Low Molecular Weight Chitosan Research Articles

Membrane Technology Application for Fractionation Process to Obtain High Quality Glucosamine

Glucosamine, monosaccharide from chitosan obtained from the chitin deacetylation process, has been used widely in various fields such as nutrition, pharmacy, and cosmetics. Glucosamine can be obtained from the hydrolysis of chitosan. Enzymatic hydrolysis provides the advantage of mild reaction conditions, environmentally friendly, and high yield. But until now, the separation of glucosamine from the chitosan hydrolysis fraction has been an obstacle. Ultrafiltration membranes offer an efficient filtration process because they do not require additional chemicals. The performance of ultrafiltration membranes was analyzed from the fractionation process of chitosan hydrolysis. The PES membranes in 10, 25, and 50 kDa were used to filter hydrolyzed Low Molecular Weight Chitosan (LMWC) in varied concentrations. The experiment was carried out in crossflow membrane module for flat sheet at room temperature in 1 bar. The permeate flux during filtration decreased rapidly at the initial and gradually over time because of fouling and concentration polarization. The more concentrated hydrolyzed LMWC solution resulted higher percentage of rejection up to almost 20% at the same membrane MWCO while higher MWCO resulted lower rejection percentage for the same hydrolyzed LMWC concentration. The FTIR spectrum of the used membranes of all types had absorption bands of glucosamine which proved that the fractionation process occurred. The time retention in HPLC chromatograms of glucosamine produced were similar with standard glucosamine. Thus, ultrafiltration could be applied for hydrolyzed LMWC fractionation process.Keywords: fractionation; glucosamine; LMWC; MWCO; ultrafiltration

Динаміка видового складу мікобіоти філоплани та ризосфери Fragaria ananassa Duch. під дією розчинів хітозану

The study is dedicated to the investigation of the chitosan influence of diverse origin, molecular mass and deacetylation degree on the dynamics of both garden strawberries' phylloplane and rhizosphere aspectual composition. It was defined that Chitosans carry a varied impact on the fungal groups of both Fragaria ananassa phylloplanes' and rhizospheres', as evidenced by the dynamics of their species composition, changes in the population level and occurrence frequency. Namely, the chitosan forms under investigation had a stimulant effect on both micromycetes' and phylloplanes' dominant genus, causing an increase in strawberry leaves' population level after treatment. Nevertheless, the epiphytic fungi species structure of garden strawberry differed 48 hours after treatment with low molecular weight (LMW) and high molecular weight (HMW) chitosan solutions. It has been demonstrated that the rhizosphere mycobiota possesses different sensitivity to LMW and HMW solutions. The greatest inhibitory effect of chitosan forms was observed on penicillium, the soil CFU number of which was less compared to the control one. Thus, the Penicillium sp. amount was 47.4 thousand CFU/g of soil before treatment, becoming 4.9 and 6.3 thousand CFU/g of soil after the low molecular weight chitosan application — 12 and 48 hours after application, accordingly. On the contrary, an increase in abundance in all application variants was observed for the Fusarium genus. This can be explained by the fact that Fusarium genus fungi in the soil are predominantly in the form of mycelium hyphae, being more resistant to chitosan. As a matter of record both incubation time and the environment into which chitosan is put are no less important for its effectiveness except for physiological activity and functional properties, depending on molecular weight.

Design of polysaccharidic nano-in-micro soft agglomerates as primary oral drug delivery vehicle for colon-specific targeting

Microencapsulation of polysaccharidic nanoparticles is met with nanoscale and biological performance changes. This study designs soft agglomerates as nanoparticle vehicle without nanoparticles undergoing physical processes that alter their geometry. The nanoparticles were made of high molecular weight chitosan/pectin with covalent 5-fluorouracil/folate. Nanoparticle aggregation vehicle was prepared from low molecular weight chitosan. The nanoparticles and aggregation vehicle were blended in specific weight ratios to produce soft agglomerates. Nanoparticles alone are unable to agglomerate. Adding aggregation vehicle (< 2 μm) promoted soft agglomeration with nanoparticles deposited onto its surfaces with minimal binary coalescence. The large and rough-surfaced aggregation vehicle promoted nanoparticles deposition and agglomeration. A rounder vehicle allowed assembly of nanoparticles-on-aggregation vehicle into agglomerates through interspersing smaller between larger populations. Soft agglomeration reduced early drug release, and was responsive to intracapsular sodium alginate coat to further sustain drug release. The soft agglomerates can serve as a primary oral colon-specific vehicle.

