Glycerol Concentration Research Articles

Factors affecting selective electrochemical glycerol oxidation to three-carbon products over cuprous oxide microcubes

BackgroundIn spite of the promising potential of selective electrochemical glycerol oxidation reaction (EGOR) as a sustainable method for converting glycerol into valuable products, the factors governing selective EGOR to desired products remain inadequately understood. MethodIn this study, we investigated the key factors governing selective EGOR using Cu2O as an electrocatalyst. By combining electrochemical studies paired with high-performance liquid chromatography, we gained a detailed understanding of the reaction pathway. Significant findingsThe results demonstrate that Cu2O is an efficient and stable electrocatalyst, producing valuable three-carbon products, including dihydroxyacetone (DHA), glyceraldehyde (GLYD), and glyceric acid (GLAC), with a selectivity of 90%. Notably, DHA was produced with selectivity as high as 45%. Our investigations reveal that while the applied potential and glycerol concentration primarily govern the reaction rates, temperature is the most significant factor for tuning the product distribution. However, it should be noted that raising the electrolyte temperature to 50 °C can lead to the self-degradation of intermediates to a certain content, which can impact product selectivity. Our work contributes to a better understanding of the factors that control EGOR and provides a foundation for future research in this field.

Coupling of NAD(P)H:FMN-oxidoreductase and luciferase from luminous bacteria in a viscous medium: Finding the weakest link in the chain.

The study aims at revealing the mechanisms of the viscous medium effects on the kinetic features of NAD(P)H:FMN-oxidoreductase from luminous bacteria (Red), which are exhibited in a single enzyme assay and in coupling with bacterial luciferase (BLuc). Different concentrations of glycerol and sucrose were used to vary the medium viscosity. The activity of Red, alone and in the presence of BLuc, was analyzed, as well as BLuc activity in the presence of Red, whereas in the absence of BLuc, the Red activity was suppressed in viscous medium, and in the presence of BLuc, the increase in Red activity was observed at low glycerol concentrations (5-20 wt%). The interaction of glycerol and sucrose with Red substrates FMN and NADH was studied using absorption spectroscopy and molecular dynamics. Glycerol was found to form hydrogen bonds with the phosphate groups of the substrates, unlike sucrose. A mechanism for the activation of Red in the presence of BLuc in glycerol solutions through the acceleration of FMN reoxidation was proposed. Thus, it was concluded that, under the conditions used, the weakest link of the coupled enzyme system BLuc-Red in viscous medium is the FMN concentration, which depends on Red activity and the medium viscosity.

Two-Stage Conversion of Used Cooking Oil to Biodiesel Using Ion Exchange Resins as Catalysts

This study focuses on the development of a novel two-stage (esterification–transesterification) synthesis of biodiesel from used cooking oil (UCO) using ion exchange resins as catalysts. Esterification of the UCO has been conducted using various types of ion exchange resin catalysts. Purolite D5081, a hyper cross-linked resin, showed the best catalytic performance among all the catalysts investigated, with 92% of free fatty acid (FFA) conversion. The transesterification of pre-treated used cooking oil (P-UCO) was carried out sequentially using several acidic and basic ion exchange resin catalysts. In the screening process, the Diaion PA306s catalyst showed the best catalytic performance and was selected for the optimisation study. A triglyceride conversion of ca. 75% was recorded at the optimum reaction conditions (9% (w/w) catalyst loading, 328 K reaction temperature, 18:1 methanol to P-UCO feed mole ratio, and 350 rpm stirring speed). Furthermore, the reusability study of the Diaion PA306s catalyst gave a similar triglyceride conversion after a couple of cycles without losing its catalytic activity. A dry purification technique was found to give the lowest percentage of glycerides and glycerine content and, therefore, was chosen as the best biodiesel purification route.

Acute Statin Withdrawal Does not Interfere With the Improvements of a Session of Exercise in Postprandial Metabolism.

