Testing of glyceryl monoesters for their antimicrobial susceptibility and their influence in emulsions.

Natural anti-microbial agents have received great attention in the cosmetic preservation area due to their well-documented safety profile. The anti-microbial activities of palm-based glyceryl monoesters (monolaurin, monocaprylin and monocaprin) were compared with commercially available tea tree oil and potassium sorbate against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Aspergillus niger, using the anti-microbial susceptibility testing procedure. Monolaurin was found to exhibit excellent inhibitory activity against S. aureus and Asp. niger, whereas potassium sorbate and tea tree oil had no activity against Asp. niger and S. aureus, respectively. Monocaprylin was shown to have low inhibitory activity against E. coli, and no inhibitory activity towards P. aeruginosa. On the other hand, tea tree oil had a higher inhibitory activity than monolaurin at 2% against E. coli but showed no activity against P. aeruginosa. Similar trends were observed for monocaprin and monolaurin which showed no anti-microbial activity towards P. aeruginosa as well as E. coli. Interestingly, the presence of monolaurin was not only effective as a preservative, but was also found to induce the formation of liquid crystals at concentrations as low as 0.5%. The formation of liquid crystals is said to enhance the stability and functionality of cosmetic emulsions

Effect of compositions in nanostructured lipid carriers (NLC) on skin hydration and occlusion.

Purpose: To study the effects of varying lipid concentrations, lipid and oil ratio, and the addition of propylene glycol and lecithin on the long-term physical stability of nanostructured lipid nanocarriers (NLC), skin hydration, and transepidermal water loss. Methods: The various NLC formulations (A1-A5) were prepared and their particle size, zeta potential, viscosity, and stability were analyzed. The formulations were applied on the forearms of the 20 female volunteers (one forearm of each volunteer was left untreated as a control). The subjects stayed for 30minutes in a conditioned room with their forearms uncovered to let the skin adapt to the temperature (22°C±2°C) and humidity (50%±2%) of the room. Skin hydration and skin occlusion were recorded at day one (before treatment) and day seven (after treatment). Three measurements for skin hydration and skin occlusion were performed in each testing area. Results: NLC formulations with the highest lipid concentration, highest solid lipid concentration, and additional propylene glycol (formulations A1, A2, and A5) showed higher physical stability than other formulations. The addition of propylene glycol into an NLC system helped to reduce the particle size of the NLC and enhanced its long-term physical stability. All the NLC formulations were found to significantly increase skin hydration compared to the untreated controls within 7 days. All NLC formulations exhibited occlusive properties as they reduced the transepidermal water loss within 7 days. This effect was more pronounced with the addition of propylene glycol or lecithin into an NLC formulation, whereby at least 60% reduction in transepidermal water loss was observed. Conclusion: NLCs with high lipid content, solid lipid content, phospholipid, and lecithin are a highly effective cosmetic delivery system for cosmetic topical applications that are designed to boost skin hydration

Kinetic study on the production of biodegradable lubricant by enzymatic transesterification of high oleic palm oil

Kinetic studies are necessary to identify inhibitors of lipase enzyme deactivation in reaction systems because varying substrate concentrations can affect the enzyme's catalytic activity. The present study aimed to analyze the reaction kinetics of palm-based polyol ester production catalyzed by commercial lipase Novozyme 435 (N435). The enzymatic transesterification reaction was performed in a solvent-free medium. The effect of substrates concentration, specifically high oleic palm methyl ester (HO-PME) and trimethylolpropane (TMP), on the kinetic constant was studied at the initial reaction rate. The study was conducted based on the Ping-pong Bi-bi model, assuming that both substrates could inhibit the reaction. The reaction was carried out at 70 °C and 15.25 mbar with a 3 % (w/w) N435 enzyme load to investigate the effect of various HO-PME and TMP concentrations. The kinetic constants obtained are as follows: = 61.112 mol/L, = 0.336 mol/L, = 0.002 mol/L, = 2.415 mol/L and = 17.24 mol/L.hr. The results implied that N435 has higher affinity towards TMP than HO-PME. Inhibition constant indicated a lower inhibitory function of the TMP than HO-PME ( > ). The reaction kinetics obtained in this study agreed well with the model used with TMP and HO-PME as competitive inhibitor during enzymatic transesterification

An improved method for the preparations of nanostructured lipid carriers containing heat-sensitive bioactives.

Heat-sensitive bioactive compounds such as β-carotene and tocols, are widely used in the pharmaceutical and cosmetic fields. Their chemical stability in delivery systems is one of the major concerns in the production of nanostructured lipid carriers (NLCs). A previously established high-temperature high-pressure homogenisation technique involved in the preparation of NLCs can cause degradation of heat-sensitive compounds. Therefore, a novel preparation process needs to be developed to minimise the degradation of heat-sensitive active compounds during the preparation of NLCs. In this work, modified methods A and B were designed to minimise the degradation of β-carotene and tocols during the production of NLCs. These methods improved the chemical stability of heat-sensitive bioactive compounds (β-carotene and tocols) significantly compared to the previously established method. The physical stability of the formulation was maintained throughout study duration

Nanostructured lipid carriers (NLC) for efficient delivery of palm phytonutrients

