Enriched Eggs Research Articles

Two-Dimensional High Performance Liquid Chromatography-Mass Spectrometry for Phosphatidylcholine Analysis in Egg Yolk

Phospholipids are one of the classes of lipids, which are a major component of all cell membranes. Phosphatidylcholine (PC) is the main phospholipid present in egg yolk. The phospholipids extract from enriched egg yolk was separated using the two-dimensional high performance liquid chromatography in off-line system coupled with electrospray ionization tandem mass spectrometry (off-line HPLC-ESI-MS/MS). In the first dimension, a preparative C18 column was used, and on the second dimension, a separation was performed on N,O-dialkylphosphoramidate bonded silica column. In the analyzed egg yolk, 15 different phosphatidylcholines was found. From among the identified fatty acid of PC, a large part constitutes docosahexaenoic acid (ω-3, 22:6, DHA) and linoleic acid (ω-6, 18:2, LA).

Effect of a commercial housing system on egg quality during extended storage

Egg producers in the United States are utilizing a variety of commercial egg production systems to provide consumer choice and meet legislative requirements. Consumer egg grades in the United States were developed for conventional cage production, and it is unclear what effect alternative production systems might have on egg quality during retail and consumer home storage. The current study was undertaken to determine what changes in egg quality characteristics occur during extended cold storage for commercially produced conventional cage, enriched colony cage, and cage-free aviary eggs. During 12 wk of cold storage, egg weight, albumen height, Haugh unit, static compression shell strength, vitelline membrane strength and deformation, yolk index, shell dynamic stiffness, and whole egg total solids were monitored. Overall, aviary and enriched eggs were significantly (P < 0.05) heavier than conventional cage. Albumen height and Haugh unit (P < 0.05) were significantly greater for conventional cage than enriched eggs. Static compression shell strength was greatest (P < 0.05) for enriched eggs compared with aviary. No overall housing system effects for yolk measurements, shell dynamic stiffness, or whole egg total solids were observed. Albumen height, Haugh unit, and yolk quality measurements were all greatest at 0 and lowest at 12 wk of storage (P < 0.05). The rate of quality change among the housing systems for each measured attribute at 4, 6, and 12 wk was determined. Other than differences in the change of egg weight at 4 wk, no significant differences in the rate of quality decline were found among the housing systems. The results of the current study indicate that current US egg quality standards should effectively define quality for commercially produced conventional cage, enriched colony cage, and cage-free aviary eggs.

Egg n-3 Fatty Acid Composition Modulates Biomarkers of Choline Metabolism in Free-Living Lacto-Ovo-Vegetarian Women of Reproductive Age

The lacto-ovo-vegetarian (LOV) dietary regimen allows eggs, which are a rich source of choline. Consumption of eggs by LOV women may be especially important during pregnancy and lactation when demand for choline is high. The aim of this single blind, randomized, crossover-feeding study was to determine how near-daily egg consumption influenced biomarkers of choline metabolism in healthy LOV women of reproductive age (n=15). Because long-chain n-3 fatty acids could influence choline metabolism, the effect of n-3–enriched vs nonenriched eggs on choline metabolites was also investigated. Three 8-week dietary treatments consisting of six n-3–enriched eggs per week, six nonenriched eggs per week, and an egg-free control phase were separated by 4-week washout periods. Choline metabolites were quantified in fasted plasma collected before and after each treatment and differences in posttreatment choline metabolite concentrations were determined with linear mixed models. The n-3–enriched and nonenriched egg treatments produced different choline metabolite profiles compared with the egg-free control; however, response to the eggs did not differ (P>0.1). Consumption of the n-3–enriched egg treatment yielded higher plasma free choline (P=0.02) and betaine (P<0.01) (vs egg-free control) concentrations, whereas consumption of the nonenriched egg treatment yielded borderline higher (P=0.06) plasma phosphatidylcholine (vs egg-free control) levels. Neither egg treatment increased levels of plasma trimethylamine oxide, a gut-flora–dependent oxidative choline metabolite implicated as a possible risk factor for cardiovascular disease. Overall these data suggest that egg fatty-acid composition modulates the metabolic use of choline.

