Development and characterization of antioxidant-fortified oleogels by encapsulating hydrophilic tea polyphenols.

The application of hydrophilic compounds in lipid systems was limited due to their poor solubility. In this study, antioxidant-fortified oleogels containing hydrophilic antioxidants tea polyphenols (TP) were developed. The hydrophilic TP was encapsulated in glyceryl monostearate (GMS) to form TP gelling agents, which successfully made TP uniformly dispersed in oleogels. The lipophilic curcumin was directly dissolved in soybean oil to distribute in oleogels. Oxidative stability experiments showed that the addition of TP greatly improve the oxidative stability of oleogels. Compared to curcumin, TP played a particularly stronger antioxidant effect, indicating that hydrophilic antioxidants had promising applications in oleogels. In addition, the synergistic value was calculated to confirm that there was a certain synergistic effect between these two antioxidants. This study initiated a method to uniformly disperse hydrophilic antioxidants in oleogels, providing an effective solution for the construction of lipid products loaded with hydrophilic bioactive ingredients.

Crystallization and phase behavior in mixture systems of anhydrous milk fat, palm stearin, and palm oil: Formation of eutectic crystals.

The comparison between the crystallization and phase behavior of binary blends of anhydrous milk fat (AMF)/palm stearin (POs) and POs/palm oil (PO) was investigated. POs/POs blends showed good compatibility, while the compatibility of AMF/POs blends showed no ideal and was dominated by eutectic behavior. And the eutectic growth of blends was found to be a phenomenon that the triacylglycerol (TAG) of AMF grew on the peripheral of POs seed crystals. In binary blends, the addition of POs not only increased the liquid phase transition temperature but also induced the formation of ß crystal forms in more than 70% POs. The addition of soybean oil to binary blends could improve the compatibility of the ternary system. It eventually provided potential formulations for the production of non-hydrogenated puff pastry margarine.

Crystallization behavior and compatibility analysis of beef tallow-based binary/ternary fat mixture systems.

Crystallization behavior and compatibility of fat blend systems are closely related to the stability fat food. The graded binary and ternary blends of beef tallow (BT), palm oil (PO), and soybean oil (SO) were comprehensively analyzed, including lipid composition, phase behavior, crystallization behavior, solid fat content (SFC), and compatibility. It was found that, unlike the monotectic behavior of BT/SO blends, BT/PO blends were dominated by eutectic behavior, while all the binary blends exhibited ß' polymorph. The addition of BT in the binary blends not only increased the liquid phase transition temperature but also played a more important role in the SFC variation at 0-40 °C. The eutectic growth behavior of blends might be that the TAG component of PO grew on the peripheral of BT seed crystals. In addition, BT/PO/SO ternary blends showed good compatibility and ß' polymorph. Our results provide potential formulations for beef tallow-based shortening production.

Comparation of micro-viscosity of liquid oil in different colloidal fat crystal networks using molecular rotors.

Micro-viscosity is an important parameter to describe the microenvironment of the fat crystal network. In this study, we evaluated the micro-viscosity of the liquid oil confined in mixtures of palm kernel stearin (PKS)/soybean oil (SO) and fully hydrogenated rapeseed oil (FHRSO)/SO using molecular rotors. The micro-viscosity was shown to increase with solid fat content (SFC), as well as with high proportion of triglycerides that crystallized and formed stronger linked networks. In addition, the thickness of nanocrystals decreased with the increase of solid fat and denser fat crystal network appeared with larger box-counting fractal dimension. Mathematic fit analysis further indicated that molecular confinement of the oil was strongly dependent on the microstructure with high-space filling colloidal fat crystal networks. Larger box-counting fractal dimension led to higher micro-viscosity. However, the critical box-counting fractal dimension was found to be 1.86 irrespective of the nature of the network.

Oleogels from sodium stearoyl lactylate-based lamellar crystals: Structural characterization and bread application.

