Different Degrees Of Polymerization Research Articles

Structure and immunostimulating activity of a galactofuranose-rich polysaccharide from the bamboo parasite medicinal fungus Shiraia bambusicola

Ethnopharmacological relevanceShiraia bambusicola is a parasitic fungus on the twigs of bamboos. Its relatively large stroma has high medicinal value and can treat a variety of diseases such as rheumatoid arthritis, cold stomach pain, sciatica, injuries, chronic bronchitis, and infantile. It is widely distributed in many provinces in Southern China and also is also found in Japan. Aim of the studyMedicinal fungi were important resources for bioactive polysaccharides. To explore bioactive polysaccharides from Shiraia bambusicola, a heteropolysaccharide SB2-1 was purified and obtained from S. bambusicola and its immunostimulating activity was researched. Materials and methodsThe polysaccharide from S. bambusicola was extracted and purified using enzyme assisted extraction, ethanol precipitation, anion-exchange and size-exclusion chromatography. Molecular weight of polysaccharide was estimated by high performance gel permeation chromatography. Monosaccharide compositions were determined by high performance liquid chromatography after pre-column derivatization and UV detection. Structure information was elucidated by IR spectrum, GC-MS analysis after methylation and gradual acid hydrolysis of the polysaccharide. The RAW264.7 cells were used to study the immunostimulating activity in vitro. ResultsPhysicochemical and structural analyses showed that SB2-1 was a neutral heteropolysaccharide with molecular weight at 22.2 kDa and consisted of glucose, galactose and mannose at a ratio of 2.0:1.5:1.0. The structure of SB2-1 was a branched polysaccharides composed of a mannan core and side chains consisted of glucose and galactose. The mannan core was composed of (1→2)-Manp as the main chain. Glucose with (1→4)-D-Glcp, (1→2)-D-Glcp and (1→6)-D-Glcp at different degrees of polymerization were linked at C-6 and C-3 of the (1→2)-Manp as the side chains. The galactose with the linages of (1→6)-D-Galf, →2)-D-Galf(1→ and terminal D-Galf(1→ also existed in the side chain. The study on the immunostimulating activities of SB2-1 and its core structure P-2 were investigated on RAW264.7 macrophages. The results showed that SB2-1 could activate RAW264.7 macrophage and significantly improve its phagocytic ability by neutral red uptake experiment. Meanwhile, SB2-1 increased significantly higher inducible nitric oxide synthase (iNOS) production and the productions of IL-1, IL-6, IL-12 and TNF-α. The effect of SB2-1 was better than its core structure P-2 produced by gradual acid hydrolysis, which meant the side chains played an important role in the immunostimulating activities. ConclusionsThe investigation demonstrated that the galactofuranose-containing mannogalactoglucan was characteristic polysaccharides in S. bambusicola and could enhance the activation of macrophages.

Electrical monitoring of photoisomerization of block copolymers intercalated into graphene sheets

Insulating polymers have received little attention in electronic applications. Here, we synthesize a photoresponsive, amphiphilic block copolymer (PEO-b-PVBO) and further control the chain growth of the block segment (PVBO) to obtain different degrees of polymerization (DPs). The benzylidene oxazolone moiety in PEO-b-PVBO facilitated chain-conformational changes due to photoisomerization under visible/ultraviolet (UV) light illumination. Intercalation of the photoresponsive but electrically insulating PEO-b-PVBO into graphene sheets enabled electrical monitoring of the conformational change of the block copolymer at the molecular level. The current change at the microampere level was proportional to the DP of PVBO, demonstrating that the PEO-b-PVBO-intercalated graphene nanohybrid (PGNH) can be used in UV sensors. Additionally, discrete signals at the nanoampere level were separated from the first derivative of the time-dependent current using the fast Fourier transform (FFT). Analysis of the harmonic frequencies using the FFT revealed that the PGNH afforded sawtooth-type current flow mediated by Coulomb blockade oscillation.

Study on chemical kinetic mechanisms of Polyoxymethylene Dimethyl Ethers (PODEn)

Based on the latest detailed mechanism of Dimethoxymethane (DMM), a new chemical kinetic mechanism model of Polyoxymethylene Dimethyl Ethers (PODEn) with high degree of polymerization was preliminarily developed by extending reaction classes of DMM to PODE3 with the same rate coefficient criterion. Compared with the existing PODEn model and experimental data, it was observed that the model of He could forecast the experimental data of PODE3 accurately, but the prediction ability of the underlying DMM mechanism was poor. The model developed in this paper could forecast DMM experimental data accurately but could not forecast the experimental data of PODE3 accurately. The same reaction classes of PODEn with different degree of polymerization did not have the same rate coefficient criterion.

