Physicochemical and Oxidative Changes in Sonicated Interesterified Soybean Oil

The effect of power ultrasound on physicochemical properties and oxidative stability of an interesterified soybean oil (IESBO) was investigated. IESBO was crystallized at 32 °C and sonicated for 10 s with acoustic power of 101 W. The sonicated IESBO was tested for melting behavior and chemical composition and compared to those of non sonicated IESBO to determine physical and chemical changes originated as a consequence of sonication. Application of power ultrasound affected the melting behavior of the crystallized fat and did not affect its chemical composition. Oxidation stability of the sonicated IESBO was measured using peroxide value (PV) and compared to that of non sonicated IESBO and liquid soybean oil (SBO) when stored at 25 °C for 105 days followed by storage at 40 °C for 42 days. Power ultrasound did not cause accelerated oxidation in SBO or IESBO until they were highly oxidized (PV > 10 mequiv/kg). At high levels of oxidation, non‐sonicated IESBO had significantly higher PV than sonicated IESBO, while non‐sonicated SBO had significantly lower PV than sonicated SBO.     

Sonocrystallization of Interesterified Soybean Oil With and Without Agitation

Interesterified soybean oil was crystallized at 29, 34, and 35 °C with and without the use of high‐intensity ultrasound. Samples were crystallized using either (1) continued agitation for the entire crystallization process (CA) or (2) agitation for 10 min (A10) followed by static crystallization. Sonication and agitation decreased the induction period of nucleation at higher temperatures and changed the crystal morphology, crystallization kinetics, and viscoelasticity of the sample. Sonication reduced the crystal sizes and significantly (P <0.05) increased the viscosity (5.2 ± 1.2 to 2369.6 ± 712.1 Pa s) and elastic modulus (83.2 ± 4.1 to 69,236.7 ± 26,765 Pa) of the crystalline networks obtained at 29 °C under A10 condition. An increase in viscosity and elasticity was also observed for sonicated samples crystallized at 34 and 35 °C under A10 and all CA conditions but these differences were not statistically significant (P >0.05). Sonication increased crystallization rates for all conditions tested. Kinetic constants obtained from an Avrami fit increased from1.3 × 10^?5 to 6.8 × 10^?5 min^?n for samples crystallized at 29 °C A10 without and with sonication, respectively, and from 2.6 × 10^?9 to 2.4 × 10^?7 min^?n for samples crystallized at 34 °C A10 without and with sonication, respectively. This increase in the crystallization rate was also observed for samples crystallized under the CA condition at 29 °C.     

Sonocrystallization of a Tristearin‐Free Fat

The objective of this study was to fractionate a purified interesterified fat to eliminate tristearin (SSS) and to evaluate the crystallization behavior of the tristearin‐free fat. The fractionated sample was crystallized with and without the application of high‐intensity ultrasound (HIU) by supercooling the sample at 2 °C. In the absence of SSS, the crystallization process was driven by low‐melting‐point triacylglycerols (TAG) such as OSS and OOS (O, oleic; S, stearic acid). There were no differences observed in the crystallinity in the sample based on the solid fat content (P > 0.05) along with any microstructural differences. In addition, an increase in the enthalpy of melting was observed upon sonication, indicating higher crystallinity (P < 0.05). Stronger intramolecular forces were formed in the sonicated samples as evidenced by increased viscoelastic parameters such as the elastic modulus (G′) and storage modulus (G″) (P < 0.05). G′ values increased from 138.25 ± 41.30 to 939.73 ± 277.45 Pa while the G″ values increased from 39.15 ± 8.98 to 149.77 ± 16.00 Pa (P < 0.05). Change in viscosity was not observed as a consequence of sonication (P > 0.05). This study showed that HIU was effective in changing the crystallization behavior of SSS‐free fats with low‐melting TAG.     