Sodium stearoyl lactylate (SSL) was used as a gelling agent to structure oleogels at concentrations of 7%, 9%, 11%, and 13% (w/w) with sunflower oils in this study, respectively. The physical characteristics of oleogels, such as solid fat content (SFC), oil bonding capability (OBC) and firmness, were influenced by SSL crystals. Therefore, the microstructure and interaction of oleogels was further investigated by polarizing light microscopy (PLM), X-ray diffraction (XRD), rheology, differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FTIR). It was found that the higher concentration of oleogelator resulted in a denser crystalline network, which provided stronger mechanical strength and enhanced the ability to retain the oil phase. Space-spanning networks were attributed to surface interactions among crystals of SSL, such as van der Waals interactions and electrostatic repulsion. Crystal network in the SSL oleogels imitated the typical functionality of crystalline network structures formed by triacylglycerol.

Improvement Motor Imagery EEG Classification Based on Regularized Linear Discriminant Analysis.

Mental tasks classification such as motor imagery, based on EEG signals is an important problem in brain computer interface systems (BCI). One of the major concerns in BCI is to have a high classification accuracy. The other concerning one is with the favorable result is guaranteed how to improve the computational efficiency. In this paper, Mu/Beta rhythm was obtained by bandpass filter from EEG signal. And the classical linear discriminant analysis (LDA) was used for deciding which rhythm can give the better classification performance. During this, the common spatial pattern (CSP) was used to project data subject to the ratio of projected energy of one class to that of the other class was maximized. The optimal projection dimension was determined corresponding to the maximum of area under the curve (AUC) for each participant. Eventually, regularized linear discriminant analysis (RLDA) is possible to decode the imagined motor sensed using electroencephalogram (EEG). Results show that higher classification accuracy can be provided by RLDA. And optimal projection dimensions determined by LDA and RLDA are of consistent solution, this improves computational efficiency of CSP-RLDA method without computation of projection dimension.

Comparative analysis of graded blends of palm kernel oil, palm kernel stearin and palm stearin.

A comprehensive analysis of graded binary and ternary blends of palm kernel oil (PKO), palm kernel stearin (PKS) and palm stearin (POs) was conducted, including solid fat content, iso-solid diagram, thermal properties, polymorphism and microstructure. Both PKO/POs and PKS/POs blends showed eutectic behavior. While PKO/PKS blends displayed good compatibility and only slightly monotectic effect at high temperature (above 30 °C). POs addition elevated binary phase transition temperature and accelerated the ß crystal formation. PKO/POs and PKS/POs binaries showed ß' polymorphism, ß and ß' polymorphism, and ß polymorphism with different POs additions, while all of PKO/PKS blends showed ß' polymorphism. Ternary blends (PKO/PKS/POs) showed eutectic effects, especially at high temperature (25 and 30 °C). POs addition made ternary blends undergo a polymorphism transformation from ß' to ß. Our findings open up the possibility of non-hydrogenated fat products as well as develop specific food formulations.

Structural and mechanical behavior of colloidal fat crystal networks of fully hydrogenated lauric acid-rich fats and rapeseed oils mixtures.

The effects of lipid composition, crystallization temperature, Solid fat content (SFC), microstructure on the rheological properties of blends of fully hydrogenated palm kernel oil (FHPKO) or fully hydrogenated coconut oil (FHCNO) with rapeseed oil (RSO) in the range of 20-100% were investigated using small and large deformation rheology. The variation of chemical composition, crystallization temperature (5-30 °C), SFC of the blends resulted in different rheological properties. Shear modulus was positive correlation with the content of saturated fatty acid of the sample. The storage modulus (G') and yield force increased with the addition of FHPKO or FHCNO and were dramatically influenced by SFC and crystallization temperature. The values of G' in FHPKO/RSO blends were higher than those of corresponding FHCNO/RSO blends. Combined analysis of SFC and microstructure related to rheological behavior revealed that smaller average crystal diameter, higher SFC and higher fractal dimension led to higher storage modulus of fat crystal networks.

