Plant-Derived Saponins: A Review of Their Surfactant Properties and Applications

In response to increasing natural surfactant demand and environmental concerns, natural plant-based surfactants have been replacing synthetic ones. Saponins belong to a class of plant metabolites with surfactant properties that are widely distributed in nature. They are eco-friendly because of their natural origin and biodegradable. To date, many plant-based saponins have been investigated for their surface activity. An overview of saponins with a particular focus on their surface-active properties is presented in this article. For this purpose, works published in the past few decades, which report better surfactant relevant properties of saponins than synthetic ones, were extensively studied. The investigations on the potential surfactant application of saponins are also documented. Moreover, some biological activities of saponins such as antimicrobial activity, antidiabetic activity, adjuvant potentials, anticancer activity, and others are reported. Plants rich in saponins are widely distributed in nature, offering great potential for the replacement of toxic synthetic surfactants in a variety of modern commercial products and these saponins exhibit excellent surface and biological activities. New opportunities and challenges associated with the development of saponin-based commercial formulations in the future are also discussed in detail.

Functional and technological properties of food additive "Magnetofood" in production of shaped jelly marmalade on agar and pectin

Jelly and marmalade products are "lyophilic colloids" – lyophilic colloidal-dispersed, ie microheterogeneous (multi- or polyphasic) systems based on high molecular weight compounds (gelatin, pectin, agar, etc.). Therefore, the problem of stabilizing their polyphasic structure is relevant. In addition, the expansion and improvement of the production of jelly and marmalade products requires the search for simplified resource- and energy-saving technology, increasing the stability of the colloidal disperse system, improving the quality and extending the shelf life of finished products. Promising technological applications have food additives in the nanometer range, due to specific and stable physical and chemical parameters, a wide range of functional and technological properties. The paper proposes the solution of the problem of stabilization of the polyphase structure of jelly-marmalade products and the formation of their quality by using the food additive "Magnetofood" (based on double oxide of divalent and trivalent iron: FeO×Fe2O3). "Magnetofood" - highly dispersed powder with a particle size (70–80) nm, which has a fairly diverse functional and technological potential: high ζ-potential and surface activity; clusterophilicity and amphiphilicity; complexing, thickening, structuring, stabilizing, thixotropic properties. This allows us to recommend "Magnetofood" as a food additive of complex action to improve the quality and prolong the shelf life of jelly-marmalade products, in particular jelly-shaped marmalade. The surface-active properties of nanoparticles of the food additive "Magnetofood" are determined: a rather significant value of ζ-potential (34-44) mV, amphiphilicity (marginal wetting angle Q<90o by polar-nonpolar medium) - show signs of stability and stability on polyphasic colloidal-dispersed systems , which increases in acidic environments, in solutions of polysaccharides, proteins on average by (55±)%, which is due to clusterophilicity and self-organization of nanoparticles "Magnetofood" into electrostatic complexes with proteins, polysaccharides and their spatial structuring. It was found that the addition of "Magnetofood" in the mass fraction (0,10–0,20)% to the mass of the structurant increases the viscosity of aqueous solutions of gelling agents in (1,22–1,27) times for agar and in (1,24–1,29) times for pectin and the rate of structuring of gel masses in (1,73±0,01) times for agar and in (1,67±0,01) times for pectin due to the structure-forming action of nanoparticles "Magnetofood". In addition, the ability of the gel structure to thixotropy increases by (1,4–1,5) times and the mechanical strength of the gel well by (1,32–1,80) times for agar and (1,49–1,57) times for pectin due to the stabilizing action of Magnetofood nanoparticles, which allows to reduce the amount of gelling agent by (9.0–11.0)% for agar and by (7.0–9.0)% for pectin.

Plant-Derived Saponins: A Review of Their Surfactant Properties and Applications

Increasing environmental concern and consumer demand for natural, sustainable and eco-friendly products have prompted the replacement of synthetic surfactants with their natural plant-based alternatives. Saponins are the plant based natural surfactants characterized by their foam forming properties in aqueous solution. Their natural origin makes them eco-friendly, bio-degradable and non-toxic. Further, they possess better physicochemical properties than the syn-thetic ones. They are also reported to exhibit a lot of useful biological activities such as anti-cancer, antifungal, anti-inflammatory, antimicrobial, antioxidant and cholesterol-lowering properties. Because of their excellent surface activity, biological activities and wide distribution in nature, saponin rich plants deserve deeper insight as a sustainable source of natural surfactants as they possess the potential to replace toxic synthetic surfactants abundant today. This review article is intended to provide a brief overview on the saponins with a special notion on their surface-active properties. It encourages further studies on development of commercial formulations based on saponins for the complete replacement of the synthetic counter parts, making better use of plants sources thereby contributing to global agenda of green environment.

STUDY OF THE SOLUBILIZING CAPACITY OF POLYMER-COLLOID COMPLEXES FORMED WITH SODIUM ALGINATE AND CHLORIDE HEXADECYLPYRIDINIUM

