Influence of environmental temperature on composition of lipids in edible flesh of rainbow trout (Oncorhynchus mykiss)

The adaptative changes in the fatty acid composition of the main lipid classes in rainbow trout (Oncorhynchus mykiss) edible flesh in response to environmental variation in water temperature were investigated. The research was carried out on intensively farmed trout sampled at different times of the year. Neutral lipids (NL), phosphatidylcholine (PC) and phosphatidylethanolamine (PE) were separated using flash chromatography. Compared with summer acclimatisation, a decrease in neutral lipids of about 19% was observed in winter, accompanied by increases in phosphatidylethanolamine and phosphatidylcholine of about 41 and 29%, respectively. The metabolic adjustment in cold adaptation caused an increase in the levels of unsaturated fatty acids and monoenes of the oleic acid ω9 family and an increase in the levels of unsaturated fatty acids of the linoleic acid ω3 family. At the same time a reduction in the levels of saturated and monounsaturated fatty acids of the oleic acid ω9 family was observed. This pattern turned out to be particularly evident in phosphatidylcholine. The net result of these changes in composition was a significant increase in the polyunsaturated/saturated and polyunsaturated/monoenic fatty acid ratios in the edible flesh. Copyright © 2003 Society of Chemical Industry     

利用核磁共振研究脂肪氧合酶酶促氧化蛋黄磷脂

利用31P核磁共振比较酶促氧化前后蛋黄磷脂的组成,通过1H核磁共振监测并比较空白组（未氧化）与脂肪氧合酶酶促氧化及95 ℃水浴加热氧化过程中脂肪酰基的相对物质的量、一级和二级氧化化合物含量的变化。结果表明：磷脂酰胆碱和磷脂酰乙醇胺是蛋黄磷脂的主要成分;蛋黄磷脂氧化后,磷脂酰胆碱和磷脂酰乙醇胺含量均下降,而溶血性磷脂含量增加;所有被氧化的蛋黄磷脂样品中总不饱和脂肪酸相对物质的量均下降,而饱和脂肪酸相对物质的量均上升;其中在pH 6酶促条件下,亚油酸降解速率最快。脂肪氧合酶在pH 6条件下催化氧化蛋黄磷脂生成更多的氢过氧化物,加热后主要生成(Z,E)-2,4-二烯醛;而在pH 9条件下蛋黄磷脂生成氢过氧化物后快速降解,在加热后生成较多正构烷醛。因此,可以利用脂肪氧合酶在pH 6条件下催化氧化蛋黄磷脂生成更多的2,4-二烯醛类风味化合物。     

二十二碳六烯酸营养强化鸡蛋及蛋黄粉中 脂质分析

目的研究不同市售二十二碳六烯酸(docosahexaenoic acid, DHA)营养强化鸡蛋及蛋黄粉的脂肪酸组成以及DHA等n-3多不饱和脂肪酸的含量。方法脂质的提取采用Folch法,极性脂与中性脂的分离采用薄层色谱层析法,磷脂酶A2 (phospholipaseA2,PLA2)水解磷脂酰胆碱sn-2位脂肪酸,气相色谱法测定脂肪酸组成。结果市售普通鸡蛋中DHA含量为总脂肪酸的0.49%(29.19 mg/100 g鸡蛋),而4种不同品牌市售DHA营养强化鸡蛋中DHA占脂肪酸百分比分别为1.16%(111.79 mg/100 g鸡蛋)、1.86%(151.17 mg/100 g鸡蛋)、2.03%(159.46 mg/100 g鸡蛋)、5.37%(313.59 mg/100 g鸡蛋)。不同品牌的营养强化鸡蛋中DHA含量差异显著(P0.05)。市售DHA蛋黄粉中DHA含量为3.35 g/100 g蛋黄粉,其磷脂中含有2.07 g/100 g蛋黄粉。PLA2水解产物表明,蛋黄粉磷脂酰胆碱中DHA连接在磷脂酰胆碱sn-2位上。结论市售营养强化鸡蛋中的DHA含量高于普通鸡蛋,不同品牌的营养强化鸡蛋之间DHA含量差别较大。蛋黄粉磷脂酰胆碱中的DHA位置连接在sn-2位上。     