In situ synthesis of Fe3O4 nanoparticles coated by chito-oligosaccharides: physico-chemical characterizations and cytotoxicity evaluation for biomedical applications

Fe3O4 nanoparticles coated with chito-oligosaccharides (COS) were prepared in situ by a simple co-precipitation method through a mixing of iron ions (Fe3+ and Fe2+) and COS aqueous solutions followed by precipitation with ammonia. The impact of COS with different degree of polymerization (DP 10, 24 and 45) and degree of N-acetylation (DA) ∼ 24% and 50% (exhibiting high solubility) on the synthesis and physical properties of the coated magnetic nanoparticles was evaluated. Several advantages were found when the magnetic nanoparticles were prepared in the presence of the studied COS, such as: preparation of functionalized magnetic nanoparticles with narrower size distributions and, consequently, higher saturation magnetization (an increase of up to 22%); and an expressive increasing in the concentration of COS-coated magnetic nanoparticles (up to twice) in the cell viability test in comparison with pure Fe3O4 nanoparticles. Furthermore, among the analyzed samples, the magnetic nanoparticles coated by COS with DA ∼ 50% present a higher cytocompatibility. Our results allow envisioning various biomedical applications, valorizing the use of coated-magnetic nanoparticles for magnetic-field assisted drug delivery, enzyme or cell immobilization, or as a marker for specific cell tracking, among others.

Sodium Coordination and Protonation of Poly(ethoxy phosphate) Chains in the Gas Phase Probed by Ion Mobility-Mass Spectrometry.

The two-dimensional shape information yielded by ion mobility-mass spectrometry (IM-MS), usually reported as collision cross section (CCS), is often correlated to the underlying three-dimensional structures of the ions through computational chemistry. Here, we used theoretical approaches based on molecular mechanics (MM), molecular dynamics (MD), and density functional theory (DFT) to elucidate the structures of sodiated poly(ethoxy phosphate) polymer ions at different degrees of polymerization (DP) for three different charge states (1+, 2+, and 3+) by comparing computational results to experimentally obtained CCS values. From the calculated structures, we extract several key interaction distances which merge in clusters for all screened charge states and DPs, independent of the three-dimensional structures and the polymer ion structural rearrangements. These distances were also used to extract the minimum coordination numbers in poly(ethoxy phosphate) and to describe the preferred coordination geometries. When sodiated and protonated polymer ions are compared, the experimental CCS evolutions differ at small DP values and merge at higher DPs. We investigated in more depth this difference for two selected species, namely, [PEtP5 + 2Na+]2+ and [PEtP5 + 2H+]2+. For the protonated ions, we explored the different protonation sites to extract three-dimensional structure candidates and rationalize the CCS behaviors.

High level production of a Bacillus amlyoliquefaciens chitosanase in Pichia pastoris suitable for chitooligosaccharides preparation

Chitooligosaccharides (COS) are hydrolytic products of chitosan that are essential in functional food, medicine, and other fields due to their biological activities. Commercial COS are often prepared by the hydrolysis of chitosan by chitosanase. In this study, a glycoside hydrolase family 46 cluster B chitosanase from Bacillus amyloliquefaciens (BaCsn46B) was efficiently expressed in Pichia pastoris. The recombinant enzyme was secreted into the culture medium that reached a total extracellular protein concentration of 4.5 g/L with an activity of 8907.2 U/mL in a high cell density fermenter (5 L). The molecular mass of deglycosylated BaCsn46B was 29.0 kDa. Purified BaCsn46B exhibited excellent enzymatic properties, which had high specific activity (2380.5 U/mg) under optimal reaction conditions (55 °C and pH 6.5). BaCsn46B hydrolyzed chitosan yielded a series of COS with different degrees of polymerization by endo-type cleavage. The end hydrolytic products of BaCsn46B were chitobiose and chitotriose, while no monosaccharide yield was evident in the hydrolytic reaction. The excellent secreted expression level and hydrolytic performance make the enzyme a desirable biocatalyst for the industrial preparation of COS.

