Preparation and characterization of gellan gum-guar gum blend films incorporated with nisin

Synergistic effect of gellan gum and guar gum on improving the foaming properties of soy protein isolate-based complexes: Interaction mechanism and interfacial behavior

Interactions among multi-component play a critical role in modulating the foaming properties of aerated foods. This study evaluated the mechanisms of synergistic improvement of gellan gum (GEG) and guar gum (GUG) on the foaming properties of soy protein isolate (SPI)-based complex. The results showed that the GEG/GUG ratio was closely related to the intermolecular interactions of SPI-based ternary complex and the dynamical changing of its foaming properties. The SPI/GEG/GUG ternary complex with a GEG/GUG ratio of 2/3 exhibited the highest foamability (195 %) and comparable foam stability (99.17 %), which were 32.95 % and 2.99 % higher than that of SPI/GEG binary complex. At this ratio, GUG promoted the interactions between SPI and GEG, and bound to complex's surface through hydrogen bonding, resulting in the increase of particle size and surface charge, and the decrease of surface hydrophobicity. Although this reduced the diffusion of complex onto the air/water interface, it increased permeation rate and molecular rearrangement behavior, which were the potential mechanisms to improve the foaming properties. Additionally, the synergistic effect of GEG and GUG also enhanced the elastic strength and solid characteristics of foam systems. This study provided a theoretical guidance for the targeted modulation of foaming properties of multi-component aerated foods.

Recent advances in gellan gum production and modification for enhanced applicability in food printing and bioactive delivery applications

The importance of Gellan gum has been increasing gradually and its unique characteristics are suitable for various advanced food technologies. This review outlines recent developments in gellan gum production, modification, and newer applications focusing on food printing and bioactive delivery applications, in the last three years. The yield and production condition of gellan gum is a major factor that affects the cost and its applications. Moreover, modified Gellan gum has been shown to have superior characteristics and functionality as compared to native one. The viscosifying, thermosensitive, gelling etc. characteristics of gellan gum makes it an crucial ingredient in case of preparation of 3D printing ink. Further, gellan gum is also found to be important wall material in case of bioactive delivery application through encapsulation. Optimized methods of production, sustainable feedstock, and stress conditions are critical for the desired functionality and yield of the Gellan gum.

Physical properties of cellulose nanocrystal/magnesium oxide/chitosan transparent composite films for packaging applications

Hitherto unreported hybrid nanofillers (CNC:MgO) reinforced chitosan (CTS) based composite (CNC:MgO)/CTS films were synthesized using a solution-casting blend technique and synergistic effect of hybrid nanofiller in terms of properties enhancement were investigated. Optical microscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD) technique, fourier-transform infrared spectroscopy (FTIR), and field emission scanning electron microscopy (FESEM) were used to characterize the films. The hybrid nanofiller considerably changed the transparency and color of the CTS films. The tensile strengths of (3 wt%) CNC/CTS, (3 wt%) MgO/CTS, (1:1)(CNC:MgO)/CTS, (1:2)(CNC:MgO)/CTS and (2:1)(CNC:MgO)/CTS films were 27.49 %, 35.60 %, 91.62 %, 38.22 %, and 29.32 % higher than pristine CTS films respectively, while the water vapor permeation were 28.21 %, 30.77 %, 34.62 %, 38.46 %, and 37.44 % lower than pristine CTS film, respectively. Moreover, the CTS composite films exhibited an improvement in overall water barrier properties after incorporating hybrid nanofillers. Our observations suggest that chitosan-based hybrid nanofiller composite films are a good replacement for plastic-based packaging materials within the food industry.

Banana fibre-chitosan-guar gum composite as an alternative wound healing material

Bio-composites, which can be obtained from the renewable natural resources, are fascinating material for use as sustainable biomaterials with essential properties like biodegradable, bio-compatibility as well cyto-compatibility etc. These properties are useful for bio-medical including wound healing applications. In this study, fibre obtained banana pseudo stem of banana plant, which is otherwise wasted, was used as a material along with chitosan and guar gum to fabricate a banana fibre-biopolymer composite patch. The physiochemical properties of the patches were examined using Fourier Transformed Infra-red spectrophotometer (FT-IR), tensile tester, Scanning Electron Microscope (SEM), contact angle tester, swelling and degradation studies. We further demonstrated that a herbal drug, Nirgundi could be loaded to the patch showed controlled its release at different pHs. The patch had good antibacterial property and supported proliferation of mouse fibroblast cells. The study thus indicates that banana fibre-chitosan-guar gum composite can be developed into an alternative wound healing material.

Advances in tissue engineering of gellan gum-based hydrogels

Gellan Gum (GG) is a large, naturally occurring, linear polysaccharide with a similar structure and biological properties to the extracellular matrix. It's appropriate as a matrix material for the development of different composite materials due to its biocompatibility, biodegradability, and injectability. Hydrogels made from GG have found various applications in the field of Tissue Engineering (TE) in recent years after being mixed with a variety of other organic and inorganic components. These composites are considered multifunctional developing biomaterials because of their impressive mechanical capabilities, biocompatibility, low cytotoxicity, etc. This review focuses on the emerging advances of GG-based hydrogels in TE, providing an overview of the applications of different types of GG-based composite materials in bone TE, cartilage TE, nervous TE, retina TE, and other fields. Moreover, the investigations of GG-based hydrogels as bioink components for 3D bioprinting in TE will be elucidated. This review offers general guidance for the development of biomaterials related to GG, as well as ideas for future clinical diagnosis and treatment.

