Yolk Powder Research Articles

Comparative proteomics and in silico allergenicity of fresh and powdered skipjack tuna and Nile tilapia

Fish is an important food source but can contain allergens which cause mild to life-threatening symptoms. The aim of this study was to compare the identified proteins in fresh and powdered fish in skipjack tuna and Nile tilapia using proteomic approach. The biological functions of the proteins were identified using the UniProt database. Potential allergens were identified based on the sequence similarity to known allergens using the Allermatch program. The major functions of the identified proteins in both the fresh and powder forms of skipjack tuna and Nile tilapia were related to metabolic processes and the cytoskeleton. Eleven proteins in skipjack tuna and seven proteins in Nile tilapia, in fresh and powdered forms, were identified as novel potential allergens using the Allermatch program. Fructose-bisphosphate aldolase, enolase, parvalbumin, glyceraldehyde-3-phosphate dehydrogenase, and tropomyosin were found in abundance as potential allergens in both fishes. For both fishes, more isoforms of tropomyosin were found in powered fish than in fresh fish. Alpha- and beta-enolase, glyceraldehyde-3-phosphate dehydrogenase, alpha-, beta- and 2-parvalbumin, and tropomyosin alpha-1 chain could be developed as peptide markers for fish adulteration in both skipjack tuna and Nile tilapia. Interestingly, the peptides from eight potential allergens in fish were most similar to peptides from chicken powder and egg yolk powder. Here, proteomic analysis was used to study protein expression in skipjack tuna and Nile tilapia (both fresh and powdered). In addition, use of the untargeted proteomics approach could aid in the discovery of potential allergens and lead to the design of peptide markers to enhance food safety.

Selective removal effect of subcritical fluid extraction on egg yolk lipids and characterization and enzymatic improvement of defatted egg yolk powder

This study investigated the effects of subcritical fluid extraction on lipid removal and the physicochemical properties of egg yolk powder. In addition, two-step enzymatic hydrolysis was used to improve the physicochemical properties. The content of total lipids and cholesterol decreased to 30.2% and 10.5 mg/g after subcritical propane-butane extraction, respectively, while phospholipids were retained. Protein solubility, surface hydrophobicity and total sulfhydryl results showed that this partial defatting avoided further quality deterioration of egg yolk powder. Scanning electron microscopy and confocal microscopy showed that the surface morphology and distribution of proteins and lipids changed with defatting degree. After two-step enzymatic hydrolysis, protein solubility of subcritical propane-butane extraction egg yolk powder significantly increased to 31.4% and soluble peptides with an average molecular weight lower than 1000 Da accounted for 70.0%. The improved defatted egg yolk powder is rich in protein, peptides and phospholipids and has great potential as a nutritional supplement.

Preparation and characterization of folate-enriched eggs and egg yolk powders

In this study, a dose-response relationship between egg folate content and dietary folic acid content was observed. Folic acid supplementation did not affect egg quality or the performance of laying hens besides feed intake and feed/egg ratio. Vitamin C supplementation (150 mg/kg) promoted folate enrichment in the eggs, with a maximum value of 78 μg/egg being achieved. Moreover, there was no obvious effect on egg quality and an improvement in laying performance. Vitamin B12 supplementation did not affect egg folate content, suggesting there was already enough present in the original diet. The folate in eggs was relatively stable to degradation during storage, which was attributed to the protection provided by egg whites and eggshells. A folate-enriched egg yolk powder (803 μg/100 g) was prepared through spray drying in a nitrogen atmosphere. This powder was yellower, redder, and darker than one produced by spray drying in air and exhibited better storage stability. However, both powders exhibited similar water solubility and emulsifying properties. These results suggest that folate-enriched eggs and egg yolk powder could be used as functional foods for folate supplementation.

