Fresh Yolk Research Articles

Yolk sac fatty acid composition, yolk absorption, embryo development, and chick quality during incubation in eggs from young and old broiler breeders

The objective of the present study was to examine the changes in yolk and yolk sac fatty acid composition and also to investigate egg content, yolk absorption, embryo development during incubation, and chick quality at hatch in eggs from 36- and 52-wk-old broiler breeders. The fatty acid profiles of the yolk, the yolk sac of embryos, and the residual yolk sac of chicks were analyzed before incubation, on d 18, and at hatch, respectively. Yolk sac weight, and embryo weight and length were measured on d 18, and chick weight and length were measured at hatch. Egg weight, yolk and albumen weight, yolk percentage, and yolk:albumen ratio increased as breeder age increased, but the albumen percentage decreased. Yolk absorption in absolute value (g) was higher in embryos from the old flock on d 18 and at hatch. Relative yolk absorption was similar between age groups on d 18, whereas it was higher in the young flock at hatch. Breeder age affected the yolk sac weight and was higher in the old flock during incubation. Embryo or chick weight and length, and yolk-free BW were affected by breeder age during incubation. These parameters were higher in the old flock with a difference of 3.7 g, 0.8 cm, and 2.6 g, respectively, on d 18 and 7.4 g, 1.4 cm, and 6.3 g, respectively, at hatch compared with the young flock. The effect of breeder age on fatty acid composition differed significantly by sampling day. Palmitic, stearic, oleic, and linoleic acids were major fatty acids in the fresh yolk, ranging from 13.02 to 29.24%. These were followed by palmitoleic and arachidonic acids ranging from 1.24 to 7.04%, with the remaining fatty acids below 1%. Higher concentrations of myristic, palmitoleic, and oleic acids and lower concentrations of heptadeconoic, stearic, linoleic, and arachidonic acids were found in the residual yolk sac of the young flock than the old flock. The results showed preferentially selective absorption of some fatty acids by the embryo during incubation.

액란과 생란의 난황으로 제조한 블루베리 쿠키의 품질특성과 항산화능 비교

We evaluated the quality characteristics and antioxidative activities of cookies containing different types of egg yolk (LEY, Liquid Egg Yolk; FEY, Fresh Egg Yolk) and percentages of blueberry powder (5, 10, and 15%). As the amount of blueberry powder increased, the levels of antioxidants based on ABTS and DPPH radical scavenging activities increased in general. Within the 15% group, contents of polyphenols and flavonoids were higher in the FEY group, whereas content of anthocyanins was higher in the LEY group. Measurement of ABTS radical scavenging activity showed that the FEY group had a higher value within the 10% group, whereas the LEY group scored higher within the 15% group. Comparison of sensory properties showed no significant difference between the two egg yolk types. If commercialized, manufacturing cookies with FEY or LEY will not make a significant difference. Regardless, 15% blueberry powder would be the most appropriate, as it scored the highest in terms of antioxidant activity and sensory characteristics.

Moisture impact on extractability of phospholipids from leftover egg yolk after enzymatic treatment using supercritical carbon dioxide

The leftover egg yolk after immunoglobulin Y (IgY) extraction was subjected to enzymatic hydrolysis with Protease P and Lipase AY30, which resulted in the formation of cream. The extractability and purity of phosphatidylcholine (PC) and total phospholipids (PL) at three levels of moisture content in cream (freeze dried cream, 20% and 45%, w/w) were studied using supercritical carbon dioxide (SC-CO2) extraction with ethanol addition (8%, mole%) as co-solvent at 48.3MPa and 70°C. The results were compared to those obtained from fresh yolk and dry yolk. The highest recoveries of PC and total PL were for freeze-dried cream and cream with 20% moisture in which the recovery of PC was about 85% and 65%, respectively, based on the initial mass of yolk used for cream formation and 94% and 106% recovery, respectively, based on the amount of cream used as extraction feed. The highest purity of PC was about 87% obtained from fresh yolk and 84% from cream with 20% moisture content. This study showed that enzymatic treatment of the pellet can improve the recovery of PC and PL from egg yolk at moisture contents of up to 20%.