Antifungal activity and fire resistance properties of nano-chitosan treated wood

Fungal decay and fire resistance properties of wood treated with nano-chitosan-TPP particles were investigated. Quaternized and non-quaternized nano-chitosan particles crosslinked with a commercial fire-retardant, tripolyphosphate, were prepared from low molecular weight chitosan (with a molecular weight of 50 to 190 kDa). Different treatments were performed on southern yellow pine wood samples via a vacuum impregnation process for both quaternized and non-quaternized nano-chitosan-TPP particles with a concentration ratio of 12% to 4.8% (nano-chitosan to TPP). Both the leached and unleached treated wood samples were exposed to brown rot (Gloeophyllum trabeum) and white rot (Trametes versicolor) fungi according to AWPA standard E10-16. The flammability test was performed with a cone calorimeter according to ASTM standard E1354-15. The heat release rate and the mass loss rate were measured. The results of the fungal tests indicated that the quaternization of the nano-chitosan particles resulted in a reduced mass loss in the pine samples when exposed to Trametes versicolor under leached conditions. Additionally, without the quaternization of the nano-chitosan particles, the mass loss in the pine samples was reduced when exposed to Gloeophyllum trabeum under unleached conditions. The production of nano-chitosan-TPP particles had a significant effect on the fire-retardant activity of the treated wood samples.

Comprehensive assessment of flocculation conditioning of dredged sediment using organic polymers: Dredged sediment dewaterability and release of pollutants

Dredged sediment contains various contaminants that are released during the process of dewatering and subsequent utilization. In this study, two organic polymers—chitosan (CS) and cationic polyacrylamide (CPAM) both in samples of varying molecular weights (MWs)—were used as flocculants to improve dewatering and rheological behaviors of dredged sediment, and floc properties were characterized to unravel the mechanisms of flocculation treatment. Moreover, pollutant transfer and release in the flocculation-dewatering process was investigated. Compared to CPAM, CS had better performance in dredged sediment dewatering, and more compact flocs were produced after treatment. The flocculated sediment belonged to the type of yield dilatant fluid and showed good shear resistance. Three-dimensional excitation–emission matrix spectroscopy and PARAFAC showed that protein-like substances were removed after treatment. The MW of CS had insignificant effects on flocculation performance, whereas CPAM removal efficiency for protein-like substances was increased at higher MWs, which may be related to the adsorption bridging effect of CPAM polymer chains. There were significant correlations between the dewatering performance of sediments, MW distribution of organics and rheological properties. CS and CPAM treatments caused the transformation of Fe/Al-P into CaP, which could reduce phosphorus release and its ecological risk. The flocculants contributed to the formation of carbonate-bound forms of As, Cr, Pb, and Ni. Ecological risk assessment results of the geo-accumulation index showed that medium- and low-MW CS reduced risk of sediment contamination, whereas CPAM and high-MW CS increased the ecological risk. CS had a greater effect on the release of VOCs than CPAM, with an increased release of total VOCs at higher flocculant MWs. The study was helpful to understand the dewatering mechanism of dredged sediment and provided a new strategy for pollution release management in sediment dewatering.

Selection of Water-Soluble Chitosan by Microwave-Assisted Degradation and pH-Controlled Precipitation.

In the field of gene therapy, chitosan (CS) gained interest for its promise as a non-viral DNA vector. However, commercial sources of CS lack precise characterization and do not generally reach sufficient solubility in aqueous media for in vitro and in vivo evaluation. As low molecular weight CS showed improved solubility, we investigated the process of CS depolymerization by acidic hydrolysis, using either long time heating at 80 °C or short time microwave-enhanced heating. The resulting depolymerized chitosan (dCS) were analyzed by gel permeation chromatography (GPC) and 1H nuclear magnetic resonance (NMR) to determine their average molecular weight (Mn, Mp and Mw), polydispersity index (PD) and degree of deacetylation (DD). We emphasized the production of water-soluble CS (solubility > 5 mg/mL), obtained in reproducible yield and characteristics, and suitable for downstream functionalization. Optimal microwave-assisted conditions provided dCS with a molecular weight (MW) = 12.6 ± 0.6 kDa, PD = 1.41 ± 0.05 and DD = 85%. While almost never discussed in the literature, we observed the partial post-production aggregation of dCS when exposed to phase changes (from liquid to solid). Repeated cycles of freezing/thawing allowed the selection of dCS fractions which were exempt of crystalline particles formation upon solubilization from frozen samples.