The risk for atherogenic plaque formation is high after ingestion of meals in individuals with high blood lipid levels (ie, dyslipidemia). Statins and exercise reduce the rise of blood triglyceride concentrations after a meal, but the effect of their combination is unclear. In a randomized crossover design, 11 individuals with dyslipidemia and metabolic syndrome treated with statins underwent a mixed-meal (970 ± 111 kcal, 24% fat, and 34% carbohydrate) tolerance test. Plasma lipid concentrations, fat oxidation, glucose, and glycerol kinetics were monitored immediately prior and during the meal test. Trials were conducted with participants under their habitual statin treatment and 96 hours after blinded statin withdrawal. Trials were duplicated after a prolonged bout of low-intensity exercise (75 minutes at 53 ± 4% maximal oxygen consumption) to study the interactions between exercise and statins. Statins reduced postprandial plasma triglycerides from 3.03 ± 0.85 to 2.52 ± 0.86 mmol·L-1 (17%; P = .015) and plasma glycerol concentrations (ie, surrogate of whole-body lipolysis) without reducing plasma free fatty acid concentration or fat oxidation. Prior exercise increased postprandial plasma glycerol levels (P = .029) and fat oxidation rates (P = .024). Exercise decreased postprandial plasma insulin levels (241 ± 116 vs 301 ± 172 ρmol·L-1; P = .026) but not enough to increase insulin sensitivity (P = .614). Neither statins nor exercise affected plasma glucose appearance rates from exogenous or endogenous sources. In dyslipidemic individuals, statins reduce blood triglyceride concentrations after a meal, but without limiting fat oxidation. Statins do not interfere with exercise lowering the postprandial insulin that likely promotes fat oxidation. Last, statins do not restrict the rates of plasma incorporation or oxidation of the ingested glucose.

Water Stability Characteristic of Nile Tilapia (Oreochromis niloticus) Feed Coated with Tapioca Flour-beeswax-based Edible Coating

One of the reasons in increasing water turbidity in nile tilapia aquaculture is the presence of spoilage in fish feed that is easily disintegrate and decompose as organic matters in the water. Therefore, a thin layer or edible coating is needed to coat the tilapia feed to slow down the decomposition of the feed due to water absorption. The main ingredients for tilapia feed are tapioca flour added with beeswax solution and glycerol as a plasticizer. In this study, the glycerol concentrations used were 3%, 5%, and 7%, and the beeswax concentrations used were 0.25% w/v, 0.50 % w/v, and 0.75 % w/v. The purpose of this study was analysed the effect of plasticizers and beeswax on the characteristics of the edible coating. The method used to coat tilapia feed is the dipping method, where the product is dipped in a coating solution. The results of the research can be demonstrated by performing a and functional group test using FTIR spectra, contact angle test, and water resistance test of coated fish feed.

Impact of Candida railenensis during fermentation on the aromatic profile of Vidal blanc icewine.

Mixed culture fermentation with non-Saccharomyces yeasts and Saccharomyces cerevisiae as multi-starters has more advantages than spontaneous fermentation, and wine products with distinctive and pleasant aromas can fulfill the diverse demands of consumers. This study was carried out to illuminate the effect of sequential inoculation of indigenous Candida railenensis and S. cerevisiae on alcoholic fermentation behavior and chemical and aromatic characteristics of Vidal blanc icewine. During the mixed culture fermentation, C. railenensis was present in the initial and middle stages but was absent after 14 days. The results of basic chemical parameters showed that the glycerol content in the mixed culture-fermented icewine was higher than that of the pure fermented icewine, but the acetic acid content was the opposite. In terms of volatile aroma compounds, C. railenensis in the mixed culture fermentation reduced some metabolites such as lower alcohols, 1-hexanol, 3-methylthiopropanol, and their unpleasant notes and increased the production of some desired volatile aroma compounds such as benzaldehyde, β-damascenone, 2-furanmethanol, and 5-methyl furfural associated with rose, honey, nut, and caramel characteristics. Furthermore, C. railenensis also changed the sensory performance of icewine by participating in the fermentation of S. cerevisiae. These findings suggest that C. railenensis with positive enological properties has the ability to be used in icewine production, which has never been reported before.

Transcriptome Analysis of Glycerin Regulating Reuterin Production of Lactobacillus reuteri.

Reuterin can be produced from glycerol dehydration catalyzed by glycerol dehydratase (GDHt) in Lactobacillus reuteri and has broad application prospects in industry, agriculture, food, and other fields as it is active against prokaryotic and eukaryotic organisms and is resistant to proteases and lipases. However, high concentrations of glycerin inhibit reuterin production, and the mechanism behind this phenomenon is not clear. To elucidate the inhibitory mechanism of glycerol on reuterin synthesis in L. reuteri and provide reference data for constructing an L. reuteri culture system for highly effective 3-hydroxypropionaldehyde synthesis, we used transcriptome-sequencing technology to compare the morphologies and transcriptomes of L. reuteri cultured in a medium with or without 600 mM of glycerol. Our results showed that after the addition of 600 mM of glycerol to the culture medium and incubation for 10 h at 37 °C, the culture medium of L. reuteri LR301 exhibited the best bacteriostatic effect, and the morphology of L. reuteri cells had significantly changed. The addition of 600 mM of glycerol to the culture medium significantly altered the transcriptome and significantly downregulated the transcription of genes involved in glycol metabolism, such as gldA, dhaT, glpK, plsX, and plsY, but significantly upregulated the transcription of genes related to D-glucose synthesis.