Inulin with different degrees of polymerization protects against diet-induced endotoxemia and inflammation in association with gut microbiota regulation in mice

Societal lifestyle changes, especially increased consumption of a high-fat diet lacking dietary fibers, lead to gut microbiota dysbiosis and enhance the incidence of adiposity and chronic inflammatory disease. We aimed to investigate the metabolic effects of inulin with different degrees of polymerization on high-fat diet-fed C57BL/6 J mice and to evaluate whether different health outcomes are related to regulation of the gut microbiota. Short-chain and long-chain inulins exert beneficial effects through alleviating endotoxemia and inflammation. Antiinflammation was associated with a proportional increase in short-chain fatty acid-producing bacteria and an increase in the concentration of short-chain fatty acids. Inulin might decrease endotoxemia by increasing the proportion of Bifidobacterium and Lactobacillus, and their inhibition of endotoxin secretion may also contribute to antiinflammation. Interestingly, the beneficial health effects of long-chain inulin were more pronounced than those of short-chain inulin. Long-chain inulin was more dependent than short-chain inulin on species capable of processing complex polysaccharides, such as Bacteroides. A good understanding of inulin-gut microbiota-host interactions helps to provide a dietary strategy that could target and prevent high-fat diet-induced endotoxemia and inflammation through a prebiotic effect.

Rheological and colour properties of apple jellies supplemented with inulin with various degrees of polymerisation

SummaryThe objective of this study was to analyse the influence of inulin with different degrees of polymerisation (DP values) and oligofructose preparation on physicochemical and rheological properties of apple jelly. It has been determined that both the addition of inulin (independently of DP) and oligofructose significantly modify the rheological and textural properties of the analysed desserts. Preparation with high DP results in increased moduli, preparation with moderate levels results in their decrease, while preparation with low DP levels initially decreases and then increases the values of both moduli. Similar tendencies are exhibited by the remaining parameters of rheological characteristics. Supplementation with inulin and oligofructose influences, but not as markedly, physicochemical properties. It has been observed that the manner in which water is bound by the applied preparations may have a significant impact on the properties of jelly. In the majority of cases, the variability of the parameters, for which statistically significant differences have been determined, depended on the type and level of the additive, and this impact varied between individual preparation types. The study conducted has enabled the conclusion that inulin may pose an attractive ingredient in desserts with health‐promoting properties.

Proton spin relaxation study with pulsed NMR on the plasticization of Na+ ion-selective electrode membranes prepared from PVCs with different degrees of polymerization.

The proton spin-spin relaxation times (T2) of ion-selective electrode membranes with differences in the polymerization degree of the incorporated poly(vinyl chloride) (PVC) polymers were investigated. T2 measurements were performed using Hahn-Echo, Solid-Echo and Carr-Purcell-Meiboom-Gill (CPMG) pulse sequences. Analyses of the T2 measurements by Hahn-Echo pulse sequences could realize the estimation of the homogeneity and compatibility for a series of ion-selective electrode membranes and reveal a relationship with the electromotive force (EMF) response in the low-concentration region of the Na+ ions. On the other hand, the normalized derivative spectra from T2 measurements by Solid-Echo and CPMG pulse sequences could approximately visualize the degree of plasticization for such potentiometric polymeric membranes. Moreover, differences in the polymerization degrees of the incorporated PVCs were scarcely found to affect the selectivity coefficients of the Na+-ISEs based on bis(12-crown-4).

Mainly Dimers and Trimers of Chinese Bayberry Leaves Proanthocyanidins (BLPs) are Utilized by Gut Microbiota: In Vitro Digestion and Fermentation Coupled with Caco-2 Transportation.

Chinese bayberry leaf proanthocyanidins (BLPs) are Epigallocatechin gallate (EGCG) oligomers or polymers, which have a lot of health-promoting activity. The activity is closely related to their behavior during in vitro digestion, which remains unknown and hinders further investigations. To clarify the changes of BLPs during gastrointestinal digestion, further research is required. For in vitro digestion, including gastric-intestinal digestion, colon fermentation was applied. Caco-2 monolayer transportation was also applied to investigate the behavior of different BLPs with different degrees of polymerization. The trimers and the tetramers were significantly decreased during in vitro gastric-intestinal digestion resulting in a significant increase in the content of dimers. The dimers and trimers were the main compounds utilized by gut microbiota and they were assumed not to degrade through cleavage of the inflavan bond. The monomers and dimers were able to transport through the Caco-2 monolayer at a rate of 10.45% and 6.4%, respectively.

Elucidation of a Unique Pattern and the Role of Carbohydrate Binding Module of an Alginate Lyase.

