Ornithogalum cuspidatum mucilage as a new source of plant-based polysaccharide: Physicochemical and rheological characterization

Assessing physicochemical characteristics of a shear-thinning polysaccharide mucilage extracted from marshmallow root (Althaea officinalis L.) by an ohmic heating system

Althaea officinalis L. root mucilage holds promise for food industries due to its functional properties. Despite various extraction techniques, ohmic systems remain underexplored for mucilage extraction. This study aimed to compare the efficacy of mucilage extraction using ohmic systems with maceration and investigate their physicochemical properties. The mucilage extraction was carried out utilizing maceration (M), ohmic-assisted extraction (OAE), and ohmic-assisted vacuum extraction (OAVE). Various parameters were evaluated, such as densities and specific energy consumption. The mucilage obtained by OAE had the highest yield (8.9 %). The highest solubility corresponded to the mucilage obtained by the OAE system (85.18 % at 65 °C). OAVE mucilage had 76.16 % swelling and 82.5 g water/g dry sample binding capacity, while OAE mucilage had 19.6 g water/g dry sample binding capacity. The OAVE mucilage oil absorption (12.3 g oil/g dry sample) was almost twice that of the OAE system. Rheological analysis characterized them as a pseudoplastic behavior. DSC thermogram of mucilage samples exhibited a singular endothermic peak (92.05 to 108.3 °C). FTIR analysis highlighted that the primary constituents of mucilage samples predominantly consisted of polysaccharides. This study concluded that ohmic-assisted extraction was the most efficient method for obtaining mucilage. Further research could explore the potential applications of this mucilage.

High pressure homogenization: A promising approach to expand food applications of chia mucilage

Two chia mucilages with different viscosities, obtained by extraction conditions optimized in a previous work, were homogenized by high pressure homogenization (HPH). Particle size, molecular weight, zeta potential, FTIR spectrum, rheological properties, water absorption capacity, water holding capacity and iron binding capacity were determined on both mucilages treated and without treatment. Homogenization led to a significant reduction in viscosity respect to chia mucilage controls, which can be related to the decrease in particle size and molecular weight. A high iron binding capacity was obtained for both mucilages. FTIR spectra of both mucilages with iron showed displacements in bands related with stretching of carboxylic uronic acids, suggesting the interaction site with this mineral. This interaction was also verified by particle size determination with a displacement to higher sizes in the presence of iron. Potential zeta showed a significant reduction in the presence of iron. A model to explain the binding between chia mucilage and iron is proposed. HPH appears as an alternative to expand chia mucilage functionality reducing the viscosity of chia mucilage solutions for the offer of a new ingredient also with optimal levels of hydration and iron binding capacity.

Electrospun Cactus Mucilage/Poly(vinyl alcohol) Nanofibers as a Novel Wall Material for Dill Seed Essential Oil (Anethum graveolens L.) Encapsulation: Release and Antibacterial Activities

This study aimed to create long-lasting carriers by producing electrospun nanofibers loaded with dill seed (Anethum graveolens L.) essential oil (DSEO), using cactus mucilage (CM) and poly(vinyl alcohol) (PVA). Continuous and uniform electrospun nanofibers with a diameter of 158 ± 18 to 230 ± 26 nm were successfully made from the CM/PVA blend solution and the CM/PVA/DSEO emulsion. Atomic force microscopy topographic images revealed that the electrospun nanofibers had a tubular morphology. The thermogravimetric curves of DSEO, CM, pure PVA, and electrospun nanofibers demonstrate that the polymers used and the essential oil have effective chemical interactions. The water contact angle results suggest that the manufactured nanofibers are hydrophilic. CM/PVA consistently achieves a remarkable encapsulation efficiency of 100% DSEO. The electrospun nanofibers enabled the controlled release of free and encapsulated DSEO, resulting in sustained long-term release. The agar disk diffusion technique was used to study the antimicrobial activity of electrospun nanofibers and nanofibers containing DSEO against Gram-positive and Gram-negative bacteria. With a minimum inhibitory concentration of 2.5 mg/mL and a minimum bactericidal concentration of 5 mg/mL, electrospun nanofibers containing DSEO demonstrated bacteriostatic and bactericidal activities against foodborne pathogenic bacteria (Staphylococcus aureus and Pseudomonas aeruginosa). The DSEO-loaded electrospun nanofibers derived from carbohydrates show promise as an active interior coating for use in biomedical and food packaging applications.

Ixiolirion tataricum mucilage/chitosan based antioxidant films activated by free and nanoliposomal fennel essential oil

Ixiolirion tataricum mucilage (ITM) was characterized and applied in fabrication of ITM/chitosan (CH) blend films activated by Foeniculum vulgare essential oil (FEO) in free and nanoliposomal forms. Uniform smooth surface structure, viscoelastic solid-like behavior and Newtonian nature of ITM were confirmed by morphological and rheological analyses. The prepared FEO nanoliposomes (FEO-NLPs) showed desirable properties in terms of particle size (57.2 nm), polydispersity index (0.243), zeta-potential (-17.6 mV), and encapsulation efficiency (85.2 %). The enhancing effects of FEO-NLPs and the adverse effects of free FEO on the crystalline, morphological and structural properties of films were confirmed by XRD, FE-SEM and ATR-FTIR tests. FEO-NLPs loaded films had better mechanical, thermal, water and gas barrier and antioxidant properties than neat film. Analysis also indicated the high controlled release of FEO from the films containing the nanoliposomal form of FEO. The films containing free FEO showed higher antibacterial activity against E. coli and S. aureus in comparison with FEO-NLPs loaded ones. The results showed the potential of FEO-NLPs loaded ITM/CH films for antioxidant food packaging applications.

Structural studies of a mannoglucan from Cremastra appendiculata (Orchidaceae) by chemical and enzymatic methods

Pseudobulb of Cremastra appendiculata (Orchidaceae) is a traditionally used medicine in China for treatment of certain cancers. The polysaccharides from this medicinal plant are poorly understood. Therefore, we focused on the isolation and fine structure characterization of C. appendiculata polysaccharides. After isolation by DE-52 and Superdex 200 gel chromatography, the purified polysaccharide (named as CAP) with Mw 557.5 kDa was obtained with a narrow and symmetric peak presented in the HPGPC. The monosaccharide composition results showed in HPAEC that CAP was a heteropolysaccharide composed of glucose and mannose at a molar ratio roughly 0.34:0.66. The methylation results indicated that CAP was a 1,4-β-mannose and 1,4-β-glucose linear linkage. The further NMR studies suggested a 0.208 acetylation substitution of CAP and a hexasaccharide repeating unit composed of 1,4-β-mannose and1, 4-β-glucose in the CAP structure. The chemical structure of CAP was confirmed further by the specific glucanase and mannanase hydrolysis results.