Effect of ingredients on oxidative stability of fish oil‐enriched drinking yoghurt

The oxidative stabilities of fish oil‐enriched milk and fish oil‐enriched drinking yoghurt were compared by following the development of lipid oxidation in plain milk, plain yoghurt and yoghurt to which ingredients present in drinking yoghurt were added one by one. All samples were enriched with 1 wt‐% fish oil. After 3 weeks of storage, development of peroxide values, volatile secondary oxidation products and fishy off‐flavors were much more pronounced in the milk compared to any of the yoghurt samples, irrespective of any added ingredients used to prepare flavored drinking yoghurt. Thus, pectin, citric acid or glucono‐delta‐lactone did not affect the oxidative stability of fish oil‐enriched yoghurt emulsions. Furthermore, the fruit preparation and added sugar did not lead to increased antioxidative activity. It is concluded that yoghurt as the dairy component in the fish oil‐enriched emulsion was responsible for the remarkably high oxidative stability and was able to protect the n‐3 PUFA against oxidative deterioration. It should be considered that this strong antioxidative effect of yoghurt might mask potential antioxidative effects of the other ingredients in the drinking yoghurt.     

Profiles of volatile compounds in milk containing fish oil analyzed by HS‐SPME‐GC/MS

Long‐chain polyunsaturated fatty acids (LC‐PUFA) have various positive biological effects. Fish oil represents a major source of LC‐PUFA; therefore it is extensively used to enrich food products as, for example, infant formulae, dairy products and fruit juices. However, in the presence of oxygen and metals, LC‐PUFA readily degrade, producing off‐flavors and decreasing the nutritional value of the product. The deterioration of sensory properties (taste and odor) can be easily perceived by the consumer, due to the formation of volatile compounds that are formed by decomposition of lipid hydroperoxides, also known as primary oxidation products. In this study, we used the headspace solid‐phase microextraction‐gas chromatography/mass spectrometry technique (HS‐SPME‐GC/MS) to characterize and quantify volatile compounds in a food matrix supplemented with fish oil. We demonstrated that the HS‐SPME‐GC/MS method is a valuable tool to monitor lipid oxidation at early stages. We identified t‐2‐hexenal and c‐4‐heptenal as possible oxidation markers during the storage of milk enriched with 5% of cod oil.     

Encapsulation of Long-Chain n-3 Polyunsaturated Fatty Acids Using Egg Yolk

Egg yolk is well known for its excellent emulsifying property. In this article, egg yolk was used as the encapsulating matrix to prevent the oxidation of n-3 long-chain polyunsaturated fatty acids from fish oil. A 2 × 2 × 5 complete block design with three replications was used. Two levels of fish oil (1% and 5%) and two levels of esterification type (triglycerides or ethyl esters) of eicosapentaenoic/docosahexaenoic fatty acids were used. Time was considered a fixed factor with five levels. Emulsions were prepared by homogenization and stored for up to 4 weeks at 4–6 °C, with weekly sampling. Emulsions were analyzed for particle size and distribution, encapsulation efficiency, and surface oil. The oxidative stability of the emulsions was evaluated before and after cooking at 150–170 °C for 75 s. The addition of triglycerides resulted in a larger average particle size (234 ± 12.4 nm). All emulsions achieved 100% encapsulation efficiency and showed no significant change in the surface oil concentration during storage. After 4 weeks of storage, the concentration of eicosapentaenoic + docosahexaenoic fatty acids in nonencapsulated fish oil triglycerides and ethyl esters decreased by 20.32% and 14.74%, respectively, while the emulsions showed no significant differences. In addition, no peroxide or propanal formation was detected in raw emulsions over the storage period. Propanal formation was negligible in cooked samples, and the peroxide value showed no differences between the egg yolk control and the emulsions. Therefore, egg yolk was observed to be an efficient encapsulating food matrix that protects n-3 polyunsaturated fatty acids against oxidation and degradation.     

