The stearin fraction of palm-based diacylglycerol (PDAGS) was produced from dry fractionation of palm-based diacylglycerol (PDAG). Bakery shortening blends were produced by mixing PDAGS with either palm mid fraction, PMF (PDAGS/PMF), palm olein, POL(PDAGS/POL) or sunflower oil, SFO (PDAGS/SFO) at PDAGS molar fraction of XPDAGS=0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%. The physicochemical results obtained indicated that C16:0 and C18:1 were the dominant fatty acids for PDAGS/PMF and PDAGS/POL, while C18:1 and C18:2 were dominant in the PDAGS/SFO mixtures. SMP and SFC of the PDAGS were reduced with the addition of PMF, POL and SFO. Binary mixtures of PDAGS/PMF had better structural compatibility and full miscibility with each other. PDAGS/PMF and PDAGS/SFO crystallised in β'+β polymorphs in the presence of 0.4-0.5% PDAGS while PDAGS/POL resulted in β polymorphs crystal. The results gave indication that PDAGS: PMF at 50%:50% and 60%:40% (w/w) were the most suitable fat blend to be used as bakery shortening.
Palm oil (PO ; iodin value = 52), palm stearin (POs1; i.v. = 32 and POs2; i.v. = 40) and palm kernel oil (PKO; i.v. = 17) were blended in ternary systems. The blends were then studied for their physical properties such as melting point (m.p.), solid fat content (SFC), and cooling curve. Results showed that palm stearin increased the blends melting point while palm kernel oil reduced it. To produce table margarine with melting point (m.p.) below 40 degrees C, the POs1 should be added at level of < or = 16%, while POs2 at level of < or = 20%. At 10 degrees C, eutectic interaction occur between PO and PKO which reach their maximum at about 60:40 blending ratio. Within the eutectic region, to maintain the SFC at 10 degrees C to be < or = 50%, POs1 may be added at level of < or = 7%, while POs2 at level of < or = 12%. The addition of palm stearin increased the blends solidification Tmin and Tmax values, while PKO reduced them. Blends which contained high amount of palm stearin showed melting point and cooling curves quite similar to that of pastry margarine.
A sensitive and rapid reversed-phase ultra performance liquid chromatographic (UPLC) method for the simultaneous determination of tocopherols (α-, β-, γ-, δ-), tocotrienols (α-, β-, γ-, δ-), α-tocopherol acetate and α-tocopherol nicotinate is described. The separation was achieved using a Kinetex pentafluorophenyl (PFP) column (150 × 2.1mm, 2.6 µm) with both photodiode array (PDA) and fluorescence (FL) detectors that were connected in series. Column was thermostated at 42°C. Under a gradient system consisting of methanol and water at a constant flow rate of 0.38 mL min(-1), all the ten analytes were well separated in less than 9.5 min. The method was validated in terms of linearity, limits of detection and quantitation, precision and recoveries. Calibration curves of the ten compounds were well correlated (r(2)>0.999) within the range of 100 to 25,000 μg L(-1) for α-tocopherol acetate and α-tocopherol nicotinate, 10 to 25,000 μg L(-1) for α-tocotrienol and 5 to 25,000 μg L(-1) for the other components. The method is simple and sensitive with detection limits (S/N, 3) of 1.0 to 3.0 μg L(-1) (FL detection) and 30 to 74 μg L(-1) (PDA detection). Relative standard deviations for intra- and inter-day retention times (<1%) and peak areas (≤ 4%) were obtained. The method was successfully applied to the determination of vitamin E in vegetable oils (extra virgin olive, virgin olive, pomace olive, blended virgin and refined olive, sunflower, soybean, palm olein, carotino, crude palm, walnut, rice bran and grape seed), margarines and supplements.
The ability of palm oil (PO) to crystallize as beta prime polymorph has made it an attractive option for the production of margarine fat (MF). Palm stearin (PS) expresses similar crystallization behavior and is considered one of the best substitutes of hydrogenated oils due to its capability to impart the required level of plasticity and body to the finished product. Normally, PS is blended with PO to reduce the melting point at body temperature (37 °C). Lipid phase, formulated by PO and PS in different ratios were subjected to an emulsification process and the following analyses were done: triacylglycerols, solid fat content (SFC), and thermal behavior. In addition, the microstructure properties, including size and number of crystals, were determined for experimental MFs (EMFs) and commercial MFs (CMFs). Results showed that blending and emulsification at PS levels over 40 wt% significantly changed the physicochemical and microstructure properties of EMF as compared to CMF, resulting in a desirable dipalmitoyl-oleoyl-glycerol content of less than 36.1%. SFC at 37 °C, crystal size, crystal number, crystallization, and melting enthalpies (ΔH) were 15%, 5.37 μm, 1425 crystal/μm(2), 17.25 J/g, and 57.69J/g, respectively. All data reported indicate that the formation of granular crystals in MFs was dominated by high-melting triacylglycerol namely dipalmitoyl-oleoyl-glycerol, while the small dose of monoacylglycerol that is used as emulsifier slowed crystallization rate. Practical Application: Most of the past studies were focused on thermal behavior of edible oils and some blends of oils and fats. The crystallization of oils and fats are well documented but there is scarce information concerning some mechanism related to crystallization and emulsification. Therefore, this study will help to gather information on the behavior of emulsifier on crystallization regime; also the dominating TAG responsible for primary granular crystal formations, as well as to determine the best level of stearin to impart the required microstructure properties and body to the finished products.