The Effect of Modified Eggs and an Egg-Yolk Based Beverage on Serum Lutein and Zeaxanthin Concentrations and Macular Pigment Optical Density: Results from a Randomized Trial

Increasing evidence suggests a beneficial effect of lutein and zeaxanthin on the progression of age-related macular degeneration. The aim of this study was to investigate the effect of lutein or zeaxanthin enriched eggs or a lutein enriched egg-yolk based buttermilk beverage on serum lutein and zeaxanthin concentrations and macular pigment levels. Naturally enriched eggs were made by increasing the levels of the xanthophylls lutein and zeaxanthin in the feed given to laying hens. One hundred healthy volunteers were recruited and randomized into 5 groups for 90 days. Group one added one normal egg to their daily diet and group two received a lutein enriched egg-yolk based beverage. Group three added one lutein enriched egg and group four one zeaxanthin enriched egg to their diet. Group five was the control group and individuals in this group did not modify their daily diet. Serum lutein and zeaxanthin concentrations and macular pigment densities were obtained at baseline, day 45 and day 90. Macular pigment density was measured by heterochromatic flicker photometry. Serum lutein concentration in the lutein enriched egg and egg yolk-based beverage groups increased significantly (p<0.001, 76% and 77%). A strong increase in the serum zeaxanthin concentration was observed in individuals receiving zeaxanthin enriched eggs (P< 0.001, 430%). No changes were observed in macular pigment density in the various groups tested. The results indicate that daily consumption of lutein or zeaxanthin enriched egg yolks as well as an egg yolk-based beverage show increases in serum lutein and zeaxanthin levels that are comparable with a daily use of 5 mg supplements.Trial RegistrationClinicalTrials.gov NCT00527553

Production of Iron-fortified eggs for changing consumer needs

An experiment was carried out in Nicobari fowl to investigate the efficiency of dietary iron supplementation on iron fortification in eggs. Birds were as-signed to each of four dietary treatments in a completely randomized de-sign: T1: Control (commercial layer feed); iron was supplemented in the form of iron- soy proteinate (Fe-SP) chelate @ 200 ppm (T2), 400 ppm (T3) and 600 ppm (T4). Birds were fed ad-libitum as per nutritional specification of BIS (2007). 60 d feeding trial showed that 200 ppm enhanced iron content in egg yolk to 64 μg/g yolk at 15th day of feeding as compared to control (50 μg/g yolk) and improved hatchability (24%). Further fortification beyond 200 ppm (400 &amp; 600 ppm) was not effective. Egg iron content was maximized at 15 days after feeding supplemental Fe. It was concluded that iron enriched egg could be produced on commercial basis to meet the consumers changing need.

Oxidative Stability of Omega-3 Polyunsaturated Fatty Acids Enriched Eggs

Omega-3 polyunsaturated fatty acids (n-3 PUFA) enriched eggs have a growing market share in the egg industry. This study examined the stability of n-3 PUFA enriched eggs fortified with antioxidants (vitamin E or organic Selenium [Sel-Plex] or both) following cooking and storage. The total fat content was not affected by cooking or simulated retail storage conditions, whereas, n-3 fatty acids were reduced. The content of n-3 fatty acids in boiled eggs was higher than in fried eggs. Lipid oxidation was significantly affected by the different cooking methods. Fried eggs contained higher levels of malondialdehyde (MDA, 2.02 μg/kg) and cholesterol oxidation products (COPs, 13.58 μg/g) compared to boiled (1.44 and 10.15 μg/kg) and raw eggs (0.95 and 9.03 μg/kg, respectively, for MDA and COPs). Supplementation of antioxidants reduced the formation of MDA by 40% and COPs by 12% in fried eggs. Although the content of MDA was significantly increased after 28 days of storage, COPs were not affected by storage. Our study indicated that the n-3 PUFA in enriched eggs was relatively stable during storage and home cooking in the presence of antioxidants.

Impact of microalgal feed supplementation on omega-3 fatty acid enrichment of hen eggs

In many Western countries, the average intake of the health beneficial omega-3 long chain polyunsaturated fatty acids (n-3 LC-PUFA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), is below the recommended level, raising interest in food enrichment with n-3 LC-PUFA. To that end, the impact of feed supplementation with EPA rich autotrophic microalgal biomass on n-3 L-PUFA enrichment of eggs was studied. Hens were divided in three groups receiving different diets for 28days: a standard diet (C) for laying hens, (C) supplemented with 5.0% spray dried Nannochloropsis gaditana, and (C) to which 10.0% of these microalgae were added. Microalgal EPA was hardly accumulated in yolk lipids, but preferentially converted to DHA and deposited in yolk phospholipids. The efficiency of deposition of microalgal n-3 LC-PUFA to eggs was rather low. Switching back to standard feed ensured that the n-3 LC-PUFA level obtained in enriched eggs decreased back to that of the control eggs. Moreover, the colour of egg yolk shifted from yellow to more orange-red, which is presumably due to transfer of microalgal carotenoids to egg yolk. Thus, the use of autotrophic microalgae as supplement for standard feed offers an alternative to current sources for the production of DHA enriched eggs.