Alginate oligosaccharides with different degrees of polymerization (DPs) possess diverse physiological activities. Therefore, in recent years, increasing attention has been drawn to the use of enzymes for the preparation of alginate oligosaccharides for food and industrial applications. Previously, we identified and characterized a novel bifunctional alginate lyase Aly7A, which can specifically release trisaccharide from three different substrate types with a unique degradation pattern. Herein, we investigated its degradation pattern by modular truncation and molecular docking. The results suggested that Aly7A adopted a unique action mode towards different substrates with the substrate chain sliding into the binding pocket of the catalytic domain to position the next trisaccharide for cleavage. Deletion of the Aly7A carbohydrate binding module (CBM) domain resulted in a complex distribution of degradation products and no preference for trisaccharide formation, indicating that the CBM may act as a “controller” during the trisaccharide release process. This study further testifies CBM as a regulator of product distribution and provides new insights into well-defined generation of alginate oligosaccharides with associated CBMs.

Viscoelastic properties of durum wheat doughs enriched with soluble dietary fibres in relation to pasta-making performance and glycaemic response of spaghetti

Pasta is a starchy staple food, which is a good carrier of health-promoting ingredients that can manipulate the glycaemic response. Dry pastas supplemented with DFs were produced substituting durum wheat semolina with Barley Balance® (BB), psyllium seed husk (P) or two inulin products with different degrees of polymerisation. The aim was to investigate the effects of soluble DFs on viscoelastic properties of durum wheat dough, pasta-making performance and glycaemic response of pasta. DFs were added individually and in combination to produce samples with large differences in structural/rheological properties and to understand their role in the manipulation of predicted glycaemic response. Dough rheological properties were investigated using frequency and temperature sweep tests in the linear viscoelastic range. DF-enriched doughs showed large differences in elastic properties between 25 and 95 °C due to differences in the number of interactions between components and the swelling of gelatinized starch granules. A correlation between in vitro glycaemic response of pasta and a swelling index obtained from temperature sweep test was observed. Swelling of starch granules decreased with the increase in elasticity and water absorption of fibre-enriched doughs up to a critical value above which only slight changes occurred. Changes in firmness was dependent on dough viscoelasticity. P and long-chain inulin gave lower detrimental effects when incorporated with BB. Pasta containing BB individually added and in combination with psyllium showed an overall sensory acceptability comparable to control and in vivo glycaemic index reduction of 33–37%.

Effect of tea root-derived proanthocyanidin fractions on protection of dentin collagen

ObjectivesProanthocyanidins (PAs) have been widely used as effective agents for dentin collagen cross-linking to enhance the biomechanics and biostability of dentin in vitro. However, the effects and protective mechanisms of various tea root-derived PA components on dentin remain undefined. This study evaluated the effects of these tea root-derived PA components on dentin biomechanics and biostability.MethodsIn this study, ethyl acetate and n-butyl alcohol were used to extract PAs with different degrees of polymerization from tea roots; the effects of these PA extracts on dentin were evaluated.ResultsDentin was treated with glutaraldehyde, ethyl acetate, n-butyl alcohol, or water. PAs with a high degree of polymerization, extracted using n-butyl alcohol, were able to more effectively improve dentin collagen cross-linking, increase resistance to bacterial collagenase digestion, and enhance dentin elasticity, relative to treatment with glutaraldehyde or PAs with a low degree of polymerization (extracted using ethyl acetate). Additionally, treatment with aqueous extract of tea roots was detrimental to dentin stability and function.ConclusionsPAs with a high degree of polymerization were effective for dentin protection and restoration in vitro, suggesting clinical treatment potential for tea root-derived PAs.

How does the degree of inulin polymerization affect the bioaccessibility of bioactive compounds from soursop whey beverage during in vitro gastrointestinal digestion?

