Commercial Monoglycerides Research Articles

Effect of monoglyceride on crystallization behavior and physical properties of cottonseed oil stearin

Slow crystallization-rate, low SFC and nonuniform mushy texture at ambient temperature hinder the application of cottonseed oil stearin (COS) in plastic fat products. Adding emulsifiers is usually used to overcome these drawbacks by modifying the crystallization of COS. In this study, different levels of commercial monoglycerides (MGs) were added to the COS, and the crystallization behavior, crystal microstructure and physical properties of the COS/MG were investigated. The addition of MGs promoted the crystallization of the COS significantly, modified the crystal subcell structure of COS and contributed to the development of the co-crystalliaztion of MG and the high melting point TGs of COS. A new crystal cluster (sphere-shaped and compact crystal clusters) was observed in COS/MG blends, which might have a relation with the co-crystallization of MG and high melting triglycerides (TGs) of COS. With the increase of MG level in the COSs, the crystalline network become denser. Further, the SFC and the rheological properties (including the viscoelasticity, the resistance to heat and shear force) of COS/MG blends improved by adding MG. The possible crystallization mechanisms were proposed to understand the effects of MG on the crystallization microstructure and rheological properties of COS.

Study of rapeseed oil gelation induced by commercial monoglycerides using a chemometric approach

Commercial oleogelators rich in monoglycerides (MGs) are complex mixtures of acylglycerides with variable gelling properties, depending on the oil used and their concentration. In this study we developed a chemometric approach to identify the key parameters involved in gelling process. Analytical parameters have been defined, using GC and NMR analysis to identify fatty acids and acylglycerides composing the mixtures. Specific acylglyceride families and compound ratios were calculated to streamline the analytical results. To determine the key analytical parameters, artificial neural networks were used in a QSPR study related to the gelling properties measured by rheology through oscillatory experiments. At low oleogelator concentrations, the MGs especially rich in C16:0 and the ratio of specific isomers both have a positive influence on G′. For high oleogelator concentrations, C18:0-rich acylglycerides and unsaturated/saturated fatty acid ratios have a positive influence on G′. Conversely, at low concentrations, C18:0-rich acylglycerides show a lesser effect on G′.

Vegetable and Mineral Oil Organogels Based on Monoglyceride and Lecithin Mixtures

We investigated the development of vegetable (VO) and mineral (MO) oil organogels using mixtures of a commercial monoglycerides (MGC) and saturated lecithin (LC). The MGC (2% wt/wt) and LC (0.25% to 2.5% wt/wt) concentrations used in the MGC-LC mixtures were below the minimal gelator concentrations in the oils. At the corresponding MolesMGC/MoleLC studied (1.5, 4.0, 7.6, and 15.3) we achieved the development of well-structured organogels in both oils. The highest elasticity (G’) of the MGC-LC organogels was achieved in each type of oil at different MolesMGC/MoleLC. Thus, in the MO we obtained the highest G’ at the lowest MolesMGC/MoleLC (i.e., the highest %LC) and in the organogels with the highest solid fat content (%SC). In contrast, in the VO we obtained the highest G’ at 15.3 MolesMGC/MoleLC (i.e., at the lowest %LC) corresponding to the organogels with the lowest %SC. This behavior suggested that a solvent dependent synergistic effect existed between the MGC and the LC. Additional experiments showed that the addition of water (2.5% to 10% of water/total mass of gelator) resulted in organogels with higher G’, particularly in the 1.5 MolesMGC/MoleLC organogels developed in the MO. The DSC and X-ray results showed that in the MGC-LC organogels the Lα to β polymorphic transition was limited, and thus the MGC-LC organogels did not show phase separation even after 12 months of storage at 15 °C. This behavior was accentuated in MGC-LC organogels developed in presence of water. Therefore, the use of MGC-LC systems open the possibility of developing organogels at lower concentrations than the concentration needed just by the use of monoglyceride. Additionally, the MGC-LC organogels achieve higher G’ with elastic recovery properties, and longer stability against phase separation than MGC organogels. This, particularly in the 1.5 MolesMGC/MoleLC organogels developed in MO with at least 5% of water/total mass of gelator.