Fortification of Skim Milk with Nanoliposomes Loaded with Shrimp Oil: Properties and Storage Stability

Shrimp oil nanoliposomes (SONL) were fortified into skim milk at various levels (2–10%, v/v), followed by pasteurization at 63 °C for 30 min. Skim milk showed lowered whiteness but increased redness and yellowness as SONL levels added increased (P < 0.05). Viscosity of fortified samples was also augmented with increasing levels of SONL (P < 0.05). Sensory analysis indicated that fortified milk skim samples had no perceivable fishy odor and were organoleptically acceptable. When skim milk fortified with 10% SONL was stored up to 15 days at 4 °C, the microbial load was less than 2.54 log CFU mL⁻¹. The pH and acidity values were also within the acceptable limits. As measured by peroxide value (PV) and thiobarbituric acid reactive substances (TBARS), shrimp oil in SONL did not undergo oxidation during the extended storage. The fatty acid profile of shrimp oil revealed no loss of polyunsaturated fatty acids taken place during the storage of fortified milk. Therefore, nanoliposomes could be an effective carrier for shrimp oil to be fortified in skim milk.     

Pigments for Aquaculture of Salmonids. A Comparative Model Study of Carophyll Pink and Panaferd AX in Cod Liver Oil

As one of the key ingredients in feed for rearing salmon the stability of the synthetic feed pigment Carophyll Pink^® (CP) and the natural pigment Panaferd‐AX^® (PAN) in pure cod liver oil were investigated. As reference, pure cod liver oil without added carotenoids was used (PURE). Carotenoid content, isomerization of astaxanthin in CP and distribution of carotenoids in PAN and the antioxidant ability of CP and PAN were followed by HPLC in two model experiments (Experiment 1: 17 days, temperature 18.5–28.2 °C, and Experiment 2: 15 days, temperature 29.7 °C). Moreover, peroxide value (PV), thiobarbituric value (TBARS) and fatty acid (FA) compositions were analyzed in CP, PAN and PURE. Relative to cod liver oil with added PAN, addition of CP resulted in significantly higher stability of ∑PUFA, slower formation of peroxides, reduced oxidation and increased carotenoid stability during storage. For the isomerization of astaxanthin in CP a significantly decrease in all‐E‐astaxanthin and an increase in 13Z‐astaxanthin was observed during storage in both experiments. Highest stability of different carotenoids in PAN were found for the carotenoid β‐carotene in both experiments, followed by echinenone and astaxanthin in Experiment 1 and astaxanthin, adonirubin and adonixanthin in Experiment 2. It is concluded that the synthetic pigment feed additive CP significantly improves the stability of cod liver oil as compared to the natural pigment feed additive PAN (order of stability; CP > PAN > PURE).     

Oxidative stability and acceptability of camelina oil blended with selected fish oils

The effects of blending camelina oil with a number of fish oils on oxidative stability and fishy odour were evaluated. Camelina oil was found to be more stable than tuna oil, ‘omega‐3’ fish oil and salmon oil as indicated by predominantly lower ρ‐anisidine (AV), thiobarbituric acid reactive substances (TBARS) and conjugated triene levels (CT) during storage at 60 °C for 20 days (p < 0.05). Peroxide values (PV) were similar for all oils until Day 13 when values for camelina oil were higher. Values for blends of the fish oils (50, 25, 15, 5%) with camelina oil were generally between those of their respective bulk oils indicating a dilution effect. Camelina oil had a similar odour score (p < 0.05) to sunflower oil (9.2 and 9.6, respectively) indicating, as expected, an absence of fishy odours. In comparison, the fish oils had lower scores of 6.1 to 6.6 (p < 0.05) indicating mild to moderate fishy odours. Odour scores were improved at the 25% fish oil levels (p < 0.05) and were not different to camelina oil at the 15 or 5% levels (p < 0.05). Practical applications: Camelina oil is a potentially important functional food ingredient providing beneficial n‐3 PUFA. Oil extracted from Camelina sativa seeds contains greater than 50% polyunsaturated fatty acids of which 35‐40% is α‐linolenic acid (C18:3ω3, ALA), an essential omega‐3 fatty acid 1 . While EPA and DHA from fish oils are more potent nutritionally, they are less stable than ALA. This work evaluated innovative blends of fish oil with camelina oil for stability and acceptability. The results demonstrate that there is potential for use of blends of camelina oil with fish oils in food products, as the results show some benefits in terms of reduction of fishy odours. Such information could be valuable in relation to formulation of food products containing high levels of n‐3 PUFA from both plant and fish sources.     