Photopyroelectric assessment of the thermal effusivity of fresh hen egg and of rehydrated egg powders

The availability of thermo-physical data of foods and their constituents is of general importance to food industry. The thermal effusivity e is one among the relevant thermodynamical quantities. The latter is normally calculated from the relationship e = (κρc)½, where c is specific heat, ρ is the density, and κ is the thermal conductivity. The necessity for performing the time consuming independent measurements of these three quantities is the major reason that the existing database with effusivity of foods is not very wide. This paper describes the application of the inverse photopyroelectric (IPPE) technique that allows the determination of effusivity from a single measurement. This approach was used to directly measure thermal effusivity of fresh egg yolk, egg white, and white/yolk blends. In addition, thermal effusivity of rehydrated egg powders (white, yolk, and the whole egg powder) has been measured and compared to that of the fresh hen egg. In case of the egg white, effusivity of rehydrated egg powders was practically the same as that of the fresh egg. However, the difference in effusivity between fresh egg yolk and rehydrated egg yolk, and between the blend of fresh egg and the rehydrated whole egg power was significant. Finally, thermal effusivity of rehydrated egg yolk, egg white, and the whole egg powder was determined as a function of dilution factor.

Cryopreservation of epididymal stallion sperm

Any event that makes semen collection or mating impossible, such as death, castration, or injury, may terminate a stallion’s breeding career. Fortunately, stallion sperm which are capable of fertilization can be harvested from the epididymis, and frozen for future use. However, the fertility of frozen–thawed epididymal sperm has been found to be lower than that of ejaculated sperm. Therefore, this study aimed to optimize the fertility of frozen epididymal stallion sperm by investigating the effects of different cryoprotectants and freezing protocols on sperm quality. Dimethylformamide was tested alone or combination with pasteurized egg yolk as substitute of fresh egg yolk. In addition, the effect of the pre-freeze stabilization on sperm quality was analyzed. Heterospermic samples obtained from stallion epididymis were collected and cryopreserved in lactose–egg-yolk extender or in the same extender with varying content of cryoprotectant and content of egg yolk, stabilized and no-stabilized. Sperm motility, viability, hypoosmotic swelling test (HOST) and acrosome integrity were evaluated post-thawing. No improvement was observed on the replacement of fresh yolk by pasteurized egg yolk, whereas the results suggest that dimethylformamide is a cryoprotectant suitable for cryopreservation of equine epididymal semen, even better than glycerol. In addition, we found that the stabilization before freezing on epididymal stallion sperm, can improve sperm quality parameters.

Trace element content in market eggs in Bohemia

The aim of this study was to analytically determine the content of iodine, copper, zinc and manganese in the yolk of consumer eggs in Bohemia in 2007 and 2008. Investigated eggs originated from six so called intensive farms with large flocks (118 eggs) and twelve backyard farms or small-flock establishments (136 eggs) from three administrative regions in Czech Republic. Eggs from intensive farms were obtained directly from the establishments, while eggs from backyard farms were purchased from private farmers. Spectrophotometric Sandell-Kolthoff method was used for determination of iodine content in egg yolk, while Cu, Zn and Mn levels were determined by the flame absorption spectrophotometric method (AAS). The average content in fresh egg yolk from intensive farms was determined to 0.9 ± 0.2 for iodine, 8.4 ± 2.1 of copper, 29.8 ± 6.9 of zinc and 1.2 ± 0.3 of manganese, all in mg·kg−1, as compared to yolk content from backyard farms with 0.4 ± 0.04 mg·kg−1 of iodine, 10.8 ± 2.9 of copper, 32.5 ± 6.9 of zinc and 1.5 ± 0.3 of manganese. Average content of copper, zinc and manganese was lower in egg yolks from intensive farms (P < 0.01) as compared to the egg yolks from backyard farms, while iodine content on the other hand was lower in eggs from backyard farms (P < 0.01).

Study on the Granulation Texture of Salty Yolk

The texture of chicken egg yolk, duck egg yolk, salty chicken egg yolk and salty duck egg yolk were tested by the A/BC probe and HDP/SR probe of TA. XT. Plus (Texture Analyzer). Sensory evaluation was made for these yolks. Test results were analyzed and combined with sensory evaluation, a test method that HDP/SR compression test can significantly distinguished cooked fresh yolk and salty yolk apart well was determined, which can indicate the salty yolk's peculiar granulate texture intuitively and accurately.