Impact of high-intensity ultrasound on physical properties and degree of oxidation of lipase modified menhaden oil with caprylic acid and/or stearic acid

The purpose of this research was to determine the effect of high-intensity ultrasound (HIU) on physical properties, degree of oxidation, and oxidative stability of structured lipids (SLs). Caprylic acid (C) and stearic acid (S) were incorporated into menhaden oil using Lipozyme® 435 lipase to obtain five samples: (1) LC 20 (menhaden oil with 20% of C), (2) LC 30 (menhaden oil with 30% C), (3) LS 20 (menhaden oil with 20% S), (4) LS 30 (menhaden oil with 30% S), and (5) Blend C (menhaden oil with 16.24% C and 13.04% S). Samples were crystallized for 90 min at the following temperatures: (1) LC 20 at 15.5°C, (2) LC 30 at 17.5°C, (3) LS 20 at 24°C, (4) LS 30 at 30°C, and (5) Blend C at 18.0°C, and HIU was applied at the onset of crystallization. Physical properties, degree of oxidation, and oxidative stability were evaluated in sonicated and nonsonicated samples. All SLs had statistically higher G′ after sonication. Sonicated LS 30, LC 30, and Blend C had a higher melting enthalpy than the nonsonicated ones, while enthalpy values in sonicated LS 20 and LC 20 samples were not statistically different than the nonsonicated ones. No significant difference between sonicated and nonsonicated samples was observed in peroxide values (1.2 ± 0.1 meq/kg, p > 0.05) and in the oxidative stability index (6.3 ± 0.2 h, p > 0.05). These results showed that HIU was effective at changing physical properties without affecting the oxidation of the samples.     

Sonocrystallization of a Palm-Based Fat with Low Level of Saturation in a Scraped Surface Heat Exchanger

Physical properties of fats are affected by the reduction of saturated fatty acids. One method for retaining desired properties is the use of high-intensity ultrasound (HIU). The aim of this study was to investigate the influence of HIU power levels, pulse time, and position on the physical properties of a low-saturated palm-based fat crystallized in a scraped surface heat exchanger (SSHE). The sample was crystallized in a SSHE at 26 °C, using a 11 L hour⁻¹ flow rate, and agitation of 344 rpm in the barrels and 208 rpm in the pin worker. HIU was applied using a 12.7 mm tip coupled to a water jacketed (26 °C) flow cell that was placed at the end of the SSHE process. Sonication conditions were 20%, 50%, or 80% amplitude using pulses (5 and 10 s) or continuous sonication. After choosing the best HIU condition, the position of the flow cell was changed to different positions within the SSHE: before the first barrel (HIU-0), between the two barrels (HIU-1), between the second barrel and the pin worker (HIU-2), and after the pin worker (HIU-3). The best sonication condition from the first set of experiments was when HIU was applied using 50% amplitude and 10 s pulses. This condition resulted in higher oil binding capacity (OBC) and storage modulus (G') compared to the non-sonicated sample (OBC: 77% against 69.5%; G':154 kPa against 108 kPa). The best HIU position was HIU-3 since no further agitation was applied. The lack of agitation after sonication induced secondary nucleation and generated a strong crystalline network.     

Dry Fractionation of Cupuassu (Theobroma grandiflorum) Fat: Physical–Chemical Properties and Polymorphic Behavior

Physical chemical properties of cupuassu fat were modified by dry fractionation. Stearin and olein fractions were obtained at 29, 26, and 24 °C. Polymorphic behavior of unfractionated cupuassu fat (UCF) and its fractions were studied in situ by small-angle (SAXS) and wide-angle (WAXS) X-ray scattering using synchrotron light. Polymorphic transitions were followed in real time tempering samples with a thermal cycle. For UCF, the main polymorphic form crystallized under selected conditions was the β’₂. α and β’₁-forms appeared in trace amounts. β₂-form was obtained after storage at 25 °C for 3 months. Stearins obtained at 26 (S-26) and 24 °C (S-24) showed a similar polymorphic behavior. However, S-26 with improved physical properties might be more suitable for chocolate production or as a trans-fat alternative than UCF. Stearin fraction obtained at 29 °C (S-29) had a complex polymorphic behavior. The α-form was the first polymorphic form detected followed by β’₂-form. There was a polymorphic transition from α to β’₁-form but no transition between β’-forms. They were independent to each other showing fractionation in two different solid solutions. Increased contents of the triacylglycerols (TAG) SOA and SOB together with lower contents of SOO compared to UCF led to co-crystallization because there was no complete compatibility among all TAG present in S-29. β₁-form crystallized after storage forming crystals with a double-layer arrangement and a characteristic morphology. This form could be useful for accelerating crystallization process in melted liquid systems.     