Review: Tepung Telur Ayam: Nilai Gizi, Sifat Fungsional dan Manfaat

Eggs are an almost perfect source of animal protein. Commercial chicken eggs are a perfect food that contains nutrients such as protein (12.8 %) and fat (11.8 %). In 100 grams of whole eggs also contain vitamin A of 327.0 IU and minerals of 256.0 mg. Eggs contain high-quality protein because they have a complete composition of essential amino acids and have a high biological value, which is 100 %. The high content of water, fat and protein in eggs make this food as a good medium for bacterial growth so that their shelf life is quite short. Drying eggs into powder offers many advantages, including ease of storage, distribution, protection against microbial growth (low water activity), reduced weight per volume of whole eggs, longer shelf life. The use of egg powder as an additive to other food products is easier than using fresh eggs. The purpose of this review is to study the nutritional characteristics, functional properties and benefits of egg flour. The nutritional value and functional properties of egg powder, egg white powder and egg yolk powder can still provide maximum results both for raw material products or as food additives. The use of egg powder will facilitate industry, especially medium and large scale industries in handling, packaging, storage and processing compared to use with fresh eggs.

Perinatal supplementation of egg yolk plus docosahexaenoic acid alters the functional organization of the brain in offspring

BackgroundMaternal diet plays a role in brain growth and development of offspring during the early stages of life. Egg yolk (EGG) and docosahexaenoic acid (DHA) are known to benefit cognitive development in fetuses and infants. Importantly, potential synergisms have been suggested between EGG and DHA on neurofunction through modulating oxidative stress in the brain. In this study, we examined perinatal supplementation of EGG plus DHA on brain anatomical and functional organization of offspring using a translational piglet model.MethodsPregnant sows were fed a control diet (n=6), a diet containing egg yolk powder (EGG, n=5, 350 mg egg yolk powder/kg BW/day, equivalent to ~3 large eggs per day for human), a diet containing docosahexaenoic acid (DHA, n=6, 75 mg DHA/kg BW/day), or a diet containing egg yolk powder plus DHA (EGG plus DHA, n=5) from late gestation throughout lactation. At weaning, offspring from sows (n=2 per sow, total n=44) underwent magnetic resonance imaging (MRI) to acquire anatomical, diffusion tensor imaging (DTI), and resting‐state functional MRI. All work in this study was conducted in accordance with the University of Georgia Institutional Animal Care and Use Committee guidelines.ResultsDTI analysis showed that maternal supplementation of EGG plus DHA increased white matter fiber length (p=0.0195) and decreased mean diffusivity (p=0.000625) in the hippocampus of offspring compared to the control diet. Interestingly, EGG or DHA alone did not alter white matter fiber length (p>0.05), and only DHA alone decreased mean diffusivity but to a lesser extent than the combination of EGG and DHA. This data suggests a potential synergism of maternal intake of EGG and DHA on hippocampal cellularity and white matter growth in offspring. Moreover, piglets from sows fed EGG plus DHA exhibited increased functional connectivity in the cerebellar network (p=0.03) compared to piglets from control group. EGG or DHA alone did not result in significant differences in the cerebellar network compared to control diet (p>0.05). EGG plus DHA did not alter (p>0.05) other functional networks identified in the study such as the executive control, visual, sensorimotor, auditory, default, salience and basal ganglia network. Maternal supplementation of EGG or DHA during late gestation and lactation did not correlate with significant volume change in nineteen brain regions examined in offspring.ConclusionThe results of this study demonstrate that perinatal supplementation of egg yolk combined with docosahexaenoic acid synergistically enhanced hippocampal cellularity and white matter growth as well as cerebellar network activity in offspring at weaning. These findings suggest that further investigation of the brain development, cognitive and behavioral effects of maternal supplementation of egg yolk with docosahexaenoic acid on offspring is warranted.

Modeling the effect of protein and fat on the thermal resistance of Salmonella enterica Enteritidis PT 30 in egg powders