Versatile hydrolyzed polyacrylamide-polyethyleneimine gels reinforced with glycerol for plugging and abandonment of oil wells

Temporary abandonment of oil wells requires isolation protocols to ensure safety of the environment and operators, for subsequent reactivation. For this, barrier materials are used to prevent influx of fluids from the rock formation to the wellbore. Polymeric gels are a promising alternative due to their ability to form a three-dimensional structure in situ with adequate elastic properties. With this goal, solid-free gels of hydrolyzed polyacrylamide and polyethyleneimine with glycerol as reinforcement material were developed. Furthermore, diethylenetriamine and diethanolamine were added to the formulations as anti-syneresis agents. The gelation kinetics and gels stability were evaluated through bottle tests and rheological measurements. The increase in glycerol content combined with DETA and DEA in the gels resulted in a reduction of gelation time varying according to the concentration of anti-syneresis agents added. This combination also enabled the increase on thermal stability of the gels with significant delay of 110% in the syneresis time. Furthermore, the storage and loss modulus and tan delta results showed that the new HPAM-PEI-Glycerol-DETA/DEA gel formulation had superior elastic properties compared to the HPAM-PEI gel.

Structural, thermal, optical, and mechanical properties of composite films developed from the button mushroom (Agaricus bisporus)-sourced high molecular weight chitosan and potato starch

Films were fabricated using the button mushroom (Agaricus bisporus) sourced high molecular weight chitosan with or without potato starch using the casting method. Glycerol was used as the plasticizer. Chitosan content in the film-forming solution (FFS) was varied (0.5, 0.75 and 1.0% w/v of FFS) while potato starch (1.0% of FFS) and glycerol (25% of the total solid content in the solution) contents were not varied. The control sample contained only chitosan (1.0% of the FFS) and glycerol. The effect of increasing the content of chitosan on the rheological properties of FFS and the properties of the films were investigated. The FFS's shear viscosity and shear modulus (elastic and viscous components) increased with increasing chitosan content. Morphological examination revealed that the films exhibited a compact structure devoid of large pores and cracks. Surface roughness captured with an atomic force microscope was reduced (19-6 nm) with increasing content of chitosan in the film. The films exhibited two hydrated crystalline phases at 9 and 20o. Light transmittance and glossiness of the films were enhanced with increasing chitosan content. FTIR analysis indicated the increasing availability of reactive sites with the increasing content of chitosan leading to an enhanced hydrogen bonds network and increased cohesion of the film structure. This may be the reason for improved mechanical properties and reduced water vapour permeability of the films with increasing chitosan content.

Rapid cold hardening and cold acclimation promote cold tolerance of oriental fruit fly, Bactrocera dorsalis (Hendel) by physiological substances transformation and cryoprotectants accumulation.

Insect response to cold stress is often associated with adaptive strategies and chemical variation. However, low-temperature domestication to promote the cold tolerance potential of Bactrocera dorsalis and transformation of main internal substances are not clear. Here, we use a series of low-temperature exposure experiments, supercooling point (SCP) measurement, physiological substances and cryoprotectants detection to reveal that pre-cooling with milder low temperatures (5 and 10°C) for several hours (rapid cold hardening) and days (cold acclimation) can dramatically improve the survival rate of adults and pupae under an extremely low temperature (-6.5°C). Besides, the effect of rapid cold hardening for adults could be maintained even 4 h later with 25°C exposures, and SCP was significantly declined after cold acclimation. Furthermore, content of water, fat, protein, glycogen, sorbitol, glycerol and trehalose in bodies were measured. Results showed that water content was reduced and increased content of proteins, glycogen, glycerol and trehalose after two cold domestications. Our findings suggest that rapid cold hardening and cold acclimation could enhance cold tolerance of B. dorsalis by increasing proteins, glycerol, trehalose and decreasing water content. Conclusively, identifying a physiological variation will be useful for predicting the occurrence and migration trend of B. dorsalis populations.