Visualized phase behavior of binary blends of coconut oil and palm stearin.

The graded blends of coconut oil (CNO) and palm stearin (POs) phase behavior was studied in the present work, by using pulsed nuclear magnetic resonance (p-NMR), differential scanning calorimetry (DSC) and X-ray scattering (XRD). The kinetic phase diagram which was fitting to DSC data by polynomial equation (R > 0.95), indicated that the CNO-POs binary blends displayed monotectic behavior. The CNO-POs binary system displayed immiscible solid structures (ß and ß' polymorphism) with the addition of POs in the range of 10-60%, beyond which it showed miscible solid structures (ß polymorphism), respectively. Moreover, the presence of POs could elevate the liquid phase transition temperature and transform ß' polymorph into ß. These variations in phase behavior were reflected in the morphology of the binary blends. Our findings not only broaden the application of CNO and POs with novel attributes, but also direct the production of high quality non-hydrogenated fat-containing products.

Influence of indigenous minor components on fat crystal network of fully hydrogenated palm kernel oil and fully hydrogenated coconut oil.

Purification of triglycerides from fully hydrogenated palm kernel oil (FHPKO) and fully hydrogenated coconut oil (FHCNO) was performed by a chromatographic method. Lipid composition, thermal properties, polymorphism, isothermal crystallization behaviour, nanostructure and microstructure of FHPKO, FHPKO-triacylglycerol (TAG), FHCNO and FHCNO-TAG were evaluated. Removal of minor components had no effect on triglycerides composition. However, the presence of the minor components did increase the slip melting point and promote onset of crystallization. Furthermore, the thickness of the nanoscale crystals increased, and polymorphic transformation from ß' to ß occurred in FHPKO after the removal of minor components, and from α to ß' in FHCNO. Sharp changes in the values of the Avrami constant K and exponent n suggested that the presence of minor components changed the crystal growth mechanism. The PLM results indicated that a coarser crystal structure with lower fractal dimension appeared after the removal of minor components from both FHPKO and FHCNO.

Non-triglyceride components modulate the fat crystal network of palm kernel oil and coconut oil.

PKO and CNO are composed of 97-98% triacylglycerols and 2-3% minor non-triglyceride components (FFA, DAG and MAG). Triglycerides were separated from minor components by chromatographic method. The lipid composition, thermal properties, polymorphism, isothermal crystallization behavior, nanostructure and microstructure of PKO, PKO-TAG, CNO and CNO-TAG were evaluated. Removal of minor components had no effect on lipid composition and equilibrium solid fat contents. However, presence of minor components did increase the slip melting point and promoted the onset of crystallization from DSC crystallization profiles. The thickness of the nanoscale crystals increased with no polymorphic transformation after removing the minor components. Crystallization kinetics revealed that minor components decreased crystal growth rate with higher t1/2. Sharp changes in the values of the Avrami constant k and exponent n were observed for all fats around 10°C. Increases in n around 10°C indicated a change from one-dimensional to multi-dimensional growth. From the results of polarized light micrographs, the transformation from the coarser crystal structure to tiny crystal structure occurred in microstructure networks at the action of minor components.

Comparative Analysis of Small-Molecule Diffusivity in Different Fat Crystal Network.

Oil migration and fat recrystallization in fat-structured food materials can result in significant deterioration in food quality. Consequently, it is important to monitor and quantify the diffusivities of the migrants in fat crystal network. The diffusion coefficients of Nile red dye in liquid oils through fully hydrogenated palm kernel oil (FHPKO)/triolein (OOO) and fully hydrogenated soybean oil (FHSO)/triolein (OOO) systems were evaluated by the fluorescence recovery after photobleaching (FRAP) method. The effective diffusion coefficients (Deff) and mobile fraction (Mf) increased with the decrease of solid fat contents (SFC), with the changes of microstructure from more densely to slightly larger packed clusters for both FHPKO/OOO and FHSO/OOO systems. In addition, microstructural parameters of these systems were estimated by the image analysis. The results showed that the diffusion of dye and liquid oil was affected by the microstructure. The higher Deff was associated with lower fractal dimensions, larger crystal thickness, and larger average particle sizes. Finally, higher-permeability coefficients were calculated according to Darcy's Law, and it was significantly correlated to the Deff.

