Mixtures Of Monoglycerides Research Articles

Natural deep eutectic solvents as green and homogeneous catalysts for the glycerolysis of stearic acid: Catalytic activity and kinetic studies

Emulsifier as the mixture of monoglycerides (MG) and diglycerides (DG) is widely used in the food industry such as bakery products, margarines, dairy products, and confectionary. This emulsifier can be produced by glycerolysis of fatty acids using acid catalyst. In this work, natural deep eutectic solvent (NADES) was chosen as a catalyst in the glycerolysis of stearic acid due to greener and sustainable catalyst with advantages such as low vapor pressure, non-toxic, biodegradable, and easy to reuse. The catalytic activity of the NADES, kinetic constants and activation energies for the reaction were investigated. The reaction was carried out at agitation speed (300 rpm), catalyst concentration (5 wt%), reaction temperatures (120 °C, 150 °C and 180 °C) and reactant mole ratios (1:2, 1:4 and 1:6). Choline chloride-sorbitol NADES has highest catalytic activity on the glycerolysis of stearic acid. The kinetic calculation results using choline chloride-sorbitol NADES as a catalyst validated that the reaction was pseudo second order with an activation energy of 64.04 kJ∙mol−1, and a collision factor of 196,696 L∙mol−1∙min−1. This kinetics data will be useful for reactor design in industrial applications.

Придание аэробной стабильности кукурузному силосу при химическом консервировании

Aerobic stability of corn silage, as well as other types of silage, can be achieved by chemical preservation. Currently, mainly organic acids and their salts are used as chemical preservatives. The highest preservative effect is provided by undissociated forms of acids. Dissociation occurs most intensely in a reaction environment close to neutral and is significantly inhibited in an acidic environment. To give silage aerobic stability, the chemical preservative must have fungicidal and static properties, since the main initiators of aerobic decomposition are yeast. Of the organic acids, propionic acid has such properties to the highest extent, and acetic acid to a somewhat lesser extent. Other representatives of organic acids with fungicidal properties not inferior to propionic acid are benzoic, sorbic, acrylic and others. Salts of these acids also have similar properties. The use of mixtures of acids and salts significantly enhances their preservative effect, provided that their components interact synergistically. In addition to these mixtures, the fungicidal effect of a mixture of monoglycerides: monopropionate and monobutyrate has recently been established. Unlike biological products, the fungicidal effect of chemical preservatives manifests itself from the first days of use.

Utilization of liquid epoxidized natural rubber as prepolymer and crosslinker in development of UV-curable palm oil-based alkyd coating

Innovation of new products from renewable resources are important for sustainable development. In this work, novel rubber-integrated palm oil-based alkyd resins were prepared using palm oil, glycerol, diacids, and liquid epoxidized natural rubber (LENR50). The synthesis started with alcoholysis of glycerol by palm oil to produce predominant mixture of monoglycerides, followed by polycondensation with diacids to form alkyd chain. In addition to glycerol, LENR50 was introduced as bio-based polyol for the alkyd synthesis. The rubber prepolymer was chemically integrated into the alkyd chain via the reaction between its epoxide or hydroxyl groups with COOH of diacids during polycondensation. Resultant alkyds were mixed with reactive diluent (styrene), crosslinker (trimethylolpropane triacrylate) and photoinitiators (benzophenone and 1-hydroxycyclohexyl phenyl ketone), and the mixtures were cured under UV irradiation. Introduction of LENR50 into the coating formulation has reduced the curing time, as well as improved some of the film properties of the coatings. Some of the LENR50-based coatings required as short as 3 mins of UV irradiation to form dry-hard films, while the control samples required much longer time. There was also notable increase in the gel content of the LENR-based alkyd coating, suggesting that the polyfunctionality of LENR50 could have increased the extent of crosslinking in the cured film. Other improvement recorded includes pencil hardness, film adhesion, solvent resistance, water resistance, and corrosion resistance. Thermal stability of the alkyd coatings is also reasonably good for general purpose coating applications. The findings from this study suggest that LENR50 could serve as an alternative polyol in synthesis of bio-based polyester binder for surface coating.

