Preparation of interesterified plastic fats from fats and oils free of trans fatty acid

Rheological characterization and fouling deposition behavior of coconut cream emulsion at heat processing temperature range

Fouling deposition in the coconut cream emulsion (CCE) is considered a severe technical issue in the industry. Since the fouling deposition results from the heating effect on the CCE bulk, the heat-induced structural changes in the CCE bulk at different temperatures were rheologically investigated in the first part of this study. The second part applied different heat treatment conditions to investigate generated fouling deposition (GFD). Chemical composition, FTIR, and SEM imaging were used to explore GFDs thoroughly. The increase in viscosity and storage modulus (G') reflect such heat-induced changes over the experimental conditions. More structural changes were predicted at around ≥85°C, accompanied by a sharp increase in viscosity and (G'), which was associated with the gelation of CCE. The conformational transition, fat agglomeration in CCE bulk, generated fouling deposits (GFDs) were significant around 70°C. The chemical composition of the GFD has shown an increasing trend in the protein, carbohydrates, and ash, meanwhile fluctuation in the fat contents with increasing temperature. The FTIR peaks showed novel peaks around temperature ≥85°C, which implied new amide groups or new protein conformation. The SEM images provided the different microstructures of GFDs at high-temperature levels. More likely the GFDs appeared at temperature ≥85°C are a gel deposit layer. These findings strongly suggest that emulsion gelation was the primary cause of coconut cream fouling.

Chemical and physical properties of fats produced by chemical interesterification of tallow with vegetable oils

This study aims at manufacturing structured lipids by chemical interesterification (CI) of beef tallow with corn, canola and safflower oils individually at various tallow blend ratios (60, 70, 80%) and catalyst concentrations (0.75, 0.875, 1%). Several physical and chemical properties of interesterified products were determined and data were analyzed using univariate and multivariate statistical techniques. Interesterified lipids were more spreadable and showed plastic behavior due to their lower consistency and solid fat contents. Decreases in melting points to a temperature range of 26.5-45.5 °C regardless of oil type were observed. Interesterified fats displayed mostly β’ and β’+β crystal forms. The CI of tallow did not result in the formation of significant amounts of trans-fatty acids. Samples interesterified with corn oil had lower free fatty acid contents (1.87-3.9%) and higher oxidation induction times (3.82-12.25h) than other lipids. Therefore, fats containing corn oil-tallow could be used in the baking industry due to their potentially good aeration properties and smooth texture.

Regiospecific Positioning of Palmitic Acid in Triacylglycerol Structure of Enzymatically Modified Lipids Affects Physicochemical and In Vitro Digestion Properties

Tripalmitin-(PPP, 81.2%), 1,3-dipalmitoyl-2-oleoylglycerol-(POP, 64.4%), 1,2-dipalmitoyl-3-oleoylglycerol-(PPO, 86.5%), and 1,3-dioleoyl-2-palmitoylglycerol-(OPO, 50.2%)-rich lipids with different regiospecific positions of palmitic acid (P) were synthesized via acetone fractionation and lipase-catalyzed acidolysis, and their physicochemical and hydrolytic characteristics were compared. Triacylglycerols (TAGs) with higher content of P, wherein P was at the sn-1 (or 3) position, had higher melting points, crystallization temperatures, and packing densities of fat crystals compared to those with a lower content of P, and with P at the sn-2 position. The in vitro digestion degree calculated as released fatty acid (FA) (%) at 30, 60, and 120 min was in the following order: OPO-rich > PPO-rich > POP-rich lipids. At 120 min, in vitro digestion of the OPO-rich lipid released 92.6% of fatty acids, resulting in the highest digestibility, while 89.7% and 87.2% of fatty acids were released from the OPO-rich and PPO-rich lipids, respectively. Over the digestion period, the TAG and monoacylglycerol (MAG) contents decreased, while the diacylglycerol (DAG) content initially increased and then decreased, and the 1,2-DAG content exceeded the 1,3-DAG content. Therefore, the content and stereospecific position of P attached to a specific TAG affected the physicochemical and in vitro digestion characteristics of the lipids.

