Fully Hydrogenated Canola Oil Research Articles

Encapsulation of water-in-oil emulsion droplets within crystal spheroids

Model water-in-oil emulsions were shear-crystallized to produce crystal spheroid-encapsulated droplets. The bulk oil phase was composed of canola oil (CO), fully-hydrogenated canola oil (FHCO), and different emulsifiers: glycerol monostearate (GMS), glycerol monopalmitate (GMP), glycerol monooleate (GMO), sorbitan monostearate (SMS), or polyglycerol polyricinoleate (PGPR). Emulsions were prepared using a rotor-stator and then further shear-crystallized using a rheometer with a parallel plate geometry. The efficacy of water droplet encapsulation was dependent on emulsifier type, with the glycerol-based emulsifiers (GMS, GMP, and GMO), due to their molecular similarity with the crystallizing phase (FHCO), producing smooth-surfaced crystal spheroid shells while SMS produced irregularly-shaped crystal shells and droplet cores. PGPR-based emulsions did not exhibit droplet encapsulation due to the emulsifier's large molecular difference to the crystallizing phase. Analysis of viscosity profiles, thermal behavior, and X-ray diffraction revealed that the addition of an aqueous phase did not significantly affect crystal polymorphism. These results serve as a foundation for the development of novel emulsions systems for use in industries where effective water droplet encapsulation is necessary for optimum product performance.

Encapsulation of Vitamin B2 in solid lipid nanoparticles using supercritical CO2

Solid lipid nanoparticles (SLN) are spherical particles prepared from solid fats, which can be used as delivery systems by encapsulating bioactives. In this study, particles from gas-saturated solutions (PGSS) were produced by a modified process, using fully hydrogenated canola oil (FHCO) to encapsulate Vitamin B2, a hydrophilic bioactive. Four operating parameters were studied in terms of their influence on encapsulation efficiency, bioactive load and particle size: pressure (10.0–25.0MPa), Vitamin B2 concentration (0.25–2%, w/w), surfactant (sodium lauryl sulfate, SLS) concentration (1–7.5%, w/w) and stabilizer (polyethylene glycol, PEG) molecular weight (2,000–35,000Da). The optimal conditions were determined as 15.0MPa, 2% Vitamin B2, 5% SLS and 35,000Da PEG, resulting in an encapsulation efficiency of 12±0.03%, bioactive load of 0.54±0.05mg/g and bimodal particle size distribution with a main peak at 104±5.7nm, showing that it is possible to generate nano-scale solid lipid particles with a high content of a hydrophilic bioactive; however, further fine tuning is needed.

Spheroidal Fat Crystals: Structure Modification via Use of Emulsifiers

Emulsifiers were used to modify the kinetics of formation and morphology of spheroidal fat crystal assemblies generated via the confined gap shear-cooling of model fat systems consisting of fully hydrogenated canola oil (FHCO), canola oil (CO), and glycerol monostearate (GMS), glycerol monopalmitate (GMP), sorbitan monostearate (SMS), or sorbitan tristearate (STS). The presence and morphology of spheroidal fat crystals were dependent on emulsifier type and concentration, with GMS, GMP, and SMS significantly reducing spheroid size at lower concentrations and causing deformation of the crystals into irregular and elongated shapes at higher concentrations. STS significantly hindered the formation of spheroidal crystals and instead promoted globular crystalline assemblies. Thermal analysis and X-ray diffraction revealed that samples crystallized primarily into the β′ polymorph along with a smaller amount of α polymorph. The ratio of α to β′ polymorphs generally increased with emulsifier concentration and imposition of higher laminar shear rates, suggesting the importance of two phenomena: (i) shear may influence the interactions between triacylglycerols at a molecular level, affecting the type of nanoplatelets formed and their interactions to form crystallites and subsequent crystals, and (ii) the extent of shear (rate/duration) may affect the rate and/or amount of emulsifier incorporated into triacylglycerol crystal lattices. Overall, these results demonstrated that fat crystal structures may be tailored with the combined use of emulsifiers and laminar shear.

