Monoglyceride Content Research Articles

Effect of water and monoglyceride concentration on the behaviour of monoglyceride containing fat systems

The effect of water and monoglycerides on the structural behaviour of a selected fat system was investigated to explore their role in structure development of products like margarine and sponge cake. Firstly, the monoglyceride and triglyceride system was selected based on solid fat content (SFC) determination. This system was further investigated by differential scanning calorimetry (DSC) and polarized light microscopy (PLM). Secondly, the role of water concentration in this system was investigated by SFC-determination and hardness measurements at different water concentrations. These investigations demonstrate clearly the important role of water, especially at lower concentrations. Finally, the influence of monoglycerides on droplet size distribution in margarines and on textural properties of sponge cakes was investigated. These investigations reveal a larger droplet size of monoglyceride containing margarines and a more dense and harder texture of sponge cakes containing monoglycerides.

Packed-Bed Reactor Running on Babassu Oil and Glycerol to Produce Monoglycerides by Enzymatic Route using Immobilized Burkholderia cepacia Lipase

The aim of this study was the glycerolysis of babassu oil catalyzed by immobilized lipase from Burkholderia cepacia, in a continuous packed-bed reactor. The best reaction conditions were previously established in batchwise via response surface methodology as a function of glycerol-to-oil molar ratio and reaction temperature. The reactor operated continuously for 22 days at 50 degrees C, and during the first 6 days, no significant decrease on the initial lipase activity was observed. Monoglycerides concentration was in the range from 25 to 33 wt.%. Subsequently, a progressive decrease in the activity was detected, and an inactivation profile described by Arrhenius model estimated values of 50 days and 1.37 x 10(-2) h(-1) the half-life and deactivation coefficient, respectively.

Viscoelastic solution of long polyoxyethylene chain phytosterol/monoglyceride/water systems

We have studied the rheology and structure of a mixed long polyoxyethylene chain phytosterol (PhyEO30) and monoglyceride (monolaurin (ML) or monopalmitin (MP)) surfactants in an aqueous system. Both ML and MP are insoluble in 10 wt.% PhyEO30 solution at normal room temperature, but their solubility is found to increase with the rise of temperature and an isotropic solution is formed at higher temperature. A maximum viscosity as a function of temperature appears as ML or MP is solubilized in the micellar solution of PhyEO30. With increasing temperature, viscosity increases rapidly for higher monoglyceride content and forms viscoelastic solution. The oscillatory rheological behavior of the viscoelastic solution can be described by Maxwell model at low-frequency region, which is the typical pattern of entangled wormlike micelles. Upon successive increase in temperature, the viscosity decreases and ultimately a phase separation occurs. Small-angle X-ray scattering measurements were performed to provide a supportive structural evidence for the rheological data.

Corticosteroid solubility and lipid polarity control release from solid lipid nanoparticles

Solid lipid nanoparticles (SLN) show promise as a drug delivery system for skin administration. The solid state of the lipid particle enables efficient drug encapsulation and controlled drug release. The present study addresses the influence of lipid composition and drug substance lipid solubility on the in vitro release profile of corticosteroids from SLN for topical administration. Firstly, the effect of lipid composition on the lipid solubility and in vitro release of betamethasone-17-valerate (BMV) was determined by varying the lipid monoglyceride content and the chain length of the fatty acid moiety. Secondly, the effect of drug substance physicochemical properties was determined by studying five different corticosteroid derivatives with different lipophilicity. A high concentration of monoglyceride in SLN increased the amount of BMV released. The corticosteroid release rate depended on the drug substance lipophilicity and it was clear that the release profiles depended on drug partitioning to the aqueous phase as indicated by zero order kinetics. The results emphasize that the corticosteroid solubility in the lipid phase greatly influence drug distribution in the lipid particles and release properties. Thus knowledge of drug substance solubility and lipid polarity contributes to optimize SLN release properties.

Optimization of the transesterification reaction in biodiesel production

In this paper response surface methodology (RSM) was used to study the transesterification reaction of rapeseed oil for biodiesel production. The three main factors that drive the conversion of triglycerides into fatty acid methyl esters (FAME) were studied according to a full factorial design at two levels. These factors were catalyst concentration (KOH), temperature and reaction time. The range investigated for each factor was selected taking into account the process of Fox Petroli S.p.A. Analysis of variance (ANOVA) was used to determine the significance of the factors and their interactions which primarily affect the first of the two transesterification stages. This analysis evidenced the best operating conditions of the first transesterification reaction performed at Fox’s plant: KOH concentration 0.6% w/w, temperature 50 °C and reaction time 90 min with a CH 3OH to KOH ratio equal to 60. Three empirical models were derived to correlate the experimental results, suitable to predict the behavior of triglyceride, diglyceride and monoglyceride concentration. These models showed a good agreement with the experimental results, demonstrating that this methodology may be useful for industrial process optimization.