Kinetic study of glycerol hydrodeoxygenation on Al2O3 and NiMo2C/Al2O3 catalysts

A kinetic study of glycerol hydrodeoxygenation (HDO) on NiMo2C/Al2O3 and Al2O3, prepared by sol-gel technique, was carried out in a batch reactor, from 250 °C to 285 °C, at high glycerol concentration (95wt%). Structural and surface properties of the catalysts were determined by XRD, nitrogen physisorption, TEM and NH3-TPD. Impregnation of alumina with Ni and Mo and subsequent carburization at 730 °C increased crystallite sizes and reduced total acidity of the catalyst to 1/3 that of pure alumina. All reactions were well fitted to a zeroth order model. Estimation of reagents mass transport rates suggests no diffusion limitation. Main products were propanediols, ethylene glycol and long-chain molecules from oligomerization reactions, as well as methane, ethane and propane. At this temperature range, long-chain compounds have the highest yields, mainly on alumina.

Optimizing the Functional Properties of Starch-Based Biodegradable Films.

A definitive screening design was used in order to evaluate the effects of starch, glycerol and montmorillonite (MMT) concentrations, as well as the drying temperature, drying tray type and starch species, on packaging film's functional properties. Optimization showed that in order to obtain films with the minimum possible thickness, the maximum elongation at break, the maximum tensile strength, as well as reduced water vapor permeability and low opacity, a combination of factors should be used as follows: 5.5% wt starch concentration, 30% wt glycerol concentration on a dry starch basis, 10.5% wt MMT concentration on a dry starch basis, 45 °C drying temperature, chickpea as the starch species and plexiglass as the drying tray type. Based on these results, starch films were prepared, and fresh minced meat was stored in them for 3 days. It was shown that the incorporation of MMT at 10.5% wt on a dry starch basis in the packaging films led to a decreased mesophilic and psychrotrophic bacteria growth factor compared to commercial packaging. When assessed for their biodegradability, the starch films disintegrated after 10 days of thermophilic incubation under simulated composting conditions. Finally, to prove their handling capability during industrial production, the starch films were rewound in a paper cylinder using an industrial-scale rewinding machine.

Continuous production of succinic acid from glycerol: A complete experimental and computational study

In this work, a bioprocess for the fermentation of A. succinogenes for the production of succinic acid from glycerol was developed, employing a continuous bioreactor with recycle. Moreover, a new bioprocess model was constructed, based on an existing double substrate limitation model, which was validated with experimental results for a range of operating parameters. The model was used to successfully predict the dynamics of the continuous fermentation process and was subsequently employed in optimisation studies to compute the optimal conditions, dilution rate, reflux rate and feed glycerol concentration, that maximise the productivity of bio-succinic acid. In addition, a Pareto front for optimal volumetric productivity and glycerol conversion combinations was computed. Maximum volumetric productivity of 0.518 g/L/h, was achieved at the optimal computed conditions, which were experimentally validated. This is the highest bio-succinic acid productivity reported so far, for such a continuous bioprocess.

Polymer Dynamics in Glycerol-Water Mixtures.

Velocity correlation spectra (VAS) in binary mixtures of water and glycerol (G/W), obtained by measurements using the modulated gradient spin echo (MGSE) NMR method, were explained by the interactions of water molecules with clusters formed around the hydrophilic glycerol molecule, which drastically change the molecular dynamics and rheology of the mixture. It indicates a thickening of the shear viscosity, which could affect the dynamics of submerged macromolecules. The calculation of the polymer dynamics with the Langevin equations according to the Rouse model, where the friction was replaced by the memory function of the retarded friction, gave the dependence of the dynamics of the polymer on the rate of shear viscous properties of the solvent. The obtained formula was used to calculate the segmental VAS of the polymer when immersed in pure water and in a G/W mixture with 33 vol% glycerol content, taking into account the inverse proportionality between the solvent VAS and friction. The spectrum shows that in the G/W mixture, the fast movements of the polymer segments are strongly inhibited, which creates the conditions for slow processes caused by the internal interaction between the polymer segments, such as interactions that cause disordered polypeptides to spontaneously fold into biologically active protein molecules when immersed in such a solvent.

