Irradiation depolymerized guar gum as partial replacement of gum Arabic for microencapsulation of mint oil

Microencapsulation of total saponins from stem and leaf of Panax notoginseng by freeze and spray drying: Process optimization, physicochemical properties, structure, antioxidant activity, and stability

Ginsenosides are the primary active substance in ginseng plants and have a variety of benefits. However, its light and heat stability are weak and easy to decompose. This study used gum arabic (GA) and maltodextrin (MD) as wall materials, and 1% Tween 80 was used as emulsifier. Response surface methodology was used to optimize the preparation process of total saponins in the stems-leaves of Panax notoginseng (SLPNs) (SSLP) microcapsules by spray drying and freeze drying techniques. Under optimal process conditions, the two microcapsules have better solubility and lower moisture content (MC). The color of spray-dried SSLP microcapsules was greener and bluer, and the color was brighter. In morphology, the spray-dried SSLP microcapsules were spherical with a slightly shrunk surface, whereas the freeze-dried ones were lamellar and porous. The two microcapsules have strong stability under different storage conditions and in vitro gastrointestinal digestion simulation. In addition, both microcapsules and free SSLP contained multiple ginsenosides. At the same time, both microcapsules had good free radical scavenging ability. These results indicate that the microencapsulation technology could improve the stability and bioavailability of SSLP, which is expected to provide a reference for the intensive processing of the SLPN. PRACTICAL APPLICATION: After microencapsulation, the stem and leaf extract of Panax notoginseng improved its stability and taste, which laid a foundation for making more nutritious and better tasting food of the stem and leaf of P. notoginseng.

Recent updates on guar gum derivatives in colon specific drug delivery

Colon specific delivery of therapeutics have gained much attention of pharmaceutical researchers in the recent past. Colonic specific targeting of drugs is used not only for facilitating absorption of protein or peptide drugs, but also localization of therapeutic agents in colon to treat several colonic disorders. Among various biopolymers, guar gum (GG) exhibits pH dependent swelling, which allows colon specific release of drug. GG also shows microbial degradation in the colonic environment which makes it a suitable excipient for developing colon specific drug delivery systems. The uncontrolled swelling and hydration of GG can be controlled by structural modification or by grafting with another polymeric moiety. Several graft copolymerized guar gum derivatives are investigated for colon targeting of drugs. The efficacy of various guar gum derivatives are evaluated for colon specific delivery of drugs. The reviewed literature evidenced the potentiality of guar gum in localizing drugs in the colonic environment. This review focuses on the synthesis of several guar gum derivatives and their application in developing various colon specific drug delivery systems including matrix tablets, coated formulations, nano or microparticulate delivery systems and hydrogels.

Encapsulation of mint essential oil: Techniques and applications

Mint essential oil (MEO) is an outstanding antibacterial and antioxidant agent, that can be considered as a promising natural preservative, flavor, insecticide, coolant, and herbal medicine. However, the low solubility and volatility of MEO limits its extensive applications. In order to utilize MEO in different products, it is essential to develop treatments that can overcome these limitations. More recently, encapsulation technology has been developed as a promising method to overcome the shortcomings of MEO. In which, sensitive compounds such as essential oils (EOs) are entrapped in a carrier to produce micro or nanoparticles with increased stability against environmental conditions. Additionally, encapsulation of EOs makes transportation and handling easier, reduces their volatility, controls their release and consequently improves the efficiency of these bioactive compounds and extends their industrial applications. Several encapsulation techniques, such as emulsification, coacervation, ionic gelation, inclusion complexation, spray drying, electrospinning, melt dispersion, melt homogenization, and so on, have been emerged to improve the stability of MEO. These encapsulated MEOs can be also used in a variety of food, bioagricultural, pharmaceutical, and health care products with excellent performance. Therefore, this review aims to summarize the physicochemical and functional properties of MEO, recent advances in encapsulation techniques for MEO, and the application of micro/nanocapsulated MEO in different products.

A Review of Regulatory Standards and Advances in Essential Oils as Antimicrobials in Foods

As essential oils (EOs) possess GRAS status, there is a strong interest in their application to food preservation. Trends in the food industry suggest consumers are drawn to environmentally friendly alternatives and less synthetic chemical preservatives. Although the use of EOs has increased over the years, adverse effects have limited their use. This review aims to address the regulatory standards for EO usage in food, techniques for delivery of EOs, essential oils commonly used to control pathogens and molds, and advances with new active compounds that overcome sensory effects for meat products, fresh fruits and vegetables, fruit and vegetable juices, seafood, dairy products, and other products. This review will show adverse sensory effects can be overcome in various products by the use of edible coatings containing encapsulated EOs to facilitate the controlled release of EOs. Depending on the method of cooking, the food product has been shown to mask flavors associated with EOs. In addition, using active packaging materials can decrease the diffusion rate of the EOs, thus controlling undesirable flavor characteristics while still preserving or prolonging the shelf life of food. The use of encapsulation in packaging film can control the release of volatile or active ingredients. Further, use of EOs in the vapor phase allows for contact indirectly, and use of nanoemulsion, coating, and film wrap allows for the controlled release of the EOs. Research has also shown that combining EOs can prevent adverse sensory effects. Essential oils continue to serve as a very beneficial way of controlling undesirable microorganisms in food systems.