Effects of Monoglycerides of Varying Fatty Acid Chain Length and Mixtures Thereof on Sponge‐and‐Dough Breadmaking Quality

Monoglycerides are widely used in the baking industry because of their antistaling effects, mainly suppressing crumb firming. Commercial monoglycerides are normally prepared from hydrogenated fats, with stearate being the most common fatty acid. In a previous study, monoglycerides such as monopalmitate (C16) and monostearate (C18) had positive effects on Canadian short process bread but no improvements on sponge‐and‐dough process (SDP) bread. The objective of this study was to investigate the effects of saturated monoglycerides of varying fatty acid chain length (C14–C22) on SDP breadmaking quality by using volume judgment, crumb image analysis, and texture measurements. Higher levels (1.00–1.50%) of all monoglycerides (C14, C16, and C18) significantly (P < 0.05) increased loaf volume and cell diameter. The larger cell diameter with increasing levels of these monoglycerides may have resulted from softer, more extensible dough handling properties and greater gas cell stability during baking. Addition of C16 and C18 caused the largest increase in crumb softness with increasing monoglyceride levels but showed relatively low resilience, which might be related to larger loaf volume (i.e., lower density of bread). However, addition of blended monoglycerides C14+C16 increased crumb softness and loaf volume while partially retaining resilience. Each monoglyceride had a different function in breadmaking quality and somewhat positive effects on SDP.

Monoglyceride organogels developed in vegetable oil with and without ethylcellulose

We used two commercial monoglycerides (MGs) with different composition (SKB, ≈79% glycerol monostearate and ≈12% glycerol monopalmitate; PKB, ≈47% glycerol monostearate and 47% glycerol monopalmitate) to develop organogels [2% and 8% (wt/wt) MG content]. The objective was to investigate the effect of shearing (SH) and the presence of 6% ethylcellulose (EC) as factors to limit the sub-α to β polymorphic transition of MG, and the subsequent crystals agglomeration that results in deleterious effect on the organogel's mechanical and oil-binding properties. The results showed that under static conditions (ST) both type of MG developed organogels (OG), but their structure, measured as the complex modulus (G*), was weak particularly in the organogels formulated with PKB at 2%. Nevertheless, the OG-ST had higher strength and lower oil loss than the OG-SH. The X-ray analysis showed that the use of shear during organogelation reduced the time at which the sub-α to β polymorphic transition occurred in both the SKB and the PKB oleogels. Additionally, shearing seemed to hinder the formation of well-organized microplatelet structure, and from there the lack of gelation in the 2% OG-SH and the higher oil loss of the 8% OG-SH compared with their static counterparts. Independent of the concentration of SKB and PKB, the presence of EC resulted in organogels with higher G* than that for OG-ST without EC. This, in spite the EC concentration used was below the critical concentration for vegetable oil gelation. The results showed that EC slowed the rate for the sub-α to β polymorphic transition in the MG organogels. Thus, irrespective of the type of MG and the concentration used, during 14days of storage at 15°C the OG-EC systems showed a lower oil loss as a function of time than the corresponding organogels developed without EC. This was particularly evident in the organogels formulated with SKB and those formulated with 8% of MG. We suggest that EC limits the molecular mobility in the MG organogels, and therefore, slows the sub-α to β polymorphic transition and the subsequent β crystals' agglomeration. The results showed that there is a synergistic interaction between MG and EC that result in organogels with higher viscoelastic properties and lower oil loss than those observed in MG-organogels without EC.

Comparing the crystallization and rheological behavior of organogels developed by pure and commercial monoglycerides in vegetable oil

We investigated the crystallization and rheological behavior of organogels developed with commercial (MSGC) and pure (MSGP) monoglycerides in safflower oil solutions (0.5% to 8% wt/wt). The MSGC was composed of 1-mono-stearoyl-glycerol (1-MSG, 37.7%) and 1-mono-palmitoyl-glycerol (1-MPG, 54.0%), and the MSGP essentially by 1-MSG (93.51%). The elastic (G′) and loss (G″) moduli of the MSGC and MSGP–oil solutions were measured from 80°C until achieving 5°C, and then during isothermal conditions. The d(G′)/d(time) rheograms, where d(G′)/d(time) is the difference in G′ between subsequent time–temperature conditions during cooling, followed closely the phase transition observed by the monoglycerides (MG). The d(G′)/d(time) profile showed that the formation of the inverse lamellar α mesophase provided a limited structure to the vegetable oil. In contrast, the crystallization of the sub-α phase in the MSGC-oil system, and of the sub-α1 and sub-α2 phases in the MSGP-oil system structured the vegetable oil through the uptake and retention of oil within their microstructure. Additionally, smaller crystals formed the three-dimensional crystal structure in the MSGC organogels. This is in comparison with the larger crystal size observed in MSGP organogels. Nevertheless, for a similar MG concentration the MSGC organogels showed higher G′ and solid fat content (SFC) than the MSGP organogels, and the differences were greater as the MG concentration increased. We consider that the mixed sub-α structure developed by 1-MSG and 1-MPG in the MSGC-oil systems favored the incorporation and retention of higher amounts of oil, in comparison with the sub-α1 and sub-α2 structures developed just by 1-MSG in the MSGP-oil systems.