The Effects of Fresh Eggs, Egg White, and Egg Yolk, Separately and in Combination with Salt, on Mixogram Properties

ABSTRACTSalt and eggs are common ingredients in some wheat flour‐based food systems and significantly impact dough mixing behavior. We evaluated the effect of either whole eggs, egg white, or egg yolk on dough formation and properties with the Mixograph. Inclusion of whole eggs in wheat flour dough recipes increased dough development time, dough stability, and dough strength upon further mixing less than inclusion of only egg white. In contrast, egg yolk addition decreased all of these parameters. Salt had a more pronounced impact on dough containing egg yolk than on dough containing egg white. The present observations can be explained in terms of shielding charges of the gluten protein's ionized groups, which largely affects dough mixing behavior. The work demonstrates that in some applications it can be useful to use egg fractions rather than whole eggs.

Effect of Different Cations on Pidan Composition and Flavor in Comparison to the Fresh Duck Egg

The effects of different cations on its composition and flavor characteristics of pidan white and yolk produced with duck egg in comparison to its fresh egg were investigated. Mineral content such as calcium, magnesium, sodium and potassium were significantly increased in pidan yolk irrespective of its cations in pickle solution in comparison to the fresh yolk (P<0.05). It confirmed the migration of minerals from the pickling solution to the egg. However, calcium and magnesium was found lower in 0.2% PbO2 treated pidan. Less pidan flavor compounds were generated in pidan white produced with the aid of 0.2% PbO2. It confirmed that binding of lead prevent the maillard reaction in the pidan treated with PbO2. Benzaldehyde, ketones, alcohol and acid found in the pidan white treated with 0.2% ZnCl2 reveals that volatiles are generated most likely from maillard reaction. However, pidan yolk of both 0.2% PbO2 and 0.2% ZnCl2 showed higher generation of volatiles more likely from yolk lipids. Butanal, pentanal, hexanal, and heptanal are of those aldehydes found in 0.2% ZnCl2 treated pidan yolk whereas hexanal is the only aldehyde detected in 0.2% PbO2 treated pidan yolk. Thus, cations in the pickling solution affect the flavor characteristics of pidan white and yolk.

다양한 HPLC Column에서의 IgY(Immunoglobulin Yolk) 분리특성

동물 혈청 중의 IgG (Immunoglobulin G)에 해당되는 난황에 포함된 면역 단백질 IgY (Immunoglobulin Yolk)는 식품 단백질로 장내 면역 물질로 중요하다. IgY를 정제하기 위해 신선란의 노른자에 카리지난이나 아라빅검을 전처리 물질로 사용하였다. 전처리 후 FPLC (Fast Protein Liquid chromatography)의 DEAE (Diethylaminoethyl) Sepharose 칼럼에서 이온교환법에 의해 불순물을 제거하여 IgY를 얻고, GF HPLC (Gel Filtration High Performance Liquid Chromatography)로 IgY의 분자량을 측정하고 표준 IgY와 비교하여 IgY 단백질을 동정하였다. GF HPLC에서 IgY의 다양성을 발견하였고 IgY 단백질 군의 다양성을 IE HPLC (Ion Exchange High Performance Liquid Chromatography)에서 AX, CX, SCX 칼럼을 사용하여 pH, NaCl 농도를 바꾸어 조사하였다. AX를 사용하여 0.5M NaCl, pH=8 조건에서 3개의 IgY 피크를 분리하였고, SCX를 이용했을 때 0.5M NaCl, pH=5 조건에서도 3개의 IgY 피크를 분리할 수 있었다. IgY (Immunoglobulin Yolk) in egg yolk corresponds to IgG (Immunoglobulin G) in animal serum and plays an important role as immunological proteins in intestines. Carrageenan and Arabic gum were used as pretreatment agents to purify IgY from fresh egg yolk. DEAE (Diethylaminoethyl) Sepharose column in FPLC (Fast Protein Liquid chromatography) was an ion exchange tool to remove contaminants as well as to elute IgY from the column. GF HPLC (Gel Filtration High Performance Liquid Chromatography) enables to measure the molecular weights of IgY and to identify the purified IgY by comparing the molecular weight of standard IgY with the purified one. IgY is a heterogeneous group of different molecular weight and ionic properties, which was investigated with various IE HPLC (Ion Exchange High Performance Liquid Chromatography) columns such as AX, CX and SCX. Three peaks of IgY were separated in the AX column under the conditions of 0.5 M NaCl and pH=8. The SCX column also gave the three peaks of IgY at 0.5 M NaCl and pH=5.