Fatty acid composition of certified organic,conventional and omega-3 eggs

The objective of this study was to compare the fatty acid composition of commercially available conventional, certified organic, and omega-3 eggs. Egg components were assessed, and the fatty acid composition of yolk lipids was determined by gas chromatography. Organic egg yolk contained a higher percentage of palmitic and stearic acids than did conventional yolk (P < 0.05) with no differences observed in the monounsaturated or polyunsaturated fatty acid compositions. Compared with organic and conventional eggs, omega-3 egg yolk contained lower percentages of myristic and palmitic acids, and higher omega-3 fatty acids. In a sub-analysis of conventional egg types, the percent of stearic acid in “cage” egg yolk was significantly lower (P < 0.05) than those of “barn-laid” and “free-range” eggs. “Cage” eggs had a significantly lower percentage (P < 0.05) of arachidonic acid than had “barn-laid” eggs. Consumption of omega-3 eggs has the potential to confer health benefits through the increase in intake of omega-3 fatty acids. With regard to organic or conventional methods of production, the small differences in saturated fatty acids observed in the present study are unlikely to have any significant metabolic effect on the consumer.     

不同饲养类型鸡蛋中脂类的含量测定

用甲醇和氯仿,使蛋黄溶液从一相系统转变成二相系统来提取脂类,通过三方向TLC来分离脂类中的组成成分;并将脂肪甲基化,用100m×0.25mm的GC毛细管柱来测定脂类中脂肪酸的组成。TLC结果表明,蛋黄脂类中由C、TG、CE、FFA、PE、PC、SM等组成,而且TG、CE和PC含量最高,其次为C和PE,含量最低的为FFA和SM。GC测定结果显示,蛋黄脂肪酸中16:0、18:0、9c18:1、18:2n6含量最高;与笼养鸡蛋相比,放养鸡蛋中18:1t、18:1c、饱和脂肪酸和单不饱和脂肪酸所占的比率都显著下降,分别为1.34%对0.69%,42.38%对39.06%,39.74%对37.90%,47.09%对43.30%。但多不饱和脂肪酸却有极显著增加,为12.09%对17.39%,这主要体现在18:2n6和ω3脂肪酸的显著增加,分别为9.91%对14.64%,0.23%对0.44%。ω3 Egg2组饱和脂肪酸比率(30.40%)比笼养鸡蛋和放养鸡蛋都极显著降低;多不饱和脂肪酸比率(25.56%)则极显著升高,且这种升高主要是18:3n3(7.55%)和ω3 (1.67%)脂肪酸的显著升高所致。表明不同的饲养类型,影响鸡蛋中某些脂肪酸的比例。     

超声辅助提取蛋黄卵磷脂工艺优化及其理化特性研究

目的:优化超声辅助乙醇提取蛋黄卵磷脂的工艺参数,并对提取产品的稳定性和抗氧化活性进行研究。方法:采用响应面方法,优化影响蛋黄卵磷脂的主要参数(液料比、乙醇浓度、时间);运用薄层色谱、红外光谱、气相-质谱联用法分析了卵磷脂结构和脂肪酸组成;并研究了卵磷脂稳定性和抗氧化活性。结果:超声辅助乙醇提取蛋黄卵磷脂最优工艺参数为:液料比15:1 (mL/g),乙醇浓度92%,提取时间22 min。在此条件下,提取所得卵磷脂含量为375.69 mg/g。薄层色谱和红外光谱确定提取物为蛋黄卵磷脂;气相色谱-质谱联用法检测了蛋黄卵磷脂中脂肪酸组成,主要为油酸、亚油酸、硬脂酸和软脂酸。稳定性和抗氧化活性分析表明,光照和温度影响卵磷脂的抗氧化活性和稳定性,蛋黄卵磷脂的稳定性和抗氧化活性优于大豆卵磷脂。结论:超声辅助乙醇法是一种较好的提取蛋黄卵磷脂的方法,本研究成果为蛋黄卵磷脂的提取、贮藏和综合利用提供了一定的技术支持。     