Addition of glyceryl monostearate affects the crystallization behavior and polymorphism of palm stearin

Low crystallization-rate and formation of crystalline clusters makes palm stearin unpopular in fat-based products especially in their post-processing stage. Addition of emulsifiers is commonly used to overcome these drawbacks, since they are believed to induce or stabilize specific polymorphs of palm stearin. Glyceryl monostearate (GMS) was applied in palm stearin (1%, 2%, and 4% w/w) in this study, and the mechanisms on crystallization of palm stearin were investigated by means of differential scanning calorimetry (DSC), X-ray diffraction (XRD), and polarized light microscopic (PLM) method. Data showed that GMS prompted the isothermal crystallization (15-30 °C) in a dose-dependent manner. Crystallization turned to low super-cooling sporadic nucleation at 30 °C. Besides, GMS led to an earlier onset of crystallization during cooling. GMS-palm stearin blends crystallized to form α polymorphs at first and subsequently underwent polymorphic transition to become β' polymorphs. Addition of 4% w/w GMS in palm stearin significantly decreased the size of crystals, which is helpful to reduce the grainy mouth feel of fat products in practice.

Production of trans-free interesterified fat using indigenously immobilized lipase

Enzymatic interesterification was carried out between high-oleic canola oil and fully hydrogenated soybean oil using indigenously immobilized Thermomyces lanuginosus lipas substrate concentration, moisture content of enzyme, and enzyme load. Interesterification resulted in a decrease in the concentration of tri-unsaturated and trisaturated TAG and an increase of mono- and di-saturated TAG as observed by reversed-phase HPLC. The alteration in TAG composition and the presence of new TAG species after interesterification was correlated with extended plasticity characterized by lower slip melting point with a significant change in functionality and consistency of the interesterified product. Thermal and structural properties of the blends before and after interesterification were assessed by differential scanning calorimetry (DSC), X-ray diffraction and polarized light microscopy. Trans-fat analysis indicated the absence of any trans fatty acid in the final interesterified product. The resultant interesterified products with varying slip melting points can be used in the formulation of healthier fat and oil products and address a critical industrial demand for trans free formulations for base-stocks of spreads, margarines, and confectionary fats.

Physico-chemical properties of Moringa oleifera seed oil enzymatically interesterified with palm stearin and palm kernel oil and its potential application in food

BACKGROUND

High oleic acid Moringa oleifera seed oil (MoO) has been rarely applied in food products due to the low melting point and lack of plasticity. Enzymatic interesterification (EIE) of MoO with palm stearin (PS) and palm kernel oil (PKO) could yield harder fat stocks that may impart desirable nutritional and physical properties.

RESULTS

Blends of MoO and PS or PKO were examined for triacylglycerol (TAG) composition, thermal properties and solid fat content (SFC). EIE caused rearrangement of TAGs, reduction of U3 and increase of U2 S in MoO/PS blends while reduction of U3 and S3 following increase of S2 U and U2 S in MoO/PKO blends (U, unsaturated and S, saturated fatty acids). SFC measurements revealed a wide range of plasticity, enhancements of spreadability, mouthfeel and cooling effect for interesterified MoO/PS, indicating the possible application of these blends in margarines. However, interesterified MoO/PKO was not suitable in margarine application, while ice-cream may be formulated from these blends. A soft margarine formulated from MoO/PS 70:30 revealed high oxidative stability during 8 weeks storage with no significant changes in peroxide and p-anisidine values.

CONCLUSION

EIE of fats with MoO allowed nutritional and oxidative stable plastic fats to be obtained, suitable for possible use in industrial food applications. © 2015 Society of Chemical Industry.