The inulin is known as a prebiotic carbohydrate with beneficial health properties in addition to its technological properties as a texture modifier and stabilizer of food products. Despite that, a little is known about the influence of the degree of inulin polymerization during gastrointestinal digestion. Then, the objective of this study was to evaluate if the degree of inulin polymerization influences the bioaccessibility of bioactive compounds during in vitro gastrointestinal digestion of a functional soursop (Annona muricata) whey beverage. Therefore, two beverages were manufactured using inulin with different degrees of polymerization (DP), inulin GR (DP ≥ 10) and inulin HP (DP ≥ 23). To evaluate the effects of the inulin DP during in vitro digestion on the microstructure, total phenolic content, antioxidant activity, sugars and fructo-oligosaccharides content, the samples produced with inulin GR and HP were submitted to a simulated gastric and intestinal digestion and the digesta samples were analyzed after each digestion step (undigested, gastric digested and intestinal digested). Overall, the whey beverages produced with inulin of different degrees of polymerization originated products and respective digesta with different characteristics related to the microstructure and the sugars and fructo-oligosaccharides. Despite the different behavior during in vitro digestion, after intestinal digestion, where the compounds could be absorbed, the bioaccessibility of the bioactive compounds and antioxidant activity of both digesta were similar, suggesting the possibility of production of a soursop whey beverage with inulin of different DP without influencing its functional quality.

PH-responsive nanomicelles of poly(ethylene glycol)-poly(ε-caprolactone)-poly(L-histidine) for targeted drug delivery

Here, a novel pH-responsive block copolymer, poly (ethylene glycol)-poly(ε-caprolactone)-poly(L-histidine) (PEG-PCL-PHis), was synthesized and designed for anti-cancer drug delivery with excellent biocompatible, biodegradable, and strong drug loading efficiency. 1H-NMR, IF-IR, and GPC were used to characterize the structure of the PEG-PCL-PHis copolymer. In addition, the morphology, particle size, Zeta potential, and critical micelle concentration (CMC) of different degree of polymerization were determined by transmission electron microscopy (TEM), dynamic light scattering granulometer (DLS), and fluorescence spectrometer, respectively. The strong affinity between the core of micelles and hydrophobic drug was manifested with 15.09% drug loading content and 84.65% entrapment efficiency. In vitro release of DOX from the block copolymer micelle demonstrated, the PEG-PCL-PHis copolymer micelle has stable and durable drug releasing ability accompanied with pH-sensitivity. From the mechanism of cellular uptake the micelles, the pathway of drug release was captured by confocal laser scanning microscope. These experiments demonstrated the safe delivery for anticancer medicine through this novel copolymer. In conclusion, the PEG-PCL-PHis copolymer micelle has great potential to become a safe drug carrier for cancer chemotherapy.

Hybrid Dendronized Polymers as Molecular Objects: Viscoelastic Properties in the Melt

Two homologous series of dendronized polymers (DPs) of the second and third generations, with different degrees of polymerization of the backbone, were synthesized combining two previously reported...

Chitosan Oligosaccharides Inhibit Tumor Progression and Induce Autophagy Through Activation of the p53/mTOR Pathway in Osteosarcoma

Background: The use of chitosan oligosaccharides (COS) as a drug carrier is an emerging new strategy for cancer therapy. However, the application of COS in osteosarcoma has not been reported. Methods: Structure and compositions of COS were identified by High-performance liquid chromatography (HPLC) and Electrospray ionization-mass spectrometry (ESI-MS). We investigated the function of COS in inhibiting osteosarcoma by in vitro Cell Counting Kit-8 (CCK-8), colony formation assay, wound healing assay, and transwell assays. Cell cycle and apoptosis induced by COS were analyzed by flow cytometry and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) apoptosis assays. The mRFP-GFP-LC3 adenovirus construct and TEM (transmission electron microscopy) were used to directly demonstrate autophagosome formation. RNA-seq analysis, quantitative real-time polymerase chain reaction (QRT-PCR), and western blotting were used to identify the molecular changes caused by COS treatment. The effect of COS treatment on osteosarcoma tumorigenesis in vivo was studied in a xenograft model. Findings: COS fractions with different degrees of polymerization (DP) ranging from 2-5 were identified, which were composed of dimers (GlcNAc-GlcN, 15.7%), trimers (GlcNAc-(GlcN)2, 30.4%), tetramers (GlcNAc-(GlcN)3, 27.2%), pentamers (GlcNAc-(GlcN)4, 14.2%), and pentamers ((GlcNAc)3-(GlcN)2, 5.6%). Cell viability assays demonstrated that COS showed cytotoxic effects on osteosarcoma cells. The 48-hour 50% inhibitory concentrations (IC50) of COS for three osteosarcoma cell lines were 3.65-11.37 mg/ml. Generally, treatment with COS had significant effects on cell cycle arrest, metastasis inhibition, apoptosis and autophagy induction in osteosarcoma cells compared with the control group. COS treatment triggered pro-apoptosis autophagy through p53/mTOR signaling in osteosarcoma cells. Moreover, p53 inhibitor Pifithrin-μ restored the autophagy promoted by COS. The COS also inhibited tumor growth and metastasis in an osteosarcoma xenograft model. More importantly, our results showed that COS could increase sensitivity to chemotherapy of cisplatin (DDP) in vitro. Interpretation: Our data confirmed COS repressed osteosarcoma cell growth, induced apoptosis, and triggered pro-apoptosis autophagy via p53/mTOR signaling in osteosarcoma. And indicated that COS can serve as a potential novel therapeutic candidate for the treatment of osteosarcoma. Funding Statement: The work is supported by the grants from the National Natural Science Foundation of China on Qing-cheng Yang (81872182) and Dong-dong Cheng (81802685), and the Shanghai Sailing Program on Dong-dong Cheng (18YF1418700). Declaration of Interests: The authors declare that they have no conflicts of interest. Ethics Approval Statement: All animal experiments were performed in accordance with a protocol approved by the State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine. All experiments were subject to approval by the Animal Care and Use Committee of Shanghai Cancer Institute (Shanghia, China).