Emulsifier type,metal chelation and pH affect oxidative stability of n‐3‐enriched emulsions

Recent research has shown that the oxidative stability of oil‐in‐water emulsions is affected by the type of surfactant used as emulsifier. The aim of this study was to evaluate the effect of real food emulsifiers as well as metal chelation by EDTA and pH on the oxidative stability of a 10% n‐3‐enriched oil‐in‐water emulsion. The selected food emulsifiers were Tween 80, Citrem, sodium caseinate and lecithin. Lipid oxidation was evaluated by determination of peroxide values and secondary volatile oxidation products. Moreover, the zeta potential and the droplet sizes were determined. Tween resulted in the least oxidatively stable emulsions, followed by Citrem. When iron was present, caseinate‐stabilized emulsions oxidized slower than lecithin emulsions at pH 3, whereas the opposite was the case at pH 7. Oxidation generally progressed faster at pH 3 than at pH 7, irrespective of the addition of iron. EDTA generally reduced oxidation, as evaluated by volatiles formation in all emulsions, irrespective of pH and emulsifier type, except in the lecithin and caseinate emulsions where a pro‐oxidative effect was observed for some volatiles. The different effects of the emulsifier types could be related to their ability to chelate iron, scavenge free radicals, interfere with interactions between the lipid hydroperoxides and iron as well as to form a physical barrier around the oil droplets.     

Oxidative Stability and Sensory Attributes of Fermented Milk Product Fortified with Fish Oil and Marine Phospholipids

Marine phospholipids (PL) are potential ingredients for food fortification due to its numerous advantages. The main objective of this study was to investigate whether a fermented milk product fortified with a mixture of marine PL and fish oil had better oxidative stability than a fermented milk product fortified with fish oil alone. Fortification of a fermented milk product with marine PL was performed by incorporating 1 % w/w lipids, either in the form of neat oil or in the form of a pre-emulsion. Lipid oxidation was investigated in the neat emulsions and fortified products by the measurements of primary, secondary volatile oxidation products and tocopherol content upon 32 days storage at 2 °C and 28 days storage at 5 °C, respectively. Analyses of particle size distribution, viscosity and microbial growth were also performed. In addition, sensory attributes such as sour, fishy and rancid flavor/odor were evaluated in fortified products by a trained panel. The results obtained showed that incorporation of a mixture of marine PL and fish oil into fermented milk products decreased the oxidative stability and sensory quality of fortified products. The pH-dependent behavior of iron seemed to be the main factor that influenced the lipid oxidation in the marine PL emulsion and fermented milk system. In addition, both oxidative stability and sensory acceptability of fortified products varied depending on the quality of the marine PL used for fortification.     

Physico-chemical Properties of Marine Phospholipid Emulsions

Many studies have shown that marine phospholipids (PL) have better bioavailability, better resistance towards oxidation and contain higher polyunsaturated fatty acids such as eicosapentaenoic (EPA) and docosahexaenoic acids (DHA) than triglycerides (TAG) present in fish oil. The objective of this study was to investigate the emulsifying properties of various commercial marine PL and the feasibility of using them to prepare stable emulsions prepared with or without addition of fish oil. In addition, this study also investigated the relationship between chemical composition of marine PL and the stability of their emulsions. Physical stability was investigated through particle size distribution (PSD), zeta potential, microscopy inspection and emulsion separation (ES); while the oxidative and hydrolytic stability of emulsions were investigated through peroxide value (PV) and free fatty acids value (FFA) after 32?days storage at room temperature and at 2?°C. In conclusion, marine PL showed good emulsifying properties and it was possible to prepare marine PL emulsions with and without addition of fish oil. Emulsion with both good oxidative stability and physical stability could be prepared by using marine PL of high purity, less TAG, more PL, cholesterol and higher antioxidant content.     