Biodiesel fuel from Jatropha oil via non-catalytic supercritical methanol transesterification

Transesterification of Jatropha oil using supercritical methanol and in absence of a catalyst has been studied under different conditions of temperature (from 512 to 613 K), pressure (from 5.7 to 8.6 MPa) and molar ratio of alcohol to oil (from 10 to 43 mol alcohol per mol oil). The reaction products were analyzed for their content of residual triglycerides, glycerol, monoglycerides, diglycerides, esters and free acids by high performance liquid chromatography (HPLC), thin layer chromatography (TLC) and titration against KOH. The results have revealed that 100% yield of esters can be obtained using super critical methanol within four min only, at a temperature of 593 K and under a pressure of 8.4 MPa pressure. The molar ratio of methanol to oil was 43:1.

Structure and thermal stability of thermoplastic films based on wheat flour modified by monoglyceride

The effects of the incorporation of monoglyceride on the structure and thermal stability of extruded thermoplastic films based on modified wheat flour have been investigated using X-ray diffraction (XRD) and thermogravimetric method (TGA). Addition of the monoglyceride reduced the intensity and widened the peaks obtained by XRD indicating a reduction in crystal size. A significant decrease of apparent length of the crystals have been noticed when the quantity of monoglyceride increases. The thermal analysis proved that the thermal stability of the polymeric material decreases as a function of the monoglyceride content. Finally an attempt is made to correlate the thermal stability of the polymeric materials, with the degree of crystallinity.

Controlled Release of Food Lipids Using Monoglyceride Gel Phases Regulates Lipid and Insulin Metabolism in Humans

We describe a solid vegetable oil–water gel structure which is stabilized through the use of low concentrations of monoglycerides, containing no added trans fats or saturated fats. The resulting structure consists of oil droplets encapsulated in self-assembled crystalline monoglyceride multilayers, surrounded by a continuous water phase. Acute ingestion human feeding trials indicated that the serum triglyceride loading was significantly lower after ingestion of the structured gel rather than a simple oil–water mixture, resulting in an attenuated increase in serum insulin. This indicates the effectiveness of encapsulation in modulating blood lipid and insulin response in humans, and suggests a strategy that can be employed for the controlled release of food macronutrients.

Quantitative Solubility Relationships and the Effect of Water Uptake in Triglyceride/Monoglyceride Microemulsions

This paper aims to elucidate quantitative relationships between small molecule solubility/water-uptake in triglyceride/monoglyceride lipid formulations, the chemical structure of the solute, and the solvent composition. Solubility and water uptake in tricaprylin/1-monocaprylin and tricaprylin/1-monocaprin mixtures in the "microemulsion" region at 37 degrees C were determined with HPLC and KF coulometry, respectively. Twelve model solutes varying in hydrogen bond acidity, basicity, polarity, and molecular volume were chosen. Linear free energy relationships (LFER) (Abraham type) were implemented to obtain solvent coefficients at various monoglyceride concentrations. Profiles for both solubility and water uptake (at different water activities) in lipid mixtures containing different monoglycerides were superimposable, producing a single master curve when the monoglyceride concentrations were plotted on a molar scale. The LFER derived solvent coefficients showed a systematic dependence on the lipid composition consistent with the view that relative solubility is determined largely by the molar concentrations of individual functional groups such as glyceride ester moieties and hydroxyl groups. At low RH, water uptake increased linearly with monoglyceride concentration while cooperativity was evident in water uptake profiles at high RH. This study provides a potential universal framework for predicting relative drug solubility in mixtures containing fully saturated triglycerides and monoglycerides.

Effect of lecithin and monoglycerides on the heat stability of a model infant formula emulsion

The effect of two common emulsifiers, lecithin and monoglycerides, on the heat stability of a model infant formula emulsion was investigated. During homogenization the droplet diameter of the emulsion was more effectively reduced by monoglycerides than lecithin. The maximum in the heat coagulation time (HCT)-pH profile at 140 °C of the emulsion with no added emulsifier coincided with the unadjusted pH (∼6.8). Addition of lecithin (0–5 g l −1) progressively increased the maximum heat stability of the emulsion from 18 to 25 min and at 3–5 g l −1 slightly shifted the maximum in the HCT-pH profile to more acidic pH values. The addition of monoglycerides on the other hand decreased the heat stability; the emulsion containing 5 g l −1 had a maximum heat stability of 12 min. Particle size distribution and average particle diameter ( D[4,3]) measurements following heating confirmed that lecithin conferred stability to heat-induced aggregation while monoglyceride destabilized the emulsions. The zeta potential of oil droplets/particles in the emulsions became increasingly less negative with increasing monoglycerides concentration which is indicative of protein displacement; this may explain the low heat stability of the monoglyceride containing emulsions. The addition of lecithin on the other hand had no effect on zeta potential possibly because negatively charged lecithin replaced interfacial protein or interacted with interfacial protein. Progressively, less hydrophobic sites were available for binding of a hydrophobic probe as the concentration of either surfactant increased; interaction of surfactant with exposed hydrophobic regions of aqueous phase and/or interfacial protein is a possible explanation and this type of interaction may explain the high heat stability of lecithin containing emulsions.