Influence of the degrees of polymerization of cellulose on the water absorption performance of hydrogel and adsorption kinetics

The cellulose with different degrees of polymerization (DPs) was successfully prepared and applied to synthesize a series of superabsorbent hydrogel (SAH) by grafting polymerization. Cellulose could be partly degraded by the combined effect of ultraviolet (UV) irradiation and sodium hypochlorite (NaClO). The DPs of cellulose decreased by 21% under this pretreatment method. The quantity of water absorption (Q) of SAH derived from the cellulose with different DPs was evaluated. Results indicated that the DPs of cellulose and the Q values of SAH had a good linear relationship when DPs ranged from 101.5 to 195. The Q value increased linearly when DPs decreased. The Q values of SAH synthesized from the cellulose (II), produced after the combined effect of UV and NaClO, were 328 and 129 g/g in distilled water and 0.9 wt% NaCl solution, respectively. The kinetic mechanism for the water absorption of SAH was efficiently described by the second-order model. This work can provide a guide for SAH synthesis based on DPs of cellulose.

Insight into the stabilization mechanism of emulsions stabilized by Maillard conjugates: Protein hydrolysates-dextrin with different degree of polymerization

The physical and oxidation stability of emulsions stabilized by conjugates prepared by Maillard reaction between whey protein hydrolysates (WPH) and linear dextrin (LD) with different degree of polymerization (DP) were investigated. In accordance with the gradient ethanol precipitation, LD1 (DP = 23.78), LD2 (DP = 47.62) and LD3 (DP = 64.96) were prepared. WPH-LD conjugates were obtained by Maillard reaction in dry-heating condition and the degree of glycation (DG) of conjugates increased with the increasing content of LD. Structural analysis (fluorescence spectra and circular dichroism) revealed that the secondary structure of WPH changed after glycation and the conjugates had less α-helix content than unmodified WPH. Meanwhile, the greater DPPH radical scavenging ability and iron chelating activity of conjugates were demonstrated compared with unmodified WPH. Conjugates containing LD with low and middle DP could form Pickering emulsions due to the aggregation of LD with short chains. The superior storage stability, oxidative stability and physical stability against environment stress of emulsions stabilized by conjugates, enhanced with increasing DP of LD in conjugates, were attributed to the combined action of stabilization of particle emulsifiers and greater steric hindrance (occupied the dominant position) provided by conjugates. Maillard reaction between LD and WPH was efficient to produce conjugates with high potential use as emulsifying agents to stabilize emulsions with excellent physical and oxidative stability.

Effects of simulated gastric and intestinal digestion on chitooligosaccharides in two in vitro models

SummaryChitooligosaccharides (COS) with different degree of polymerisation (DP) have different physiological activities such as anti‐tumour and anti‐hyperlipidemia activities. However, the digestive process might lead to the change of DP of COS as well as cause the change of physiological activities in vivo. In this study, two in vitro digestion models (static and dynamic) were used to investigate digestion behaviours of COS and the influencing factors during digestion with or without food matrix. The results showed that COS with DP 2–5 were indigestible and COS with DP 6–10 degraded with time during gastric and intestinal digestion. Pepsin, pancreatin and lipase were the main factors leading to degradation. Food matrix could protect COS with DP 6–10 from degradation during gastric digestion. However, the degradation of COS with DP 6–10 accelerated and the degradation of COS with DP 5 occurred during intestinal digestion with food matrix due to pancreatin, lipase and bile salt.