Egg yolk fatty acid profile in relation to dietary fatty acid concentrations

BACKGROUND: The health benefits of n‐3 fatty acids have led to much research on manipulating the fatty acid composition of animal‐derived foods. In this study, two experiments were conducted to investigate the interaction of dietary fatty acids on egg yolk fatty acid concentrations. In experiment I, 32 dietary treatments with three replicates of three birds each were fed for 35 days. Diets were prepared by mixing one type of fish oil with four vegetable oils in different proportions. In experiment II, three different types and two levels of fish oil in combination with two vegetable oils were tested under the same conditions as in experiment I. RESULTS: In experiment I the results showed that the egg yolk saturated (SFA) and monounsaturated (MUFA) fatty acid concentration was determined by the dietary SFA, MUFA and 18:2n‐6 content. The egg 18:2n‐6 concentration was mainly explained by the dietary inclusion of 18:2n‐6 and negatively by the dietary MUFA content. The egg C18:3n‐3, C20:5n‐3 and C22:6n‐3 concentration is almost exclusively determined by their direct supply from the diet. The egg 20:4n‐6 concentration was inversely proportional to the long‐chain n‐3 polyunsaturated fatty acid content of the diet. The results of experiment II showed that the egg yolk C20:5n‐3 and C22:6n‐3 concentration was determined by both the level of dietary fish oil (1 or 2%) and the C20:5n‐3/C22:6n‐3 ratio in the fish oil. CONCLUSION: The results of this study demonstrated that the direct dietary supply of fatty acids is the most important factor determining the egg yolk fatty acid composition, in particular for the n‐3 fatty acids. The interaction effect from other dietary fatty acids was in general small. Copyright © 2011 Society of Chemical Industry     

Chemical Compositions of Egg Yolks and Egg Quality of Laying Hens Fed Prebiotic,Probiotic, and Synbiotic Diets

A 16‐wk feeding experiment was conducted to investigate the effects of a prebiotic, isomaltooligosaccharide (IMO), a probiotic, PrimaLac®, and their combination as a synbiotic on the chemical compositions of egg yolks and the egg quality of laying hens. One hundred and sixty 16‐wk‐old Hisex Brown pullets were randomly assigned to 4 dietary treatments: (i) basal diet (control), (ii) basal diet + 1% IMO (PRE), (iii) basal diet + 0.1% PrimaLac® (PRO), and (iv) basal diet + 1% IMO + 0.1% PrimaLac® (SYN). PRE, PRO, or SYN supplementation not only significantly (P < 0.05) decreased the egg yolk cholesterol (24‐ and 28‐wk‐old) and total saturated fatty acids (SFA; 28‐, 32‐, and 36‐wk‐old), but also significantly (P < 0.05) increased total unsaturated fatty acids (UFA; 28‐, 32‐, and 36‐wk‐old), total omega 6 and polyunsaturated fatty acids (PUFA), including linoleic and alpha‐linolenic acid levels in the eggs (28‐wk‐old). However, the total lipids, carotenoids, and tocopherols in the egg yolks were similar among all dietary treatments in the 24‐, 28‐, 32‐, and 36‐wk‐old hens. Egg quality (Haugh unit, relative weights of the albumen and yolk, specific gravity, shell thickness, and yolk color) was not affected by PRE, PRO, or SYN supplementation. The results indicate that supplementations with IMO and PrimaLac® alone or in combination as a synbiotic might be useful for improving the cholesterol content and modifying the fatty acid compositions of egg yolk without affecting the quality of eggs from laying hens between 24 and 36 wk of age.     

