Low Methoxyl Pectin Research Articles

Effect of microwave-vacuum drying on the physicochemical properties of a functional tomato snack bar.

Tomato is an indispensable ingredient of the Mediterranean diet. Reformulation of traditional Mediterranean products to increase the adherence of consumers is becoming popular. In this study, a tomato snack bar enriched with olive powder and pea protein was developed by using microwave-vacuum drying. Formulations also included tomato powder (TP) and low-methoxylated pectin (LMP) as a structuring agent. The moisture content of microwave-vacuum-dried samples varied in the range 13.6-19.8% and water activity (aw ) values were ~0.6. LMP and TP concentrations affected the color of microwave-vacuum-dried samples. However, the color mainly changed in conventionally dried samples due to browning. In microwave-vacuum-dried samples, lycopene content decreased with increasing LMP, but increased with increasing TP. Textural properties of microwave-vacuum-dried snack bars increased with increasing LMP and TP. Both texture and Fourier transform infrared spectroscopy results indicated that there was a network formation due to the contribution of protein and pectin; however, the type of interaction was highly dependent on the drying mechanism. Nuclear magnetic resonance relaxometry data showed that microwave-vacuum-dried samples had a more uniform water distribution. Besides its time and energy efficiency, microwave-vacuum drying improved the color and textural properties of tomato snack bars compared to conventionally dried ones. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

High methoxyl pectin can improve the extrusion characteristics and increase the dietary fiber content of starch-cellulose extrudates.

Improving total dietary fiber content while maintaining the texture/expansion of extruded products is a challenge. Pectin has a dual function; it is a source of dietary fiber and it also functions as a hydrocolloid, which could improve the texture of high-fiber extruded foods. The objective of this study was to evaluate the impacts of pectin types from citrus peel on the expansion characteristics of starch-cellulose extrudates. High and low methoxyl pectin (HMP and LMP) was added to the starch-cellulose mixtures and extruded using a twin-screw extruder. The pasting properties of raw mixtures, extrusion properties, microstructure, and dietary fiber contents of the extrudates were studied. The inclusion of HMP in raw materialimproved the peak viscosity (629.7±8.1 to 754.7±80.1 mPa s) and maintained the final viscosity compared to the control (starch-cellulose mixture alone), unlike LMP. HMP relatively maintained the extrusion process parameters such as torque, back pressure, and specific mechanical energy as the control. Interestingly, the addition of 7% of HMP had a similar expansion ratio (3.41±0.08 to 2.35±0.06) compared to the control (3.46±0.08 to 2.32±0.09) under the extrusion conditions studied. The total dietary fiber content improved from 12.22±0.01% to 18.26±0.63% (w/w). HMP maintained the expansion characteristic of starch-cellulose extrudates and improved its total dietary fiber content relative to LMP. Adding HMP to the mixtures improved the extensibility of the melt, favoring bubble growth and expansion of the starch-cellulose extrudates. Fourier transform infrared spectroscopy data suggested that there could be intermolecular interactions between starch, cellulose, and pectin, but the nature of these interactions needs further investigation. PRACTICAL APPLICATION: The study provides practical information on the influence of the addition of high and low methoxyl pectin on starch-cellulose extrudates. The results can help the industry to produce snack products that are more nutritious but are still well accepted by the consumers.

Image-based assessment and machine learning-enabled prediction of printability of polysaccharides-based food ink for 3D printing

Despite the growing demand and interest in 3D printing for food manufacturing, predicting printability of food-grade materials based on biopolymer composition and rheological properties is a significant challenge. This study developed two image-based printability assessment metrics: printed filaments’ width and roughness and used these metrics to evaluate the printability of hydrogel-based food inks using response surface methodology (RSM) with regression analysis and machine learning. Rheological and compositional properties of food grade inks formulated using low-methoxyl pectin (LMP) and cellulose nanocrystals (CNC) with different ionic crosslinking densities were used as predictors of printability. RSM and linear regression showed good predictability of rheological properties based on formulation parameters but could not predict the printability metrics. For a machine learning based prediction model, the printability metrics were binarized with pre-specified thresholds and random forest classifiers were trained to predict the filament width and roughness labels, as well as the overall printability of the inks using formulation and rheological parameters. Without including formulation parameters, the models trained on rheological measurements alone were able to achieve high prediction accuracy: 82% for the width and roughness labels and 88% for the overall printability label, demonstrating the potential to predict printability of the polysaccharide inks developed in this study and to possibly generalize the models to food inks with different compositions.