Effect of processing conditions on physical properties of a milk fat model system: Microstructure

The effect of processing conditions on the microstructure of three blends of 30, 40, and 50% high-melting fraction [Mettler dropping point (MDP)=47.5°C] in the lowmelting fraction (MDP=16.5°C) of milk fat was studied. The effect of cooling and agitation rates, crystallization temperature, chemical composition of the blends, and storage time on crystalline microstructure (number, size, distribution, etc.) was investigated by confocal laser scanning microscopy (CLSM). To improve resolution, a mix of Nile blue and Nile red dyes was dissolved in the melted samples in proportions that did not modify the nucleation kinetics. Samples were then crystallized by cooling (0.2 or 5.5°C/min) to crystallization temperature (25, 27.5, and 30°C). After 2 h at crystallization temperature, a slurry was placed on a microscope slide and samples were stored 24 h at 10°C. During this period, more material crystallized. Slowly crystallized samples (0.2°C/min) formed different structures from rapidly crystallized samples (5.3°C/min). Crystals were sometimes diffuse and hard to distinguish from the liquid. Samples were darker as a result of this solid-mass distribution. However, rapidly crystallized samples had well-defined crystals and seemed to be separated by a distinct liquid phase. These crystals were not in touch with each other as was the case for slowly crystallized samples. Higher agitation rates led to smaller crystal size due to enhanced nucleation. Larger crystals were formed when crystallization occurred at higher temperatures. Storage time resulted in an increase of crystal size. Larger crystal size and structures with more evident links had a more elastic behavior with higher elastic modulus E’.     

Relationship between oil binding capacity and physical properties of interesterified soybean oil

The objective of this study was to identify the physical properties of an interesterified soybean oil (EIESOY), containing 45% saturated fatty acids (SFA), that correlates with high oil binding capacity (OBC) and low oil loss (OL). In this study, three EIESOY samples were analyzed; a 100% sample, a 50% sample diluted with 50% soybean oil, and a 20% sample diluted with 80% soybean oil. All samples were crystallized using fast (7.78°C/min) and slow (0.1°C/min) cooling rates as well as with and without high-intensity ultrasound (HIU, 20 kHz). The 100%, 50%, and 20% samples were crystallized at 38.5, 27.0, and 22.0°C, respectively. HIU was applied at the onset of crystallization and all samples were allowed to crystallize isothermally for 90 min. After 90 min, physical properties such as crystal microstructure, hardness, solid fat content (SFC), elasticity, and melting behavior were evaluated. Physical properties were also measured after storage for 48 h at 22 and 5°C. Results show that OBC was positively correlated with hardness, G′, and SFC after 48 h (r = 0.738, p = 0.006; r = 0.639, p = 0.025; r = 0.695, p = 0.012; respectively), OL was negatively correlated with hardness after 48 h (r = −0.696, p < 0.001), G′ after 90 min and 48 h (r = −0.704, p < 0.001; r = −0.590, p = 0.002), and SFC after 90 min and 48 h (r = −0.722, p < 0.001; r = −0.788, p < 0.001). Neither OBC nor OL were correlated with crystal diameter or the number of crystals.     