Enhancing the Stability of Lipid Nanoparticle Systems by Sonication during the Cooling Step and Controlling the Liquid Oil Content

Aggregation of unstable particles in water limits the application of lipid nanoparticle (LNP) systems to foods despite the capability to encapsulate lipophilic bioactive components. This study exploits a preparation process that can reduce the aggregation of LNPs. Sonication during the cooling step (postsonication) for 4, 5, or 6 min was applied to increase the covering effect of Tween 20 on the particle. Additionally, LNPs were prepared using fully hydrogenated canola oil (FHCO) blended with 0-30 wt % liquid canola oil (LCO) of the lipid phase. Surfactant surface load data indicate that the postsonication might make nonemulsifying Tween 20 diffuse from the aqueous phase to droplet surfaces, which could decrease the crystallinity index (CI) of LNPs due to the inhibition of lipid crystallization. Moreover, the LCO content in lipid matrix could decrease the CI, which could reduce the formation of hydrophobic patches on the particle surface. Therefore, the postsonication and the LCO addition in the matrix could effectively prevent aggregation among hydrophobic patches. This improved colloidal stability of LNPs was verified by the particle shape in transmission electron microscopy and the gelation test. Consequently, LNPs fabricated using 6 min postsonication and 30 wt % LCO in the lipid exhibited the greatest stability (size, 202.3 nm; CI, 57.5%; Tween 20 surface load, 10.29 mg m(-2)). This study may serve as a basis for further research that aims to develop delivery systems for functional foods.

Spheroidal Fat Crystal Microstructures Formed with Confined Gap Shearing

Confined gap shear-cooling was used to structure a model solid fat/liquid oil system consisting of fully hydrogenated canola oil (FHCO) and canola oil (CO). Samples were cooled at various cooling rates (0.2–5.0 °C/min) and shear rates (0, 500, 1000, and 2000 s–1) and characterized via polarized light microscopy and rheology. In the absence of shear (0 s–1), FHCO crystallized into an aggregated network of spherulites. Upon shearing, HCO crystallized into distinct spheroids whose size and structure were dependent on the cooling and shear rates used as well as crystallization duration and temperature. Lower shear rates resulted in larger, more irregularly shaped spheroids, whereas with higher shear rates these were more numerous and smaller. The simultaneous action of cooling and shear was required for spheroid formation, with shear having a greater impact. A mechanism was proposed to identify the multiple steps involved in the formation of the spheroids. Overall, these results demonstrated that it is possible to tailor the aggregation behavior of individual fat crystals toward novel morphologies that may be used to control fat crystal network microstructure and rheology.

Performance of two immobilized lipases for interesterification between canola oil and fully-hydrogenated canola oil under supercritical carbon dioxide

The performance and stability of Lipozyme RM IM and TL IM for the interesterification between canola oil and fully-hydrogenated canola oil (FHCO) in the presence of SCCO2 were studied using a high pressure batch stirred reactor at 65 °C/17.5 MPa. The influence of exposure time (4, 8, and 12 h) in SCCO2 and pressurization/depressurization cycles of up to 12 times on the enzyme's resultant activity were studied. There was no significant difference (p > 0.05) in the performance of the two enzymes over reaction time, reaching a constant degree of interesterification of about 23% after 2 h. Although FE-SEM images illustrated some morphological changes on the surface of the enzymes after 4 cycles of 7 h each, similar degrees of interesterification were achieved after each cycle. However, the amount of reaction intermediates decreased by 50–60% in the product obtained by using SCCO2-treated enzymes after 12 pressurization/depressurization cycles compared to untreated enzymes, while there were no significant changes in the conformational and morphological structure of the treated enzymes based on FTIR and FE-SEM analysis. Findings enhance our understanding of enzymatic conversions of lipids under high pressure CO2, targeting production of base-stock for zero-trans margarines.

Characterization of Enzymatically Interesterified Canola Oil and Fully‐Hydrogenated Canola Oil Blends Under Supercritical CO2