Formation of genotoxic dicarbonyl compounds in dietary oils upon oxidation

Dietary oils—tuna, salmon, cod liver, soybean, olive, and corn oils—were treated with accelerated storage conditions (60°C for 3 and 7 d) and a cooking condition (200°C for 1 h). Genotoxic malonaldehyde (MA), glyoxal, and methylglyoxal formed in the oils were analyzed by GC. Salmon oil produced the greatest amount of MA (1070±77.0 ppm of oil) when it was heated at 60°C for 7 d. The highest formation of glyoxal was obtained from salmon oil heated at 60°C for 3 d. More glyoxal was found from salmon and cod liver oils when they were heated for 3 d (12.8±1.10 and 7.07±0.19 ppm, respectively) than for 7d (6.70±0.08 and 5.94±0.38 ppm, respectively), suggesting that glyoxal underwent secondary reactions during a prolonged time. The amount of methyglyoxal formed ranged from 2.03±0.13 (cod liver oil) to 2.89±0.11 ppm (tuna oil) in the fish oils heated at 60°C for 7 d. Among vegetable oils, only olive oil yielded methylglyoxal (0.61±0.03 ppm) under accelerated storage conditions. When oils were treated under cooking conditions, the aldehydes formed were comparable to those formed under accelerated storage conditions. Fish oils produced more MA, glyoxal, and methylglyoxal than did vegetable oils because the fish oils contained higher levels of long-chain PUFA, such as EPA and DHA, than did the vegetable oils. A statistically significant correlation (P<0.05) between the α-tocopherol content and the oxidation parameters was obtained from only MA and fish oils heated at 60°C for 3 d.     

Oxidative stability of fish oil‐enriched mayonnaise‐based salads

The oxidative stability of fish oil‐enriched mayonnaise‐based salads and the influence of different vegetables in shrimp and tuna salads were evaluated. Moreover, the lipid oxidation in the presence of 1% oregano, rosemary, or thyme in fish oil‐enriched tuna salad was assessed. The results obtained showed that the mayonnaise itself was more oxidatively stable without vegetables and tuna or shrimp, in spite of the higher oil content in mayonnaise (63 and 6.3% fish oil, respectively) compared to salads (～24 and 2.4% fish oil, respectively). Surprisingly, the fish oil‐enriched mayonnaise was only significantly different from the standard mayonnaise in the volatile concentration during the end of storage. In fish oil‐enriched shrimp salad, asparagus had an anti‐oxidative effect and shrimp a pro‐oxidative effect, where the anti‐oxidative effect of asparagus was strong enough to prevent the pro‐oxidative effect of shrimp. The effect of ingredients in tuna salads was inconclusive, possibly due to a high content of volatiles in the vegetables themselves. However, the addition of spices increased the oxidative stability of tuna salad (oregano>rosemary>thyme).     

Rancidity development during the chilled storage of farmed Coho salmon (Oncorhynchus kisutch)

Coho salmon (Oncorhynchus kisutch) is a fatty fish species whose farming production has greatly increased in recent years. Lipid damage produced during Coho salmon chilled storage was studied for up to 24 d. Lipid hydrolysis (free fatty acids, FFA) and oxidation (conjugated dienes; peroxide value, PV; thiobarbituric acid index, TBA‐i; fluorescent compounds formation, FR; browning development) were determined and compared to lipid composition (polyene index, PI; astaxanthin, AX) changes and sensory assessment (rancid odour development) results. Most lipid damage indices developed slowly during storage; thus, values obtained for FFA, PV, TBA‐i and FR were in all cases under 1.5 g/100 g, 4.0 meq oxygen/kg lipid, 0.40 mg malondialdehyde/kg muscle and 0.40, respectively. Odour assessment showed a significant (p <0.05) rancidity development at day 10, when compared to starting fish material; then, non‐acceptable values were obtained at days 19 and 24. The PI analysis showed not many differences during the storage time, with the lowest mean value at day 19. AX analysis indicated a relatively high content in the white muscle, which was maintained till the end of the experiment. A low oxidation development is concluded for Coho salmon lipids when compared to other fatty fish species under the same chilling conditions. AX was found to contribute to the oxidation stability of Coho salmon lipids, due to its free radical scavenger properties.     

Characterization of Oxidative Stability of Fish Oil- and Plant Oil-Enriched Skimmed Milk

The objective of this research was to determine the oxidative stability of fish oil blended with crude plant oils rich in naturally occurring antioxidants, camelina oil and oat oil, respectively, in bulk and after supplementation of 1 wt% of oil blends to skimmed milk emulsions. Ability of crude oat oil and camelina oil to protect fish oil in bulk and as fish oil-enriched skimmed milk emulsions was evaluated. Results of oxidative stability of bulk oils and blends assessed by the Schaal oven weight gain test and by the rancimat method showed significant increase in oxidative stability when oat oil was added to fish oil in only 5 and 10 %, whereas no protective effect of camelina oil was observed when evaluated by these methods. Moreover, fish oil blended with oat oil conferred the lowest PV and lower amounts of volatile compounds during the storage period of 14 days at 4 °C. Surprisingly, skimmed milk supplemented with fish-oat oil blend gave the highest scores for off-flavors in the sensory evaluation, demonstrating that several methods, including sensory analysis, should be combined to illustrate the complete picture of lipid oxidation in emulsions.     