Interfacial polymerization process based on diffusion control: Role of chemical composition and morphology on fouling resistance

Nanofiltration, as a technology with low energy consumption, no secondary pollution, and continuous and compact operation, is widely used in the fields of seawater desalination, resource recovery and reuse, and drinking water purification, etc. However, “trade-off” effect and membrane fouling are the main problems limiting the application of nanofiltration membranes. Herein, glycerol was introduced into the aqueous reactive solution in interfacial polymerization (IP) for regulating chemical composition and membrane structure simultaneously. As glycerol raised the viscosity of the reactive solution which slowing down the diffusion rate of amine monomer, crumpled structure generated by the diffusion-driven instability. At the same time, the addition of glycerol varied the oxygen content in the skin layer of the membrane. At 60% glycerol content, the as-prepared membrane achieved a pure water permeance of 21.14 L·m−2·h−1·bar−1 with sodium sulfate rejection of 95.6%. However, the oxygen content in the chemical composition of the membrane showed a minimum value with the increase of glycerol concentration indicating a competitive reaction between the amine monomer and glycerol. Through the anti-fouling analysis of membranes with different chemical compositions and structures, it was found that the increase in roughness of nanofiltration membranes with similar chemical composition resulted in an increase of irreversible pollution. The nanofiltration membrane with similar membrane structure and higher oxygen content had stronger anti-fouling ability to humic acid. It is concluded that the rational design of the crumpled membrane with high oxygen-chemical composition is expected to obtain a high flux nanofiltration membrane with anti-fouling performance.

Photoperiod-Dependent Effects of Grape-Seed Proanthocyanidins on Adipose Tissue Metabolic Markers in Healthy Rats.

Variations in photoperiod patterns drive metabolic adaptations in mammals, involving important changes in body weight and adiposity. Moreover, (poly)phenols can help heterotrophs adopt metabolic adaptations to face the upcoming environmental conditions. Particularly, proanthocyanidins from grape-seeds show photoperiod-dependent effects on different metabolic parameters. The present study aims to explore whether grape-seed proanthocyanidin extract (GSPE) consumption differently affects the expression of metabolic markers in WAT (subcutaneous and visceral depots) and BAT in a photoperiod-dependent manner. GSPE (25mgkg-1 day-1 ) is orally administrated for 4 weeks to healthy rats exposed to three photoperiods (L6, L12, and L18). In WAT, GSPE consumption significantly upregulates the expression of lipolytic genes in all photoperiods, being accompanied by increased serum concentrations of glycerol and corticosterone only under the L6 photoperiod. Moreover, adiponectin mRNA levels are significantly upregulated in response to GSPE regardless of the photoperiod, whereas Tnfα and Il6 expression are only downregulated in L6 and L18 photoperiods but not in L12. In BAT, GSPE upregulates Pgc1α expression in all groups, whereas the expression of Pparα is only increased in L18. The results indicate that GSPE modulates the expression of important metabolic markers of WAT and BAT in a photoperiod-dependent manner.

EVALUATION OF ETHANOL AND BIOMASS PRODUCTION RATE BY DIFFERENT $SACCHAROMYCES~CEREVISIAE$ STRAINS DEPENDING ON EXTERNAL pH AND TEMPERATURE

Bioethanol production is in high demand due to its potential to replace transportation fuel and its ability to be renewable and long-lasting. Therefore, the bioconversion of fermentable sugars to ethanol is of central importance. The work aimed to explore yeast properties changes during fermentation at different pHs and temperature conditions. Biomass production, specific growth rate (SGR), fermentation products, and metabolite composition and quantity changes were studied at 25℃, 30℃, and 37℃ as well as pH 5 and pH 6.5 conditions. SGR data shows that at 25℃ and 30℃ pH 5 is optimal for yeast biomass production. At pH 5.0–6.5, the biomass production of the ATCC 9804 strain almost 2 times exceeds the same parameter for another strain. The highest biomass production was detected at 30℃ and pH 5. Ethanol production by yeast increases as the growth temperature decreases at pH 5 in contrast to pH 6.5, where the temperature changes within 30–37℃ range have no significant effect on it in both strains. At 30℃ ethanol concent­ra­tion in the extracellular medium reached ~117 mM in the case of ATCC 13007 strain, whereas for ATCC 9804 the same parameter was 1.4-fold lower. Both strains had the same substrate assimilation rate. Glycerol production reduces with increasing growth temperature and pH; the highest glycerol concentration (6.1 mM) was observed within 32 h growth of ATCC 9804 strain at 25℃, pH 5 and reaches 5.5 mM within 24 h growth of ATCC 13007 strain under the same conditions. At pH 5 and 6.5, the free energy for glycerol production was 2.3-fold and 4-fold higher compared to that of ethanol and acetate production processes in both strains. Gibbs free energy of ethanol production reaches the lowest value compared to the same parameter of acetate and glycerol production at pH 5, suggesting a preference for the alcoholic fermentation metabolic pathway under these conditions. The lowest acetate production was observed after 24 hours of growth of the ATCC 13007 strain at 37°C and pH 5, with ΔG = 173.9 kJ/mol. Obtained data highlights temperature stress mechanisms regulation of yeast and can be used for improving ethanol production processes and yeast genetic modification tools.