A preliminary study effects of supplement food to the content of omega-3 in eggs

Omega-3 fatty acids contribute significantly in preventing cardiovascular disease, reducing the concentration of triglycerides, and lowering cholesterol. Therefore, worldwide there are many studies on Omega-3 and foods fortified with Omega -3 have been developed and commercialized on the market, most notably Omega-3 enriched eggs. Initially this study was to evaluate the effect of some food supplements on levels of Omega-3 in eggs of Isa Brown hens from 38-48 weeks of age. The experiment was divided into three treatments: (NT) is completely random, NT1 additional 10% supplement 1 (CBS1) and NT additional 10% CBS2. After 2 months, the hens fed 10% CBS1 supplement in the diet increased the highest amount, with Omega-3 content 356 mg/egg, compared to control of 100 mg/egg, and hens fed with 10% CBS2 supplement with 222 mg/egg. Additional 10% CBS1 and 10% CBS2 in the diet of Isa Brown hens did not only no effect on egg production and egg quality parameters but also increased content of Omega-3 in eggs. This study aimed to produce Omega-3 enriched eggs for the market, serving the health of people with a cheaper price than other imported foods with enriched omega-3. This study was applied and approved during the Inventions/Utility Solution at the National Office of Intellectual Property of Vietnam No. 2-2011-00287.

Omega-3 enriched egg production: the effect of α -linolenic ω -3 fatty acid sources on laying hen performance and yolk lipid content and fatty acid composition

1. Diets high in total lipids, saturated fatty acids, trans fatty acids, and having high ω-6:ω-3 fatty acid ratios, have been shown to be related to increased instances of coronary heart disease, while diets high in ω-3 fatty acids have been shown to decrease the risk. 2. Feeding ω-3 fatty acid diets to laying hens has been shown to improve the quality of eggs produced in terms of saturation and ω-3 content. 3. A study was undertaken to determine if the ω-3 fatty acid source, when fed to hens, influences the amount transferred to eggs. 4. Flaxseed and flaxseed oil, along with chia seed and chia seed oil, were the two main sources of ω-3 fatty acid examined during the 84 d trial. 5. All α-linolenic enriched treatments yielded significantly higher ω-3 fatty acid contents per g of yolk and per yolk, than the non-α-linolenic enriched diets. Chia oil and chia seed yielded 54·5 and 63·5% more mg of ω-3 fatty acid per g of yolk for the 56 d test period, and 13·4 and 66·2% more for the 84 d test period, than flaxseed oil and flaxseed, respectively. 6. The differences in omega-3 content were significant, except for the chia oil compared with the flax oil, at the end of the trial. 7. This trial has shown that differences in conversion exist among ω-3 fatty acid sources, at least when fed to hens, and indicates that chia may hold a significant potential as a source of ω-3 fatty acid for enriching foods, thereby making these foods a healthier choice for consumers.

Effect of Adding Flaxseed in the Diet of Laying Hens on Both Production of Omega-3 Enriched Eggs and on Production Performance

2 Abstract: Since eggs are an important part of the human diet and people have strong health awareness, it is beneficiary to produce eggs that are considered healthier products such as omega-3 enriched eggs. Omega-3-fatty acids have been shown to improve the human health in many aspects. Lowering circulating levels of cholesterol and lowering blood pressure are just some of their effects. It has been shown that feeding laying hens with flaxseeds leads to an increase levels of omega-3-fatty acids in the eggs and change the Omega-6 to Omega-3 ratio to an appropriate one. However, studies on the effects of feeding flaxseed to laying hens on both increase levels of omega-3 fatty acids and production performance are limited. Therefore, the purpose of the current study was to study the effects of adding flaxseed in the diet of laying hens on both producing omega-3 enriched eggs and on the production performance. Twenty four wk old Lohmann Selected Line (LSL) laying hens were used in the current study. The hens were divided randomly into four groups, the first received a diet with no flaxseed added and served as a control, the second, third and fourth group received 5.0%, 7.5% and 10% of flaxseed in the diet, respectively. The treatments continued for 32 wks. Egg production and feed consumption were recorded and feed efficiency was calculated. In addition, eggs from the different groups were collected at four, eight and 32 wks following treatment and levels of omega-3 and omega-6 fatty acids were measured and the ratio between the two was calculated. At eight wks following treatment, it was found that using either 7.5 or 10% flaxseed in the diet significantly (p<0.05) increased levels of omega-3 fatty acids in the eggs compared to the control. Levels were 267, 232 and 64 mg/egg for the 10%, 7.5% and control group, respectively. In addition, ratio of omega-6 to omega-3 was 2.33:1, 2.98:1 and 10.05: 1, for the same groups, respectively. Furthermore, adding flaxseed in the diet did not adversely affect egg production, egg weight, or feed efficiency. It can be concluded that using flaxseed in the diet of laying hens can result in producing omega-3 enriched eggs and reducing the omega-6: omega- 3 ratio without any adverse effects on production performance.