Effect of α‐, γ‐, and δ‐tocopherol on the distribution of volatile secondary oxidation products in fish oil

The relative ability of α‐, γ‐ and δ‐tocopherol (TOH) to influence the distribution of volatile secondary oxidation products in fish oil was studied, with particular emphasis on oxidation products expected to be important for adverse flavour formation. Purified fish oil samples with 100 ppm or 1000 ppm of the different tocopherols were analysed by dynamic headspace analysis of the volatiles formed after 2, 5 and 8 d of storage at 30 �C. The tocopherol type and concentration affected not only the overall formation of volatile secondary oxidation products, but also the composition of this group of oxidation products. Principal component analysis of the data obtained suggested that high tocopherol hydrogen‐donating power, i.e. a high tocopherol concentration or the use of αTOH as opposed to γTOH or δTOH, directs the formation of hydrocarbons, unsaturated carbonyl compounds of relatively high molecular weight, as well as the formation of cis, trans isomers of unsaturated aldehydes. Although an active inhibitor of overall volatile formation, αTOH at a high concentration thus appears to direct the formation of the more flavour‐potent aldehydes, such as those linking the carbonyl group with ethylenic conjugated unsaturation.     

Sensory evaluation of the odour of a sunflower oil emulsion throughout oxidation

Oxidation of unsaturated fatty acids is responsible for off‐flavours, often described as rancid flavours. This study was aimed at describing the evolution of the odour of a sunflower oil‐in‐water emulsion during oxidation at 50 °C in the dark. Appearance of an odour and occurrence of oxidation were first tested for at short‐time aging (0–4 h) by the triangle test and measurements of oxygen consumption, respectively. The odour of the emulsion oxidised for up to 240 h was then characterised by sensory profile, while volatiles issued from lipid oxidation were analysed in the headspace by SPME. From 1 h of aging, while oxygen consumption remained weak, a significant change of the odour was detected by the panel. Up to 21 volatile compounds were identified in the headspace of long‐time‐oxidised emulsions. Beyond the rancid attribute, seven attributes were chosen to describe the odour of oxidised emulsions, four of which referring to solutions of a single volatile oxidation compound. The contribution of the fresh oil attribute, initially dominant, was progressively overtaken from 6 to 24 h of aging by the deep‐fried attribute, which later declined in favour of the painty attribute, predominant after 100 h. Evolution of intensity scores and contribution to odour profiles of attributes could not be easily related to one reference volatile compound or another, confirming the complex relationship between the generated volatile compounds and the perceived odour.     

Monitoring peroxide value in oxidized emulsions by Fourier transform infrared spectroscopy

Soybean oil (SBO) was blended with 10–40% palm kernel olein (PKO) to obtain SBO:PKO blends with different degrees of unsaturation. Oil‐in‐water (O/W) emulsions were then prepared with 70 wt‐% of SBO or SBO:PKO blends and monitored for their chemical destabilization after an accelerated oxidation process up to 12 days at 60 °C. The formation rate of hydroperoxides, as demonstrated by peroxide value (PV) evolution, throughout the oxidation period was relatively high for a fully SBO‐based emulsion as compared to those with PKO incorporation. Fourier transform infrared (FTIR) spectroscopic method was also performed in parallel with PV determination, providing further information on structural changes of the functional groups due to lipid oxidation in the emulsions. By using a partial least square chemometric method, a developed calibration model that was based on the spectral region between 1800 and 1480 cm^?1 was shown to be able to predict the PV in oxidized emulsions over the range of 4–45 meq/kg. With a ‘leave‐one‐out’ cross‐validation optimization procedure, the calibration model provides a good coefficient of determination of 0.98 and a root mean standard error of cross‐validation of 2.09. In general, FTIR spectroscopy is a suitable technique to monitor PV in oxidized emulsions.     