Effect of using low molecular weight Chitosan on water quality, quality indices and stress reduction of Nile tilapia

The study investigated the efficiency of adding extracted chitosan from shrimp wastes to enhance water quality, reduce stress and enhance tilapia flesh quality. Water quality parameters showed no significant differences among all treatments in (Dissolved oxygen, Temperature, pH, NO2 and Orthophosphate values). Treatment fish water with chitosan affected some nitrogenous parameters such as NH3 and NO3, where the values were (0.7, 0.6, 0.1 and 0.5 mg / l) for NH3, and (0.62, 0.61, 0.36 and 0.59 mg / l) for NO3, respectively. The lowest value of NH3 and NO3 was recorded in T3 (15 mg / l chitosan) followed by T4 (20 mg / l chitosan), T2 (10 mg / l chitosan) and finally T1 (negative control). Chemical composition of the samples revieled that the adding chitosan to the water improved moisture, protein, fat and increased ash content for fish flesh respectively, followed by control. Physiochemical quality parameters such as pH, acid value, Free amino nitrogen (FAN), Free fatty acids (FFA), total volatile bases nitrogen (TVB-N) and trimethylamine (TMA-N) showed that the addition chitosan reduce the increase in this parameters of the three treatments compared to the control The blood chemistry indices revealed that; T3 had the lowest AST; T4 had the lowest ALT values compared to control and T2, respectively. Despite the variation in Alb, Glob and ALP values among treatments they showed no significance differences. T3 showed the lowest values among all treatments for GLU, CHO, HDL, LDL and TG followed by T4, T2 and control, respectively.

Micelle Encapsulation of Ferromagnetic Nanoparticles of Iron Carbide@Iron Oxide in Chitosan as Possible Nanomedicine Agent

In this work, the synthesis and characterization of core/shell nanoparticles of iron carbide@iron oxide (Fe3C/γ-Fe2O3) encapsulated into micelles of sodium dodecylsulfate and oleic acid and stabilized with chitosan was developed. The materials were sonosynthesized at low intensities using standard ultrasonic baths with iron pentacarbonyl (Fe(CO)5) and oleic acid as iron source and hydrophobic stabilizer, respectively; obtaining nanoparticles with a hydrodynamic diameter of 19.71 nm and polydispersive index (PDI) of 0.13. The iron carbide@iron oxide nanoparticles (ICIONPs) in oleic acid were used as the organic phase during the self-assemble of nanoemulsion with sodium dodecylsulfate in water to obtain the metastable micelles. The final step involved the stabilization of the micelles using low molecular weight chitosan solution at 2% in acetic acid by ultrasonication bath. The nanosystem showed a hydrodynamic diameter of 185.30 nm, a PDI of 0.15 with a superficial charge ζ of 36.70 mV. Due to the magnetic, physical and chemical properties previously measured of the ICIONPs, it is believed that this type of nanoparticles can be used as a possible nanomedicine agent.

Bioprocessing of Squid Pens Waste into Chitosanase by Paenibacillus sp. TKU047 and Its Application in Low-Molecular Weight Chitosan Oligosaccharides Production.

Chitosan oligosaccharide (COS) has become of great interest in recent years because of its worthy biological activities. This study aims to produce COS using the enzymatic method, and investigates Paenibacillus sp. TKU047, a chitinolytic-producing strain, in terms of its chitosanase productivity on several chitinous material-containing mediums from fishery process wastes. The highest amount of chitosanase was produced on the medium using 2% (w/v) squid pens powder (0.60 U/mL) as the single carbon and nitrogen (C/N) source. The molecular mass of TKU047 chitosanase, which could be the smallest one among chitinases/chitosanases from the Paenibacillus genus, was approximately 23 kDa according to the sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) method. TKU047 chitosanase possessed the highest activity at 60 °C, pH 7, and toward chitosan solution with a higher degree of deacetylation (DDA) value. Additionally, the hydrolysis products of 98% DDA chitosan catalyzed by TKU047 chitosanase showed the degree of polymerization (DP) ranging from 2 to 9, suggesting that it was an endo-type activity chitosanase. The free radical scavenging activity of the obtained chitosan oligosaccharide (COS) was determined. The result showed that COS produced with Paenibacillus sp. TKU047 chitosanase expressed a higher 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity than that from the commercial COSs with maximum activity and IC50 values of 81.20% and 1.02 mg/mL; 18.63% and 15.37 mg/mL; and 15.96% and 15.16 mg/mL, respectively. As such, Paenibacillus sp. TKU047 may have potential use in converting squid pens waste to produce chitosanase as an enzyme for bio-activity COS preparation.