Tailoring Crystalline Structure Using High-Intensity Ultrasound to Reduce Oil Migration in a Low Saturated Fat

The objective of this study was to use high-intensity ultrasound (HIU) to change the crystalline structure of an interesterified soybean oil (IESBO) with 33% of saturated fats and to evaluate how these changes affect oil migration. The IESBO was crystallized at different temperatures (26, 28, 30, and 32 °C) with and without HIU. Results show that oil migration was significantly affected by HIU (P < 0.05). HIU promoted crystallization and induced the formation of harder crystalline networks that were more resistant to oil migration with lower melting peak temperatures and sharper melting profiles. Samples processed with HIU had fewer crystalline clusters as observed by microscopy. Changes observed on the physical properties of the IESBO due to sonication that consequently improved oil migration were attributed to the ability of HIU to induce secondary nucleation and crystallize low-melting point triacyclglycerols (SUU) that would not crystallize without the HIU and to the stronger and stable crystalline network formed capable of entrapping liquid TAG (UUU).     

Retardation of Crystallization through the Addition of Dairy Phospholipids

The objective of this work was to identify the effects that milk phospholipids (PL) have on crystallization of anhydrous milk fat (AMF). Three mixtures were prepared by adding 0%, 0.01%, and 0.1% PL to AMF. Each mixture was crystallized for 90 min at 24, 26, and 28 °C. The solid fat content was measured as a function of time and fitted to the Avrami equation. Melting point, thermal behavior, viscoelastic properties, and crystal morphology were all measured at 90 min. All assays were repeated, as well as hardness, after being stored at 5 °C for 48 hours. Samples containing PL showed slower crystallization as concentration increased especially at higher temperatures (26 and 28 °C). The addition of PL caused a difference in crystal morphology resulting in visibly larger crystals at 90 min. The elasticity and hardness at 90 min were influenced by the addition of PL at 24 °C with lower values obtained in samples with PL compared to the AMF alone. No differences in hardness nor in elasticity was observed for samples crystallized at 26 and 28 °C. A decrease in melting enthalpy was observed in samples with PL indicating a reduction in crystallization at all temperatures, which was supported by crystal morphology.     

Effect of processing conditions on physical properties of a milk fat model system: Rheology

The effect of processing conditions on rheological behavior of three blends of 30, 40, and 50% of high-melting fraction [melting point measured as Mettler dropping point (MDP)=47.5°C] in low-melting fraction (MDP=16.5°C) of milk fat was studied. The effects of cooling and agitation rates, crystallization temperature, chemical composition of the blends, and time of storage on complex, storage and loss moduli were investigated by dynamic mechanical analysis (DMA). Compression tests were performed on samples using frequency values within the linear viscoelastic range (1 to 10 Hz). Loss modulus was, on average, 10 times lower than elastic modulus and was generally not affected by processing conditions. Samples showed a more solid-like behavior that was better described by storage modulus. Storage modulus varied with all processing conditions used in this study, and even for the same solid fat content, different rheological properties were found. Storage and complex modulus increased with temperature of crystallization (25 to 30°C), even though solid fat contents of samples measured after 24 h at 10°C were the same. Moduli were higher for samples crystallized at slow cooling rate, decreased with agitation rate, and were lower for the 30–70% blend at all processing conditions used. Storage moduli also increased with storage time. Shear storage modulus was calculated from the DMA experimental data, and the results were in agreement with the values reported in literature for butter systems. Fractal dimensions calculated for these systems showed a significant decrease as agitation rate increased in agreement with the softening effect reported for working of butter.     

