Protein and Amino Acid Content in Four Brands of Commercial Table Eggs in Retail Markets in Relation to Human Requirements

Comparative Metabolomic Profiling of Eggs from 3 Diverse Chicken Breeds Using GC-MS Analysis

Eggs, as a crucial source of essential nutrients for consumers, possess a high nutritional value owing to their rich composition of vital components essential for human health. While previous research has extensively investigated genetic factors influencing egg quality, there has been a limited focus on exploring the impact of specific strains, particularly within the African context, on the polar metabolite profile of eggs. In this extensive study, we conducted an untargeted analysis of the chemical composition of both albumen and yolk from 3 distinct strains of hens-Blue Holland, Sasso, and Wassache-raised under identical feeding conditions. Utilizing gas chromatography coupled with mass spectrometry (GC-MS), we meticulously examined amino acids, carbohydrates, fatty acids, and other small polar metabolites. In total, 38 and 44 metabolites were identified in the whites and yolk, respectively, of the 3 studied strains. The application of chemometric analysis revealed notable differences in metabolite profiles with 8 relevant metabolites in each egg part. These metabolites include amino acids (N-α-Acetyl-L-lysine, lysine, L-valine, L-Tryptophan), fatty acids (oleic acid, linoleic acid, palmitic acid and stearic acid), and carbohydrates (d-glucose, maltose, lactose). These findings shed light on strain-specific metabolic nuances within eggs, emphasizing potential nutritional implications. The ensuing discussion delves into the diverse metabolic pathways influenced by the identified metabolites, offering insights that contribute to a broader understanding of egg composition and its significance in tailoring nutritional strategies for diverse populations.

A Eu-MOF-Based Fluorescent Sensing Probe for the Detection of Tryptophan and Cu2+ in Aqueous Solutions

Abnormal tryptophan (Trp) metabolism can be used as an important indicator of chronic hepatitis, paranoia, Parkinson's disease and other diseases. Deficiency or excessive accumulation of Cu2+ can cause diseases such as Wilson's disease and Alzheimer's disease. Eu-based metal-organic framework (Eu-MOF) was successfully prepared for fluorescence sensing of Trp and Cu2+ in an aqueous solution (pH = 7.4). Eu-MOF showed high selectivity and sensitivity for Trp and Cu2+ with detection limits of 0.22 µM and 0.09 µM and Ksv of 6.17 × 103 M- 1 and 2.37 × 104 M- 1 respectively. Trp and Cu2+ had overlapped UV absorption spectra with that of Eu-MOF and competed for the excitation light source. Trp also attenuated the antennae effect of organic ligands on Eu-MOF, thus quenching the red fluorescence of Eu-MOF. This study provides insights into the application of MOFs in bioanalysis and diagnostics.

The Influence of Whey Protein Isolate on the Quality Indicators of Acidophilic Ice Cream Based on Liquid Concentrates of Demineralized Whey

The use of liquid whey concentrates in the composition of ice cream, especially in combination with other powdered whey proteins, is limited due to their understudied properties. This article shows the main rheological and thermophysical characteristics of ice cream mixes, as well as color parameters, microstructure, analysis of ice crystals and quality indicators of ice cream during storage. The most significant freezing of free water (p ≤ 0.05) was observed in the temperature range from the cryoscopic temperature to -10 °C. The microscopy of experimental ice cream samples based on hydrolyzed whey concentrates indicates the formation of a homogeneous crystalline structure of ice crystals with an average diameter of 13.75-14.75 μm. Microstructural analysis confirms the expediency of using whey protein isolate in ice cream, which ensures uniform distribution of air bubbles in the product and sufficient overrun (71.98-76.55%). The combination of non-hydrolyzed whey concentrate and 3% whey protein isolate provides the highest stability to preserve the purity and color intensity of the ice cream during storage. The produced ice cream can be classified as probiotic (number of Lactobacillus acidophilus not lower than 6.2 log CFU/g) and protein-enriched (protein supply from 15.02-18.59%).

Evaluation of Physicochemical Changes in Hard-Boiled Eggs Stored at Different Temperatures

Eggs that have been hard-boiled are frequently used as ready-to-eat food. Refrigerated and frozen storage of hard-boiled eggs causes issues, such as customer rejection owing to textural changes. The objective of this research is to ascertain how storage temperature affects hard-boiled eggs' alteration in texture over time. Medium-sized brown shell eggs were acquired from a local market, boiled at 100°C for 15 min, and then stored at room temperature (25°C), refrigeration (4°C), and freezing (-18°C) conditions for 0, 12, 24, and 48 h. Fourier transform infrared spectroscopy (FTIR), texture profile, visual observation using a gemological microscope, free amino acid content, and color were measured. Freezing had a substantial impact on the eggs' hardness, gumminess, chewiness, and cohesiveness (p<0.05). The FTIR spectrums confirmed the textural changes in bonds of amide A (3,271 cm-1), amide I (1,626.2 cm-1), amide II (1,539.0 cm-1), C=O stretch of COO- (1,397 cm-1), asymmetric PO2- stretch (1,240 cm-1). Microscopic images confirmed structural changes in eggs stored at -18°C. The free amino acid content was lower in fresh and frozen eggs than in the rest (p<0.05). However, there was no discernible variation in the egg white's color when eggs were kept at 4°C (p>0.05). Salmonella spp. was found exclusively in eggs kept at room temperature. In conclusion, hard-boiled eggs did not exhibit structural or chemical changes when stored at 4°C for up to 48 h compared to freezing and room temperature conditions.