Low molecular weight chitosan nanoparticles for CpG oligodeoxynucleotides delivery: Impact of molecular weight, degree of deacetylation, and mannosylation on intracellular uptake and cytokine induction

Although synthetic CpG oligodeoxynucleotides (ODNs) have shown substantial potential as immunotherapeutic agents, their effective intracellular delivery remains challenging. In this work, nanoparticles prepared from low-molecular weight (LMW) chitosans were investigated as CpG ODN delivery systems. Chitosan samples with a molecular weight (Mw) of 5 and 15 kDa and degree of deacetylation (DDA) of 50 and 80% were prepared. Additionally, mannosylated chitosans with a substitution degree of 15% were synthesized. The impact of LMW chitosan Mw and DDA on nanoparticle physical properties and the associated immunostimulatory effect in RAW 264.7 cells was studied. Nanoparticles prepared with chitosan of higher DDA and larger Mw exhibited better CpG ODN binding ability and intracellular uptake. Nevertheless, the most efficient immunostimulatory effect was observed while using 50% acetylated and mannosylated samples. The decreased charge density on chitosan backbone resulted in the enhanced intracellular CpG ODN release, which promoted in vitro cytokine secretion. Moreover, mannose ligand grafting promoted nanoparticle uptake through receptor-mediated recognition. Overall, this research suggests that chitosan structural parameters can be modulated to prepare LMW chitosan nanoparticles that first efficiently encapsulate CpG ODN, and then release it in immune cells, thus may be used as an efficient vector for intracellular CpG ODN delivery.

Microencapsulation of Lactobacillus acidophilus La-05 and incorporation in vegan milks: Physicochemical characteristics and survival during storage, exposure to stress conditions, and simulated gastrointestinal digestion

The effect of microencapsulation of L. acidophilus La-05 (8 log CFU/mL) by external ionic gelation technique in alginate (30 g/L; AM) and alginate coated with a low molecular weight chitosan solution (5 g/L; AC5M) on the survival of the freeze-dried probiotic culture during storage (7 °C; 0, 7, 15, 30, 60, 90 and 120 days), and exposure to temperature (72, 85 and 90 °C), pH (2, 4, and 6), and NaCl (10, 15 and 20 g/L) were studied. Furthermore, vegan milks (soybean and rice milks) added with microencapsulated probiotic cultures were evaluated for the physicochemical characteristics and survival of the probiotic culture during refrigerated storage (7 °C; 7 days) and in vitro digestion. Free cells were used as control. AM and AC5M showed similar microencapsulation yield (>90%) with uniform and spherical microparticles dispersed without agglomeration. Scanning electron microscopy showed that chitosan was able to cover the porous structure of the alginate particles, resulting in a more stabilized microparticle. The microencapsulation provided higher probiotic protection to storage, thermal treatment, NaCl and pH (decreases of ~1 log CFU/mL) compared to the free cells (decreases of ~3, 4, 2 and 3 log CFU/mL, respectively), and increased probiotic survival during refrigerated storage and in vitro digestion of vegan milks compared to free cells (decreases of ~1 and 4 log CFU/mL, respectively). Only microencapsulated probiotic cultures (AM and AC5M) maintained suitable probiotic counts (>6 log CFU/mL) during storage, exposure to stress conditions and simulated gastrointestinal digestion. Chitosan coating increased the probiotic survival in the vegan milks during refrigerated storage. Microencapsulation by external ionic gelation in alginate proved to be a suitable microencapsulation technique to improve the probiotic survival to storage, stress conditions (temperature, pH and NaCl) and simulated gastrointestinal conditions. This was the first study that evaluated the addition of probiotic cultures to rice and soybean milks, proving that the vegan milks could be considered suitable carriers for microencapsulated probiotic cultures.

Synthesis, characterization and antioxidant activity of chitosan Schiff base derivatives bearing (−)-gossypol

In this work, two new chitosan-Schiff base derivatives (HCS-GSP and LCS-GSP) were synthesized by the condensation reaction of high molecular weight chitosan (HCS) and low molecular weight chitosan (LCS) with (−)-gossypol (GSP), respectively. For this purpose, racemic gossypol was isolated from cotton seeds and it was further enantiomerically purified by diastereomeric resolution technique using l-tryptophan methyl ester hydrochloride. Then, chitosan polymers were derivatized with (−)-gossypol by the condensation reaction. The isolated and synthesized coumpounds were characterized by physical measurements and spectroscopic methods (elemental analysis C,H,N, Uv–vis, FT-IR, 1H&13C NMR and TG/DTG/DTA). The antioxidant activity of high molecular weight chitosan (HCS), low molecular weight chitosan (LCS) and their gossypol derivatives was evaluated as radical scavengers against 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH). The results showed that both of the chitosan-gossypol derivatives (HCS-GSP and LCS-GSP) had a better ability to scavenging DPPH radical (IC50, 12 μg/mL and 16 μg/mL, respectively) than its unmodified chitosan.