Microorganisms in low-moisture foods (LMFs) exhibit prolonged survivability and high heat resistance. Various external factors (water, food texture, nutritional compounds, etc.) influence the microbial heat resistance in LMFs; yet, the influential degree of each factor is not fully understood. In this study, the thermal resistance parameters (D and z values) of Salmonella enterica Enteritidis PT 30 (S. Enteritidis) at 80, 85, and 90 °C at the room-temperature water activity (aw, 25°C) of 0.32 ± 0.02 were measured. A series of egg powders with different fat and protein ratios (obtained by mixing egg white and yolk powders) were chosen as the model foods. Primary and secondary models were built from the isothermal inactivation kinetics of S. Enteritidis in the tested samples. The importance of fat and protein was then confirmed by controlling the water activity at the treatment temperature (aw, treatment temperature) via thermal water activity cells. The survivor curves of S. Enteritidis fitted well with the Weibull-type and log-linear models. The D values of S. Enteritidis increased with increasing fat (0–56.7%, w.b.) and decreasing protein contents (83.59–31.81%, w.b.). Incorporating the modified Bigelow model into the log-linear model yielded the zfat and zprotein of 58.96 and 57.14, respectively. At the controlled aw, 90°C of 0.32 ± 0.02, the D90°C values of S. Enteritidis increased remarkably (P < 0.05), but the values in egg white, whole egg, and egg yolk powders (11.73 ± 1.24, 23.82 ± 2.0, and 60.0 ± 2.4 min) were remarkably different. Our study identified that the influential degrees of fat, protein (zfat and zprotein values), and aw on the thermal resistance of S. Enteritidis in egg powders is in the order: aw,treatment temperature > fat > protein. Fat considerably increased the thermal resistance of S. Enteritidis even at the same aw,treatment temperature. This study quantified the effect of fat and protein on the thermal resistance of S. Enteritidis and emphasized the non-negligible effects of food components in LMFs’ microbial safety.

Improved effect of ultrasound-assisted enzymolysis on egg yolk powder: Structural properties, hydration properties and stability characteristics

Preparation of egg yolk powder (EYP) with excellent hydration properties and dissolution stability is important for the efficient utilization of its functional properties and nutritional properties in food. In this work, a new method utilizing ultrasound-assisted enzymolysis (UP-EM) was investigated to obtain EYP. Compared to enzymolysis-alone treated (EM), ultrasonic pre-treatment (UP) significantly increased the enzymatic hydrolysis rate by 106.28%. In particular, the UP 60 W 20 min-EM group obtained the desired solubility and coefficient of stability. The observed microstructure of EYP showed that the egg yolk particles obtained by UP-EM were more uniformly distributed and smaller in particle size. The protein structure was confirmed by Fourier transform infrared spectrum, which showed that UP enhanced the hydrogen bonding force between egg yolk proteins. Therefore, it can be believed that UP-EM can significantly improve the hydration properties and dispersion stability of EYP, laying the foundation for its wide applications in food industry.

Effect of the varying inclusion levels of the egg yolk powder on growth, stress tolerance, and pigmentation of Guppy (Poecilia reticulata)

ABSTRACT The newly hatched nauplii of Artemia is extensively used as a live feed for ornamental fish hatchlings; however, its high cost and unbalanced nutrients necessitate exploring sustainable alternatives. An experiment was conducted to evaluate the effects of four formulated diets of 0%,5%, 10%, and 20% inclusion levels of egg yolk powder and other ingredients (fish meal, soybean meal, rice polish, corn) during the nursery stage of Guppy (Poecilia reticulata) compared to Artemia salina as a control. Results showed that survival did not differ (P > 0.05) among the diets. Weight gain, daily weight gain, and specific growth rate of the fry fed with 10% egg yolk-included diet containing 49.6% fish meal and 18.8% soybean meal were significantly higher (P < 0.05) than those of the other test diets and the A. salina. All the diets showed higher stress indexes (P < 0.05) than the control; the test diets did not affect pigmentation.

Emulsifying properties of pea protein/guar gum conjugates and mayonnaise application

SummaryModified plant protein may be used as a healthy and more functional emulsifier in food products. The objective of this study was to evaluate the emulsifying properties of functionally enhanced pea protein (i.e. pea protein conjugated with guar gum, G‐PPI) and its potential application to mayonnaise, compared with unmodified pea protein. Emulsions containing G‐PPI were prepared at different pH, salt concentrations, protein concentrations and oil/water ratios. Mayonnaise samples were prepared using the pea proteins or egg yolk powder. Various characteristics of the emulsions, including droplet size, apparent viscosity, viscoelasticity and microstructure, were analysed. The emulsions with G‐PPI had significantly increased stability of up to 89.4% and apparent viscosity of up to 48.62 mPa.s. The G‐PPI emulsion had a smaller average droplet size of 934.4 nm at pH 7 compared with the PPI emulsion (stability 62.7%, apparent viscosity 22.8 mPa.s and droplet size 1664.8 nm). The pH, NaCl concentration, protein concentration and oil/water ratio greatly affected the emulsifying properties. The G‐PPI mayonnaise at higher protein concentrations (6 or 8%) exhibited excellent emulsifying and rheological properties. The modified pea protein through the green modification process with natural polysaccharides could be used as a safe and functional emulsifier in different emulsified foods.