Key role of three-dimensional reticular interface membranes in the formation of single polysaccharide–stabilized high internal phase emulsions

Although the interfacial activity of polysaccharides is believed to be insufficient for their applications as individual emulsifying stabilizers, four single polysaccharides examined herein, namely sodium carboxymethyl cellulose (Na-CMC), sodium alginate (SA), high-methoxyl pectin (HMP), and low-methoxyl pectin (LMP) are shown to effectively stabilize high internal phase emulsions (HIPEs) at loadings as low as 0.1 wt% under acidic conditions, that is, at pH 0.5–5.2 (Na-CMC), 0.5–4.0 (SA), 1.0–4.2 (HMP), and 1.0–3.0 (LMP). Despite their structural differences, the four studied polysaccharides feature similar HIPE stabilization mechanisms that mainly involve the formation of three-dimensional reticular interface membrane structures with fiber branching chains. Within the pH range suitable for HIPE formation, the polysaccharides mainly exist as nanofiber network structures with a grid width of 50–100 nm but adopt flake-like and other structures at higher pH. Further insights are provided by the relationship between network membrane structures formed at the interface and the fiber network structures formed by polysaccharides in the original aqueous phase. In addition, the inferred emulsification and stabilization mechanisms are shown to be significantly different from those observed for mainstream Pickering HIPE stabilizers. Thus, our work expands the understanding of the interfacial activity function of polysaccharides, provides conceptual thinking reference and design rules for the development of simple, efficient, safe, and cheap polysaccharide-based HIPEs, and supplements and furthers the theory of HIPE stabilization.

Valorization of pectic polysaccharides from Gardenia jasminoides Ellis flower: Physicochemical, structural, rheological, and functional properties

Gardenia jasminoides Ellis is a widely cultivated garden plant, but its flower resources are underutilized. In this study, three pectic polysaccharides extracted from Gardenia flowers (GFPPs) were obtained, including acid-extracted pectin (ACP), hot water-extracted pectin (HWP), and alkaline-extracted pectin (ALP). The physicochemical, structural, rheological, and functional properties of GFPPs were compared and analyzed. The results showed that the yield of all GFPPs exceeded 21%, and the proportion of the rhamnogalacturonan I (RG-I) regions ranged from 42.20% to 54.66%. The GFPPs were identified as low-methoxyl pectin with a semi-crystalline and amorphous structure. Among them, ACP had the highest molecular weight and neutral sugar content, while ALP had the highest content of galacturonic acid and protein. Rheologically, all three GFPPs exhibited pseudoplastic behavior with thixotropic properties, particularly ACP. Storage at low temperatures increased the apparent viscosity of ACP and HWP, while that of ALP was decreased. Importantly, emulsions prepared with 2% GFPPs and 10% medium-chain triglycerides remained stable at 4 °C and 25 °C for 21 days. Moreover, the ALP-based emulsion demonstrated excellent emulsifying capability, maintaining stability at 60 °C for 21 days with an emulsion appearance. These findings suggest that GFPPs hold promise as a pectin source for hydrocolloids and can be used in various food applications.

Evaluation of structural and functional properties of citrus pectin film enriched with green tea extract