Stability of the pigmentation of egg yolks enriched with omega-3 and carophyll stored at room temperature and under refrigeration

The objective of this experiment was to study yolk pigmentation stability in omega 3 (ω-3) enriched eggs stored under different temperatures in zeaxanthin equivalent (by using visible light spectrophotometer) and visual score (with values obtained by yolk color fan) and to verify the correlation among those methodologies. Three hundred big eggs from Isa Brown hens were distributed into two lots each one containing 150 eggs, stored at room temperature (26.5ºC) or under refrigeration (7.9ºC) for 35 days. It was used a completely randomized design in a 2 × 6 factorial arrangement (storage temperature × storage period). Pigmentation observed with the yolk color fan was steady during the experiment period when eggs were kept under refrigeration and it reduced when stored at room temperature. At spectrophotometric quantification, carotenoids decreased in both temperatures studied. There is a high correlation between the methods of analysis for eggs stored at room temperature and for eggs stored under refrigeration as well, but this correlation is sharper when eggs are stored under refrigeration.

Consuming iodine enriched eggs to solve the iodine deficiency endemic for remote areas in Thailand

BackgroundEvidence showed that the occurrence of iodine deficiency endemic areas has been found in every provinces of Thailand. Thus, a new pilot programme for elimination of iodine deficiency endemic areas at the community level was designed in 2008 by integrating the concept of Sufficient Economic life style with the iodine biofortification of nutrients for community consumption.MethodsA model of community hen egg farm was selected at an iodine deficiency endemic area in North Eastern part of Thailand. The process for the preparation of high content iodine enriched hen food was demonstrated to the farm owner with technical transfer in order to ensure the sustainability in the long term for the community. The iodine content of the produced iodine enriched hen eggs were determined and the iodine status of volunteers who consumed the iodine enriched hen eggs were monitored by using urine iodine excretion before and after the implement of iodine enrichment in the model farm.ResultsThe content of iodine in eggs from the model farm were 93.57 μg per egg for the weight of 55 - 60 g egg and 97.76 μg for the weight of 60 - 65 g egg. The biological active iodo-organic compounds in eggs were tested by determination of the base-line urine iodine of the volunteer villagers before and after consuming a hard boiled iodine enriched egg per volunteer at breakfast for five days continuous period in 59 volunteers of Ban Kew village, and 65 volunteers of Ban Nong Nok Kean village. The median base-line urine iodine level of the volunteers in these two villages before consuming eggs were 7.00 and 7.04 μg/dL respectively. After consuming iodine enriched eggs, the median urine iodine were raised to the optimal level at 20.76 μg/dL for Ban Kew and 13.95 μg/dL for Ban Nong Nok Kean.ConclusionsThe strategic programme for iodine enrichment in the food chain with biological iodo-organic compound from animal origins can be an alternative method to fortify iodine in the diet for Iodine Deficiency Endemic Areas at the community level in Thailand.

Fatty acid composition of egg yolk phospholipid fractions following feed supplementation of Lohmann Brown hens with humic-fat preparations

The effect of feed supplementation with humic-fat preparations on the fatty acid composition of egg yolk phospholipid fractions was studied. The Lohmann Brown was the experimental hen strain and two feeding mixtures were applied – the standard feed and the mixture supplemented with humic-fat preparations. The fatty acid profile of yolk lipids was significantly affected (P=.05) by the supplementation of feed and total increase of n-3 polyunsaturated fatty acids (PUFA) was established. A different distribution of n-3 PUFA in egg yolk lipid fractions was observed: α-linolenic acid (18:3) was found in the triacylglycerol fraction, whereas docosahexaenoic acid (22:6) was detected in the phospholipid fractions. Supplementation of the hen’s diet with humic-fat preparations resulted in the production of n-3 enriched eggs with decreased n-6/n-3 ratio in all phospholipid fractions in comparison to the eggs from the control group.