Blends of palm stearin (PS), palm kernel oil (PKO) and soybean oil (SBO) at certain proportions were formulated using a mixture design based on simplex-lattice (Design Expert 8.0.4 Stat-Ease Inc., Minneapolis, 2010). All the 10 oil blends were subjected to chemical interesterification (CIE) using sodium methoxide as the catalyst. The solid fat content (SFC), triacylglycerol (TAG) composition, thermal properties (DSC), polymorphism and microstructural properties were studied. Palm-based trans-free table margarine containing ternary mixture of PS/PKO/SBO [49/20/31 (w/w)], was optimally formulated through analysis of multiple isosolid diagrams and was found to have quite similar SMP and SFC profile as compared to the commercial table margarine. This study has shown chemical interesterification are effective in modifying the physicochemical properties of palm stearin, palm kernel oil, soybean oil and their mixtures.
Optimum processing conditions on palm oil-based formulations are required to produce the desired quality margarine. As oils and fats contribute to the overall property of the margarine, this paper will review the importance of beta' tending oils and fats in margarine formulation, effects of the processing parameters -- emulsion temperature, flow-rate, product temperature and pin-worker speed -- on palm oil margarines produced and their subsequent behaviour in storage. Palm oil, which contributes the beta' crystal polymorph and the best alternative to hydrogenated liquid fats, and the processing conditions can affect the margarine consistency by influencing the solid fat content (SFC) and the types of crystal polymorph formed during production as well as in storage. Palm oil, or hydrogenated palm oil and olein, in mixture with oils of beta tending, can veer the product to the beta' crystal form. However, merely having beta' crystal tending oils is not sufficient as the processing conditions are also important. The emulsion temperature had no significant effect on the consistency and polymorphic changes of the product during storage, even though differences were observed during processing. The consistency of margarine during storage was high at low emulsion flow-rates and low at high flow rates. The temperature of the scraped-surface tube-cooler is the most important parameter in margarine processing. High temperature will produce a hardened product with formation of beta-crystals during storage. The speed of the pin-worker is responsible for inducing crystallization but, at the same time, destroys the crystal agglomerates, resulting in melting.
Inter-esterification is one of the processes used to modify the physico-chemical characteristics of oils and fats. Inter-esterification is an acyl-rearrangement reaction on the glycerol molecule. On the other hand, hydrogenation involves addition of hydrogen to the double bonds of unsaturated fatty acids. Due to health implications of trans fatty acids, which are formed during hydrogenation, the industry needs to find alternatives to hydrogenated fats. This paper discusses some applications of inter-esterified fats, with particular reference to inter-esterified palm products, as alternatives to hydrogenation. Some physico-chemical properties of inter-esterified fats used in shortenings are discussed. With inter-esterification, more palm stearin can be incorporated in vanaspati. For confectionary fats and infant formulations, enzymatic inter-esterification has been employed.
A capillary electrophoresis (CE)-capacitively coupled contactless conductivity detection (C(4)D) method for the simultaneous separation of eleven underivatized fatty acids (FAs), namely, lauric, myristic, tridecanoic (internal standard), pentadecanoic, palmitic, stearic, oleic, elaidic, linoleic, linolenic and arachidic acids is described. The separation was carried out in normal polarity mode at 20 °C, 30 kV and using hydrodynamic injection (50 mbar for 1 s). The separation was achieved in a bare fused-silica capillary (70 cm × 75 μm i.d.) using a background electrolyte of methyl-β-cyclodextrin (~6 mM) and heptakis-(2,3,6-tri-O-methyl)-β-cyclodextrin (~8 mM) dissolved in a mixture of Na2HPO4/KH2PO4 (5 mM, pH 7.4):ACN:MeOH:n-octanol (3:4:2.5:0.5, v/v/v/v). C(4)D parameters were set at fixed amplitude of 100 V and frequency of 1000 kHz. The developed method was validated. Calibration curves of the ten FAs were well correlated (r(2)>0.99) within the range of 5-250 μg mL(-1) for lauric acid, and 3-250 μg mL(-1) for the other FAs. The method was simple and sensitive with detection limits (S/N=3) of 0.9-1.9 μg mL(-1) and good relative standard deviations of intra- and inter-day for migration times and peak areas (≤9.7%) were achieved. The method was applied to the determination of FAs in margarine samples. The proposed method offers distinct advantages over the GC and HPLC methods, especially in terms of simplicity (without derivatization) and sensitivity.