Effects of High Intensity Ultrasound Frequency and High-Speed Agitation on Fat Crystallization

The objective of this research was to examine the effect of ultrasound frequency and high-speed agitation on lipid crystallization. Interesterified soybean oil was crystallized at 44 °C without and with the application of high intensity ultrasound (HIU—20 and 40 kHz) or with high-speed agitation (6000 and 24,000 rpm). Two tip amplitudes (24 and 108 µm) and three pulse durations were evaluated (5, 10, and 15 s) for the acoustic frequencies tested. Sonication at 20 kHz of frequency significantly reduced crystal size, increased (p < 0.05) elasticity (435.9 ± 173.3–80,218 ± 15,384 Pa) and SFC (0.2 ± 0.0–4.5 ± 0.4%). No significant difference was observed in the crystallization behavior of these samples when sonicated at different amplitudes for 5 and 10 s. The crystallization behavior was significantly delayed (p < 0.05) in samples sonicated using 108 µm amplitude for 15 s. Larger crystals were formed in samples sonicated at 40 kHz compared to those obtained with 20 kHz and lower SFC (3.7 ± 0.0%) and elasticity (3943 ± 1459 Pa) values were obtained. High-speed agitation at 24,000 rpm increased SFC (5.5 ± 0.1%) and crystallized area and decreased the elasticity (42,602 ± 11,775 Pa) compared to the samples sonicated at 20 kHz.     

Effects of Pilot Plant-Scale Ultrasound on Palm Oil Separation and Oil Quality

The effects of ultrasonic standing waves on palm oil separation of ex-screw press feed from the mesocarp of the palm oil fruit, oil recovery and oil quality were determined. The ex-screw press feed at 85 °C was pumped simultaneously into two identical vessels. One vessel was the control (non-ultrasound) and the other vessel (ultrasound) was fitted with two 400 kHz transducer plates operating at 13.4 kJ/kg, which were placed in direct contact with the feed. Oiling-off by gravity settling occurred at faster rates after sonication. The total recoverable oil after 30 min gravity settling and upon centrifuging the underflow sludge (remaining colloidal fraction) at 1000×g was higher after sonication. Total recoverable oil was 30.7 ± 2.9 % and 43.5 ± 8.6 % (w/w original feed basis) for the non-sonicated and sonicated samples respectively. Sonication reduced the oil content of the sludge ex-centrifuge, demonstrating that higher recovery of palm oil was obtained with ultrasound application. Sonication did not affect the DOBI (deterioration of bleachability index) value, and vitamin E and free fatty acid contents of the separated oil. High-frequency ultrasound enhances the separation rate of palm oil and increases oil recovery without compromising oil quality.     

Effect of High‐Intensity Ultrasound on the Crystallization Behavior of High‐Stearic High‐Oleic Sunflower Oil Soft Stearin

The objective of this research was to evaluate the effect of high‐intensity ultrasound (HIU) and crystallization temperature (T_c) on the crystallization behavior, melting profile, and elasticity of a soft stearin fraction of high‐stearic high‐oleic sunflower oil. Results showed that HIU can be used to induce and increase the rate of crystallization of the soft stearin with significantly higher SFC values obtained in the sonicated samples, especially at higher T_c. SFC values were fitted using the Avrami model, and higher k_n and lower n values were obtained when samples were crystallized with sonication, suggesting that sonicated samples crystallized faster and through an instantaneous nucleation mechanism. In addition, the crystal morphology, melting behavior, and viscoelasticity were significantly affected by sonication.     

Sonocrystallization of Interesterified Fats with 20 and 30% of Stearic Acid at the sn-2 Position and Their Physical Blends

Physical blends (PB) of high oleic sunflower oil and tristearin with 20 and 30% stearic acid and their interesterified (IE) products where 20 and 30% of the fatty acids are stearic acid at the sn-2 position crystallized without and with application of high intensity ultrasound (HIU). IE samples were crystallized at supercooling temperatures (ΔT) of 12, 9, 6, and 3 °C while PB were crystallized at ΔT = 12 °C. HIU induced crystallization in PB samples, but not in the IE ones. Induction in crystallization with HIU was also observed at ΔT = 6 and 3 °C for IE C18:0 20 and 30% and at ΔT = 9 °C only for the 30% samples. Smaller crystals were obtained in all sonicated samples. Melting profiles showed that HIU induced crystallization of low melting triacylglycerols (TAGs) and promoted co-crystallization of low and high melting TAGs. In general, HIU significantly changed the viscosity, G′, and G″ of the IE 20% samples except at ΔT = 12 °C. While G′ and G″ of IE 30% did not increase significantly, the viscosity increased significantly at ΔT = 9, 6, and 3 °C from 1526 ± 880 to 6818 ± 901 Pa.s at ΔT = 3 °C. The improved physical properties of the sonicated IE can make them good contenders for trans-fatty acids replacers.     