A Simple Model for Understanding the Origin of the Amide Proton Transfer MRI Signal in Tissue

Amide proton transfer (APT) imaging is a new molecular MRI technique that gives contrast at the cellular protein level. To better understand the origin of the APT signal in tissue, fresh and cooked hen eggs (n = 4) were imaged at 4.7 Tesla. The APT effect was quantified using the asymmetry in the magnetization transfer ratio (MTR(asym)) at the composite amide proton resonance frequency (3.5 ppm from the water resonance). The measured APT signals were significantly higher in the fresh egg white (20.1% ± 0.9%) than in the fresh egg yolk (-1.4% ± 1.1%; P < 0.001), and in the cooked egg white (2.8% ± 0.7%; P < 0.001), all of which have similar absolute protein contents. The data support the notion that the APT effect observed in vivo is associated with mobile proteins in tissue, such as those in the cytoplasm.

EFFECT OF PHOSPHOLIPASE A1ON THE PHYSICOCHEMICAL AND FUNCTIONAL PROPERTIES OF HEN'S EGG YOLK, PLASMA AND GRANULES

ABSTRACT Fresh egg yolk was separated into plasma and granules. Then, the egg yolk and its fractions were enzymatically modified with phospholipase A1 (PLA1). Changes in physicochemical and functional properties were investigated. We observed that enzymatic treatment showed a significant impact on the properties of egg yolk and its fractions with regard to emulsifying properties, protein solubility and foaming properties. Meanwhile, the color changes and the microstructure and the thermal behavior of egg yolk, plasma and granules before and after enzymatic treatment were also studied. This study indicated that the existence of lysophospholipids and structural changes in egg yolk granules could be responsible for significant differences in the functional properties of untreated and PLA1-modified egg yolk, plasma and granules. PRACTICAL APPLICATIONS This study aimed to investigate the physicochemical and functional properties of egg yolk, including its fractions (plasma and granules), before and after phospholipase A1 (PLA1) treatment. Such modified egg yolk would have higher protein solubility, thermal stability and emulsifying properties, and present high resistance to extreme temperatures. As these properties of egg yolk powder were improved through PLA1 treatment, the application of PLA1 could make egg yolk have a good practical effect and extend the scope of application.

Preparation and evaluation of semi-permanent hair dyes liposome

This study used phospholipids from fresh egg yolks to prepare liposome-encapsulated semi-permanent hair dyes in different pH buffer solutions and evaluated the functions and colour fastness to washing of the dyes. The extraction ratio of egg yolk phospholipids was 5%, and the purity was 91.8%. Empty liposome solutions were then prepared using high-speed homogenizer with particle size 219–848 nm. After being stored at 4°C for 28 days, the average particle size of the liposome-encapsulated dye formulas increased from 1.36–1.92 µm to 1.99–2.38 µm. The ΔE colour difference values of the five hair extension sets dyed with the control group and hair dyes on the market were of the range 6.56–13.39 after eight times of washing, whereas the ΔE values of the four hair extension sets dyed with the liposome-encapsulated dyes were of the range 3.56–5.21 after eight times of washing. The liposome-encapsulated dye at pH 3 showed the best result.

Usefulness of powdered and fresh egg yolk for cryopreservation of Zebu bull spermatozoa

This experiment was designed to compare powdered egg yolk with fresh egg yolk in an extender for cryopreservation of Zebu bull semen. Sperm motility, plasma membrane integrity and viability were assessed at different stages of cryopreservation (post-dilution, pre-freezing and post-thawing). Sperm plasma membrane integrity remained similar at all the stages of cryopreservation. Sperm motility and viability were significantly higher after thawing in the extender containing powdered egg yolk. In conclusion, powdered egg yolk may be used in an extender for the cryopreservation of Zebu bull spermatozoa.