AbstractThe effects of green tea extract (GTE) concentrations (0%, 1%, 2%, 3%, 4%, and 5%) on the thicknesses, mechanical strengths, storage/loss moduli, glass transition temperatures (Tg), chemical structures, morphologies, antioxidant activities, moisture contents, and gas permeabilities of low methoxyl pectin films were investigated in this study. A decrease in the percent elongation and moisture contents accompanied by an increase in the tensile strengths, Tg and elastic and storage moduli were observed with increasing, but low concentrations of GTE in the pectin films. This rate of change slowed at higher GTE concentrations. The thicknesses of the pectin films were not significantly affected by the concentrations of GTE. The FTIR results showed increasing ester and hydrogen bonding formations with increasing concentrations of GTE from 0% to 2% in the pectin. When the GTE concentration increased from 2% to 5%, there was an increase in ester, but a decrease in the H‐bonding. The x‐ray diffraction results showed that the crystallinity of the films increased as a result of increasing GTE contents. The results of the antioxidant activities and oxygen and water vapor barrier properties showed an enhancement due to the higher concentrations of GTE. Therefore, GTE can be incorporated into low methoxyl pectin in order to make films with desired mechanical strength, gas barrier, and antioxidant properties.

Tyramine modification of high and low methoxyl pectin: Physicochemical properties, antioxidant activity, and gelation behavior

Pectin modification is an effective approach for changing its functional properties and discovering new applications. To provide more insight into the modified pectin structure-function relationships, tyramine (Tyr) modified high (HMP) and low methoxylated pectin (LMP) were prepared to construct novel pectin gel systems. FTIR, 1H NMR, and UV–vis analyses confirmed that Tyr groups were successfully grafted onto pectin chain and obtained the unreacted galacturonic acid (GalA) content. Physiochemical characterization revealed that Tyr modified pectin exhibited enhanced solubility, amphiphilicity and antioxidant activity. Tyr modified pectin gels possessed good viscoelastic property, but obviously decreased elasticity and strength compared to native pectin gel. Entanglement network number (ENN) and scanning electron microscopy (SEM) image demonstrated the decreased internal cross-linking networks density which contributed to the altered gelling properties of Tyr modified pectin gels. The proposed gelling mechanism indicated that bulky Tyr involved physical interactions were mainly responsible for the changed pectin gelling behavior and gelation process in nature. Similarly, the textural properties and water holding capacity (WHC) of Tyr modified pectin gels were closely related to their physical interaction categories and gelling network microstructure. Sucrose induced gellation of the Tyr modified LMP with strong carboxyl groups related hydrogen bonding showed higher hardness. Calcium ions induced gellation of the Tyr modified LMP formed a larger porous gel matrix which resulted in a poor WHC. The findings provide theoretical basis on physicochemical properties and gelling behaviors of Tyr modified pectin for expanding their application in the fields of food preservation, emulsifiers, stabilizers, and tunable gel-type foods.

A novel technique to obtain polysaccharide gels that emulate encapsulation beads with size and shape suitable for rheological, mechanical and other measurements

In this work we built up and tested diffusion cells designed to obtain polysaccharide hydrogels by ionotropic gelation. The objective was to obtain gel samples that emulated the wall material of encapsulation beads but, unlike them, have appropriate size and shape for measurement of their structural properties, since these are of paramount importance for the protection, carry and delivery of bioactive compounds. Three polysaccharides widely used for encapsulation and with different gelation mechanisms were tested: kappa/iota-carrageenan (which gels mainly in the presence of K+ ions), and sodium alginate and low methoxyl pectin (which both gel in the presence of Ca2+ ions). The diffusion cells consisted of two nitrocellulose membrane filters supported between three rings made by 3D printing. They were filled with the polysaccharide solution, hermetically tightened with screws and nuts, and submerged into the saline solution. The membrane filters effectively avoided the loss of the polysaccharide solution but allowed the diffusion of the ions (either Ca2+ or K+) into the polysaccharide solutions to promote their gelation. Firm, self-standing gels were obtained, and their rheological and mechanical properties were successfully measured. Samples of different shapes and sizes could be obtained with this technique, for other types of measurement.