Palm phy­tonu­tri­ents found in crude palm oil con­sist of carotenes and tocols as well as other minor com­po­nents includ­ing sterols, squa­lene, ubiquinones, coen­zyme Q10 and phos­pho­lipids. Palm phy­tonu­tri­ents con­tains all the nat­u­rally occur­ring phy­tonu­tri­ents present in crude palm oil, whereas com­mer­cially avail­able indi­vid­ual phy­tonu­tri­ents, such as Gold-tri E and Tocomin 50% mainly con­sist of palm tocotrienols. The encap­su­la­tion of palm phy­tonu­tri­ents by nanos­truc­tured lipid car­ri­ers (NLC) was inves­ti­gated using Trans­mis­sion Elec­tron Microscopy. NLC was proven to effec­tively encap­su­late palm phy­tonu­tri­ents in oil droplets. Based on the par­ti­cle size analy­sis and rhe­o­log­i­cal study, NLC was found to be the most phys­i­cally sta­ble deliv­ery sys­tem when com­pared to the macro-emulsion and the nano-emulsion car­ri­ers. The long-term chem­i­cal sta­bil­ity of the palm phy­tonu­tri­ent using β-carotene as the pro­to­type active in NLC was also deter­mined. The degra­da­tion of β-carotene in NLC was lower when com­pared to the macro-emulsion and the nano-emulsion car­ri­ers. The effi­cacy of NLC as a deliv­ery sys­tem and the effect of the addi­tion of lecithin and propy­lene gly­col to the NLC for­mu­la­tion were also stud­ied. The para­me­ters inves­ti­gated were skin hydra­tion and trans-epidermal water loss (TEWL). NLC with the pres­ence of 1% lecithin and 2% propy­lene gly­col were found to enhance skin hydra­tion and pre­vent water loss

Physical Properties of Normal Grade Biodiesel and Winter Grade Biodiesel

In this study, optical and thermal properties of normal grade and winter grade palm oil biodiesel were investigated. Surface Plasmon Resonance and Photopyroelectric technique were used to evaluate the samples. The dispersion curve and thermal diffusivity were obtained. Consequently, the variation of refractive index, as a function of wavelength in normal grade biodiesel is faster than winter grade palm oil biodiesel, and the thermal diffusivity of winter grade biodiesel is higher than the thermal diffusivity of normal grade biodiesel. This is attributed to the higher palmitic acid C16:0 content in normal grade than in winter grade palm oil biodiesel

Broadband Determination of Biodiesel Content in Petroleum Diesel Blends by Terahertz Time Domain Spectroscopy

The biodiesel content in petroleum diesel-biodiesel blends is determined using broadband terahertz time-domain spectroscopy (THz-TDS). We model the spectra of the blend components based on the non-polar characteristics of the samples. The biodiesel content in diesel is determined from the coefficients that best fit the measured spectra to the optimal linear combination of the model for each individual component (pure diesel and pure biodiesel). This method proves to be valid for real-time applications. A simpler approach based on the maximum observed dispersion is also demonstrated to be a distinctive characteristic of a given blend

Critical relationship between biodiesel fuel properties and degradation of fuel delivery materials of a diesel engine

This work aims to disseminate the critical relationship present between biodiesel fuel properties and the degradation of commonly present fuel delivery materials (FDM) of a diesel engine. This was achieved by quantifying the adverse effects of palm biodiesel fuel exposure towards aluminium, galvanized steel, stainless steel, fluoroelastomer, silicone rubber and nylon under novel immersion method. Under the novel immersion method which was designed to resemble the biodiesel fuel deterioration under diesel engine operation, fuel renewal was incorporatedinthetypicalstandardmethods.Theutilizedfuelrenewaldurationswere108hand192hformetal and elastomers, respectively. Through this, the resulting biodiesel fuel properties under diesel engine operation were primarily simulated under the immersion methods. The experimentations were carried out for 540h and 960h for metals and elastomers, respectively, at 100°C. Based on the obtained results, as well as the comparisons madetoanexistingstudy, galvanizedsteel,aluminium andstainlesssteel hadlowercorrosionrateby33%, 74% and 80%, respectively, as compared to copper. On the other hand, 26%, 78% and 106% lower volume changes were determined for silicone rubber, fluoroelastomer and nylon, respectively, as compared to nitrile rubber. Significantly lower degradation rate of up to 20 times for metals and 5 times for elastomers were critically obtained under novel immersion method as compared to under typical immersion methods from existing studies. This demonstrates that through the employment of novel immersion method which simulates biodiesel fuel properties as per under diesel engine operation, much better compatibility is deemed present between biodiesel fuel and FDM contrasting to the existing studies

Enzymatic synthesis of palm oil-based trimethylolpropane ester as biolubricant base stock catalyzed by Lipozyme 435

The application of enzymes in the organic synthesis of polyol esters for biolubricants is one of the initiatives in the development of sustainable processes in the oil palm industry. In this study, trimethylolpropane (TMP) ester was synthesized from high oleic palm methyl ester (HO-PME) via enzymatic transesterification. Lipozyme 435, which is an immobilized form of lipase B from Candida antarctica (CALB), was investigated as a substitute for chemical catalyst in the production of palm oil-based lubricant. Response surface methodology (RSM) via Central Composite Rotatable Design was employed to optimize the reaction conditions. The results showed that only 3% (w/w) enzyme dosage was required to obtain the highest triester of 82% without purification. The optimum process conditions predicted by RSM were 3.45:1 M ratio of HO-PME: TMP, 15.25 mbar pressure, and 48 h reaction time. The TMP ester exhibited excellent lubricant properties. This study demonstrated a reduction in overall production cost including waste management due to the elimination of the product purification step. As compared to chemical catalyst, milder reaction conditions and no formation of side products were observed in this study. The physicochemical characteristics of the TMP ester synthesized via enzymatic transesterification complied satisfactorily with the requirements of biolubricant base stock. Our findings offer a greener and economical approach for producing high-performance biolubricant, which can be applied for scale-up production