A novel high water-soluble antibacterial films-based guar gum incorporated with Aloe vera gel and ε-polylysine

The high water-soluble films are commonly used in food coating and food encapsulation. In this study, the effect of Aloe vera gel (AV) and ε-polylysine (ε-PL) on the comprehensive properties of films based on guar gum (GG) were investigated. When GG to AV was 8:2, the GG:AV:ε-PL composite films (water solubility = 68.50%) had an 82.42% higher water solubility than pure guar gum (PGG) films (water solubility = 37.55%). Compared with PGG films, the composite films more transparent, better thermal stability and elongation at break. X-ray diffraction and SEM analysis showed the composite films were amorphous structures and the AV and ε-PL did not change the structure of PGG. FITR analysis confirmed the formation of hydrogen bonds within the composite films. Antibacterial properties showed the composite films had a good antibacterial effect against Escherichia coli and Staphylococcus aureus. Therefore, the composite films can be a new option of high water-soluble antibacterial food packaging materials.

Preparation of an elderberry anthocyanin film and fresh-keeping effect of its application on fresh shrimps

A smart packaging film was developed employing the pH-indicating activity of elderberry anthocyanins to solve the problem of refrigerated food freshness monitoring. The effect of elderberry anthocyanins on the properties of gellan gum, gelatin composite films and preservation of fresh shrimp as an indicator of freshness was investigated. The results showed that the elderberry anthocyanin-gellan gum/gelatin film had improved on film thickness (7.8×10-2 mm), TS (tensile strength) (14.57×103 MPa), WVP (water vapor permeability) (36.96×10-8 g/m·s·Pa), and a reduced EAB (elongation at break) (17.92%), and water solubility (water-soluble time of 60.5 s). SEM (scanning electron microscopy) and FTIR (infrared spectrum analysis) showed excellent compatibility between its components. Moreover, the elderberry anthocyanin film exhibited good mechanical properties and pH indication effects. Therefore, the film can be considered suitable for maintaining the quality of fresh shrimp. The results could provide a reference for research and development into new active intelligent packaging films.

Synthesis, characterization and evaluation of in vitro antimicrobial and anti-diabetic activity of berberine encapsulated in guar-acacia gum nanocomplexes

In the present study, the anti-diabetic and antimicrobial properties of berberine were improved using non-ionic guar gum and ionic acacia gum as nanocarriers. Berberine loaded guar-acacia gum nanocomplexes were synthesized by employing ionic complexation method. The formulation was characterized by dynamic light scattering (DLS), Fourier-transform infrared spectroscopy (FTIR), Transmission electron microscopy (TEM), Scanning electron microscopy (SEM) and evaluated for in vitro dissolution study, anti-diabetic activity and antimicrobial activity. The optimized berberine loaded guar-acacia gum nanocomplexes had a particle size of 290.2 nm as indicated by DLS and drug entrapment efficiency of 96.5%. Morphological analysis revealed that berberine nanocomplexes were spherical-shaped with a smooth surface and size in the range of 100–250 nm. Moreover, berberine loaded guar-acacia nanocomplexes showed good stability and controlled released property in vitro. Antimicrobial activity against bacterial strains and fungal strains demonstrated the higher antimicrobial potential of berberine loaded gum nanocomplexes than gum nanocomplexes (blank) and pure berberine as indicated by the greater zone of inhibition diameter. In vitro anti-diabetic assessment showed higher percentage inhibition of the α-amylase enzyme by berberine loaded gum nanocomplexes as compared to pure berberine and blank nanocomplexes. In conclusion, the improved biological potency of berberine upon encapsulation into gum nanocomplexes indicates that berberine loaded guar-acacia gum nanocomplexes can be used as a promising candidate against diabetes and pathogenic microorganisms in the near future.

Composites Based on Gellan Gum, Alginate and Nisin-Enriched Lipid Nanoparticles for the Treatment of Infected Wounds

Due to growing antimicrobial resistance to antibiotics, novel methods of treatment of infected wounds are being searched for. The aim of this research was to develop a composite wound dressing based on natural polysaccharides, i.e., gellan gum (GG) and a mixture of GG and alginate (GG/Alg), containing lipid nanoparticles loaded with antibacterial peptide-nisin (NSN). NSN-loaded stearic acid-based nanoparticles (NP_NSN) were spherical with an average particle size of around 300 nm and were cytocompatible with L929 fibroblasts for up to 500 µg/mL. GG and GG/Alg sponges containing either free NSN (GG + NSN and GG/Alg + NSN) or NP_NSN (GG + NP_NSN and GG/Alg + NP_NSN) were highly porous with a high swelling capacity (swelling ratio above 2000%). Encapsulation of NSN within lipid nanoparticles significantly slowed down NSN release from GG-based samples for up to 24 h (as compared to GG + NSN). The most effective antimicrobial activity against Gram-positive Streptococcus pyogenes was observed for GG + NP_NSN, while in GG/Alg it was decreased by interactions between NSN and Alg, leading to NSN retention within the hydrogel matrix. All materials, except GG/Alg + NP_NSN, were cytocompatible with L929 fibroblasts and did not cause an observable delay in wound healing. We believe that the developed materials are promising for wound healing application and the treatment of bacterial infections in wounds.