Species‐specific differences in the fatty acid profiles of the lipids of the yolk and of the liver of the chick

Differences between four avian species of commercial importance (chicken, turkey, duck and goose), in terms of the relationship between the dietary fatty acids supplied in the diet of the layers and the fatty acid composition of the egg yolk lipids, were investigated. Laying hens of the four species were provided with diets with very similar fatty acid compositions. The polyunsaturated fatty acid content of the diets consisted of linoleic and α‐linolenic acids at approximately 50% and 6% (w/w of total fatty acids), respectively, for all four species. In spite of the very similar dietary provision of fatty acids, the subsequent fatty acid profiles of the yolk lipids differed markedly between the four species. In particular, the proportion of docosahexaenoic acid in the total lipid of the yolk was three to five times greater for the chicken compared to the other three species. By contrast, the proportion of arachidonic acid in total yolk lipid was approximately two times greater for the goose and duck than for the chicken and turkey. Thus the chicken was more efficient at incorporating long‐chain (C₂₂ ) fatty acid of the n‐3 series into yolk lipid whereas the duck and goose preferentially incorporated C₂₀ fatty acid of the n‐6 series. The turkey eggs contained a similar proportion of arachidonic acid but less docosahexaenoic acid than the chicken eggs. The main differences between the avian species in terms of the yolk levels of C_{20 –22} polyunsaturated fatty acids were in the phospholipid fraction since only low levels of these fatty acids were present in the triacylglycerol fraction. The relative proportions of docosahexaenoic acid in the phospholipid and triacylglycerol fractions of the livers of the newly‐hatched chicks of the four species reflected the differences displayed by the yolks. The proportions of arachidonic acid in these liver lipid fractions, however, did not reflect the species differences in yolk lipid composition. © 1999 Society of Chemical Industry     

The effects of sources of supplemental fat on performance,egg quality,and fatty acid composition of egg yolk in laying hens

BACKGROUND: The objective of this study was to determine the effects of sources of supplemental fat on laying performance, egg quality, and fatty acid composition of egg yolk. RESULTS: Two hundreds Isa Brown layers were assigned randomly to be fed ad libitum a standard commercial layer feed (BD), basal diet plus 2% tallow (T), basal diet plus a mixture of 1% tallow and 1% flaxseed oil (MTFO), basal diet plus 2% sunflower oil (SO), or basal diet plus 2% flaxseed oil (FO), which were offered for 8 weeks. Each diet was given to five groups, each containing 10 hens. The feed efficiency and egg production were 2.78 and 53.51% for BD; 2.30 and 63.47% for T; 2.45 and 60.14% for MTFO; 2.29 and 64.30% for SO, and 2.62 and 61.18% for FO groups, respectively. Dietary fat supplementation affected the laying performance but had no significant effects on egg quality parameters. The fatty acid composition of egg yolk lipids were significantly affected by dietary fatty acid composition. The supplemental tallow increased palmitic fatty acid. The proportions of linoleic and arachidonic fatty acids in egg yolks for layers fed the SO diet were higher than in the BD group and those on diets containing other fats. Concentrations of oleic and omega‐3 fatty acids were the highest in layers fed the FO diet during the laying period. CONCLUSION: The results indicated that dietary animal and plant fats changed the fatty acid composition of egg yolk. Copyright © 2008 Society of Chemical Industry     

六种禽蛋中脂肪酸、氨基酸及胆固醇的营养成分分析

对六种禽蛋营养成分进行分析,以期为禽蛋开发利用提供技术基础.本文对六种禽蛋(白羽鸡、金定鸭、贵妃鸡、珍珠鸡、中国环颈雉、鹌鹑)物理指标及冻干禽蛋蛋黄脂肪酸、蛋白氨基酸和胆固醇等成分进行研究.结果表明,六种禽蛋蛋黄中共鉴定出24种脂肪酸,金定鸭蛋黄中总脂肪酸含量最高(20.67 g/100 g),饱和脂肪酸(22.49％...     

Enrichment of eggs in n-3 polyunsaturated fatty acids by feeding hens with different amount of linseed oil in diet

The production of n-3 polyunsaturated fatty acid enriched eggs by addition of linseed oil to the laying hens' diet has been evaluated in terms of production parameters and n-6/n-3 ratio. A total of 150 18weeks old Lohmann Brown laying hens were housed in cages and fed with basal diet and four experimental diets containing 1%, 2%, 3% or 4% of linseed oil added to the basal diet. The effect of the altered level of linseed oil on hens laying performance, fatty acid content and composition and cholesterol content in egg yolk has been evaluated during 13weeks of experiment. Egg weight, yolk fat content, yolk weight, yolk percentage and shape index were not influenced by dietary treatment. The ratio between n-6 and n-3 polyunsaturated fatty acids in eggs decreased in first 5weeks and then remained stable until the end of the experiment for all experimental groups. Different contents of linseed oil in feed highly influenced the n-6/n-3 ratio (P<0.0001). Addition of linseed oil did not influence the cholesterol content in yolks (P=0.5200) while the only factor affecting the cholesterol content was the hens age (P<0.0001).     