Optimization of n-Hexane-Acetone System for Extraction of Phosphatidylcholine and Phosphatidylethanolamine by Response Surface Methodology.

Eggs are nutritious and cheap and easily available. Egg yolk is one of the sources of phosphatidylcholine (PC) and phosphatidylethanolamine (PE). PC and PE have good emulsifying properties, and they are widely used and in high demand for pharmaceutical, feed and cosmetic applications. Red cordyceps egg yolk powder (RCEYP) was selected as the raw material to obtain high content of PC and PE by ethanol extraction and low temperature cryoprecipitation in n-hexane-acetone system (HAS), in which the process conditions of PC and PE extraction by HAS process were optimized. The phospholipids were quantified by high performance liquid chromatography (HPLC) with evaporative light scattering detector (ELSD). The effects of freezing time, material-liquid ratio, acetone washing times, solvent ratio of n-hexane to acetone and freezing temperature on the PC and PE contents and the phospholipid yield were investigated. The optimal conditions for the extraction of PC and PE from RCEYP by HAS were determined by Box-Behnken design (BBD) as follows: the solvent ratio of n-hexane to acetone was 1:6, the freezing time was 11.31 h, and the freezing temperature was -19°C. The total content of (PC+PE) in the phospholipids precipitated under these conditions amounted to 96.16%, of which 81.12% was PC and 15.04% was PE.

Physicochemical properties of muffins prepared with lutein & zeaxanthin-enriched egg yolk powder

Designing functional foods relies not only on incorporating bioactive compounds into a formulation but also on their ability to remain useful within the product. In this study, lutein and zeaxanthin (L&Z)-enriched egg yolk powder (EEYP), sourced from hens fed with Dunaliella tertiolecta mp3, was incorporated as a functional ingredient in muffins. Two formulations were prepared: with butter (EEYP-B) and butter-free (EEYP-BF). The color and texture of the muffins and the thermal stability and bioaccessibility after simulated digestion of the carotenoids were assessed. The results indicated that the physical properties of the muffins were not influenced by the L&Z addition. Moreover, L&Z in EEYP-B were less heat labile than in EEYP-BF and control samples with degradation rates of 10–12%, 15–17%, and >20%, respectively. Surprisingly, the bioaccessibility of L&Z in the EEYP-BF muffins was higher than in the control and butter-containing samples after digestion. As a result, enriching a daily product with L&Z was proved successful at increasing its carotenoid content after baking, evidencing also that the butter-free formulation exhibited the highest bioaccessibility.

The Re-Addition of Seminal Plasma after Thawing Does Not Improve Buck Sperm Quality Parameters.