Effects of a mixture of mono-glycerides of butyric-, capric-, and caprylic acid with chlortetracycline on the growth performance, intestine morphology, and cecal microflora of broiler birds

This study aimed to investigate the effects of a mixture of mono-glycerides of butyric-, capric-, and caprylic acid (MMG) on the growth performance, intestinal morphology, and cecal microflora of broilers. A total of 960 male Arbor Acre broilers were offered basal diets with or without Chlortetracycline additive (CA) at 500 g/t, and MMG at 3,000, 1,000, or 650 g/t, with 8 replicates of 20 birds per treatment. The results confirmed 500 g/t CA with/without 1,000 g/t MMG increased the average daily weight gain (ADG) of birds compared to the control group 1 during the 42-d experimental period (P < 0.05). Comparing to the control group 1, 500 g/t CA with either 650 g or 1,000 g/t MMG or 1,000 g MMG alone increased the ADG of birds during the late growth stage (22–42 d) (P < 0.05). On d 42, the serum triglyceride levels were higher (P < 0.05) in groups supplemented with CA and CA + 1,000 g/t MMG comparing to the control group; while urea nitrogen level was higher in the control group comparing to the rest of treatment groups Compared to the control group 1, 1,000 g/t MMG alone without CA decreased the abundance of Faecalibacterium and Bacteroides but increased the abundance of Escherichia/Shiegella. About 500 g/t CA alone treatment group had higher abundance of Lactobacillus comparing to the rest of groups. In conclusion, dietary supplement with MMG showed beneficial efficacy on the growth and intestinal function of broilers, demonstrating the potential value of MMG to poultry industry. In terms of dosage, the current trial shows that 3,000 g/t (1–21 d) and 1,000 g/t (22–42 d) MMG without CA was the appropriate dietary supplemented rate for broilers. And the mixed use of 500 g/t CA and 1,000 g/t MMG was benefit for broilers at 22 to 42 d.

A comparison of formic acid or monoglycerides to formaldehyde on production efficiency, nutrient absorption, and meat yield and quality of Cobb 700 broilers

After being banned by the European Commission in 2018, the use of formaldehyde as a feed amendment in the United States has come into question. Therefore, this study was conducted to explore alternatives to formaldehyde, such as formic acid and monoglycerides, and their effects on poultry production. In total, 1,728 Cobb 700 broilers were randomly assigned to 96-floor pens on day of hatch (18 birds/pen). Using a randomized complete block design (4 blocks), treatments were assigned to pens with blocking based on location within the barn, with the eastern half of the barn designated for digestibility and the western half designated for production (per experiment: 8 control pens and 10 pens per treatment). All diets were based on a negative control (NC), basal diet. Dietary treatments consisted of: NC, NC + 0.25% formalin (F), NC + 0.25 and 0.50% Amasil NA (AML and AMH; 61% formic acid and 20.5% Na-formate), and NC + SILO Health 104L (SILO; mixture of monoglycerides; 0.5% from 0 to 14 d, 0.4% from 14 to 28 d, and 0.2% from 28 to 42 d). Water and feed were provided ad libitum. Performance data were collected during feed changes on d 0, 14, 28, and 42, with digestibility data collected at d 14 (2 per pen) and carcass quality (6 per pen) assessed at d 46 with a randomly selected group of broilers. A one-way ANOVA followed by Dunnett's multiple comparison, where treatments were evaluated against F were conducted using JMP 14.0 (P ≤ 0.05). Main effect of treatment was significant for performance, nutrient digestibility, and carcass quality. Differences in body weight and ADG were observed from d 14 to d 28, resulting in a trending improvement in lysine digestibility on d 14 and carcass quality on d 46 of birds fed AML and AMH in comparison to those fed F (P < 0.05). Whereas birds fed SILO had reduced digestibility of methionine on d 14 and a decrease in meat quality on d 46 in comparison to those fed F (P < 0.05). Therefore, Amasil NA at 0.25 or 0.50% may be an effective alternative to formaldehyde as a feed amendment for poultry production.