Potential of polysaccharides for food packaging applications. Part 1/2 : An experimental review of the functional properties of polysaccharide coatings

Environmental issues related to the use of plastic packaging have sparked a growing interest in the development of more sustainable solutions. Biopolymers, used alone or in combination with other materials, have been considered a potential alternative to conventional fossil-based plastics. Hence, this study aimed at unraveling the potentiality offered by polysaccharides for food packaging applications. To that purpose, an extended characterization of the barrier (to oxygen and water vapor), mechanical and optical properties (transparency and UV-blocking ability) of nine different polysaccharide films (hydroxypropyl methylcellulose, methylcellulose, hydroxypropyl cellulose, low-methoxyl pectin, cationic starch, sodium alginate, kappa-carrageenan, chitosan, and pullulan) was performed to provide a broad overview of their main physicochemical properties under standardized conditions. In addition, the properties of the film-forming solutions, such as viscosity and surface tension, were also evaluated. All polysaccharides obviously presented low water vapor barrier performance due to their hydrophilic nature (water vapor permeance from 10−6 to 10−8 mol.m-2.s-1.Pa-1). Among all the polysaccharides studied, chitosan, low-methoxyl pectic, kappa-carrageenan, pullulan, cationic starch and sodium alginate, displayed medium to very high oxygen barrier performance in semi-dry (50% RH) and humid (80% RH) conditions (oxygen permeance from 10−13 to 10−15 mol.m-2.s-1.Pa-1), contrarily to cellulose derivatives which showed the poorest performance (oxygen permeance >10−12 mol.m-2.s-1.Pa-1). This opens on interesting perspectives for the use of polysaccharides as coating materials for high oxygen barrier packaging.

Potential of polysaccharides for food packaging applications. Part 2/2: An experimental review of the effect of aging conditions on the functional properties of polysaccharide films

In recent years, polysaccharides have attracted interest for their potential use in food packaging due to their functional properties, such as film-forming ability and oxygen barrier property. However, when considering polymers extracted from natural resources for packaging applications, one of the most critical issues is their stability over time. Accordingly, this study conducted a comprehensive evaluation of the effect of storage on the functional properties of films made from the most popular polysaccharides (hydroxypropylmethylcellulose, methylcellulose, hydroxypropylcellulose, low methoxyl pectin, cationic starch, sodium alginate, kappa-carrageenan, chitosan, and pullulan) to be potentially used in packaging or coating applications. The optical, mechanical and barrier (to oxygen and water vapor) properties of these polysaccharide films were measured after 6 and 12 months of storage at 50% relative humidity (RH) and 25 °C. The values obtained were compared with those initially determined for starting materials just after their production (0 month). The functional properties of almost all of the polysaccharide films showed remarkable stability during the 12 months of storage. However, small changes were observed in some of the properties, especially in the optical ones. This was the case for the chitosan films which exhibited a color change indicative of Maillard reaction, as also evidenced by changes in the UV visible spectrum (especially in the 280–350 nm range) with a sharp decrease in the transmittance. Furthermore, after 12 months of storage, all polysaccharide films lost 4–60% of their initial glycerol content. Surprisingly, this did not significantly affect either the mechanical or barrier properties of the films.

Effect of different NaCl concentrations on the structure-function relationship of citrus peel pectins modified by electrochemistry

In this study, the modified citrus peel pectins (CPPs) were successfully produced by electrochemistry with varying NaCl concentrations of 0, 0.01 % and 0.1 % w/v using an H-type cell at 40 mA current. After 4 h, the pH and oxidation-reduction potential (ORP) of oxidized CPP solution in the anodic region were 2.00– 2.52 and 371.17– 564.45 mV, respectively, due to the electrolysis of water, whereas those of reduced CPP solution in cathodic region were 9.46– 10.84 and − 202.77 ∼ −230.57 mV. The modified CPPs in the anodic region (A-0, A-0.01, and A-0.1) exhibited significantly higher weight-average molecular weights and methyl esterification degrees than those in the cathodic region (C-0, C-0.01 and C-0.1). In contrast, the K+, Mg2+, and Ca2+ contents of A-0, A-0.01, and A-0.1 were lower than those of C-0, C-0.01 and C-0.1 due to the electrophoretic migration. Furthermore, the antioxidant activities of A-0 and A-0.01 solutions were stronger than those of the C-0, C-0.01, and C-0.1, while rheological and texture properties of their hydrogels showed contradictory results. Finally, the potential structure-function relationships of CPPs were explored by combining PCA and correlation analysis. Overall, this study introduced a potential approach for pectin purification and functional low-methoxyl pectin manufacturing.