Influence of rapeseed cake, linseed cake and hemp seed cake on laying performance of hens and fatty acid composition of egg yolk

In hens the effects of expeller/cakes from rapeseed, linseed, and hemp seed were investigated on feed intake, laying performance and fatty acid composition of egg yolk. A total of 216 individually caged laying hens were allocated to nine dietary treatments (5, 10, 15 % cake) and fed for six laying months. For feed intake, egg mass production and feed-to-egg mass ratio at 15 % dietary cake level a significant lower performance was shown compared with the 5 and 10 % cake level groups. Also interaction was significant for all these parameters, indicating that the cake level acted differently for the three cakes. The egg mass production was lower in the linseed cake than in the hempseed groups and the hens fed the linseed cake needed significantly more feed per kg egg mass compared with both the other cakes tested. Increasing dietary level of all oil seed cakes lowered the yolk percentage and increased the egg white percentage. Increased dietary levels of all three oil seed cakes lowered the percentages of most saturated fatty acids and also the percentages of the monounsaturated fatty acids. The linoleic acid and the linolenic acid as polyunsaturated fatty acids were heightened by increasing the cake levels from 5 to 10 and 15 % in the diet. The results allow the conclusion that compound feeds with up to 10 % of cakes does not negatively influence the laying performance of hens and provides the possibility of the enrichment of yolk fat with polyunsaturated fatty acids.     

Fatty acid profile and sensory characteristics of table eggs from laying hens fed hempseed and hempseed oil

Hempseed (HS) is rich in omega-3 polyunsaturated fatty acids, with approximately 17% of total fatty acids as alpha-linolenic acid. As such, HS and its oil may be used in hen diet formulations to produce eggs enriched in essential fatty acids. Because omega-3 eggs have the potential for unpleasant aromas and flavors, the current study was designed to assess the fatty acid profile and sensory attributes of eggs procured from hens consuming diets containing hempseed oil (HO) or HS. A total of 48 individually caged White Bovan hens received 1 of 6 diets containing 4%, 8%, 12% HO, 10%, 20% HS or 0% hemp (w/w) for 12 wk. Total omega-3 polyunsaturated fatty acid content was highest in the 12% HO group (15.3 mg/g of yolk) compared to the control (2.4 mg/g of yolk). Trained panellists (n= 8) found no significant differences (P≥ 0.05) in aroma or flavor between cooked eggs from different dietary treatments, with the exception of sweet flavor. The 4% HO group yielded the least sweet eggs compared to the 20% HS group, which was highest. For yolk color, L*, a*, and b* values (Mean ± SEM) for control eggs were 61.2 ± 0.10, 1.1 ± 0.05, and 43.0 ± 0.22, respectively. Addition of hemp led to significant (P < 0.001) reductions in L*, and significant increases in a* and b*, with the largest changes observed in the 20% HS treatment (L*= 58.7 ± 0.10; a*= 5.8 ± 0.05; b*= 60.5 ± 0.22). The results show that hemp use in hen diets leads to increased omega-3 polyunsaturated fatty acid content and color intensity of egg yolks, but does not have adverse effects on the sensory profiles of the cooked eggs. PRACTICAL APPLICATION: This study provides evidence that HS and hempseed oil (HO) can safely be utilized as feed ingredients for laying hens to produce table eggs that are enriched in essential fatty acids. Additionally, the eggs procured from these hens had similar aroma and flavor compared to eggs from hens not fed any hemp. The greater the dietary hemp inclusion, the more pigmented the resulting yolks became in terms of darkness, redness, and yellowness.     

