70 to 14.20 J/g whereas for native starch, the value was 9.47 J/g. CL resulted in increased resistant starch (from 49.8 to 61.1%), the highest value was for CL (5%). CL starch films exhibited lower moisture content, water solubility and WVP. Film thickness, however, was not affected by modification. CL (5%) starch film showed the highest tensile strength (14.28 MPa) and the lowest elongation at break (25.62%). CL resulted in improved mechanical and barrier properties of starch films.

Degradable porous carboxymethyl chitin hemostatic microspheres

Lethal hemorrhage could endanger lives. Although many hemostatic agents are commercially available with good clinical effect, it is necessary to develop novel hemostatic materials with high efficacy, biological safety, low cost, easily preparation and excellent biodegradability and biocompatibility. Here, novel biodegradable and uniform microspheres with regular spherical architecture and porous microstructure were prepared by thermosensitive carboxymethyl chitin (CMCH) with low substitution degree and low deacetylation through physical-crosslinking at high temperature without using any toxic crosslinkers. The obtained CMCH microspheres (CMCH-MS) were non-cytotoxic, low hemolytic potential and biodegradable in the presence of lysozyme. In vitro blood clotting evaluation indicated that the porous microsphere network structures and the hydrophilicity of the CMCH could promote hemostasis due to the quick blood absorption and local concentration of the coagulation factors for the CMCH-MS. The CMCH-MS showed much better hemorrhage control than negative control and traditional hemostatic chitosan, similar hemostatic performance as commercialized cross-linked starch microspheres in both rat tail and liver models. Thus, the new biodegradable porous CMCH-MS may hold great potential for hemorrhage control in medical treatment.

Comparison of utilisation and fermentation of highly cross-linked phosphate starches produced from two different plant origins, potato and tapioca in rats and humans

The utilisation and fermentation of highly cross-linked phosphate starches made from two different origins, potato (HXL-P) and tapioca (HXL-T) were investigated in rats and humans. HXL-P and HXL-T were highly resistant to digestion by carbohydrate enzymes and were also resistant to fermentation by gut microbiota in rats. The postprandial blood glucose scarcely increased after administration of HXL-P or HXL-T in healthy humans. Incremental AUC of both HXL-P and HXL-T for 180 min was significantly lower than that of glucose (p < .05). Breath hydrogen excretion was very low after oral administration of HXL-P or HXL-T, and AUCs of breath hydrogen excretion for 13 h after administration were significantly lower than that of fructooligosaccharide as a reference of fermentation (p < .05). These results show that HXL-P and HXL-T were hardly digested and were highly resistant to fermentation. In conclusion, HXL-P and HXL-T could be good low-energy bulking ingredients to replace wheat flour.

The fabrication of bilayer polylactic acid films from cross-linked starch as eco-friendly biodegradable materials: Synthesis, characterization, mechanical and physical properties

In this study, pure potato starch (PPS) was purified from waste potato residual to fabricate cross-linked bilayer materials with the casting method. Malonic acid (MA) was employed to get cross-linked material from PPS as PPS-MA. Then polylactic acid (PLA) was also implemented onto PPS and PPS-MA to produce bilayer materials as PPS-PLA and PPS-MA-PLA. The obtained these bilayer films were characterized by FTIR, XRD, and TGA. The mechanical and physical applications such as water vapor permeability, water uptake, moisture content, solubility, and opacity were investigated. The biodegradation calculations were also done by the process of composting. It has demonstrated that each application onto PPS increased the mechanical features. However, elongation wasn’t seen during the breaking test of PPS and PPS-MA films, whereas the PPS-PLA and PPS-MA-PLA films demonstrated 9.34% and 10.14% elongation at break that substantiates the structural durability against rupture, fragmentation, and feeble. Furthermore, the water vapor permeability, water uptake, moisture content, and solubility decreased but the opacity has increased.

Precision Microbiome Modulation with Discrete Dietary Fiber Structures Directs Short-Chain Fatty Acid Production

Dietary fibers (DFs) impact the gut microbiome in ways often considered beneficial. However, it is unknown if precise and predictable manipulations of the gut microbiota, and especially its metabolic activity, can be achieved through DFs with discrete chemical structures. Using a dose-response trial with three type-IV resistant starches (RS4s) in healthy humans, we found that crystalline and phosphate cross-linked starch structures induce divergent and highly specific effects on microbiome composition that are linked to directed shifts in the output of either propionate or butyrate. The dominant RS4-induced effects were remarkably consistent within treatment groups, dose-dependent plateauing at 35 g/day, and can be explained by substrate-specific binding and utilization of the RS4s by bacterial taxa with different pathways for starch metabolism. Overall, these findings support the potential of using discrete DF structures to achieve targeted manipulations of the gut microbiome and its metabolic functions relevant to health.

Green preparation of citric acid cross-linked starch for improvement of physico-chemical properties of Cyperus starch

Green preparation of citric acid cross-linked starch for improvement of physico-chemical properties of Cyperus starch