Comparing the crystallization and polymorphic behaviour of saturated and unsaturated monoglycerides

The crystallization and melting behaviour of pure monoglyceride standards and two types of commercial monoglycerides were analyzed by differential scanning calorimetry (DSC) and X-ray diffraction (XRD). Firstly, a series of saturated monoglycerides, ranging from monolaurin to monobehenin, were analyzed by DSC using a specific temperature program to obtain a complete image of the crystallization behaviour and polymorphism. The different crystallization and melting peaks were characterized by wide angle X-ray diffraction (WAXD) and small angle X-ray scattering (SAXS). Three polymorphic forms (sub-α, α and β) could be discerned for the shorter chain length saturated monoglycerides, while a second sub-α polymorph was observed for the longer chain length samples. Secondly, unsaturated monoglyceride standards were analyzed using the same methodology. These results reveal a less complex behaviour with the occurrence of only one polymorph. Finally, the analysis of two commercial monoglycerides revealed the importance of minor components for the crystallization of unsaturated monoglycerides.

Liquid Crystalline Phases in the Structuring of Food Products

It has been explored whether liquid crystalline phases of surfactants and water would offer opportunities for the development of low-calorie food products. Commercial monoglycerides and esters of monoglycerides are used as nonionic and anionic surfactants, respectively. Such mixtures allow the incorporation of large amounts of water in a liquid crystalline lamellar phase. On cooling, this phase transforms into a so-called α-gel state, with a remarkable ointment-like consistency. In turn, the α-gel may transform into a crystalline coagel state with a more fat-like consistency, which also is able to incorporate large amounts of water. The characteristics of these gel phases and their transformation have been investigated. The transformation appears to be a rather slow process which can be influenced by thermal, mechanical or chemical treatments. Shear and temperature increase, in general, enhance the transition rate. For proper gel formation the amounts of nonionic and anionic surfactants and of salt and pH have to be matched carefully. Addition of compounds such as other surfactants or biopolymers, in general, retards the transition process. Electrostatic interactions between added proteins and the bilayer in the lamellar phase strongly stabilize the α-gel state. Coagel and α-gel phases can be used as main components in low-calorie food products. Both phases show a different functionality, in particular with respect to firmness and foaming characteristics. Applications are discussed.

Emulsifying Properties of Whey Protein and Casein Composite Blends

Fluid emulsions containing 30% fat were produced with various ratios of casein and whey protein. The effects of adding commercial monoglycerides to the oil phase and of heat treating protein solutions before emulsion formation were also investigated. Interfacial pressure and protein load determination both indicated preferential adsorption of casein over whey proteins. The addition of monoglycerides reduced the amount of protein adsorbed, except for emulsions produced from heated protein solutions containing high proportion of whey protein, for which an increasing trend was observed. Resistance to stirring-induced coalescence decreased with an increasing proportion of whey in the mixture except for emulsions from heated pure whey protein solution with added monoglycerides, which improved the resistance. Emulsions containing casein showed extensive creaming and coalescence upon storage. Heat treatment reduced creaming and coalescence but induced slight sedimentation. Monoglycerides were also effective in reducing coalescence of emulsions containing casein. Pure whey protein emulsions showed no coalescence but considerable creaming upon storage. Creaming was inhibited by heating whey protein solution, which produced viscous emulsions. Conflicting results between stirring-induced coalescence and storage coalescence suggest important changes in membrane properties during storage.

Quantitative Determination of Mono- and Diglycerides with and without Derivatization by Capillary Supercritical Fluid Chromatography

Abstract Mono- and diglycerides, as well as commercial monoglyceride emulsifiers, were analyzed by capillary supercritical fluid chromatography (SFC). Carbon dioxide without modifier was used as the mobile phase in the chromatography. Samples were prepared by simply being dissolved in solvents or by propionyl ester derivatization. A capillary SFC methyl silicone column (SB-methyl 100, 100 μm X 10 m, 0.5 μm film thickness, Lee Scientific) was used for the separation, and a flame ionization detector was used for the detection. A calibration standard containing known concentrations of monomyristln, monopalmitin, monostearin, dimyristin, dlpalmitin, and distearin were used for the determination of the response factor (unit weight per peak area) of each analyte. The response factors were used in the quantitation of the analytes in the test samples from their respective integrated peak areas. Monomyristin was used as an internal standard for the quantitation of monoglycerides In commercial emulsifiers. The accuracy of the methods was demonstrated by comparing the percent area (%A) determined by the chromatography with the percent weight (%W) of each of the components in the standard mixture, and the precision of the methods was indicated by the relative standard deviation (RSD). The mean ratio and RSD of %A/%W were 0.98 ± 0.09 (<5%) and 1.01 ± 0.03 (<2.5%) for underlvatized and derivatized samples, respectively. Two lots of commercial monoglyceride emulsifiers were analyzed with and without derivatization, and the results were compared to those obtained by gas chromatography (GC). 7-tests comparing the method means did not indicate any significant mean differences (95% confidence level) between the GC and SFC methods. Nor did the variance ratio F-test indicate that the overall variances of the methods were significantly different. However, the error variance of the SFC-underivatized method was significantly higher than that of the GC and SFCderivatized methods. These results demonstrated the feasibility of applying the SFC technology in the analysis of monoand diglycerides with and without derivatization