Supported lipid bilayer platform for characterizing the optimization of mixed monoglyceride nano-micelles

The development of real-time measurement strategies to quantitatively characterize dynamic morphological changes of cell membrane-mimicking biomaterial platforms is an important technological need for membrane-active drug development. One of the most promising classes of membrane-active drug candidates is medium-chain monoglycerides, which demonstrate potent antimicrobial and immunomodulatory activities. Each monoglyceride has distinct membrane-disruptive behaviors and biological activities and it would be advantageous to combine different monoglycerides into a mixed micellar formulation. Herein, we evaluate the development of nano-micellar formulations that are composed of C12-based glycerol monolaurate (GML) and C10-based glycerol monocaprate (GMC) mixtures and characterize the interactions of GML/GMC nano-micelles with two-dimensionally confined supported lipid bilayer (SLB) platforms in terms of real-time interaction kinetics, dynamic shape transformations, and resulting membrane lysis. Our findings indicate that GML/GMC molecules self-assemble into ideally mixed nano-micelles and GML/GMC nano-micelles trigger membrane budding to varying extents depending on the GML/GMC molar ratio. Membrane budding was minimized at intermediate GML/GMC molar ratios. Among the two components, the data further support that GMC is the main one contributing to membrane lysis and thus tuning the micellar composition can enable precise control over the balance between the extent of membrane budding and membrane lysis. Taken together, this work advances our understanding of how monoglyceride mixtures can be developed into nano-micellar formulations and demonstrates the broader potential of developing cell membrane-mimicking biomaterial platforms for medical and biotechnology applications.

Extrusion 3D printing of nutraceutical oral dosage forms formulated with monoglycerides oleogels and phytosterols mixtures.

Among the potential applications of 3D printing, the development of products with personalized characteristics in the area of food and nutraceuticals represents an important field that must still be explored. The aim of this work was to evaluate the production of nutraceutical oral forms by extrusion-based 3D printing (E3DP) using mixtures of monoglycerides (MG) oleogels and phytosterols (PS) as printing materials. These materials were obtained using MG (10 or 20%wt), high oleic sunflower oil, and variable amounts of PS (20-50%wt PS/oleogel). An ad-hoc extrusion 3D printer composed of a heated syringe and a cooling build platform was used. Rheological tests were carried out to determine the mixtures gel point, in order to select appropriate printing temperatures, as well as the yield stress of the final materials. Hardness of printed forms was obtained by compression tests. Additionally, oral forms were produced by manual extrusion using molds for comparison. It was found that oral forms were successfully printed when using mixtures containing a maximum of 30 and 40%wt PS/oleogel for oleogels formulated with 10 and 20%wt of MG, respectively. Moreover, the best printed forms corresponded to the mixtures with the lowest gelation temperatures. These printed forms were structurally stable, with uniform weight and shape, and maximum hardness of 12.55 N. Hardness values of printed oral forms did not show a correlation with those obtained by manual extrusion using molds, indicating that this parameter was affected by solid composition, cooling rate, and the fragility generated for layers superposition. In conclusion, it was demonstrated that mixtures of MG oleogels and PS can be used for E3DP production of nutraceutical oral forms suggesting that oleogels have excellent potential as materials able to incorporate liposoluble active ingredients to be used as extrusion printing materials.

Main features and applications of organogels in cosmetics.

Cosmetic treatments aim at improving skin appearance through vehicles of good sensory properties. Those vehicles are mainly emulsions and gels designed to deliver safe and effective compounds to skin. Creams and serums are widely used to achieve these goals, but recently a new type of formulation known as organogels triggered scientific attention, particularly in the design of both topical and cosmetic formulations. It has been established that the lipophilic nature of organogels makes it an excellent candidate for the delivery of cosmetic molecules through skin. In this review, we discuss the properties and characteristics of organogels and present the advantages of the application of these systems in cosmetics.