Ultrasound Assisted Extraction and Characterization of Pectin from Red Dragon Fruit (Hylocereus Polyrhizus) Peels

Pectin has numerous applications in the food industry because of its gelling capability. Dragon fruit peel is an ideal source of pectin since it contains pectin of around ± 10.8% of the weight. In this research, the extraction of pectin from dragon fruit peels used ultrasonic waves. This study was an experimental research with three independent variables that was a type of acid (HCl and CH3COOH), acid concentration (0.1 N and 0.2 N), and extraction time (30, 60, and 90 minutes). The control sample was pectin extracted by conventional methods, dipped in 0.1 N acids at room temperature for 24 hours. The result showed that the ultrasound-assisted extraction was an effective method to extract pectin from peels of red dragon fruits, whereas the yield was even twice that compared with the control sample. The treatment of 90 minutes of sonication in 0.2 N HCl produced the highest yield (2.71%). The pectin has a yellowish to a white degree of color and a 2.22 g.s/cm viscosity. It has a 902.2 mg equivalent weight, 6.14% methoxyl content, 54.4% galacturonic acid content and 63.8% esterification degree. The value of esterification degree and methoxyl content indicated that pectin from this research is high ester-pectin and low-methoxyl pectin.

Self-demise of soft rot bacteria by activation of microbial predators by pectin-based carriers.

Soft rot pectobacteria (SRP) are phytopathogens of the genera Pectobacterium and Dickeya that cause soft rots on a wide range of crops and ornamental plants. SRP produce plant cell wall degrading enzymes (PCWDEs), including pectinases. Bdellovibrio and like organisms are bacterial predators that can prey on a variety of Gram-negative species, including SRP. In this research, a low methoxyl pectin (LMP)-based immobilization system for B. bacteriovorus is established. It takes advantage that pectin residues induce PCWDE secretion by the pathogens, bringing upon the release of the encapsulated predators. Three commercial LMPs differing in the degree of esterification (DE) and amidation (DA) were tested as potential carriers, by examining their effect on SRP growth, enzymes secretion and substrate breakdown. A clear advantage was observed for pectin 5 CS with the lowest DE and DA content. The degradation of 5 CS pectin-based carriers was further optimized by reducing cross-linker and pectin concentration, by adding gelatin and by dehydration. This resulted in SRP-induced disintegration of the carrier within 72 h. The released encapsulated predator caused a large decrease in SRP population while its own significantly increased, demonstrating the efficiency of this system in which the pathogen brings about its own demise.

Amidated Pectic Polysaccharides (Pectin) as Methane Hydrate Inhibitor at Constant Cooling and Isobaric Condition.

This study aims to address the environmental impact of using common commercial hydrate inhibitors such as Methanol (MeOH) in extremely cold oil and gas environments. As a greener alternative, Pectic Polysaccharides (pectin) can act as a kinetic hydrate inhibitor (KHI) to delay hydrate formation. We evaluated the performance of amidated pectin (AMP), a type of pectin with higher electronegative functional groups, using a high-pressure micro-differential scanning calorimeter (HP µ-DSC) under isobaric conditions with constant cooling. We compared AMP to low-methoxylated pectin (LMP) and high-methoxylated pectin (HMP) and found that AMP was the best KHI among the tested pectin types. At a concentration of 1.0 wt.%, the AMP Relative Inhibitor Performance (RIP) was 0.10, and at 0.1 wt.%, it had an RIP of 0.07, which were the only positive RIPs obtained amongst the tested KHIs. The results suggest that AMP can be a sustainable KHI option in extremely cold environments where the KHI effectiveness typically declines.

Construction and Performance Evaluation of Nicandra physalodes (Linn.) Gaertn. Polysaccharide-Based Nanogel.