Trans-free margarine fat produced using enzymatic interesterification of rice bran oil and hard palm stearin

Trans-free interesterified fats were prepared from blends of hard palm stearin (hPS) and rice bran oil (RBO) at 20:80, 30:70, 40:60, 50:50, 60:40, 70:30, and 80:20 weight % using immobilized Mucor miehei lipase at 60°C for 6 h with a mixing speed of 300 rpm. Physical properties and crystallization and melting behaviors of interesterified blends were investigated and compared with commercial margarine fats. Lipase-catalyzed interesterification modified triacylglycerol compositions and physical and thermal properties of hPS:RBO blends. Slip melting point and solid fat contents (SFC) of all blends decreased after interesterification. Small, mostly β' form, needle-shaped crystals, desirable for margarines were observed in interesterified fats. Interesterified blend 40:60 exhibited an SFC profile and crystallization and melting characteristics most similar to commercial margarine fats and also had small needle-like β' crystals. Interesterified blend 40:60 was suitable for use as a transfree margarine fat.

Heterogeneous interesterification of triacylglycerols catalyzed by using potassium-doped alumina as a solid catalyst

Heterogeneous interesterification of vegetable oils offers an environmentally more attractive option for the modification of edible oils to meet the specifications for certain food applications. In this work, potassium-doped alumina (KNO3/Al2O3) was prepared using an impregnation method, followed by calcinations at a temperature of 700 °C, and was then employed as heterogeneous catalysts for the interesterification of triacylglycerols. The solid catalyst was characterized by means of Hammett titration method, power X-ray diffraction, scanning electron microscopy, and nitrogen adsorption-desorption techniques. It was determined that the catalyst with KNO3 loading of 35% on alumina support and calcined at 700 °C exhibited the best catalytic activities toward the interesterification between soybean oil and methyl stearate under solvent-free conditions. Also, the solid base catalyst was successfully applied to the interesterification of soybean oil and lard blends in a heterogeneous manner. The physicochemical properties of the interesterified products were investigated using gas chromatography, high-performance liquid chromatography, and confocal laser scanning microscopy. It was found that the slip melting point and crystal morphology had a significant variation after the interesterification reaction as a result of the modification in the TAG profile. With the solid base catalyst, an environmentally friendly approach for the interesterification of triacylglycerols in a heterogeneous manner was developed.

Preparation of low calorie structured lipids catalyzed by 1,5,7-triazabicyclo[4.4.0]dec-5-ene(TBD)-functionalized mesoporous SBA-15 silica in a heterogeneous manner

1,5,7-Triazabicyclo[4.4.0]dec-5-ene (TBD, a strong bicyclic guanidine base) functionalized SBA-15 material has been found to be an efficient solid catalyst for the interesterification between tributyrin and methyl stearate in a solvent-free system for the production of low-calorie structured lipid (LCSL). The solid base catalyst was characterized by using small-angle X-ray scattering, Fourier transform infrared spectra, thermo gravimetric analysis, scanning electron microscopy, transmission electron microscopy, nitrogen adsorption-desorption, and elemental analysis techniques. The obtained LCSL was analyzed by reverse-phase high-performance liquid chromatography for triacylglycerol composition. The influence of various reaction parameters, such as the substrate ratio, reaction temperature, and reaction time, on the interesterification reaction was investigated systematically. More than 90% LCSL was obtained at 80 °C within 1 h when the methyl stearate/tributyrin molar ratio of 2:1 was employed. The obtained solid catalyst could be recovered easily and reused for several recycles with a negligible loss of activity. By using the solid base catalyst, an eco-friendly more benign process for the interesterification reaction in a heterogeneous manner was developed.

Interesterification of soybean oil and lard blends catalyzed by SBA-15-pr-NR₃OH as a heterogeneous base catalyst

A novel heterogeneous SBA-15-pr-NR₃OH catalyst has been prepared by reactions of dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride with mesoporous SBA-15 materials. The solid base catalysts were characterized by using Fourier transform infrared spectra, thermogravimetric analysis, nitrogen adsorption-desorption, and elemental analysis techniques. By using the solid catalyst, an environmentally benign process for the interesterification of soybean oil and lard blends in a heterogeneous manner was developed. The interesterification was investigated regarding the slip melting point (SMP), iodine value (IV), triacylglycerols (TAGs) profile, fatty acid composition at the sn-2 position in TAGs, and differential scanning calorimetry (DSC). The obtained results revealed that the solid base catalyst was capable of catalyzing TAG interesterification. It was shown that interesterification significantly modified the physicochemical properties of the oil and fat blends. The interesterified products had lower SMPs than their corresponding physical blends. These changes in melting behaviors were mostly due to the alterations in TAG compositions. The DSC cooling and melting thermograms showed an obvious change in thermal properties after the interesterification reaction.