The effect of glycerol additive on high value-added chemicals from tobacco waste pyrolysis

It is of significant importance to understand the role of glycerol additive for the improvement of the energy recovery during tobacco-waste pyrolysis. Utilizing ReaxFF-based molecular dynamic simulation, herein, we systematically studied the pyrolysis mechanism of tobacco with different concentrations of glycerol (5%, 10%, 16.5%, 20%, 25%) at different temperatures (1800 K, 2000 K, 2300 K, 2500 K, 2800 K). The calculation shows that a temperature of 2000 K is the optimal temperature for producing methanol and ethanol. Furthermore, the concentration of glycerol had a significant effect on promoting methanol production at high temperatures. Methanol's main generation pathway was influenced by temperature and glycerol concentration, while the primary pathway of ethanol production was independent of them. Moreover, a pyrolysis reaction framework was created for methanol and ethanol production, and their main formation reactions were validated. Finally, a chemical kinetic analysis of the pyrolysis process confirmed the accuracy of the ReaxFF MD simulations.

Exploring the sustainable frontier by investigating structural, electrochemical and ion transport properties of potassium salt-doped PVA-based polymer electrolyte for supercapacitor application

In the current study, a biodegradable green polymer was used for energy storage application. Solid polymer electrolytes (SPEs) are fabricated by incorporating constant loading weight percent (40 wt%) potassium thiocyanate (KSCN) and various glycerol into PVA by the solution cast method. The X-ray diffraction (XRD) test shows that the most conductive electrolyte (σdc = 4.34 × 10−3 S cm−1) determined by electrochemical impedance spectroscopy (EIS) possesses the lowest degree of crystallinity (Xc = 11.4). The EIS test reveals that the PVKSG4 sample has the minimum resistance. The interaction between various constituents of the electrolyte was observed by the fourier transform infrared (FTIR) spectroscopy. The transport parameters (D, n, and μ) associated with moving cations as determined by both EIS and FTIR approaches are comparable and well matched with DC conductivity results. Ionic conductivity and dielectric parameters have the same trend with glycerol concentration. Transference numbers of ions (ti) and electrons (te) for the PVKSG4 are calculated to be 0.918 and 0.082, respectively, meaning that ions are the dominant species contributing to conduction. Linear sweep voltammetry (LSV) study displays that the PVKSG4 film possesses a breakdown voltage of 2.3 V which is enough for device construction. The equivalent series resistance (ESR) of the electric double layer capacitor (EDLC) device has been slightly increased from 59 to 68 Ω over the initial and finial cycle. The capacitive nature of EDLC was confirmed by the cyclic voltammetry (CV), and from the galvanostatic charge/discharge (GCD) test the values of specific capacitance, specific energy density, and specific power density were found to be 72 F g−1, 11 Wh Kg−1, and 1800 W Kg−1. The parameters of EDLC device is an indicative for the fact that the future of green energy is linked to supercapacitors as an alternative for toxic Li-ion batteries.

W/O/W type lotion formulation of “arum manis” mango (Mangifera indica L.) pell as antioxidant

Arum manis mango peel contains compounds, namely flavonoids. Flavonoid compounds act as natural antioxidants. The weakness of flavonoid compounds is that they are not stable to the influence of high temperature and light intensity, so that the arum manis mango peel extract is made in the form of lotion type W/O/W. This study aims to determine the physical characteristics and stability of the W/O/W type emulsion form optimum formula in double emulsion preparations and lotion preparations, determine the stability of W/O/W type lotion preparations during storage using the cycling test method and determine the IC50 value in the optimum formula. lotion preparation type W/O/W. The optimum formula for double emulsion type W/O/W is found in formula 5 with a ratio of primary emulsion: secondary emulsion (80%:20%) with span 80 (10%) and tween 20 (5%) concentrations while the optimum formula for lotion preparations found in formula 3 with a ratio of double emulsion type W/O/W: lotion base (80%:20%) with a concentration of stearic acid (5%), cetyl alcohol (2.5%) and glycerin (10%). In the antioxidant activity of lotion preparations, the IC50 value was 136.543 ppm and the stability test on the cycling test method had an unstable form.