Effect of silicone oil on the microstructure, gelation and rheological properties of sorbitan monostearate–sesame oil oleogels

Oleogels contain oil or a non-polar liquid which is gelled with an agent called an organogelator. The aim of this study was to evaluate the effects of the addition of silicone oil(cyclopentasiloxane) to the gelation process and to the properties of sorbitan monostearate(SMS)–sesame oil oleogel and compared with that of SMS–sesame oil oleogel and SMS–cyclopentasiloxane oleogel. Three different oil phases; sesame oil phase, cyclopentasiloxane phase and a mixture of cyclopentasiloxane and sesame oil, were used to prepare oleogels with SMS gelator. The critical gelling concentrations(CGC) for oleogels were determined using different concentration of SMS in a range of 5%–22%(w/w). The characterization of the developed oleogels was done using Fourier transform infrared spectroscopy(FTIR), polarized light microscope, rheometer, X-ray diffraction(XRD) and differential scanning calorimetry(DSC). The addition of cyclopentasiloxane reduced the CGC of SMS–sesame oil oleogel from 20% to 10%(w/w). In microscopic characterization, the oleogels with a mixture of oil phases showed the longer and thicker three-dimensional gel network than that of oleogels with sesame oil and cyclopentasiloxane. FTIR studies demonstrated that this network formation was mainly due to hydrogen bonding. Rheological measurements revealed that the combination of cyclopentasiloxane and sesame oil produced strong gel with higher complex modulus values and longer linear viscoelastic region than oleogels prepared with sesame oil and cyclopentasiloxane. In addition, oleogels with the combination of the two oils had higher enthalpy( H m) and entropy( S m) thus could increase thermodynamic stability of the oleogels. Therefore, the addition of cyclopentasiloxane can improve the physical, ther-mal properties and stability of SMS–sesame oil oleogel, provide greater sensory profile and better product aesthetics. The developed oleogel can be a novel carrier for topical drug delivery.

Oleogels for development of health-promoting food products

Metabolic health and the maintenance of good levels of triglycerides,high-density lipoprotein cholesterol,blood pressure and glucose levels are concerns that can greatly impact human quality of life.Healthdriven consumers’demands,together with technological innovations,have led to a diversification of the food industry.The fostering of off-the-shelf available and affordable healthy food products is necessary,as detrimental effects on human health from the ingestion of saturated fat sources urge the efforts to find alternatives.Oleogels can be tailored using specific triglycerides and oleogelators,that can be selected to yield targeted fatty acids,reduce higher levels of cholesterol with competing binding-molecules(e.g.phytosterols),reduce saturated fat content,lessen appetite(e.g.modelling the shape of foods)or carry exclusive bioactive compounds to be absorbed in the digestive tract.Oleogels are foreseen as an important technological advance in food science due to their versatility,easy processing and affordability.This review explored the strategies in place to develop and produce oleogels,foreseeing their introduction in foods and how they might represent an important source of functionality through the use of healthy molecules.It also explored how oleogels can act on the human overall metabolic health if they are used in human diet.

Investigation of the effect of hydrocarbons and monoesters in the gelators’composition on the properties of edible oleogel

Natural wax gelators have different compositions of compounds(hydrocarbons,wax esters,free fatty alcohols,and free fatty acids),which results in oleogels with varying properties.To maintain a consistent composition,the individual components can be added to the original wax gelator.The content of hydrocarbons and wax esters greatly affects the structuring process of liquid edible oils with waxes.The aim of this study was to evaluate the possibility of modifying the properties of beeswax as a gelling agent by adding hydrocarbons or monoesters to obtain oleogels with specific properties.Various tests were conducted to assess the changes in the oleogel properties,such as color,microstructure,oil-binding capacity,thermal and textural properties.The research results have shown that the addition of the studied fractions has led to a significant change in all properties of oleogels.The initial size of oleogel crystals(7.29±1.80μm)changed after adding fractions,varying from 5.28μm to 12.58μm with hydrocarbons and from 9.95μm to 30.41μm with wax esters.The addition of 30%–50% hydrocarbons decreased the ability of the oleogels to bind oil and made them less firm compared to samples with 10%-20% hydrocarbons.Adding 10%-20% monoesters increased the firmness of the oleogels,but this indicator decreased when their content was increased to 50%.The obtained data indicate that hydrocarbons and wax esters can be used for targeted correction of the gelling properties of beeswax.