The Enrichment of Hen Eggs with ω-3 Fatty Acids

A study was conducted to determine the omega-3 fatty acid compositions of enriched eggs obtained from hens by feeding flaxseed and fish oil. Laying hens were fed a diet containing fish oil (FOD) (1.5%) or a mixture of flaxseed (10%) and fish oil (FFOD) (1.5%) for 15 and 30 days. Another group was fed commercial diet as a control. Eicosapentaenoic acid (EPA) and docosapentaenoic acid (DPA) were not determined in the control group's eggs. However, the EPA level was 0.87% and 0.82% in the FOD group's eggs and 0.49% and 0.55% in the FFOD group's eggs, obtained after a 15- and 30-day feeding period, respectively. Corresponding values for DPA were 0.45% and 0.50% in the FOD group's eggs and 0.41% and 0.44% in the FFOD group's eggs. Docosahexaenoic acid contents of eggs obtained from the FOD group were 4.85% and 4.92% after a 15- and 30-day feeding period, respectively, compared with 3.29% and 3.91% in the FFOD group's eggs and 1.03% in the control group's eggs. The alpha-linolenic acid content of eggs was 0.45% and 0.49% in the FOD group's eggs after a 15- and 30-day feeding period, respectively, and 0.43% in the control group's eggs, whereas it was 3.61% and 4.10%, respectively, in the FFOD group's eggs.

The effect of fermentation of sludge with Neorospora sp. on the egg performances and quality of laying hens.

The purpose of this research is to produce enriched eggs (high concentration in protein, amino acid and β-karoten) but law in lipid and cholesterol content. An experiment was conducted to study the utilization of fermented palm oil sludge (LSF) using neurospora sp for layer. The present study was done based on Randomized Design in which 100 layer were distributed to five treatment group as follow: Layers were fed diet with (0, 5, 10, 15 and 20% LSF). Experimental results showed that LSF significantly (P 0.05). LSF reduced egg smell, improved taste of egg and yolk colur (P < 0.05). Protein and fat, contents of eggs were significantly reduced (P < 0.05) and cholesterol content of eggs was significantly reduced (P < 0.01). Utilization LSF increased the content of β-karoten yolk (P < 0.01), and modified the composition of amino acid in yolk. In conclusion, utilization of LSF improved egg quality, reduced egg cholesterol dan lipid and modified the composition of amino acid in yolk. Key Words: Palm Oil Sludge, Neorospora sp, Egg Quality

Consumption of either one egg or lutein‐enriched egg per day increases HDL cholesterol, reduces apolipoprotein B while increasing plasma carotenoids and macular pigment density in adult subjects

In this study, subjects were assigned to consume either one egg (n =11), one egg substitute (n = 12) or one egg fortified with 600 μg of lutein (n = 11) per day. We measured plasma lipids, LDL subfractions and circulating carotenoids, macular pigment density (MPOD) by use of a densitometer, and hand carotenoids by use of a biophotonic scanner at baseline and after 12 wk. No changes in plasma LDL cholesterol or triglycerides were observed over time. However, both egg groups presented increases in HDL cholesterol compared to baseline (P &lt; 0.01). All subjects had decreases in apolipoprotein B (P &lt; 0.05) associated with a lower number of small LDL particles (P &lt; 0.01). Independent of source, egg intake increased MPOD (P &lt; 0.01) while hand carotenoids did not change over time for any of the groups. Plasma lutein concentrations increased by 9% (P &lt; 0.01) and by 35% (P &lt; 0.001) in the egg and lutein‐enriched egg groups, respectively. In this study we have demonstrated that MPOD increases whether subjects are consuming regular eggs or lutein enriched eggs. However, circulating lutein concentrations were associated with higher intake of this carotenoid, which may increase antioxidant protection in plasma. These studies demonstrate that consuming one egg per day may protect the eye against macular degeneration while increasing HDL cholesterol and favoring the formation of less atherogenic particles. [Supported by the Egg Board]