It was examined the behavior of systems which contain surfactants and biopolymers is considered by the example of cationic surfactants and sodium alginate. The rheological and surface-active properties of the systems have been experimentally investigated. It was found that the presence of oppositely charged surfactants in the solution significantly affects the properties of sodium alginate, due to the fact that associates or polymer-colloidal complexes are formed in the solution. Their formation significantly affects the solubilizing ability in relation to non-polar liquids. Hydrodynamic parameters of macromolecules of sodium alginate in comparison with macromolecules of chitosan correspond to the conformation of the loose ball. The state of the SN is determined by the pH of the medium and temperature. The increase in temperature leads to a violation of the structure of the chain, its destruction and a subsequent decrease in viscosity. At a temperature of 293K, the macromolecule is in a more ordered state. In the alkaline environment there is a change in the conformation of the macromolecule. As a result of this change, the viscosity naturally increases. This is explained by the fact that in an alkaline environment, the macromolecule acquires an excess negative charge, there is a repulsion of the carboxyl groups of the same name in the chain links. The macromolecule acquires an expanded configuration. The viscosity increases. In acidic environment, sodium alginate has almost zero charge as a result of protonation of carboxyl groups. The molecule acquires the conformation of a loose ball with the lowest value of viscosity. The isoelectric state of the alginate macromolecule is observed in the pH range of 5.5 to 6.0. The described state of the macromolecule in solution is confirmed by our calculations. The interaction of surface-active cations with carboxyl groups of SN leads first to the formation of associates, then to polymer-colloidal complexes. The association as a result of electrostatic interaction of active groups is enhanced by the hydrophobic interaction of hydrocarbon fragments of surfactant molecules with each other and with the alginate matrix. The association ends with the formation of a polymer-colloidal complex.

Study of Steel Electro-dissolution Behavior in Presence of Some Surfactants. Electrochemical Investigation and Surface Active Properties Determination

Steel electro-dissolution performance was investigated in orthophosphoric acid in the presence of N-oleyl 1.3 diaminopropane, Benzalkounuim chloride, Soduim lauryl sulphate and Di-Isononyl phthalate as a surfactant using potentiodynamic polarization measurements. The retardation performance of these surfactants was examined. The surfactant surface active parameters were estimated based on surface tension measurements. The parameters calculated comprise the critical micelle concentration (CMC), maximum surface excess (Гmax), minimum surface area (Amin) and effectiveness (πCMC). The micellization thermodynamic parameters (ΔGmic, ΔSmic) for the estimated surfactants were also computed. Results obtained from surface active properties are comparable with those gained from galvanostatic polarization measurements. Temperature influence on the steel dissolution performance was examined at 25 to 40oC range. Steel kinetic study in orthophosphoric acid- free solution and orthophosphoric acid containing surfactant was also examined. The dissolution kinetic and activated parameters were computed. Results based on microscopy measurement indicate that, addition of new four surfactants, resulting in the solution shows potential, a discrete progress in the metal texture was monitored. Improvement produced in electro-polishing bath by the investigated SAS that owing to the adsorption of such surface active agents on the anode surface.

The Synergistic Effects of Rhamnolipids and Antibiotics Against Bacteria

Antibiotics are used to combat bacterial infections by slowing down and preventing the proliferation of bacteria. Antibiotic resistance is a threat to human health, attributed to its overuse and misuse. Altering the membrane permeability to induce antibiotic uptake may be an effective strategy used against both Gram-positive and Gram-negative infectious bacteria. Rhamnolipids (RLs) are biosurfactants produced by Pseudomonas aeruginosa. RLs surface-active properties operate by creating holes in bacterial cell membranes, increasing target cell permeability; allowing antibiotics to penetrate the cell. Rhamnolipids enhance the effect of antibiotics by targeting the intracellular machinery of bacteria. This project tested the susceptibility of bacteria when exposed to antibiotics with and without the addition of RLs, to quantitatively determine if RLs increase antibiotic potency. By analyzing the zones of inhibition data, the results demonstrated that RLs potentiated the antibiotics. Notably, kanamycin coupled with RLs had the most effect inhibiting bacterial growth. To further assess rhamnolipid biosynthesis, a BLAST search was performed exclusively on two genes, rhlA and rhlB. These genes code for the production of two proteins necessary for rhamnolipids. The search indicated a 48% correlation with putative proteins found in Burkholderia pseudomallei. Therefore, based on the experimental results and the BLAST analysis, further research should be conducted to explore the possible role of using rhamnolipids as antibiotic enhancers. Specifically, future experiments could focus on isolating the putative proteins of B.pseudomallei to genetically modify E.coli. Furthermore, isolated studies analyzing the genes of proteins to determine their role in the pathogenicity of Burkholderia species.

STUDY OF SEDIMENTS OF COLLECTING AGENTS IN ELEMENTARY FLOTATION ACT

The operating mechanism of physically sorbed derivatives of collector obtained at a nonstoichiometric ratio between collecting agents with heavy metal salts is proposed. It is found that by changing the ratio of the components, it is possible to adjust their surface-active properties with respect to the gas-liquid interface and, consequently, the ability to remove the kinetic restriction to the formation of flotation contact. The physical form of sorption on a mineral can be represented by collector sediments and ion-molecular associates. The research results show that when the interlayer breaks through, these forms can desorb from the mineral and spread over the bubble surface, dragging the liquid from the interlayer into motion, thereby “drying” the mineral surface. In turn, the removal of liquid from the interlayer leads to a reduction in the induction time, which affects the efficiency of flotation. The results make it possible to reveal the mechanism of flotation activation with heavy metal salts and can be used in the development of fundamentally new engineering solutions.

FLOTATION OF LEAD-ZINC ORE USING A MIXTURE OF DITHIOCARBAMATE AND XANTHATE

The collecting capacity of xanthate, dithiocarbamate and their combination was studied. The effect of activity with respect to the gas-liquid interface of derivative forms of reagents represented by physically sorbed forms of collector was considered. Flotation experiments of lead-zinc ore from the Gorevsky deposit showed an increase in flotation performance when using reagent combinations. The use of a collector with pronounced chemisorbable properties in combination with a reagent having surface-active properties towards the gas-liquid interface caused an increase in the recovery of useful component. It was determined that activity of the physical form of sorption affects the selectivity of lead and zinc recovery - as activity of the physically sorbed form of reagent decreases, the selectivity of recovery grows.