Influence of temperature‐induced phase transitions on fat emulsions

AbstractThe polymorphic behavior of a commercial monoglyceride emulsifier together with a liquid vegetable oil and water has been investigated by means of microscopic examination and differential scanning calorimetry. The results show that the stability regions of the liquid crystalline phases formed are highly dependent on the temperature and related both to the solubility of the monoglyceride emulsifier in the oil phase and to its polymorphic behavior. The formation and stability of emulsions are discussed in connection with the results obtained.

Continuous deglycerination of monoglycerides

AbstractA relationship was established between the smoke point of a superglycerinated shortening and free glycerol content. A maximum free glycerol content of 0.02% was established for smoke points of 340F or better.Based on a 6% usage in emulsifier type shortening, commercial monoglycerides should have 0.30% glycerol or less to meet a desirable smoke point. A 2‐stage extraction with 5% NaCl solution reduced free glycerol from 5.51% to 0.14%.A continuous process was developed for removing glycerol from commerical monoglyceride preparations with a thin‐film, evaporator. Operation at 340F and 6 mm Hg absolute pressure with stripping steam reduced glycerol content to 0.3%. Analysis showed substantially no monoglyceride reversion under process conditions, and considerable improvement in flavor and odor was obtained.

Appraisal of methods of total monoester estimation in commercial monoglycerides

AbstractAnalytical techniques of estimating total monoglycerides in industrial products and difficulties encountered in their estimation are critically discussed. A modification is suggested of a recently published procedure which combines the “Partition method” with the methods of Martin and of Brokawet al. A tentative method of determining total monoglycerides based on simultaneous isomerization and periodate oxidation is described.

The β‐monoester content of commercial monoglycerides after prolonged storage

AbstractThe technique of determining ‘total’ and β‐monoglycerides by isomerisation with perchloric acid has been re‐examined and slightly modified to improve the reproducibility of results. The content of β‐monoglycerides in commercial monoglyceride preparations stored for 1 1/2–5 years has been found to be in the range of 5–9% of the total monoglycerides. This is contrary to a recent report that β‐monoglycerides are present in freshly prepared products only and disappear on prolonged storage.

Urea complexes of technical monoglycerides

SummaryTechnical monoglycerides have been fractionated with urea in methyl alcohol. Complexes were formed more easily with diglycerides than with monoglycerides as shown by Bradley, Mueller, and Shokal and contrary to the observation of Heckles and Dunlap. Further, in stepwise crystallization of commercial monoglycerides, there was no methanolysis of the monoglycerides as observed by Aylward and Wood.

Separation of monoglycerides, diglycerides, and triglycerides by liquid‐liquid extraction

SummaryTernary‐equilibrium data were obtained at 60°C. for mono‐ and dilaurin, and di‐ and trilaurin with aqueous alcohols. Distribution between phases and solvent selectivity are shown graphically. Variation of solvent polarity by water addition caused a shift in the phase boundary curve so that either Type 1 or Type 2 diagrams could be obtained.Pure mono‐, di‐, and trilaurin mixtures, and commercial monoglycerides were studied as quaternary systems for monoglyceride distribution with 50 wt.‐% aqueous ethanol. Pure and commercial systems showed similar distribution tendencies even with differences in molecular weight and degree of unsaturation.Solvent selectivity data (β) for quaternary systems were predicted from ternary systems studied with a common solvent.Aqueous ethanol will separate mixtures of mono‐, di‐, and triglycerides by selective liquid‐liquid extraction; however the literature favors more complex systems based on two immiscible solvents.Continuous countercurrent extraction of commercial monoglycerides by 40% aqueous ethanol solution in a four‐stage agitated column gave a 15% over‐all stage efficiency. Cooling the extract to 0°C. precipitated 96.6% of the extract solids.Flow diagrams were prepared for batch and continuous extraction processes.

The countercurrent distribution of pure monoglycerides and some related substances

Conclusions The countercurrent distribution curves have been determined for eight pure and one commercial monoglyceride, one diglyceride, and one diglycerol monoester. Certain generalities exist between the partition coefficients and the structures of the acid radicals of the monoglyceride. An increase in the chain length of the acid produces an increase in the partition coefficient. The 2‐monoesters have lower partition coefficients than the corresponding 1‐isomers. Unsaturation in the acid decreases the value of the partition coefficient. The direct separation of mixtures of 1‐ and 2‐monoglycerides by countercurrent distribution is thwarted by the rapid isomerization of the 2‐isomer to the 1‐form.

The most concentrated commercial monoglycerides

the most concentrated commercial monoglycerides