Volatiles from microwave-treated,stored soybeans

Soybeans were microwaved to inactivate enzymes and prevent oil deterioration during storage. Microwave time was varied from 4 to 10 min, in 2-min increments, and the treated and control soybeans were stored for 8 weeks at 40°C. Damage was monitored by analysis of peroxide value and free fatty acid content of the extracted oil and by volatile analysis of the full-fat meal and extracted oil. Volatiles were measured by multiple headspace extraction, and the formation of hexanal was monitored in both oil and meal. During storage of the control beans, peroxide value increased from 0.41 to 1.20 meq/kg, hexanal concentration changed from 29 to 94 ppb and free fatty acid content increased from 0.4 to 1.7%. Oils extracted from soybeans that were microwaved for 4 or 6 min had peroxide values of about 1 meq/kg and hexanal concentrations of 39–44 ppb after storage, indicating partial inactivation of lipoxygenase enzymes. However, soybeans that were microwaved for 8 min or more tended to oxidize during storage to a greater extent than the control soybeans, showing higher peroxide values and greater formation of hexanal in the samples. This suggests that soybeans microwave-treated in excess of 8 min are heat-damaged and susceptible to deterioration during storage. Free fatty acid content of the oils from all of the microwave-treated soybeans was about 0.4% initially, and did not increase with storage, indicating inactivation of hydrolytic enzymes. The mention of firm names or trade products does not imply that they are endorsed or recommended over other firms or similar products not mentioned.     

Effects of rainbow trout freshness on n‐3 polyunsaturated fatty acids in fish offal

The effects of rainbow trout cold storage on the quality of offal left after fish processing to fillets with skin were determined. The intact farmed rainbow trout were kept at 2 °C in ice for 0, 4, 7, and 14 days of storage. The offal was, immediately after processing, frozen at ?20 °C and analysed after a month‐long frozen storage; fillets (non‐frozen) were analysed as well. Non‐protein nitrogen, volatile bases, trimethylamine, lipid oxidation (peroxide value, anisidine value, UV‐VIS spectra, and fluorescence) and fatty acid composition were determined. The offal consists in 15% of protein and in about 20% of chloroform/methanol‐extractable lipids, with n‐3 polyunsaturated fatty acids (n‐3 PUFA) accounting for 20.37 ± 1.25% of the fatty acids. The fish storage duration was found to exert a significant (p = 0.05) effect on the changes in lipids and nitrogen compounds. No losses of long‐chain n‐3 PUFA in the offal were detected during the 2 wk of storage in ice plus 1 month at ?20 °C. The rainbow trout offal is a valuable – rich and stable – source of n‐3 PUFA.     

Canola Proteins Used as Co‐Emulsifiers with Phospholipids Influence Oil Oxidability,Enzymatic Lipolysis,and Fatty Acid Absorption in Rats

The objective of this study is to formulate and characterize oil‐in‐water emulsions with plant‐derived ingredients only, that is, proteins extracted from canola oil bodies, used as co‐emulsifiers with a canola lecithin, and to assess their suitability for food applications. Using the protein extract increases the chemical stability of rapeseed oil emulsions toward oxidation, based on the delay in conjugated diene formation under accelerated storage conditions, and favors pancreatic lipase activity. Bioaccessibility of rapeseed fatty acids is compared in lymph‐duct‐cannulated rats fed oil or emulsion. Fatty acid absorption by the intestine is increased by 78% when the oil is emulsified with canola proteins as co‐emulsifier: 28.7 mg mL^?1 versus 16.1 mg mL^?1 for oil (p < 0.05). In vitro lipolysis results are in overall agreement with fatty acid absorption in vivo. Practical Applications: Results obtained for rapeseed oil emulsified with canola proteins and phospholipids suggest that increased bioaccessibility of n‐3 polyunsaturated fatty acids could be offered in vegan food products.     

Characterization and Oxidative Stability of Structured Lipids: Infant Milk Fat Analog

Structured lipids (SLs) for infant milk formulation were produced by enzymatic interesterification of tripalmitin with vegetable oil blends and fish oil. The SLs were characterized by fatty acid content and structure, melting profiles, oxidative stability index, free fatty acid (FFA) concentration, and tocopherol content. Oxidative stability was studied using accelerated methods by quantifying FFA, peroxides (peroxide value) and aldehydes (p-anisidine value) production. Total oxidation (TOTOX value) was calculated as 2 × (peroxide value) + (p-anisidine value). The structured lipids after purification by distillation and addition of antioxidants had melting profiles, oxidative stability index, and initial FFA concentration that were similar to that of the starting oil blends, while the fatty acid composition and structure of the SLs were similar to that of human milk fat. Oxidative stability of the SLs was improved with tocopherol addition as antioxidants and was comparable to that of the vegetable oils and oil blends.