The products from lipase-catalysed hydrolysis of bovine milkfat killHelicobacter pylori in vitro

Free fatty acids and monoglycerides released from milkfat by partial pregastric lipase-catalysed hydrolysis are bactericidal towards Helicobacter pylori. Two milkfat preparations were investigated: a normal bovine milkfat, and a fractionated milkfat preparation, termed ModFat, enriched in triglycerides containing short- and medium-chain fatty acids. The released products were tested for bactericidal potency against H. pylori. The potencies of the respective preparations were consistent with expected potencies calculated from individual free fatty acid and monoglyceride concentrations and their lauric acid equivalence factors (Ki). ModFat products were more bactericidal, in accordance with release of free fatty acid types of high potency, and addition of the surfactant Tween 80 to the hydrolysed lipid increased potency eight times more than did addition of lecithin. Tween 80 micelles have smaller aggregation numbers, and the mixed micelles of Tween 80/free fatty acids would be more likely to expose the bacteria to higher apparent free fatty acid concentrations.

Effect of Operating Conditions on the Concentration of Monoglycerides Using Molecular Distillation

In this work, one-factor-at-a-time experiments and factorial design were carried out in order to study the effect of operating conditions on the monoglycerides (MG) concentration using molecular distillation (MD) process in laboratory scale. Therefore, producers of distilled MG can use the results obtained here to optimize industrial plants. Firstly, a 2 4−1 factorial design was employed to select the most important operating variables of the process. Among the four variables studied, evaporator temperature (ET), feed flow rate (Q), feed temperature (FT) and condenser temperature (CT), just ET and Q are important at the experimental conditions studied. Furthermore, using empirical models and experimental data, it is shown the dependence of the outlet stream compositions to ET and Q, which were selected from the fractional factorial design.

Spreading of Monoglycerides onto β-Casein Adsorbed Film. Structural and Dilatational Characteristics

The effect of monoglycerides (monopalmitin and monoolein) on the structural, topographical, and dilatational characteristics of betacasein adsorbed film at the air-water interface has been analyzed by means of surface pressure (pi)-area (A) isotherms, Brewster angle microscopy (BAM), and surface dilatational rheology. The static and dynamic characteristics of the mixed films depend on the interfacial composition and the surface pressure. At surface pressures lower than that for the beta-casein collapse (at the equilibrium surface pressure of the protein, pi(e)(beta-casein)) a mixed film of beta-casein and monoglyceride may exist. At higher surface pressures the collapsed beta-casein is partially displaced from the interface by monoglycerides. However, beta-casein displacement by monoglycerides is not quantitative at the monoglyceride concentrations studied in this work. The protein displacement by a monoglyceride is higher for monopalmitin than for monoolein and for spread than for adsorbed films. The viscoelastic characteristics of the mixed films were dominated by the presence of beta-casein in the mixture. Even at the higher surface pressures (at pi > pi(e)(beta-casein)) the small amounts of beta-casein collapsed residues at the interface have a significant effect on the surface dilatational properties of the mixed films. The structural, topographical, and viscoelastic characteristics of the mixed films corroborate the fact that protein displacement for monoglycerides is higher for spread than for adsorbed mixed films.

The Effect of Monoglycerides on Structural and Topographical Characteristics of Adsorbed β-Casein Films at the Air−Water Interface

The effect of monoglycerides (monopalmitin and monoolein) on the structural and topographical characteristics of beta-casein adsorbed film at the air-water interface has been analyzed by means of surface pressure (pi)-area (A) isotherms and Brewster angle microscopy (BAM). At surface pressures lower than that for the beta-casein collapse (pi(c)(beta-casein)), attractive interactions between beta-casein and monoglycerides were observed. At higher surface pressures, the collapsed beta-casein is partially displaced from the interface by monoglycerides. However, beta-casein displacement by monoglycerides is not quantitative at the monoglyceride concentrations studied in this work. From the results derived from these experiments, we have concluded that interactions, miscibility, and displacement of proteins by monoglycerides in adsorbed mixed monolayers at the air-water interface depend on the particular protein-monoglyceride system, the interactions between film-forming components being higher for adsorbed than for spread films. The adsorbed films are more segregated than spread films, and both collapsed protein domains and monoglyceride domains in adsorbed films are smaller than for spread films.