Effect of sample storage on quantitation of lipoprotein (a) by an enzyme-linked immunosorbent assay

This study evaluated the effect of storage on the quantitation of lipoprotein (Lp)(a) in 25 serum samples. Aliquots of serum were stored for up to three years at either −20°C or−70°C and Lp(a) subsequently analyzed using an enzyme-linked immunosorbent assay kit. Concentrations of Lp(a) declined during storage, and the temperatures employed elicited significantly different (P<0.05) values within 12 mon which further diverged during three years of storage. Compared to baseline values, significant decreases (P<0.05) in Lp(a) levels were evident after six months of storage at−20°C with apparent losses (geometric mean) reaching 36.9% (95% confidence interval: 30.9%, 42.9%) after three years. Similarly, significantly lower (P<0.05) Lp(a) values were recorded after six months of storage at−70°C and at three years the decrease (geometric mean) was 19.1% (95% confidence interval: 14.3%, 24.0%). The losses, after three years, in terms of the arithmetic mean were 53.5 and 26.2% at−20 and−70°C, respectively. Phenotype analysis suggested that large isoforms are more susceptible to degradation than smaller moieties. This may be related to the observation that apparent losses are reduced in samples containing over 8 mg/dL Lp(a). Nevertheless, Lp(a) levels in stored samples retained a strong correlation with the baseline values. These results must be considered specific for the storage conditions and analytical procedures employed.     

Storage stability of margarines produced from enzymatically interesterified fats compared to those prepared by conventional methods – Chemical properties

In this study, four margarine hardstocks were produced, two from enzymatically interesterified fats at 80 and 100% conversion, one from chemically randomized fat and one from physically mixed fat. These four hardstocks, blended with 50% sunflower oil, were mainly used for the production of table margarines in a pilot plant. Storage stability studies were carried out at storage temperatures of 5 and 25 °C for 12 wk. Margarines from the enzymatically interesterified fats were compared to the margarines produced by the conventional methods (chemical interesterification and physical blending) and to selected commercial margarines. The changes in the chemical properties of the products, including peroxide values (PV), tocopherols, free fatty acids, volatile oxidation products, and sensory evaluation, were examined during storage. It was observed that the margarine produced from the chemically interesterified fat had higher PV in weeks 4, 8 and 10 than the margarines produced from the enzymatically interesterified fats and the physically blended fat. These differences were not caused by different contents of tocopherols in the hardstocks. The differences between the processes for chemical and enzymatic interesterification, including further treatment stages, might be responsible for the development of a high PV in the margarine produced from the chemically interesterified fat. However, the contents of volatiles did not show the same tendency as observed for PV for the margarines stored at 25 °C during 12 wk. Storage at 25 °C accelerated oxidation compared to storage at 5 °C. The content of δ‐ and γ‐tocopherols decreased faster than the content of α‐ and β‐tocopherols during storage. This phenomenon was only affected by storage time, not by storage temperature. Sensory analysis did not show consistent differences between the produced margarines and commercial margarines, and no hydrolysis occurred for these four margarines during storage. The margarines produced from the enzymatically interesterified fats had low PV and a similar taste and smell compared to the margarine produced from the chemically interesterified fat.     