Characterization and toxicology evaluation of low molecular weight chitosan on zebrafish

Chitosan is suggested as no or low toxicity and biocompatible biomaterial. Digestion of chitosan to reduce molecular weight and formulate nanoparticle was generally used to improve efficiency for DNA or protein delivery. However, the toxicity of low-molecular-weight chitosan (LMWCS) towards freshwater fishes has not been well evaluated. Here, we reported the toxic mechanism of LMWCS using zebrafish (Danio rerio) liver (ZFL) cell line, zebrafish larvae, and adult fish. LMWCS rapidly induced cytotoxicity of ZFL cells and death of zebrafish. Cell membrane damaged by LMWCS reduced cell viability. Damaged membrane of epithelial cell in zebrafish larvae induced breakage of the yolk. Adult fish exhibited hypoxia before death due to multiple damages induced by LMWCS. Although the toxicity of LMWCS was revealed in zebrafish model, the toxicity was only present in pH < 7 and easy be neutralized by other negative ions. Collectively, these data improved a new understanding of LMWCS properties.

Spectral analysis combined with nonlinear optical measurement of laser printed biopolymer composites comprising chitosan/SWCNT

Biopolymer composites based on two types of chitosan (chitosan succinate and low-molecular weight chitosan) with single-walled carbon nanotubes (SWCNT) were created by laser printing. SWCNT have good dispersibility in chitosan solutions and therefore, can form relatively homogeneous films that was shown in scanning electron microscopy images. For the studies film composites were formed under the action of laser radiation on aqueous dispersion media. Study of the nonlinear optical process during the interaction of laser radiation with a disperse media has shown that low-molecular chitosan has a large nonlinear absorption coefficient of 17 cm/GW, while the addition of SWCNT lead to a significant increase up to 902 cm/GW. The threshold intensity for these samples was 5.5 MW/cm2 with nanotubes. If intensity exceeds the threshold value, nonlinear effects occur, which, in turn, lead to the transformation of a liquid into a solid phase. Characterization of films by FTIR and Raman spectroscopy indicated arising molecular interactions between chitosan and SWCNT detected as a small frequency shift and a change in the shape of radial breathing mode (RBM). The results indicate the possibility using aqueous dispersion media based on chitosan and SWCNT to create three-dimensional films and scaffolds for tissue engineering by laser printing.

Structure-properties relationship of chitosan/collagen films with potential for biomedical applications

Chitosan/collagen films were developed and characterized in order to assess the suitability of these films for biomedical applications. Hence, physicochemical, thermal, barrier and mechanical properties were analyzed and related to the film structure, which showed the prevalence of the triple helix of native collagen after the addition of chitosan. Furthermore, collagen fiber diameter changed from 3.9 ± 0.6 μm, for collagen films without chitosan, to 1.8 ± 0.5 μm, for collagen films with low molecular weight chitosan. These results suggested interactions between collagen and chitosan molecules, as observed by Fourier transform infrared (FTIR) analysis. Regarding film barrier properties, chitosan/collagen films showed a water vapor transmission rate around 1174 g m−2 day−1, suitable for biomedical applications such as wound healing. Additionally, biological tests confirmed that the chitosan/collagen films developed are suitable for biomedical applications.

Foliar Application of Micronutrients and Low Molecular Weight Chitosan on Tomatoes Grown in Silt Loam Soil

Foliar Application of Micronutrients and Low Molecular Weight Chitosan on Tomatoes Grown in Silt Loam Soil