Effects of a membrane-based soft purification process on olive oil quality

Because of the high temperatures applied in classical refining processes, many quantitative and qualitative changes occur in the chemical compositions of oils. This causes refined olive oil to lose many of its organoleptic and nutritional properties. Research has been carried out to ascertain the influence of a soft purification process, based on oil conditioning, to form micronic aggregates which were subsequently removed by a microfiltration operation. The quasi total acidity and the resulting soaps were removed in a single microfiltration step. The deacidified and filtered oils showed similar peroxide values and the variation of the specific extinction around 270 nm (Δ K) was slightly improved. The process lowered the monoglyceride contents up to 78% while the diglyceride contents were just slightly decreased. The various sterol components were also lowered (in the range 36–50%) upon treatment. Phenolics were the most affected components; reductions reached 93%. The partitioning of such components between the bulk triglyceridic medium and the aggregate phase are considered with regard to their properties. Despite the low operating temperature, the sensory evaluation of the deacidified and filtered oils still showed poor organoleptic characteristics.

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

Determination of monoglycerides, diglycerides, triglycerides and glycerol in fats by means of gel permeation chromatography [C‐VI 5b(02)

AbstractThe “Joint Committee for the Analysis of Fats, Oils, Fatty Products, Related Products and Raw Materials (GAFett)” has developed the following method for the determination of the content of monoglycerides, diglycerides, triglycerides and glycerol in fats and fat derivatives. It is intended to include this method in Section C, Chapter VI of the German Standard Methods.

Monoglyceride content in glycerides by means of gas chromatography

The “Joint Committee for the Analysis of Fats, Oils, Fatty Products, Related Products and Raw Materials (GAFett)” has developed the following method for the determination of the monoglyceride content in fats and fat derivatives. It is intended to include this method in Section C, Chapter VI of the German Standard Methods.

The antimicrobial properties of milkfat after partial hydrolysis by calf pregastric lipase

Studies on the kinetic characteristics of calf pregastric lipase (EC 3.1.1.3) have shown that it preferentially releases short chain fatty acids (SCFAs) from bovine milkfat. The released fatty acids form mixed micelle structures. The aim of this investigation has been to test whether hydrolysed milkfat is antimicrobial, and how the state of the emulsion alters the bactericidal or bacteriostatic effects. Partial hydrolysis of milkfat by pregastric lipase was carried out in two types of emulsion systems, containing either Triton X-100 or casein/lecithin, plus milkfat in citrate/phosphate buffer (pH 5.0–6.0). The concentrations and compositions of fatty acids were determined by gas chromatography. The minimum percentages of hydrolysed milkfat which affected growth and survival of selected Gram-positive and Gram-negative bacteria were measured. The bacterial experiments were repeated using pure fatty acids at similar concentrations. Lauric acid (C12:0) was found to be the most potent bactericidal fatty acid against Enterococcae (Gram-positive), and caprylic acid (C8:0) was the most potent against coliforms (Gram-negative). Use of Triton X-100 for milkfat emulsification provided a more compatible medium for studying bacterial growth in the hydrolysed milkfat than did use of casein/lecithin. The results also show that the antimicrobial effects of individual fatty acids released from hydrolysed milkfat were at least additive and suggest that hydrolysis of milkfat may be a significant factor in controlling growth of organisms imbibed with food in pre-weaned animals. The amount of pregastric catalyzed triglyceride hydrolysis in the digestive tract is sufficient to produce an antibacterial concentration of fatty acids and monoglycerides.

Whey Protein Isolate−Monoglyceride Mixed Monolayers at the Air−Water Interface. Structure, Morphology, and Interactions

The surface pressure (π)−area (A) isotherms and Brewster angle microscopy (BAM) of monoglyceride and whey protein isolate (WPI) mixed films spread on buffered water at pH 5 and 7 and at 20 °C were determined as a function of the mass fraction (X) of monoglyceride (monopalmitin or monoolein) in the mixture. From the X and π-dependence on excess area, free energy, collapse pressure, BAM images, and the evolution with π of the relative reflectivity (I) of BAM images, it was deduced that the structural characteristics, miscibility, and morphology of monoglyceride−WPI mixed films are very dependent on surface pressure and monolayer composition. The monolayer was more expanded as the monoglyceride concentration in the mixture was increased. Over the overall range of existence of the mixed film, the monolayer presents some heterogeneities. At higher π, after the WPI collapse, characteristic squeezing-out phenomena were observed. At the monoglyceride monolayer collapse, the mixed film was practically dominated by the presence of monoglyceride. However, some degree of interactions exists between monoglyceride and WPI in the mixed film, and these interactions are more pronounced as the monolayer is compressed at the highest surface pressures.