Production of prebiotic gellan oligosaccharides based on the irradiation treatment and acid hydrolysis of gellan gum

Biologically active gellan oligosaccharides (GOSs), newly found plant elicitors and biostimulants, are produced from the hydrolysis of gellan gum. Traditional hydrolysis with concentrated acid suffers from the problems of high pollution and low functional oligosaccharide yield because the process is difficult to control. Irradiation (⁶⁰Co γ-ray) with a dosage ranging from 0 kGy to 175 kGy was used to degrade gellan gum efficiently and cleanly into low molecular weight (M_w) gellan with an average M_w ranging from 449,119 Da to 72,903 Da. The low M_w gellan irradiated at 70 kGy was further hydrolyzed with low concentration acid (0.5 mol/L HCl) to produce GOSs with DPs mainly 4 and 8, indicating that the Rha-β-(1 → 3)-Glc bonds in gellan gum were easily cut to produce residues with tetrasaccharide repeat subunits. Besides antioxidant activity, GOSs were also proved with prebiotic activity by in vitro fecal fermentation in a self-designed bionic intestinal reactor.

S-Edge-rich MoxSy arrays vertically grown on carbon aerogels as superior bifunctional HER/OER electrocatalysts

Molybdenum disulfide (MoS₂) is a potential earth-abundant electrocatalyst for the hydrogen evolution reaction (HER), but the lack of in-depth understanding of its intrinsic activity still impedes the further optimization and design of MoS₂-based electrocatalysts. Herein, we report a facile in situ hydrothermal synthetic method to prepare vertical Mo_xS_y arrays grown on guar gum-derived carbon aerogels (GCA), termed Mo_xS_y@GCA. The obtained well-assembled Mo_xS_y@GCA architectures consist of uniform, few-layered and S-edge-rich Mo_xS_y nanoflakes with a length of approximately 100 nm, which effectively prevent the inherent stacking among Mo_xS_y layers and connect the charge transfer path between interlayers, thus endowing Mo_xS_y@GCA with a huge number of active sites and high conductivity. Benefitting from all these advantages, the optimal Mo₄S₁₆@GCA exhibited extraordinary HER/OER performances, including a low onset potential for both the HER (24.28 mV) and OER (1.53 V), and a low overpotential at 10 mA cm^-2 for the HER (54.13 mV) and OER (370 mV), which are both extremely close to that of the noble Pt/C. Furthermore, a series of operando Raman spectroscopy measurements on Mo₄S₁₆@GCA were conducted to identify the intrinsic HER/OER-active sites during the HER and OER process. The results show that the S-H bond is generated simultaneously as HER/OER excitation, indicating the rich S-edge may be the intrinsic active site, which will accelerate the HER/OER kinetic process. Density functional theory (DFT) calculations revealed that the observed superb HER/OER activity can be attributed to the synergistic effect of rich S-edge of Mo_xS_y and confinement effect of GCA, which collaboratively promote the proton adsorption and electrocatalytic kinetics. Reasonably, this study will have profound guiding value for the rational tailoring of the microstructure and size of transition metal electrocatalysts via hierarchical porous carbon aerogels.

Influence of Different Wall Materials on the Microencapsulation of Virgin Coconut Oil by Spray Drying

The main objective of this study was to evaluate the influence of the different wall material combinations on the microencapsulation of virgin coconut oil (VCO) by spray drying. Maltodextrin (MD) and sodium caseinate (SC) were used as the basic wall materials and mixed with gum Arabic (GA), whey protein concentrate (WPC) and gelatin (G). The stability, viscosity and droplet size of the feed emulsions were measured. MD:SC showed the best encapsulation efficiency (80.51%) and oxidative stability while MD:SC:GA presented the lowest encapsulation efficiency (62.93%) but better oxidative stability than the other two combinations. Microcapsules produced were sphere in shape with no apparent fissures and cracks, low moisture content (2.35–2.85%) and high bulk density (0.23–0.29 g/cm3). All the particles showed relatively low peroxide value (0.34–0.82 meq peroxide/kg of oil) and good oxidative stability during storage. MD:SC:GA microencapsulated VCO had the highest antioxidant activity in both of the 2,2-diphenyl-1-picrylhydrazyl (DPPH) (0.22 mmol butylated hydroxyanisole (BHA)/kg of oil) and 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays (1.35 mmol trolox/kg of oil).

Chromium (VI) Induced Biochemical Changes and Gum Content in Cluster Bean (Cyamopsis tetragonoloba L.) at Different Developmental Stages

Chromium (Cr) contamination by various industries and other activities is known to inhibit plants growth and development. The present study was conducted using pot experiments in a net house to determine the effect of Cr (VI) on biochemical parameters such as photosynthetic pigments, reducing sugars, and important minerals at different stages of growth in leaves, stem, and roots of clusterbean, a multipurpose fodder crop including a source of guar gum. Guar gum content was estimated in seeds at maturity. All biochemical contents showed a great variation with respect to increase in Cr concentration at different stages of growth. The levels of K, Fe, and Zn decreased, while Cr and Na content increased with increase in Cr concentration. Cr induced toxicity in clusterbean appears at 0.5 mg Cr (VI) Kg−1 soil with maximum inhibitory effect at 2 mg Cr (VI) Kg−1 soil, where impaired sugar supply resulted in decreased guar gum synthesis and altered micronutrient content. The study reveals the possible role of these biochemical parameters in decreasing plant growth and development under heavy metal stress.