Thermo-driven oleogel-based self-healing slippery surface behaving superior corrosion inhibition to Mg-Li alloy

Bioinspired by Nepenthes, lubricant infused surfaces(LIS) have attracted widespread attention in the field of anticorrosion. However,the lubricant coating has some disadvantages such as complex construction processing and easy loss of oil phase in air or dynamic water phase. In this study, oleogel is infused into a lotus leaf inspired super-hydrophobic matrix to form an oleogel infused surface(OIS) for enhancing corrosion resistance of active Mg-Li alloy. For reserving oleogel, firstly, a facile one-step electrodeposition method is used to construct super-hydrophobic surface(SHS) composed by samarium/myristic acid complex micro-nano flower structure onto Mg-Li alloy.The coating exhibits excellent superhydrophobic property at a static contact angle of 160° by applying 30 V electrolysis for 30 min. The protection efficiency of single SHS highly relates with the metal itself. For short period immersion in water phase, SHS can afford protection to Mg-Li alloy. However, the long-term immersion will see the rapid failure of SHS, and the high activity of Mg-Li alloy is one main reason.We assume that SHS cannot be a good choice for protecting Mg-Li alloy. Then, a Nepenthes inspired liquid coating is formed by infusing oleogel into the micro-nano structure by a spin-coating method. The liquid coating performs prominent corrosion resistance with Rctreaching as high as 1.51 × 10^(10)Ω cm^(2). After the mechanical damage from the external environment, the liquid coating can realize self-repair through thermal assistance, and the liquid coating can still restore Rctup to 1.24 × 10^(10)Ω cm^(2) after healing. The corrosion resistance of the liquid coating remains strong by showing Rctas high as 1.14 × 10^(9)Ω cm^(2), even after immersion in representative corrosive 3.5 wt% Na Cl solution for 30 d.

Interaction of monopalmitate and carnauba wax on the properties and crystallization behavior of soybean oleogel

The aim of this work was to investigate the possible synergistic interaction between monopalmitate(MP)and carnauba wax(CW)on the properties and crystallization behavior of oleogels.The soybean oleogels were prepared from MP and CW,and were characterized by oil binding capacity(OBC),solid fat content(SFC)and isothermal crystallization.The results showed that the OBC of the prepared oleogels changed in a W-shape trend with the increase of CW content.The mass ratio of MP and CW greatly affected the SFC.At 40,50 and 60°C,the SFC of these oleogels showed a slight deep eutectic effect with the increase of CW content in the gelators.The mass ratio of MP to CW also apparently affected the peak temperature and enthalpy during the crystallization and melting process analyzed by differential scanning calorimeter.The hysteresis occurring in the study indicated that crystallization temperature was lower than melting temperature and crystallization enthalpy was higher than melting enthalpy.The isothermal crystallization of these oleogels was characterized by Avrami equation,the Avrami exponent(n)and the apparent crystallization constant(k)of these oleogels were affected by the mass ratio of MP to CW as well as the crystallization temperature.Great difference in the values of n and k between the MP(or CW)oleogel and these oleogels suggested that the crystal growth mechanism had changed.However,the factor k for the oleogel formed of MP and CW with a mass ratio of 2:8 was about 1,unaffected by the crystallization temperature.From these results,we could deduce that the synergistic interaction between MP and CW did happen and affect the properties and crystallization behavior of these oleogels.