Yolk sac nutrient composition and fat uptake in late-term embryos in eggs from young and old broiler breeder hens

In the present study, we examined the composition, amount, and uptake of yolk nutrients [fat, protein, water, and carbohydrates (COH)] during incubation of eggs from 30- and 50-wk-old broiler breeder hens. Eggs were sampled at embryonic d 0 (fresh eggs), 13, 15, 17, 19, and 21 (hatch). Egg, embryo, yolk content, and yolk sac membrane were weighed, and the yolk sac (YS; i.e., yolk content + yolk sac membrane) composition was analyzed. From 30 to 50 wk of age, the albumen weight increased by 13.3%, whereas the yolk increased by more than 40%. The proportion of fat in the fresh yolk of the 30-wk-old group was 23.8% compared with 27.4% in the 50-wk-old group, whereas the proportion of protein was 17.9% compared with 15.6%, respectively. During incubation, results indicated that water and protein infiltrated from other egg compartments to the YS. Accordingly, the calculated change in the content of water and protein between fresh yolk and sampled YS does not represent the true uptake of these components from the YS to the embryo, and only fat uptake from the YS can be accurately estimated. By embryonic d 15, fat uptake relative to embryo weight was lower in the 30-wk-old group than in the 50-wk-old group. However, by embryonic d 21, embryos of both groups reached similar relative fat uptake, suggesting that to hatch, embryos must attain a certain amount of fat as a source of energy for the hatching process. The amount of COH in the YS increased similarly during incubation in eggs from hens of both ages, reaching a peak at embryonic d 19, suggesting COH synthesis in the YS. At hatch, the amount of protein, water, and COH in the residual YS, relative to the weight of the yolk-free chick, was similar in eggs from young and old hens. However, chicks from the younger hens had less fat in the YS for their immediate posthatch nutrition compared with those from the older hens.

Effects of rice bran oil, oxidised, and fresh egg yolk powder on the development of arteriosclerosis in growing rabbits (&lt;i&gt;Oryctolagus cuniculus&lt;/i&gt;)

Dietary cholesterol is known to increase the risk of atherosclerosis, whereas antioxidants reduce the risk. It is not clear what effects the oxidation of cholesterol before ingestion could have on the development of atherosclerosis in rabbits (Oryctolagus cuniculus). A study was conducted to investigate the effects of rice (Oryza sativa L.) bran oil, oxidised, and fresh egg yolk powder, on the development of arteriosclerosis in growing rabbits. Rabbit pellets were mixed with 4% of either fresh egg yolk powder, or oxidised egg yolk powder, and the control diet made of rabbit pellets only. The diets were fortified with either 2% corn (Zea mays L.) oil, or rice bran oil, and fed to 10week-old rabbits for 90 days, at the rate of 100 g per day. Water was given ad libitum. Blood lipids and general performance of the rabbits were monitored during the feeding period. Blood vessels and hearts were examined after the feeding period. Results showed that oil type had no significant effects on all the parameters determined. Total plasma cholesterol was significantly (P < 0.05) higher for rabbits fed on egg yolk powder than control. Low density lipoprotein cholesterol (LDL) was significantly (P < 0.05) higher for fresh egg yolk powder-fed rabbits than oxidised or control diet-fed rabbits, whereas very low density lipoprotein cholesterol (VLDL) was significantly (P < 0.05) higher in fresh egg powder and control diet-fed rabbits than oxidised egg powder-fed rabbits. There was no significant difference in the cumulative mass gain from the different diets. All rabbits fed on fresh egg yolk powder developed some abnormalities in the heart and major blood vessels, while 60% of those on oxidised egg yolk powder developed abnormalities in the heart and blood vessels. No abnormalities were detected in the heart tissues and arteries of rabbits fed the control diet. These results demonstrated that the fresh and oxidized egg yolk powder could have the potential of causing arteriosclerosis and fresh egg yolk powder was more potent than oxidised egg yolk powder. It is recommended that excessive egg consumption be avoided to reduce the risk of cardiovascular diseases. 1Department of Home Economics, University of Swaziland, P/B Luyengo, Swaziland *Corresponding author’s email address: nanuajn@uniswa.sz 2 Egerton University, P. O. Box 536 Egerton, Kenya 3 Egerton University, Chuka University College, P. O. Box 109 Chuka, Kenya