AbstractBlends of canola oil and fully‐hydrogenated canola oil (FHCO) containing 10, 30, and 50 wt% FHCO were interesterified enzymatically using Lipozyme TL IM (6 % of initial substrates, w/v) under supercritical CO2 at 10 MPa and 65 °C for 2 h. Changes in polymorphic behavior and crystal morphology of non‐interesterified initial blends (NIB) and purified enzymatically interesterified products (PEIP) were studied using X‐ray diffraction spectroscopy (XRD) and polarized light microscopy. As well, the effects of blend ratio and enzymatic interesterification on rheological behavior were investigated. XRD analysis demonstrated the predominance of α form in FHCO while blending it with canola oil induced the formation of β form after crystallizing the samples at 24 and 5 °C for 12 h. Enzymatic interesterification caused the appearance of β′ forms and dramatically changed crystal morphology. The PEIP samples contained fewer crystal particles compared to NIB, but the crystals were more symmetrical. The elastic modulus (solid‐like behavior) (G′) was lower in NIB with 30 wt% FHCO compared to the one with 50 wt% FHCO. Enzymatic interesterification also had a strong effect on G′ of the samples as it decreased after interesterification. The results of this study will help the development of conversion technologies under supercritical conditions in order to formulate more healthy fats having appropriate functional properties to address the industrial demand for the production of margarine and pastry shortenings.

Lipase-catalysed interesterification between canola oil and fully hydrogenated canola oil in contact with supercritical carbon dioxide

The processing parameters in enzymatic reactions using CO2-expanded (CX) lipids have strong effects on the physical properties of liquid phase, degree of interesterification, and physicochemical properties of the final reaction products. CX-canola oil and fully hydrogenated canola oil (FHCO) were interesterified using Lipozyme TL IM in a high pressure stirred batch reactor. The effects of immobilised enzyme load, pressure, substrate ratio and reaction time on the formation of mixed triacylglycerols (TG) from trisaturated and triunsaturated TG were investigated. The optimal immobilised enzyme load, pressure, substrate ratio and time for the degree of interesterification to reach the highest equilibrium state were 6% (w/v) of initial substrates, 10MPa, blend with 30% (w/w) of FHCO and 2h, respectively. The physicochemical properties of the initial blend and interesterified products with different FHCO ratios obtained at optimal reaction conditions were determined in terms of TG composition, thermal behaviour and solid fat content (SFC). The amounts of saturated and triunsaturated TG decreased while the amounts of mixed TG increased as a result of interesterification. Thus, the interesterified product had a lower melting point, and broader melting and plasticity ranges compared to the initial blends. These findings are important for better understanding of CX-lipid reactions and for optimal formulation of base-stocks of margarine and confectionary fats to meet industry demands.

Serial connection of packed-bed reactors with different reaction temperatures: enhanced operational stability for enzymatically interesterified trans-free lipid production

A packed-bed enzyme reactor (PBER) system using immobilized lipase was successfully developed for the continuous production of trans-free interesterified oil with fully hydrogenated canola oil (FHCO) and soybean oil. Optimal interesterification conditions were established by determining the effects of reaction temperature, flow rate, and substrate weight ratio on conversion degree. It was found out that flow rate had a significant effect on conversion degree. Optimal conditions were as follows: FHCO concentration, 38.2 %; flow rate, 0.4 mL/min; and reaction temperature, 81.4 °C. Predicted and experimental conversion degrees were 89.5 and 87.1 %, respectively. The operational stability of the immobilized lipase and conversion degree using the serially connected PBER was higher than a single PBER. The adjustment of the interesterification conditions made possible to produce the interesterified oils having various melting range. This study demonstrates that a multi-stage PBER system can be used to enzymatically produce trans-free interesterified oils with various polymorphic properties.

Density and volumetric expansion of carbon dioxide-expanded canola oil and its blend with fully-hydrogenated canola oil

Physical properties of lipids in equilibrium with high pressure carbon dioxide are influenced by CO2 solubility in the liquid lipid phase, which is a strong function of temperature and pressure. The experimental data of CO2 solubility in canola oil at 40 and 70°C and its blend with fully-hydrogenated canola oil (FHCO) (30wt%) at 70°C up to 25MPa were correlated using Peng–Robinson and modified Soave–Redlich–Kwong equations of state with quadratic and Panagiotopoulos–Reid mixing rules. The relative volumetric expansion of canola oil at 40°C up to 20MPa and 70°C up to 25MPa and its blend with FHCO (30wt%) at 70°C up to 25MPa in equilibrium with CO2 was 41, 46, and 43%, respectively. The densities of canola oil at 40, 55, and 70°C and its blend with FHCO at 70°C in equilibrium with CO2 were measured up to 30MPa and increased by 4.7, 4.3, 3.5, and 3.6% of its value at atmospheric pressure, respectively. The density of CO2-expanded lipids increased with pressure and decreased with temperature. Physical properties of CO2-saturated lipids are important for designing high pressure processes and especially here for better understanding of enzymatic interesterification of canola oil and FHCO using supercritical CO2, since these physical properties influence the reaction rates due to changes in mass transfer.