Simple SummaryThe Cabra Blanca de Rasquera is a native goat breed from Catalonia (Spain) facing the danger of extinction. To preserve its genetic diversity, ex situ conservation programs for semen cryopreservation and the development of a genetic sperm bank are of major importance. However, the post-thaw sperm quality in this species is still a major concern. Therefore, the aim of this research work was to establish an approach in the thawing protocol of cryopreserved sperm bank doses of this breed in order to achieve a better post-thaw sperm quality and improve reproductive outcomes through artificial insemination. Since seminal plasma has been found to provide a source of nutrients, improve sperm motility, and prevent premature activation during migration of spermatozoa in the female reproductive tract, our study proposed to assess the effect of the addition of 20% seminal plasma (SP) during a 3 h incubation period under in vitro conditions mimicking the in vivo survivability of thawed sperm, in relation to donor age, the season of collection, and melatonin implants of the males in the non-breeding season. However, the strategy of adding seminal plasma to the sperm after thawing failed to improve buck post-thawed sperm quality, thus further investigation is needed.In order to achieve a higher post-thaw buck sperm quality, an approach in the thawing protocol of cryopreserved sperm doses under in vitro capacitation conditions mimicking the in vivo female environment was studied. Therefore, functional and kinetic characteristics of buck thawed sperm from males of different ages, the season of collection, and melatonin implanted males in the non-breeding season were assessed after 3 h of incubation in an in vitro fertilization (IVF) media with 20% of buck seminal plasma (SP). Previously, fresh ejaculates were collected via artificial vagina from eight males of the Cabra Blanca de Rasquera breed during two consecutive years in breeding and non-breeding periods. Prior to semen collection in non-breeding seasons, males were split into two groups: one group was implanted with melatonin, while the other was not. In each group, semen samples were pooled, centrifuged, and diluted in an extender containing 15% powdered egg yolk and 5% glycerol before freezing. After thawing, sperm were washed and incubated in three different media: (a) control media (modified phosphate-buffered saline (PBS), (b) IVF commercial media, and (c) IVF media + 20% SP. Sperm motility was evaluated by CASA, while plasma and acrosome membrane integrity, mitochondria activity, and DNA fragmentation were analysed by flow cytometer at 0 h and after 3 h incubation. A significant reduction in motility, mitochondrial activity, plasma, and acrosome membrane integrity were observed after incubation in the presence of SP, although similar to that observed in IVF media alone. DNA integrity was not affected under in vitro capacitation conditions, regardless of SP addition. In conclusion, the addition of SP failed to improve post-thaw buck sperm quality under in vitro conditions irrespective of male age, the season of collection, and melatonin implant.

The Potential Use of Cold-Pressed Pumpkin Seed Oil By-Products in a Low-Fat Salad Dressing: The Effect on Rheological, Microstructural, Recoverable Properties, and Emulsion and Oxidative Stability.

The cold-pressed pumpkin seed oil by-product (POB) was evaluated for its application as a natural fat substitute and stabilizer in the reduced-fat salad dressings. For this aim, the samples were prepared by combining the xanthan gum (0.2–0.4 g/100 g), POB (1.0–5.0 g/100 g), egg yolk powder (3 g/100 g), and sunflower oil (10–30 g/100 g) in 17 different formulations. The optimization was carried out using response surface methodology (RSM) and full factorial central composite design (CCD). Results showed that all samples presented the shear-thinning (or pseudoplastic) flow behavior with 3.75–16.11 Pa·sn and 0.18–0.30, K and n values, respectively. The flow behavior rheological data were fitted to a power-law model (R2 > 0.99). The samples with high POB and low oil content showed similar K and n values compared to high oil content samples. Additionally, the dynamic rheological properties and three interval thixotropic test (3-ITT) were determined. The G′ value was larger than G″ in all frequency ranges, indicating viscoelastic solid characteristics in all samples. The optimum formulation was determined as 0.384% XG, 10% oil, and 3.04% POB. The samples prepared with the optimum formulation (POBLF-SD) were compared to low-fat (LF-SD), and high-fat (HF-SD) control salad dressing samples based on the rheological properties, emulsion stability, oxidative stability, zeta potential, and particle size. The oxidation kinetic parameters namely, IP, Ea, ΔS++, and ΔG++ showed that the oxidative stability of salad dressing samples could be improved by enriched by POB. The results of the present study demonstrated that POB could be considerably utilized as a natural fat substitute and stabilizer in salad dressing type emulsions.

Chebulagic acid attenuates HFD/streptozotocin induced impaired glucose metabolism and insulin resistance via up regulations of PPAR γ and GLUT 4 in type 2 diabetic rats