Erratum to: Predicting Solid–Liquid Equilibrium of Fatty Acid Methyl Ester and Monoglyceride Mixtures as Biodiesel Model Fuels

Erratum to: Predicting Solid–Liquid Equilibrium of Fatty Acid Methyl Ester and Monoglyceride Mixtures as Biodiesel Model Fuels

Predicting Solid–Liquid Equilibrium of Fatty Acid Methyl Ester and Monoglyceride Mixtures as Biodiesel Model Fuels

AbstractFatty acid methyl esters from plant oils are the main component of biodiesel and used as a substitute for petroleum diesel. Biodiesel generally contains a small amount of monoglycerides as intermediate compounds, which have high melting points and often solidify and clog fuel filters. The prediction of the cold‐flow property of biodiesel is of great importance for practical application. In this study, a thermodynamic study was conducted for mixtures of monoglycerides and fatty acid methyl esters. Temperatures of the solid–liquid equilibrium for the mixtures were measured by differential scanning calorimetry and visual observation, while the theoretical values were calculated using the modified Universal Quasi‐chemical Functional‐group Activity Coefficients (UNIFAC) model (Dortmund). The theoretical and experimental results were in good agreement, especially for binary mixtures of monoglycerides and methyl esters. The importance of monoglycerides on the cold‐flow properties of biodiesel was determined, and the effects could be well described by the modified UNIFAC model (Dortmund).

Effect of Moisture on the Thermoresponsive Properties of Binary Mixtures of Monoglycerides for Triggerable Drug Delivery Systems.

The crystallization behavior and temperature-dependent phase transition of monoglycerides have been utilized to develop thermal-sensitive drug delivery systems. The presence of excess water has been reported to influence the phase transition. The present study investigates the effect of moisture on the thermal behavior of binary blends of monoglycerides. Various compositions (0-100wt%) of glyceryl monooleate (GMO) and glyceryl monostearate (GMS) were prepared by fusion method, and exposed to varying relative humidity (RH) levels (0-100%). The moisture uptakes, sorption isotherm, and the thermal behavior of GMO-GMS samples were analyzed using differential scanning calorimeter (DSC), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The in vitro nifedipine (NF) release was studied at 37 and 42°C. Samples of GMO-GMS (25:75, 50:50, and 75:25wt%) stored at 97%RH at 25°C for 3weeks increased in weight by 14.0, 14.7, and 15.8%, respectively. Despite such high moisture uptake, the GMO-GMS matrices maintained crystalline structure. The melting point (T m) and heat of fusion (ΔH f) of the samples were reduced as the amount of moisture in the matrices increased. However, the heat of fusion calculated on dry basis remained constant at 139.4 ± 1.25, 102.7 ± 1.14, and 46.7 ± 1.16J/g for GMO-GMS 25:75, 50:50, and 75:25wt%, respectively. The comparison of the XRD measurements of the dry samples with those containing 30% water confirmed the preserved crystalline arrangement in the matrices. This study indicates that despite the high moisture uptakes, the GMO-GMS matrices retained their crystalline properties and provided temperature-dependent drug release indicating the potential application for thermoresponsive local drug delivery systems.