Cooling rate and dilution affect the nanostructure and microstructure differently in model fats

AbstractThe effects of cooling rate and solid mass fraction on the polymorphism, nano and microstructure, thermal and rheological properties of binary mixtures of fully hydrogenated canola oil and canola oil at 20°C have been studied. The β‐polymorph was observed in fully hydrogenated canola oil (FHCO) when crystallized at slow cooling rates (0.1C°/min), however crystallization at higher cooling rates (0.7 and 10°C/min) resulted in the formation of the α form. The β‐polymorph was detected in all the binary mixtures of FHCO/canola oil and was not affected by crystallization at different cooling rates. Melting thermograms obtained from 100% FHCO displayed three melting peaks, associated with the development of the β‐polymorph via α→ β′→ β‐polymorphic transition in the DSC pan. Some solubilization of solid FHCO into canola oil was observed and the solubility was proportionally higher with increasing liquid oil fraction. The strong influence of the matrix concentration on micro/nanoscale structure was demonstrated by characterization of crystal size using cryogenic transmission electron (Cryo‐TEM) and polarized light microscopy (PLM). Crystallization under higher cooling rates lead to formation of smaller nano and meso‐structural elements. Furthermore, oscillatory rheology showed the influence of structural elements' size and polymorphism on material strength. The shear storage modulus (G′) of the mixtures was higher when crystallized at fast cooling rates (10°C/min). In contrast, for pure FHCO, G′ increased by lowering the cooling rate and the highest storage modulus was observed after crystallization at 0.1°C/min.

Quantification of oil binding capacity of structuring fats: A novel method and its application

A robust, well-defined and reproducible method to accurately measure the oil binding capacity (OBC) of structuring fats was developed. The method was validated using two oil/fat model systems, i.e., fully hydrogenated canola oil (FHCO) in canola oil (CO) (FHCO/CO) and fully hydrogenated soybean oil (FHSO) in CO (FHSO/CO). The mixtures were crystallized from the melt down to three different temperatures (15, 25 and 35 °C) at constant rates of cooling and the OBC was measured after different periods of storage time. The critical concentration of hard fat at which the solid fat network is stable and effectively binds oil has been also measured for mixtures crystallized at temperatures close to room temperature, i.e., 25 °C. Crystal structure, melting behavior, microstructure, and solid fat content of these binary systems have been investigated in relation to the OBC of the solid fat network using X-ray diffraction (XRD), differential scanning calorimetry (DSC), polarized light microscopy (PLM), and wide-line pulsed nuclear magnetic resonance (pNMR) techniques. The two model systems exhibited similar trends in OBC over time, a behavior attributed to their similar TAG composition and polymorphism. However, relatively smaller OBC values were achieved by the CO/FHSO compared to CO/FHCO samples, largely due to differences in their solid network structure. Four successive decreasing linear segments, identifying successive mechanisms of oil migration/binding, were observed in the experimental OBC versus fat weight fraction curves. The critical concentration of hard fat, at which the solid fat network is effective in binding oil, was also determined and found to be ∼6 wt% for both systems.

Structural and Mechanical Behavior of Tristearin/Triolein-rich Mixtures and the Modification Achieved by Interesterification

The effects of chemical and enzymatic interesterification on the structure and rheological behavior of blends of fully hydrogenated canola oil (FHCO) with high oleic acid sunflower oil in the range of 10–90% was studied. Relationships between chemical composition, crystallization temperature (20–50°C), solid fat content (SFC) of the blends, and their rheological properties, characterized using both small and large deformation mechanical testing, were investigated. The storage modulus (G′) and yield force increased with FHCO concentration in the blends and was affected strongly by interesterification. The SFC in the interesterified samples was lower than in the non-interesterified blends, but they had higher values of G′. This increase in G′ at 30°C upon interesterification was attributed to a decrease in the fractal dimension of the fat crystal network which translates into a decrease in crystal cluster size in the interesterified samples. The higher G′ in the chemically interesterified samples relative to the enzymatic interesterified samples, on the other hand, was due to a higher λ parameter which is directly proportional to the strength of interparticle interactions and inversely proportional to crystal size. Microscopy and nucleation kinetics studies allowed for the independent determination of λ.