The nanogels made from these polysaccharides and their derivatives are often used to construct drug delivery systems owing to their biocompatible, biodegradable, non-toxic, water-soluble, and bioactive characteristics. In this work, a novel pectin with unique gelling properties was extracted from the seed of Nicandra physalodes (NPGP). The structural research indicated that NPGP was a low methoxyl pectin with a high content of galacturonic acid. NPGP-based nanogels (NGs) were accomplished employing the water in oil (W/O) nano-emulsion method. The cysteamine containing reduction-responsive bond and integrin-targeting RGD peptide were also grafted onto NPGP. The anti-tumor drug doxorubicin hydrochloride (DOX) was loaded during the formation of NGs, and the performance of DOX delivery was studied. The NGs were characterized by UV-vis, DLS, TEM, FT-IR, and XPS. The results showed that the prepared NGs were nanosized (167.6 ± 53.86 nm), had excellent encapsulation efficiency (91.61 ± 0.85%), and possessed a fine drug loading capacity (8.40 ± 0.16%). The drug release experiment showed that DOX@NPGP-SS-RGD had good redox-responsive performance. Furthermore, the results of cell experiments revealed good biocompatibility of prepared NGs, along with selective absorption by HCT-116 cells through integrin receptor-mediated endocytosis to play an anti-tumor effect. These studies indicated the potential application of NPGP-based NGs as targeted drug delivery systems.

Valorization of Grape Pomace as a Renewable Source of Techno-Functional and Antioxidant Pectins.

The food industry's increasing demand for new functional ingredients that meet both organoleptic and healthy requirements has driven the exploration of new sources of functional ingredients in agro-industrial by-products. The aim of this work was to valorize grape pomace (Vitis vinifera L. garnacha) as a source of pectins using food-grade extracting agents. Obtained pectins were evaluated for monomeric composition, methyl esterification, molecular weight, water retention, oil-holding capacity, and antioxidant properties. The relatively soft extraction conditions used permitted obtaining low methoxyl pectin (10-42%) enriched in homogalacturonan (38-45%) or rhamnogalacturonan (33-41%) with different branching degrees, molecular weight, and fewer impurities than those found in the scarce previous literature. The relationship between structure and functionality was studied. Among the different pectins obtained, the sample derived from the extraction with sodium citrate could resume the best characteristics, such as pectin purity and higher water retention and oil holding capacity. These results underscore the relevance of grape pomace as a viable alternative source of pectin.

Physicochemical and in vitro digestion properties of gelatin/low-methoxyl pectin synbiotic microgels co-encapsulating Lacticaseibacillus casei and pectic oligosaccharides via double-crosslinking with transglutaminase and calcium ions

In this study, we investigated the physicochemical and in vitro digestion properties of gelatin (GEL)/low-methoxyl pectin (LMP) synbiotic microgels co-encapsulating Lacticaseibacillus casei (L. casei) and pectic oligosaccharides. A single-crosslinked microgel containing L. casei was fabricated via enzymatic crosslinking with transglutaminase. The single-crosslinked microgel was incubated in calcium chloride solution at different concentrations (1%, 2%, and 3%) to produce double-crosslinked microgels. In field emission scanning electron microscopy (FE-SEM) analysis, the double-crosslinked microgels exhibited a more spherical shape with a smoother surface than the single-crosslinked microgel. The crosslinks and possible interactions in the microgels were described using X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy analyses. The encapsulation efficiency of both single- and double-crosslinked microgels was relatively high (95.64%–95.99%). After exposure to simulated gastrointestinal conditions (salivary, gastric, and intestinal phases), the survival rate of L. casei in double-crosslinked microgels (GEL/LMP3) prepared with 3% calcium ions was the highest among all the samples studied. After heat treatment (72 °C for 15 s and 63 °C for 30 min) and 20 days of storage (4 °C and 37 °C), L. casei encapsulated in all microgels, especially double-crosslinked microgels, maintained greater viability than free cells. These results suggest that double-crosslinked GEL/LMP synbiotic microgels, particularly GEL/LMP3, can be used to improve the viability of probiotic cells under gastrointestinal, heating, and storage conditions.