Separation of phospholipids from hen egg yolk by short packed silica gel column chromatography

Short packed silica gel column chromatography has been performed to optimize the production of phosphatidylethanolamine (PE) and phosphatidylcholine (PC) from hen egg yolk with very low or no toxic solvents. The effects of silica type, sample loading amount, dimension of the glass chromatotube, and mobile phase compositions were investigated and high separation efficiency was achieved: gradient elution as 200 mL ethanol followed by 300 mL 95% ethanol to fractionate PE and PC after neutral lipids (NL) removed by 120 mL ethyl acetate, 40 mm silica gel (54 to 74 μm) bed height of the chromatotube with 22 mm inner dia (ID), and 0.25 g sample loading amount. By this procedure, 3.69 g PE and 2.88 g PC per 100 g egg yolk lipids were obtained, respectively. The refined PE and PC were identified by high-performance liquid chromatography/ultraviolet detector (HPLC-UV) with purity over 96%. The fatty acids in egg yolk revealed that PE and PC characterized higher ratios of n- 6/n- 3 (PE, 7.41; PC, 8.99). 18:2 n- 6 of PC (15.21%) predominated over PE (10.29%), whereas the level of 20:4 n- 6 of PC (8.78%) was lower than PE (15.67%).     

Phospholipids of marine origin. VI. The octopus (Octopus vulgaris)

The composition of octopus (Octopus vulgaris) phospholipids was determined by analysis of hydrolytic breakdown products and by chromatography on silicic acid. The most remarkable feature of octopus phospholipids was the high content (13%) of ceramide aminoethylphosphonic acid. In addition the phospholipids contained phosphatidylcholine (42%), phosphatidylethanolamine (30%), phosphatidylserine (5%), phosphatidylinositol (4%) and sphingomyelin (3%). The fatty acid distribution of the phospholipids and the non-phosphorylated lipids was determined by gas chromatography. The major saturated fatty acids in the phospholipids and non-phosphorylated lipids were 16:0 (24 and 23%, respectively) and 18:0 (10 and 15%, respectively). The major highly unsaturated fatty acids in phospholipids and non-phosphorylated lipids were 20:5 (18 and 7%, respectively) and 22:6 (23 and 9% respectively).     

Phospholipids of marine origin. II. The rock lobster (Jasus lalandii)

The composition of rock lobster roe and hepatopancreas phospholipids was determined by chromatography on silicic acid and by an hydrolytic procedure. Rock lobster roe phospholipids were similar in composition to those of hen egg yolk except for the very low content of lysophosphatides. Rock lobster hepatopancreas phospholipids were similar in composition to hake flesh phospholipids. Fatty acids from the phospholipids and the non-phosphorylated lipids of both roe and hepatopancreas had the same average equivalent weight and unsaturation; the fatty acid composition showed a close resemblance. Large differences, however, were observed in the fatty acid composition of the phosphatidyl choline and cephalin fractions, the latter containing more of the polyunsaturated fatty acids.     

蛋黄甘油三酸酯的脂肪酸组成分析

采用毛细管气相色谱法分析酶法制备的蛋黄甘油三酸酯的脂肪改组成及相对含量，结果表明：其主要合有棕榈酸、油酸、硬脂酸、亚油酸、棕榈油酸，此外还含有微量的亚麻酸、花生四烯酸和二十二碳六烯酸。不饱和脂肪酸超过60％，是一种极具开发价值的营养保健油脂。     

腌制对鸭蛋中油脂品质的影响

以新鲜鸭蛋为原料,采用裹蛋腌制法制备咸鸭蛋。研究了腌制过程中不同腌制时间对咸鸭蛋的蛋黄指数、水分含量,以及对蛋黄油皂化值、酸值、胆固醇含量、脂肪酸构成等指标的影响。研究结果表明,随着腌制时间的延长,鸭蛋中的水分含量逐渐降低,而蛋黄指数、蛋黄油皂化值、酸值、胆固醇含量逐渐增加。腌制后的鸭蛋中不饱和脂肪酸含量略有降低,而饱和脂肪酸和反式脂肪酸含量略有增加。总体而言,腌制并没有鸭蛋中蛋黄油的食用品质产生严重的影响。     

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.