Oil structuring properties of monoglycerides and phytosterols mixtures

Oleogelation has recently emerged as a subject of growing interest among industrial and academic researchers. One of the main concerns when working with oleogels is finding the ideal food‐grade oleogelators with right functionalities and universal applications. Identifying synergistic combinations of well‐known food ingredients could possibly help us overcome this issue. In this work we have identified for the first time, that the combination of monoglycerides (MGs) and phytosterols (PS) at certain ratios leads to the formation of mixed component gels that are better than either of the mono component gels. Oleogels were investigated in terms of their rheological properties, crystallization aspects, and microstructural attributes. Three different types of MGs were combined with commercial‐grade PS in different ratios to structure sunflower oil into viscoelastic gels. Polarized light microscopy images of all the samples revealed the formation of three‐dimensional network of entangled crystals, leading to the physical trapping of liquid oil within the interspace structures. Amplitude sweeps showed that the gels formed from these oleogelators had predominantly solid‐like structure (G′ &gt; G″). The mixtures of MGs:PS at 8:2 ratio showed a promising combination as the G′LVR obtained was much higher than gels prepared by using individual components. Based on the crystallization and microstructure studies, it can be speculated that the presence of PS assisted in disintegrating the crystalline clusters and flocs of MGs crystals resulting in gels with better rheological properties compared to mono component oleogels.Practical applications: Oleogelation has emerged as a subject of growing interest in the last couple of years fuelled both by real industrial needs and curiosity for fundamental research among academic researchers. However, one of the main bottlenecks in commercial application of this approach is the lack of ideal food‐grade oleogelators. In this work we have identified for the first time, the synergistic interactions among monoglycerides and phytosterols which leads to the formation of mixed component gels. The resultant gel from that combination can later be used as either an alternative to saturated fat or delivery of functional ingredients. Saturated fat replacement in margarine or butter formulation could be the main application of this oleogel. This is due to the fact that both of the oleogelators used to structure sunflower oil in this research have been used widely in food application. In addition, oleogelators used to structure sunflower oil are available widely in the market.Oleogelation has recently emerged as a subject of growing interest among industrial and academic researchers. One of the main concerns when working with oleogels is finding the ideal food‐grade oleogelators with right functionalities and universal applications. Identifying synergistic combinations of well‐known food ingredients could possibly help us overcome this issue. In this work we have identified for the first time, that the combination of monoglycerides (MGs) and phytosterols (PS) at certain ratios leads to the formation of mixed component gels that are better than either of the mono component gels. Oleogels were investigated in terms of their rheological properties, crystallization aspects, and microstructural attributes. Three different types of MGs were combined with commercial‐grade PS in different ratios to structure sunflower oil into viscoelastic gels. Polarized light microscopy images of all the samples revealed the formation of three‐dimensional network of entangled crystals, leading to the physical trapping of liquid oil within the interspace structures. Amplitude sweeps showed that the gels formed from these oleogelators had predominantly solid‐like structure (G′ &gt; G″). The mixtures of MGs:PS at 8:2 ratio showed a promising combination as the G′LVR obtained was much higher than gels prepared by using individual components. Based on the crystallization and microstructure studies, it can be speculated that the presence of PS assisted in disintegrating the crystalline clusters and flocs of MGs crystals resulting in gels with better rheological properties compared to mono component oleogels.

The Monoglyceride Content Affects the Self-Assembly Behavior, Rheological Properties, Syringeability, and Mucoadhesion of In Situ–Gelling Liquid Crystalline Phase

This article reports the development of a precursor liquid crystalline system based on a mixture of monoglycerides (MO) and Cremophor® (CREM) that exhibits in situ gelation to a liquid crystalline phase. The effects of different MO/CREM ratios and the water content (WC) on several performance characteristics were investigated with a full factorial design. The formulations were characterized by polarized light microscopy, small-angle X-ray scattering, and water uptake assays. Rheological, syringeability, and mucoadhesion evaluation were also performed. The polarized light microscopy and small-angle X-ray scattering results for average and high MO/CREM ratios (2.1 and 4.0, respectively) indicated the coexistence of phases in transition to the liquid crystalline phase, independently of the WC. These systems became more viscous after taking up water, showing peaks characteristic of a cubic phase. Systems that had average and high MO/CREM ratios also exhibited shear-thinning behavior and high elasticity. Most systems showed suitable mucoadhesion for buccal purposes. Response surface methodology results demonstrated that the relative contribution of MO was the principal factor that affected the performance of the system. Accordingly, these precursor systems with average to high MO/CREM ratios and an average WC (10% w/w) demonstrated physicochemical and mucoadhesive properties that could enable them to be used as an in situ-gelling controlled drug delivery platform.