Rheological Properties of Egg Yolk Subjected to High Hydrostatic Pressure

A high hydrostatic pressure of 100-400 MPa was applied to fresh egg yolks. The rheological properties 、of the resulting egg yolks were evaluated by measuring viscosity at a high shear rate (10-'103 S:-I) in steady-state and at a very low shear rate (10-1 -lO-:J S-I) in spring relaxation. The f10w curves for the egg y61ks showed non-thixotropic behavior after the application of 200-300 MPa ，but thixotropic behavior after 400 MPa. The thixotropic property and yield values were then evaluated. The thixotropic parameter Th of the egg yolk pressurized at 400 MPa (12.8X 103 Pa's-') was larger than that of egg yolk pressurized at 100 MPa (0.09X 10:1 Pa's-1). The viscosity of allpressurized egg yolksobeyed the power law. While the consistency index K was increased ，the f10wbehavior index n was d 巴creased with increasing pressure and time applied. Casson'syield value in the spring relaxation was 140 MPa for the egg yolk which had been pressur 包 ed at 400 MPa for 10 min. This value is less than the 340 MPa which was evaluated for the steady state. This result indicates that a spring relaxation study would be useful for evaluating theyield value (Rec 巴ived October 20 ，1999;Accepted in revised form July 19 ，2000)

Effects of Different Rearing and Feeding Systems on Lipid Oxidation and Antioxidant Capacity of Freeze-Dried Egg Yolks

Lipid oxidation and antioxidant capacity of freeze-dried egg yolks produced with two rearing systems (battery cages and free-range) and two types of feedings (conventional and organic) were studied. Nine fresh egg yolks of each crossed treatment were pooled, frozen for a month, freeze-dried, vacuum-packed, and kept at -18 degrees C until analysis. No significant differences were observed in the lipid (58.0-62.1%) and total sterol contents (33.0-35.5 g/kg of lipids) of the freeze-dried egg yolks. Free rearing and conventional feeding systems resulted in significantly higher total tocopherol, alpha-tocopherol, and lutein contents, as compared to the battery cage and the organic feed, respectively. However, no significant differences were found in lipid oxidation (peroxide value = 0.7-0.9 mequiv of O(2)/kg of fat; thiobarbituric reactive substances = 1.0-1.3 mg of malonylaldehyde/kg of sample) and cholesterol oxidation (28.8-43.5 mg of cholesterol oxidation products/kg of lipids; 0.08-0.12% oxidized cholesterol) of freeze-dried egg yolks except for 7alpha-hydroxycholesterol, which was significantly lower in samples obtained with organic feed.

Use of a vital fluorescent stain to identify apoptosis in bovine oocytes

s / Theriogenology 70 (2008) 576–591 581 in post-thaw semen quality were the percentage of progressively motile sperm and membrane integrity, with LE extender having the lowest mean progressive motility, but greatest mean membrane integrity. Differences in thawing protocols resulted in LE samples being analyzed for motility at a relatively high concentration, which may have affected the accuracy of the computerized semen analyzer for assessing progressive motility. Unlike the CaniPRO, the CanFreeze and the LE protocols do not require the addition of fresh egg yolk. CanFreeze and LE are simplified freezing protocols that may be of benefit for semen freezing laboratories with limited technical assistance.

Optimization of the enzymatic modification of egg yolk by phospholipase A 2 to improve its functionality for mayonnaise production

Egg yolk (EY) was enzymatically modified by phospholipase A 2 to improve its functional properties for mayonnaise production. The optimum reaction conditions predicted by response surface methodology were enzyme concentration of 7432 LEU for 74 min in the presence of 11.5% (w/w) salt. The predicted values were in good agreement with the experimental values. The mayonnaise prepared with 6% (w/w) of the enzymatically modified EY (EM-EY) had no significant differences in overall acceptability or in the perceived intensities of umami, nutty flavor, sourness, oiliness, and rancid flavor as compared to the mayonnaise prepared with 8% (w/w) fresh EY. The stability of the mayonnaise prepared with 6% (w/w) EM-EY was greater than that of the mayonnaise prepared with 10% (w/w) fresh EY. Based on the results, EM-EY, when produced at optimum conditions, has great potential to replace fresh EY.