Treatment of phosphoric acid sludge for rare earths recovery II: effect of sonication and flocculant solution temperature on settling rate

The effect of sonication on sludge exhibited a faster settling rate. Sonication creates acoustic cavitation preparing the slurry for better interaction with flocculant and generating faster settlement. Five samples of flocculants were conditioned at 25, 50, 60, 75 and 100° C for settlement. The flocculant conditioned at 60°C had the best performance in terms of settlement. However, further increase in temperature damaged polymer chains of the flocculant decreasing its effectiveness. ICP analysis showed sonicated samples trapped 11% more rare earth elements (REEs) in their residue and that temperature above 60º C is not favorable for the flocculant preparation in terms of coagulation.     

Relationship between crystallization behavior, microstructure, and mechanical properties in a palm oil-based shortening

In this study, the effects of cooling rate, degree of supercooling, and storage time on the microstructure and rheological properties of a vegetable shortening composed of soybean and palm oils were examined. The solid fat content vs. temperature profile displayed two distinct regions: from 5 to 25°C, and from 25°C to the end of melt at 45–50°C. A peak melting temperature of 42.7°C was determined by DSC. Discontinuity in the crystallization induction time (determined by pulsed NMR) vs. temperature plot at 27°C also suggested the existence of two separate groups of crystallizing material. Isothermal crystallization kinetics were characterized using the Avrami and Fisher-Turnbull models. In using DSC and powder X-ray diffraction, the α polymorph formed upon fast cooling (>5°C/min), and the β′ form predominated at lower cooling rates (<1°C/min). An α to β′ transition took place upon storage. Fractal dimensions (D _f ) obtained by microscopy and image analysis showed no dependence on the degree of supercooling since D _f remained constant (∼1.89) at crystallization temperatures of 5, 22, and 27°C. Crystallization at 22°C at 1°C/min and 15°C/min yielded D _f values of 1.98 and 1.93, respectively. Differences in microstructure were observed, and changes in particle properties increased the parameter λ at higher degrees of supercooling.     

Use of α-tocopherol acetate to improve fresh pig meat quality of full-fat rapeseed-fed pigs

Thirty-two pigs were allocated to one of four diets, FFRD0 and FFRD200, containing full-fat rapeseed (FFR), 150 g/kg [25–50 kg liveweight (LW)], and 250 g/kg (50–90 kg LW), or CD0 and CD200, containing equivalent quantities of rapeseed meal and 34 g/kg (25–50 kg LW) or 59.2 g/kg (50–90 kg LW) coconut oil and lard (0.5:0.5, w/w). Diets FFRD200 and CD200 were supplemented with 200 mg/kg α-tocopherol acetate (ATA). ATA supplementation significantly (P<0.001) reduced muscle drip loss. The melting point (°C) of subcutaneous fat was significantly lowered by FFR (P<0.001) but increased by ATA supplementation (P<0.05). Tissue α-tocopherol (AT) concentrations were significantly increased by ATA supplementation. Longissimus dorsi AT concentration was positively correlated with AT concentration in subcutaneous fat (r=0.86) and in plasma at 35 (r=0.65) and 77 (r=0.85) days of feeding (P<0.001). In both L. dorsi and subcutaneous adipose tissue lipids, FFRD caused a significant (P<0.001) decrease in the ratio of n-6 to n-3 fatty acids and a significant (P<0.001) increase in the ratio of polyunsaturated to saturated fatty acids. AT supplementation significantly reduced the susceptibility of L. dorsi and subcutaneous fat to lipid oxidation during storage at 4°C for up to 16 d. For all dietary treatments and storage times, lipid oxidation [mg malondialdehyde (MDA)/kg muscle] was greater in the surface layer (0–2.5 mm) of L. dorsi than below the surface (2.5–5 mm). Oxidative stability of L. dorsi lipids to iron-induced lipid peroxidation was significantly improved (P<0.001) by AT supplementation. Meat from pigs fed FFRD diets was significantly less stable to iron-induced oxidation (nmoles MDA/mg protein) at the longer incubation periods (100 and 200 min). The susceptibility of L. dorsi to iron-induced lipid oxidation decreased as the ratio of the tissue concentration of AT to unsaturated fatty acid increased.