An Extensive Review of Natural Polymers Used as Coatings for Postharvest Shelf-Life Extension: Trends and Challenges

Global demand for minimally processed fruits and vegetables is increasing due to the tendency to acquire a healthy lifestyle. Losses of these foods during the chain supply reach as much as 30%; reducing them represents a challenge for the industry and scientific sectors. The use of edible packaging based on biopolymers is an alternative to mitigate the negative impact of conventional films and coatings on environmental and human health. Moreover, it has been demonstrated that natural coatings added with functional compounds reduce the post-harvest losses of fruits and vegetables without altering their sensorial and nutritive properties. Furthermore, the enhancement of their mechanical, structural, and barrier properties can be achieved through mixing two or more biopolymers to form composite coatings and adding plasticizers and/or cross-linking agents. This review shows the latest updates, tendencies, and challenges in the food industry to develop eco-friendly food packaging from diverse natural sources, added with bioactive compounds, and their effect on perishable foods. Moreover, the methods used in the food industry and the new techniques used to coat foods such as electrospinning and electrospraying are also discussed. Finally, the tendency and challenges in the development of edible films and coatings for fresh foods are reviewed.

Molecular weight effects of low acyl gellan gum on antioxidant capacity and rheological properties

The current study investigated the antioxidant capacity of enzymatically cleaved low acyl gellan gum (LA-GAGR) fragments, named midi-GAGR (MW_v : 1.2 × 10⁵  Da) and mini-GAGR (MW_v : 2.5 × 10⁴  Da). Three different methods-hydroxide assay, superoxide assay, and DPPH assay-were used to measure the antioxidant capacity of the low acyl gellan gum fragments. Both mini-GAGR and midi-GAGR showed similar antioxidant capacities, 27.1% and 25.6%, respectively, for hydroxide radicals, whereas ascorbic acid showed 9.8%. For superoxide radicals, the fragments scavenged 41.7% (mini) and 35.6% (midi) of free radicals compared to 10.6% removal by ascorbic acid. Mini- and midi-GAGR displayed modest scavenging capabilities with DPPH radicals (8.5% and 6.6%, respectively) as compared to ascorbic acid (96.3%). Both midi- and mini-GAGR showed less gel-like behaviors than LA-GAGR. Midi-GAGR was observed to have a transition from liquid to gel at 63 rad/s. PRACTICAL APPLICATION: The results in the manuscript are helpful when gellan gum and its derivatives are directly applied to food processing as a dietary fiber supplement or a stabilizer for functional beverages. The antioxidant capacity results can be used to promote the functionality of gellan gum as a food additive and for controlling cell adhesion and growth on gellan gum scaffolds. The rheology results will be useful for synthesis of scaffolds for bone tissue generation and facilitating clinical treatments when gellan gum is injected as an adsorbent or a filler for treating bone fractures. In the pharmaceutical industry, they are useful when controlling the therapeutic effects of drug delivery systems.

Antimicrobial and cytocompatible chitosan, N,N,N-trimethyl chitosan, and tanfloc-based polyelectrolyte multilayers on gellan gum films

In this work free-standing gels formed from gellan gum (GG) by solvent evaporation are coated with polysaccharide-based polyelectrolyte multilayers, using the layer-by-layer approach. We show that PEMs composed of iota-carrageenan (CAR) and three different natural polycationic polymers have composition-dependent antimicrobial properties, and support mammalian cell growth. Cationic polymers (chitosan (CHT), N,N,N-trimethyl chitosan (TMC), and an amino-functionalized tannin derivative (TN)) are individually assembled with the anionic iota-carrageenan (CAR) at pH 5.0. PEMs (15-layers) are alternately deposited on the GG film. The GG film and coated GG films with PEMs are characterized by infrared spectroscopy with attenuated total reflectance (FTIR-ATR), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and water contact angle (WCA) measurements. The TN/CAR coating provides a hydrophobic (WCA = 127°) and rough surface (R_q = 243 ± 48 nm), and the TMC/CAR coating provides a hydrophilic surface (WCA = 78°) with the lowest roughness (R_q = 97 ± 12 nm). Polymer coatings promote stability and durability of the GG film, and introduce antimicrobial properties against Gram-negative (Salmonella enteritidis) and Gram-positive (Staphylococcus aureus) bacteria. The films are also cytocompatible. Therefore, they have properties that can be further developed as wound dressings and food packaging.