The aim of the present study was to evaluate the effects of chebulagic acid on enzymes involved in carbohydrate metabolism in high-fat diet/streptozotocin-induced diabetic rats. Diabetes was induced in albino male Wistar rats by feeding them with a high-fat diet comprising of 84.3% standard laboratory rat chow, 5% lard, 10% yolk powder, 0.2% cholesterol, and 5% bile salt for 2 weeks. After 2 weeks, the animals were kept in an overnight fast and injected with a low dose of streptozotocin (35 mg/kg, dissolved in 0.1 M sodium citrate buffer, pH 4.5). At the end of the experimental periods, the blood glucose, plasma insulin, hemoglobin, glycated hemoglobin levels, homeostatic model of insulin resistance, glycogen content, glycogen synthase, glycogen phosphorylase were measured in high-fat diet and streptozotocin-induced diabetic rats whereas the glucose metabolic enzymes such as hexokinase, glucose 6 phosphate dehydrogenase, glucose 6 phosphatase, fructose 1,6 bisphosphatase and protein expression of peroxisome proliferator-activated receptor–γ (PPAR-γ) and Glucose transporter 4 (GLUT4) were analyzed. Administration of chebulagic acid to HFD/STZ -induced diabetic rats for 30 days significantly decreased the levels of plasma glucose, homeostatic model assessment of insulin resistance, glycogen phosphorylase and glycosylated hemoglobin and increased the levels of insulin, glycogen content and glycogen synthase. On the other hand, the altered activity of carbohydrate metabolic enzymes, PPAR-γ and GLUT4 were brought back to near-normal levels on treatment with chebulagic acid. The effect produced by chebulagic acid on various parameters was comparable to that of metformin.

Comparison of some functional properties and protein profiles of different protein sources with egg components

Emulsifying and foaming properties of plant and animal-sourced proteins; wheat protein hydrolysates (WP1, WP2, and WP3), potato protein isolates (PP1, PP2), pea proteins isolates (PeP1, PeP2), whey protein concentrate (WPC), and buttermilk powder (BMP) were compared with the egg white powder (EWP) and egg yolk powder (EYP). Foaming capacity, stability, emulsion activity, stability, heat stability, morphology, and electrophoretic protein profiles were determined. The proteins representing competitive emulsifying functions were PeP1, WPC, and BMP. Heat treatment for 30 min at 80°C remarkably reduced the emulsion activity (EA) of EYP. Our findings demonstrated that patatin-rich potato protein (PP1), an allergen-free and vegan option, has great potential to replace the foaming function of the egg white. The relationship between the protein profiles of the samples and their functional properties was further discussed in detail.

Cheese powders as emulsifier in mayonnaise

Egg is well known to have great emulsifying properties in emulsion systems such as mayonnaise. However, egg yolk is a food allergen leading to the need for alternatives. The emulsification properties of cheese powder in mayonnaise were studied in comparison with egg yolk powder. Four percent of cheese powders were added during mayonnaise production and the resultant rheological properties, stability, and microstructure were evaluated. The cheese powders were based either on Cheddar or Camembert and powders from the latter were made with and without use of emulsifying salt. Use of cheese powder enabled development of a gel-like structure in the mayonnaise. Mayonnaise made using Cheddar cheese powder showed the highest degree of similarity to egg yolk powder in terms of rheological properties and exhibited a high consistency index (a K-value of 33.6 Pa sn) and higher stiffness (G'~2.2 kPa). On the other hand, samples with Camembert cheese powder showed decreased consistency index (a K-value of 4.1–7.3 Pa sn) and lower G'~1 kPa even if emulsifying salts were added (G'~1.6 kPa). All cheese powders ensured good fat emulsification but were less able to bind water.

Protective effects of egg yolk immunoglobulins (IgY) on juvenile groupers (Epinephelus fuscoguttatus × Epinephelus lanceolatus) with red-spotted grouper nervous necrosis virus infection

Red-spotted grouper nervous necrosis virus (RGNNV) is a highly infectious, explosive, and lethal virus that mainly infects marine fish larvae. Currently, there is no effective method to mitigate the impact of RGNNV on aquaculture production. Previous studies have shown that yolk immunoglobulin (IgY) can neutralize RGNNV in grouper fin-1 (GF-1) cells. In this study, RGNNV propagated in GF-1 cells was harvested and purified successfully. The purified RGNNV was used as an immunogen to immunize laying hens. Water-soluble fractions were separated from egg yolk, and IgY was harvested using a two-step precipitation method with saturated ammonium sulfate salt. In vitro analysis showed that the purified IgY could neutralize RGNNV. An in vivo protection assay with groupers revealed that fish fed with 10% lyophilized egg yolk powder from immunized hens were significantly protected during RGNNV challenge. The relative protection rates of groupers under treatment after RGNNV infection and continuous feeding during RGNNV infection were 68% and 70%, respectively, when fed with 10% specific egg yolk powder. This is the first study to validate that anti-RGNNV IgY can effectively protect groupers from RGNNV infection, laying a foundation for the development of anti-RGNNV products.