Fat crystal migration and aggregation and polymorphism evolution during the formation of granular crystals in beef tallow and palm oil.

Six rectangular block all beef tallow (BT)-based and all palm oil (PO)-based model shortenings prepared on a laboratory scale, denoted BTMS and POMS, respectively, were stored under two storage conditions, (1) constant temperatures (5 and 20 °C, respectively and (2) temperature fluctuations (5 °C for 12 h and 20 °C for 12 h for a cycle), to induce granular crystals. The fat crystal migration and aggregation, sensory evaluations, and polymorphism evolutions during the formation of granular crystals in the above samples were investigated systematically. In comparison to the constant temperature storage, the crystal growth and hierarchical aggregation process were more quick and the conversion rate of the ß-form crystal was also faster in both BTMS and POMS under temperature cycling storage and, concomitantly, easier to induce the formation of granular crystals. From the comprehensive analysis of crystal sizes and the sensory evaluation results, it can be concluded that the detection threshold for graininess ranged from 40 to 90 µm, with the smaller size being perceived only at higher crystal concentrations. The possible formation mechanism and the realistic control approaches for granular crystals in plastic fats also are clarified in the present study.

Enzymatically catalyzed synthesis of anti-blooming agent 1,3-dibehenoyl-2-oleoyl glycerol in a solvent-free system: optimization by response surface methodology.

Products rich in 1,3-dibehenoyl-2-oleoyl glycerol (BOB) triglyceride (TAG) were produced by enzymatic interesterification of high oleic acid sunflower oil (HOSO) and behenic acid methyl ester (BME) by 1,3-regiospecific lipase Lipozyme RM IM in a solvent-free system. The impact factors of enzyme load, substrate molar ratio of BME to HOSO (BME/HOSO), reaction time, reaction temperature, and pre-equilibration water activity of the enzyme on BOB content and BME conversions were investigated by single-factor experiments and then optimized using the response surface methodology (RSM). The optimum conditions were as follows: reaction temperature, 72 °C; reaction time, 7.99 h; substrate molar ratio, 2.5:1; enzyme load, 10%; and pre-equilibration water activities of the enzyme, 0.28. The results from the experiments conducted according to the predicted optimal conditions were as follows: the content of BOB was 32.76%, and the conversion of BME was 65.16%. The experimental values agreed with the predicted values, which verified the sufficiency of the quadratic regression models. After purification under the optimal short-range molecular distillation and two-step solvent fractionation, the content of BOB in the target product can reach 77.14%, indicating the great potential for industrial production of the anti-blooming agent.

Comparative analysis of lipid composition and thermal, polymorphic, and crystallization behaviors of granular crystals formed in beef tallow and palm oil.

Six rectangular block all beef tallow (BT)-based and all palm oil (PO)-based model shortenings prepared on a laboratory scale, respectively denoted BTMS and POMS, were stored under temperature fluctuation cycles of 5-20 °C until granular crystals were observed. The lipid composition and thermal, polymorphic, and isothermal crystallization behaviors of the granular crystals and their surrounding materials separated from BTMS and POMS, respectively, were evaluated. The changes of nanostructure including the aggregation of high-melting triacylglycerols (TAGs) and polymorphic transformation from ß' form of double chain length structures to complicated crystal structures, in which the ß and ß' form crystals of triple and double chain length structures simultaneously coexist, had occurred in granular crystals compared with surrounding materials, whether in BTMS or in POMS. Consequently, a slower crystallization rate appeared in granular crystal parts of both model shortenings noted above, which would yield larger and fewer crystals indicated by the Avrami model analysis that would further aggregate to form large granular crystals.