The phase behaviour of mixed saturated and unsaturated monoglycerides in water system

Abstract Lyotropic liquid crystalline phases are formed over a limited range of surfactant concentrations and temperatures as represented by regions on the phase diagram. Acknowledgement of the surfactant phase diagram is a major step in developing any industrial application. In this work; we have examined the phase behaviour of mixed saturated and unsaturated monoglycerides 1:1 (by weight) together with water. The main technique employed was X-ray diffraction, supplemented by optical microscopy and differential scanning calorimetry (DSC). The phase diagram which is a novel finding shows six phases for GMS/GMO mixture without water: α-gel (Lβ) phase, new α-gel (Lβ1) structure, β1 crystal phase, sub-α phase, β2-crystal, as well as an isotropic, L2, phase. In the presence of water five additional phases are formed, fluid lamellar phase, three bicontinous cubic phases, Ia3d, Pn3m and Im3m with increasing the water content, and on further heating all bicontinous cubic phase convert to a hexagonal phase. Our results show that the maximum swelling capacity of the mixture of monoglycerides in water is obtained at 50% (w/w) water content, and there are important differences in the phase behaviour between mixed saturated and unsaturated monoglycerides with and without water.

Self-assembling gelling formulation based on a crystalline-phase liquid as a non-viral vector for siRNA delivery

Liquid crystalline systems (LCSs) form interesting drug delivery systems. These include in situ gelling delivery systems, which present several advantages for use as self-assembling systems for local drug delivery. The aim of this study was to develop and characterize in situ gelling delivery systems for local siRNA delivery. The influence of the components that form the systems was investigated, and the systems were characterized by polarized light microscopy, Small Angle X-ray Scattering (SAXS), swelling studies, assays of their ability to form a complex with genes and of the stability of the genes in the system, as well as assays of in situ gelling formation and local toxicity using an animal model. The system containing a mixture of monoglycerides (MO), oleylamine (OAM), propylene glycol (PG) and tris buffer (8.16:0.34:76.5:15, w/w/w/w) was considered the most appropriate for local siRNA delivery purposes. The molecular structure was characterized as hexagonal phase; the swelling studies followed a second order kinetic model and the water absorption was a fast process reaching equilibrium at 2h. The system formed a complex with siRNA and remained in a stable form. The gel was formed in vivo after subcutaneous administration of a precursor fluid formulation in mice and was biodegradable in 30days. The inflammatory process that took place was considered normal. Therefore, the developed liquid crystalline delivery system shows the appropriate characteristics for use as a local siRNA delivery method for gene therapy.

Influence of the Dissolution Rate on the Collapse and Shedding Behavior of Monostearin/Monopalmitin-rich Coated Microbubbles

A low cost food grade emulsifier (a mixture of monoglycerides, diglycerides, and sodium stearoyl lactylate) in combination with polyethylene glycol-40 stearate (PEG-40S) was used as an alternative to pure saturated phospholipids to form the thin shell of a microbubble. To investigate the stability of these microbubbles in a water system over time, their dissolution behavior was studied at various degas factors and at two percentages of PEG-40S. It was found that the favored shell collapse/shedding mechanism switched, as the dissolution rate increased (degas factor decreased), from folding with a smooth surface contour to buckling accompanied by surface folding/expulsion with a cyclic buckled-smooth surface contour. The compositional change that we made played a more minor role, mainly controlling the resistance to mass transfer of the microbubble shell and again modifying the mechanism-determinant dissolution rate. The shell resistance behavior for these microbubbles varied from that of previous lipid/PEG-40S-coated microbubbles by the presence of a maximum in shell resistance during dissolution. We hypothesize that the dominance of one collapse mechanism over another for these compositions is related to the time scales of two competing processes, fold nucleation and area compression. For these mixtures at room temperature, we estimate that the maximum area compression rate for folding as the major collapse mechanism is approximately 0.2 s (-1), a rate unattainable in a traditional Langmuir trough but achievable by the use of a dissolving microbubble.