Oral delivery of porous starch-loaded bilayer microgels for controlled drug delivery and treatment of ulcerative colitis

We prepared one type of bilayer microgels for oral administration with three effects: pH responsiveness, time lag, and colon enzyme degradation. Combined with the dual biological effects of curcumin (Cur) for reducing inflammation and promoting repair of colonic mucosal injury, targeted colonic localization and release of Cur according to the colonic microenvironment were enhanced. The inner core, derived from guar gum and low-methoxyl pectin, afforded colonic adhesion and degradation behavior; the outer layer, modified by alginate and chitosan via polyelectrolyte interaction, achieved colonic localization. The porous starch (PS)-mediated strong adsorption allowed Cur loading in inner core to achieve a multifunctional delivery system. In vitro, the formulations exhibited good bioresponses at different pH conditions, potentially delaying Cur release in the upper gastrointestinal tract. In vivo, dextran sulfate sodium-induced ulcerative colitis (UC) symptoms were significantly alleviated after oral administration, accompanied by reduced levels of inflammatory factors. The formulations facilitated colonic delivery, allowing Cur accumulation in colonic tissue. Moreover, the formulations could alter gut microbiota composition in mice. During Cur delivery, each formulation increased species richness, decreased pathogenic bacterial content, and afforded synergistic effects against UC. These PS-loaded bilayer microgels, exhibiting excellent biocompatibility, multi-bioresponsiveness, and colon targeting, could be beneficial in UC therapy, allowing development into a novel oral formulation.

Impact of probiotic cell inclusion and metabolic activity on the rheological properties of low-methoxyl pectin solutions and gels

The rheological behavior of low-methoxyl (LM) pectin solutions and gels was characterized to evaluate the impact of the inclusion of probiotic cells (Lactobacillus rhamnosus GG and L. casei) and its metabolites. Considering that probiotic cells metabolize macro and/or micro-nutrients in growth media and/or can modulate pectin-Ca2+ interactions occupying the free volume in the gel, two scenarios were tested: 1) A 2% pectin in free-carbohydrate basal medium (P-MRS-B) (control sample) was mixed with probiotic cells (∼107 cells/mL) and incubated at 37 °C for 48 h (fermented samples); 2) A probiotic suspension in P-MRS-B was prepared as described above and used immediately to measure rheological properties (in situ samples).All gel-forming solutions presented Newtonian behavior and their corresponding gels showed an intermediate behavior between weak-gel and strong-gel. Mean viscosity (η) values ranged between 15.9 and 20.1 mPa s and no significant differences (p = 0.643) were observed between the samples. Mean elastic modulus at 1 rad/s (G′1) values ranged between 447 and 499 Pa, with no significant differences (p = 0.975) between the samples. These results suggest that: 1) The volume fraction of probiotics was so low that its presence did not have a significant effect on the viscosity and on the elastic modulus, and neither on the gelation mechanism of the LM-pectin; 2) Metabolic products of LM-pectin fermentation did not have a significant effect on the viscosity of the solutions, nor on the elastic modulus of the gels and their gelation mechanism.

Merging konjac glucomannan with other copolymeric hydrogels as a cutting-edge liquid raft system for dual delivery of etoricoxib and famotidine

This study aimed to formulate and evaluate a floating raft system for the co-delivery of etoricoxib (ETO) and famotidine (FAM) using a combination of glucomannan with natural/semi-synthetic polysaccharides. Formulation variables affect gelation lag time (GLT), floating lag time (FLT), and release percentage of drugs after 1–8 h, Stability, and viscosity parameters were evaluated. In vivo X-ray studies, followed by the pharmacokinetic study, were performed on human volunteers. Formulations exhibited pseudoplastic behavior for ease of swallowing. The optimum raft system (ORS) comprised 1% Na alginate, 0.1% Low Methoxyl (LM) pectin, 0.8% Konjac glucomannan (KGL), 1% Precirol, and 1% CaCO3. ORS exhibited rapid GLT and FLT (around 42 and 8 sec respectively) in 0.1 N HCl as well as controlled release of ETO (15% in 1 h and 82% in 8 h) and FAM (29% in 1 h and 85% in 8 h). Formulation stability with the absence of any drug-excipient interactions was observed. The X-ray imaging showed a promising buoyancy ability for approximately 8 h. Compared with marketed products, ORS showed superior relative bioavailability for both drugs. These findings revealed the successful preparation of a promising raft system with improved dual drug delivery.