THE PRODUCTION OF FREEZE-DRIED EGG YOLK POWDER AND ITS EFFECT ON THE QUALITY OF GARUT RAM LIQUID SEMEN

This research aims to evaluate the protective potency of freeze-dried egg yolk powder on Garut ram sperm during the liquid semen preservation process. Semen with good sperm quality was divided into three groups and diluted using the following Tris diluents: fresh egg yolk-Tris (FEY-Tris), commercial egg yolk powder-Tris (CEY-Tris), and freeze-dried egg yolk powder-Tris (DEY-Tris). Semen that had been diluted was observed every 12 hours until sperm progressive motility was 50%. Sperm quality was tested for progressive motility percentages, viability, intact plasma membrane (IPM), and intact acrosome (IA). Fresh egg yolk had a particle size of 14460.00±330.76 nm, with polydispersity index value (PI) and zeta potential (ZP) being 1.00±0.11 and -9.22±0.30 mV, respectively. The particle size of commercial egg yolk powder was 877.90±168.86 nm with PI value 0.34±0.04 and ZP-28.7±1.24 mV. The particle size of freeze-dried egg yolk powder was 1296.00±86.73 nm, with PI value 0.70±0.04 and ZP -34.5±0.64 mV. Progressive motility percentage showed that DEY-Tris diluent managed to survive to 51.11±6.06% for 168 hours, compared to FEY-Tris (51.25±6.74%) which survived for 156 hours, although no longer than CEY-Tris diluent (53.47±6.33%) which survive for 180 hours (P0.05). Higher sperm motility was also supported by viability percentage, IPM, and IA, which were all higher (P0.05). In conclusion, freeze dried egg yolk powder mixed with Tris buffer was able to maintain sperm quality during the liquid semen preservation process.

Improvement of egg yolk powder properties through enzymatic hydrolysis and subcritical fluid extraction

Egg yolk powder is a widely used functional food ingredient due to its beneficial physicochemical and nutritional properties. However, its utilization in food can be limited due to its relatively high lipid content and low water-solubility. To address this issue, a two-step processing method utilizing enzymatic treatment combined with subcritical fluid extraction was investigated in this study. This method effectively reduced lipid content and improved water-solubility of egg yolk powder. An alcalase enzyme concentration of 500 U/g, extraction temperature of 313.15 K, extraction time of 120 min and a solid-liquid ratio of 1:9 (g:mL) produced powder with 20% lipid content and 71% water-solubility. Enzymatic hydrolysis clearly enhanced subcritical fluid extraction efficiency. This was attributed to hydrolysis disrupting the structure of egg yolk particles and facilitating the release of enclosed lipid molecules and was confirmed by scanning electron microscopy and laser confocal microscopy.

Obesity Causes Abrupt Changes in the Testicular Microbiota and Sperm Motility of Zebrafish.

BackgroundObesity is a recognized risk factor for low fertility and is becoming increasingly prevalent in many countries around the world. Obesity changes intestinal microbiota composition, causes inflammation of various organs, and also reduces sperm quality. Several microorganisms are present in the testis. However, whether obesity affects the changes of testicular microbiota and whether these changes are related to reduced fertility in obese men remain to be elucidated.MethodsIn the present study, a zebrafish obesity model was established by feeding with egg yolk powder. Sperm motility was measured by the Computer Assisted Sperm Analysis system, testicular microbial communities was assessed via 16s RNA sequencing, the immune response in zebrafish testis was quantified by quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay, and the testicular tissue structure was detected by electron microscopy and hematoxylin–eosin staining.ResultsCompared with the control group, zebrafish sperm motility was dramatically reduced, the expression of testicular proinflammatory cytokines in the testes was upregulated, and the blood–testis barrier structure was disrupted in the obese group. In addition, testicular microbiome composition was clearly altered in the obese group.ConclusionObesity alters testicular microbiota composition, and the reason behind the decreased sperm motility in obese zebrafish may be related to changes in the testicular microbial communities.