English

Two experiments were planned to study the influence of dietary fat sources (fish oil (FO) or sunflower oil (SO)) and dietary doses of &alpha;-tocopheryl acetate (&alpha;-TA) (0, 60 and 120 mg/kg of feed) and vitamin A (0 IU, 10000 IU and 20000 IU) on lipid oxidation of stored eggs in three stages of 0 or fresh, 1 and 2 months of storage time. In the first experiment, 96 hen layers in six treatments including two oil sources (FO and SO) and two dietary [0, 60 and 120 mg/kg doses of &alpha; -tocopheryl acetate (&alpha;-TA)] were fed for 75 days. In the second experiment, 96 hen layers in six treatments including two sources of &omega;3 and &omega;6 (FO and SO) and three doses&nbsp; 0, 10000 and 20000 IU of vitamin A were fed for 75 days. The results showed that using &alpha;-TA supplementation, lipid stability of enriched eggs increased and was very effective throughout the stored period of the eggs. Yolk TBA value was higher in fish oil than sunflower oil groups (p &lt; 0.01). The treatments that contained 120 mg/kg of &alpha;-TA in diets, showed lower lipid peroxidation than other groups in stages of 2 and 3 storage time (30 and 60 days). The degree of lipid oxidation in fresh, 1 and 2 months of storage eggs was measured by the lipid TBA values. The results showed that TBA value in fresh and stored eggs was higher in groups containing fish oil than other groups (p &lt; 0.01). The MDA value in stage 1 was higher in fish oil group and in 2 and 3 stages was lower in FO + A1. Therefore, addition of Vitamin E and A as natural antioxidants in diets containing oil source for the prevention of lipid oxidation is recommended. &nbsp; Key words:&nbsp;Fish oil, sunflower oil, &alpha;-tocopheryl acetate, vitamin A, TBA value, egg. &nbsp; &nbsp;

Composition en acides gras des œufs : intérêt nutritionnel et valeur santé

The average composition in lipids and fatty acids of the hen’s egg is reported. The fact that the egg is a source of phospholipids is pointed out. The enrichment in essential fatty acids in response to different dietary lipids is reported with a focus on enrichment with omega 3 fatty acids. The results of the different approaches of enrichment through seeds oils, marine oils or both are described. The potential interest of using omega 3 enriched egg, specially DHA enriched egg, in human nutrition is documented through the specific properties of DHA-bearing egg phospholipids in terms of stability to oxidation, better bioavailability and specific physiological effects.

Internal quality of conventional and omega-3-enriched commercial eggs stored under different temperatures

The internal quality of conventional and ω-3 enriched commercial eggs stored at different temperatures was evaluated. Eggs derived from Isa Brown layers fed two different diets. In Group 1, 432 hens were fed throughout their productive life with a diet based on corn and soybean meal (production of conventional eggs). In Group 2, starting at 22 weeks of age, other 432 hens were fed a diet containing 1.5% of marine algae substrate and 1.8% of fish oil (production of ω-3 enriched eggs). The following parameters were evaluated: Haugh unit, yolk index, albumen pH, and yolk pH. There were no significant differences between conventional and enriched with ω-3 eggs as to internal quality parameters. Only the interaction between storage time and temperature was significant, and therefore their effects were evaluated, independent of egg type (conventional eggs and ω-3 enriched eggs). Eggs stored at 25ºC presented lower Haugh units and yolk index, and higher albumen pH and yolk pH as compared to those kept at 5ºC. In addition, internal quality was reduced when eggs were stored for 7, 14, and 21 days, particularly when maintained at 25ºC. It was concluded that conventional and ω-3 enriched eggs have good internal quality; however, to maintain this quality, eggs must be stored under refrigeration.

Increase of Cholesterol Oxidation and Decrease of PUFA as a Result of Thermal Processing and Storage in Eggs Enriched with n-3 Fatty Acids

In this work, cholesterol oxide formation and alteration of fatty acid composition were analyzed in n-3 enriched eggs under different storage periods and two temperatures. The eggs enriched with n-3 fatty acids were stored at 5 or 25 degrees C for 45 days and subsequently boiled or fried. For each treatment, 12 yolks were analyzed every 15 days including time zero. The concentrations of the cholesterol oxides 7-ketocholesterol, 7beta-hydroxycholesterol, and 7alpha-hydroxycholesterol increased during the storage period and were higher in fried eggs. Only the 7-ketocholesterol was affected by the storage temperature, and its concentration was highest in eggs stored at 25 degrees C. There was no significant difference in the contents of cholesterol and vitamin E at the different storage periods; however, the concentration of vitamin E decreased with thermal treatment. In addition, the n-3 polyunsaturated fatty acids, especially 18:3, 20:5, and 22:6, were reduced throughout the storage at 5 and 25 degrees C.