Stability and rheological behavior of concentrated monodisperse food emulsifier coated microbubble suspensions

Nearly monodispersed populations of microbubbles were produced using flow focusing with a food grade emulsifier. The microbubbles produced by this technique have diameters in the range of 120–200 μm. The flow focusing device uses metered streams of air and liquid to produce a jet that periodically pinches to make individual microbubbles. The size of the microbubbles can be controlled by changing the relative flow rates of the gas and the liquid. The emulsifier consists of a mixture of monoglycerides, diglycerides and sodium stearoyl lactylate in combination with polyethylene glycol (PEG)-40 stearate. The emulsifier forms a thin shell that stabilizes the microbubbles. The microbubbles are stable over time with their sizes remaining roughly constant over 2 h. Such stability allows suspensions of microbubbles to be formed and their rheological properties tested. The sizes of the microbubbles are also monitored off-line while testing, examining the effect of shearing on the bubble sizes, as well as their stability over time. These results show that the microbubble suspensions are viscoelastic and exhibit power law behavior. The relationship between the air fraction of the suspension and fluid viscosity is determined.

Kinetic Study of Polyurethane Reaction between Castor Oil/TMP Polyol and Diphenyl Methane Diisocyanate in Bulk

Polyols as precursors of crosslinked polyurethanes were prepared by alcoholysis between castor oil (CO) and Trimethylol propane (TMP). The alcoholysis reaction produced an equilibrium mixture of monoglycerides, diglycerides, and triglycerides of TMP and some free TMP. The polyol thus prepared was characterized using FTIR, Atmospheric Pressure Chemical Ionization (APCI) under positive ion mode and various analytical techniques. A series of bulk polyurethane polymerization reactions were then carried out using the polyol and Diphenyl methane diisocyanate (MDI) at 25°C, and were investigated using Fourier transform Infrared (FTIR) spectroscopy with different NCO/OH ratios, that is, 0.75, 1.0, and 1.25. All the reactions obeyed second order kinetics. Second order rate constants were calculated and found to be 2.49 × 10−4 lit/eq. sec., 3.4 × 10−4 lit/eq. sec. and 2.38 × 10−4 lit/eq. sec. for NCO/OH ratio 1.25, 1.0, and 0.75, respectively.

Effects of monoglyceride content, cooling rate and shear on the rheological properties of olive oil/monoglyceride gel networks

AbstractFunctionality of conventional fat spreads can be achieved without hydrogenation by the formation of stable network structures upon cooling of mixtures of monoglycerides (MGs) and vegetable oils from the melt. Such mixtures are healthy substitutes for margarine and butter. The effects of MG content, cooling rate and shear on the temperature ramp, mechanical spectra and hardness of olive oil/MG gel networks were investigated. A minimum MG volume fraction was necessary for formation of a gelled network, but this concentration was less than that needed for a space‐filling network structure. Onset of gel network or structure formation was indicated by a sudden divergence in value of the elastic modulus G′. The temperature at onset of structure formation, To, final G′ value and network hardness all increased with increase in MG content. High cooling rates led to low final G′ values but harder networks, and vice versa. Maximum gel network development occurred when moderate shear (about 300 s−1) was applied at incipient gelation. Copyright © 2004 Society of Chemical Industry

Surface rheology of aqueous casein–monoglyceride dispersions

The interfacial properties of homogenised mixtures of monoglycerides and milk proteins (casein) have been examined using dynamic surface rheology. Using applied oscillation it was shown that the adsorption and surface properties of these mixtures varied considerably in comparison with the individual components. Homogenised dispersions made with casein and saturated monoglycerides (C16) at 40 °C displayed controlled deposition of monoglyceride at the air–water interface. Cooling of the solution to 5 °C resulted in crystallisation of the monoglyceride at the air–water interface. This was characterised by increasing surface elasticity and viscosity. Both surface elasticity and viscosity reached steady state, implying that there was no adsorption from bulk phase to the interface. Similar adsorption behaviour was observed when an unsaturated monoglyceride (C18:1) was used, although the steady-state values for surface elasticity on cooling were consistently lower in comparison with the saturated monoglycerides. The shorter chain length monoglyceride, monolaurin, was found not to produce a metastable dispersion on homogenisation, and consequently controlled deposition at the air–water interface was not observed. The results have some important implications for foam stabilisation using monoglycerides and other food grade surfactants.