Cloning, sequencing, and characterization of lipase genes from a polyhydroxyalkanoate (PHA)-synthesizing Pseudomonas resinovorans

Lipase (lip) and lipase-specific foldase (lif) genes of a biodegradable polyhydroxyalkanoate (PHA)-synthesizing Pseudomonas resinovorans NRRL B-2649 were cloned using primers based on consensus sequences, followed by polymerase chain reaction-based genome walking. Sequence analyses showed a putative Lip gene product (314 amino acids, a.a.) with its catalytic active site (Ser(111), Asp(258), and His(280)) identified. The foldase lif gene that is located 55 bp downstream of lip codes for a putative Lif (345 a.a.). To verify the biological function of the cloned lip gene for lipase expression in P. resinovorans, we constructed a lip knock-out mutant (lip::Tn5<KAN-2>) by transposon insertion. Complementation of the lip knock-out P. resinovorans mutant with a lipase expression plasmid (pBS29-P2-lip) was performed, and its effect on lipase expression was investigated. The wild-type P. resinovorans and the lip::Tn5<KAN-2>[pBS29-P2-lip] recombinant (but not the lip::Tn5<KAN-2> mutant) showed fluorescence on rhodamine B plates indicative of lipase activity. The wild type exhibited extracellular lipase activity when grown on medium containing triacylglycerol substrates (tallow, olive oil, and tributyrin) as sole carbon sources, but the lip::Tn5<KAN-2> mutant did not show such activity. Lipase activity of various strains was also confirmed by TLC analysis of the composition of acylglycerols and free fatty acid in the extracts of the spent culture medium. We further found that tributyrin was more effective than olive oil in inducing lipase expression in P. resinovorans.

Characterization of graininess formed in all beef tallow-based shortening

A batch of all beef tallow (BT)-based model shortening (divided into six rectangular block samples) was stored under temperature fluctuation cycles of 5-20 °C until granular crystals were observed. The lipid composition, thermal properties, and polymorphism of the granular crystals and their surrounding materials were evaluated. Furthermore, the isothermal crystallization behavior of two parts noted above was also examined by pulsed nuclear magnetic resonance (pNMR), rheology, and polarized light microscopy (PLM). The changes of nanostructure including the aggregation of high-melting triacylglycerols (TAGs) and transformation into the most stable β polymorph occurred in granular crystals compared with surrounding materials. Concomitantly, a slower crystallization rate with a simultaneous increase in crystal growth led to the formation of large crystals and further aggregated to larger granular crystals when the size ultimately exceeded the sensory threshold.

Production of trans-free margarine stock by enzymatic interesterification of rice bran oil, palm stearin and coconut oil

BACKGROUND

Trans-free interesterified fat was produced for possible usage as a spreadable margarine stock. Rice bran oil, palm stearin and coconut oil were used as substrates for lipase-catalyzed reaction.

RESULTS

After interesterification, 137-150 g kg(-1) medium-chain fatty acid was incorporated into the triacylglycerol (TAG) of the interesterified fats. Solid fat contents at 25 degrees C were 15.5-34.2%, and slip melting point ranged from 27.5 to 34.3 degrees C. POP and PPP (beta-tending TAG) in palm stearin decreased after interesterification. X-ray diffraction analysis demonstrated that the interesterified fats contained mostly beta' polymorphic forms, which is a desirable property for margarines.

CONCLUSIONS

The interesterified fats showed desirable physical properties and suitable crystal form (beta' polymorph) for possible use as a spreadable margarine stock. Therefore, our result suggested that the interesterified fat without trans fatty acid could be used as an alternative to partially hydrogenated fat.