Ammonium ion removal using activated zeolite and chitosan

AbstractStudies have previously been done on efficacies of chitosan and zeolite in ammonium ion (NH4+) removal. However, no study compares the adsorption performance of natural zeolite (NZ) and activated NZ (ANZ) with high molecular weight chitosan (HMWC) and low molecular weight chitosan (LMWC). Hence, this study investigates the potentials of NZ, ANZ, LMWC, and HMWC in NH4+ removal. The characteristics of NZ, ANZ, LMWC, and HMWC such as functional groups, surface morphology, elemental composition, zeta potential, and particle size was also investigated. The deposition of NH4+ on the surface of NZ and ANZ was confirmed with the absence of nitrogen by the adsorption spectrum of energy dispersive X‐ray (EDX) and supported by the presence of an Fourier transform infrared (FTIR) stretching band at ~3,500–3,300 cm−1, as well as broader and less intense bands ~1,600 cm−1 after the adsorption for all the adsorbents. The particle size of LMWC, HMWC, NZ, and ANZ were 98, 813, 22,354, and 9,826 nm, respectively. Meanwhile, after the activation process, the composition of O, Si, Al, Fe, Ca, and Na was reduced. NH4+ batch adsorption was also studied. HMWC, NZ, and ANZ reached adsorption equilibrium at 15 h, meanwhile for LMWC, the equilibrium reached at t = 20 h. The adsorption capacity of LMWC, HMWC, NZ, and ANZ at an initial concentration of 50 mg/L was 0.769, 0.331, 2.162, and 2.937 mg/g, respectively.

Chitosan oligomers and related nanoparticles as environmentally friendly wood preservatives

The efficacy of chitosan oligomers and related nanoparticles as environmentally friendly wood protection agents was evaluated in this study. Commercially sourced low-molecular weight chitosan was depolymerized using sodium nitrite. Evaluation of depolymerized chitosan to the nano level by thin layer chromatography confirmed acceptable results for obtaining a degree of polymerization of four. Then, oligomers were modified to form quaternized chitosan oligomers. Both quaternized and non-quaternized oligomers were mixed with tripolyphosphate (TPP) to form nano-chitosan-TPP particles via an ionic gelation method. Southern pine wood samples were treated with different chitosan-based solutions and suspensions under a vacuum impregnation process. The mass and volume of the treated samples were calculated before and after treatments to evaluate bulking. The mass loss after leaching of the treated wood samples was calculated. The mass and volume gain results indicated that quaternized nano-chitosan-TPP treated samples had more mass and volume gain after treatment in comparison with non-quaternized nano-chitosan-TPP-treated and control samples. The mass loss results revealed that mass loss increased in quaternized nano-chitosan-TPP particles. Although quaternized nano-chitosan particles were positively charged, they could not fix to the cell walls and became leached out. Therefore, these nanoparticles can likely be used as wood preservatives in non-leaching applications.

Preparation of low molecular weight chitosan by pawpaw protease

Pawpaw protease was used to degrade chitosan, and then obtained low molecular weight chitosan and reducing sugar in this study. According to the orthogonal experiment on the degradation of chitosan by pawpaw protease, the effects of temperature, pH value, reaction time and enzyme dosage on the decomposition efficiency of chitosan were investigated with the concentration of reducing sugar in the degradation solution as the index. The experimental results show that the optimal conditions for the degradation reaction are: the pH value of 4.1 and the reaction temperature of 42 °C, the reaction time of 1.4 h and the amount of enzyme of 30 U/mg, the concentration of reducing sugar in the degradation solution of 1.57 g/L and the yield of 15.7%.

Fabrication, characterization, physicochemical stability of zein-chitosan nanocomplex for co-encapsulating curcumin and resveratrol

The present study aimed at the design and fabrication of a novel co-delivery system to encapsulate and protect curcumin and resveratrol. Curcumin and resveratrol had synergistic physiological activities when used together, but it was challenging to co-encapsulate them in traditional delivery vehicles due to their difference in molecular polarity. The curcumin-zein-resveratrol-chitosan nanocomplexes were developed and their formation mechanism and physicochemical properties were investigated. Hydrogen bonding and hydrophobic effects were dominant binding forces to stabilize the nanocomplexes. As the relative molecular weight of chitosan was increased, the mean size and surface positive charge of the nanocomplexes were elevated. The optimized nanocomplex based on zein and low molecular weight chitosan (50000−190000 Da) had a relatively high encapsulation efficiency of curcumin (91.3 %) and resveratrol (82.1 %), as well as exhibited the best physical stability. In addition, the half-life times of curcumin and resveratrol in the nanocomplex were extended by 4.5- and 1.9-fold during photodegradation, and the retention rates were increased by 3.7- and 1.1-fold than their free forms during thermal degradation. The nanocomplexes could also remain stable and delay the degradation of both bioactive compounds during long term storage. In summary, the nanocomplex showed to be an effective vehicle for the co-delivery of synergistic nutraceuticals.