A novel approach for the protein determination in food-relevant microalgae

Microalgae are gaining interest as food ingredient. Assessments of functional and nutritional properties are necessary to forward their implementation. In this study, protein content and composition of eight commercially available microalgae biomasses were determined and compared to conventional food proteins. A novel procedure for the determination of the true protein content was proposed: Multiplication of proteinic nitrogen with a sample-specific nitrogen-to-protein conversion factor kA. The proteinic nitrogen was derived from the difference of total nitrogen minus non-protein nitrogen. The average kA for microalgae was 5.3 and considerable variation between different microalgae biomasses were detected. In addition, the content of non-protein nitrogen varied between 3.4% and 15.4%. The amino acid profiles of Chlorella samples were nutritionally superior to the tested plant proteins but indicated lower protein interaction tendency, potentially limiting their structuring functionality. In contrast, Auxenochlorella contained lower amounts of indispensable amino acids while showing comparable interaction potential to plant proteins.

Egg Yolk as a New Source of Peptides with Antioxidant and Antimicrobial Properties

A significant increase in interest in food-derived peptides obtained mostly through enzymatic reactions has been observed in the past few years. One of the best sources of bioactive peptides are defatted egg yolk proteins, which can potentially find application as high-quality nutritional supplements for infants with cow's milk protein intolerance and as natural preservatives. The aim of this study was to obtain peptides from defatted egg yolk protein, to study their antioxidant and antimicrobial properties, and to identify peptides with bioactive properties To control the course of the process, MALDI-TOF/MS (matrix-assisted laser desorption/ionization time-of flight/mass spectrometry) spectra were also examined. The peptide mixture obtained through enzyme digestion was tested for its antioxidant properties by measuring the scavenging activity in 2,2-diphenyl-1-picrylhydrazyl radical (DPPH•), 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radical cation decolorization (ABTS•+), and ferric reducing activity (FRAP) assays. Antimicrobial activity was also studied. The peptide mixture exhibited significant antioxidant activity: DPPH-1776.66 ± 32.99, ABTS-390.43 ± 8.92, and FRAP-16.45 ± 0.19. The inhibition of bacterial growth by two concentrations of the peptide mixture was examined. The best result was obtained in Bacillus cereus, with an inhibition zone of 20.0 ± 1.0 and 10.7 ± 0.6 mm at the concentrations of 50 and 25 mg/mL, respectively. The results of the study suggest that the mixture of egg yolk peptides may exhibit a number of health-promoting properties.

Combined Effect of Feed and Housing System Affects Free Amino Acid Content of Egg Yolk and Albumen in Brown Layer Chickens

In recent years, the market share for cage-free eggs has gradually increased. Because commercially available cage-free eggs are often produced not only by several housing systems but also with different feed crude protein (CP) levels, there are combined effects of feed and housing systems between cage-free and cage eggs. Therefore, using field data, this study aimed to determine the combined effects of feed and housing systems on egg traits and yolk and albumen amino acids in table eggs. Brown layers (n = 40) at the middle laying stage under two feed and housing systems (cage, CP 15.5% diet; barn, CP 17.0% diet) were used. One-way analysis of variance and Pearson's correlation analysis were used to evaluate 10 egg traits, 19 yolk amino acid traits, and 20 albumen amino acid traits. We observed significant effects of feed and housing on two egg traits (yolk weight and eggshell color redness), 16 yolk amino acids (Asp, Glu, Asn, Ser, Gln, His, Arg, Thr, Ala, Tyr, Met, Cys, Ile, Leu, Phe, and Lys), and 14 albumen amino acids (Asp, Asn, Ser, Gln, Gly, His, Arg, Thr, Ala, Val, Met, Cys, Ile, and Leu). This study revealed that eggs from the barn system (CP 17.0%) contained higher levels of free amino acids in 15 yolk and nine albumen amino acid traits. Phenotypic correlations among the 49 egg traits indicated similar correlation patterns in both systems, which implies that the balance of free amino acid content in yolk and albumen is similar in each system. Although some potential confounding factors may be present for comparing egg content between cage (CP 15.5%) and barn (CP 17.0%) systems, this study suggests that commercially available cage-free eggs may be different from cage eggs not only in external egg traits but also yolk and albumen amino acid traits.

Is now the time for a Rubiscuit or Ruburger? Increased interest in Rubisco as a food protein

Much of the research on Rubisco aims at increasing crop yields, with the ultimate aim of increasing plant production to feed an increasing global population. However, since the identification of Rubisco as the most abundant protein in leaf material, it has also been touted as a direct source of dietary protein. The nutritional and functional properties of Rubisco are on a par with those of many animal proteins, and are superior to those of many other plant proteins. Purified Rubisco isolates are easily digestible, nutritionally complete, and have excellent foaming, gelling, and emulsifying properties. Despite this potential, challenges in efficiently extracting and separating Rubisco have limited its use as a global foodstuff. Leaves are lower in protein than seeds, requiring large amounts of biomass to be processed. This material normally needs to be processed quickly to avoid degradation of the final product. Extraction of Rubisco from the plant material requires breaking down the cell walls and rupturing the chloroplast. In order to obtain high-quality protein, Rubisco needs to be separated from chlorophyll, and then concentrated for final use. However, with increased consumer demand for plant protein, there is increased interest in the potential of leaf protein, and many commercial plants are now being established aimed at producing Rubisco as a food protein, with over US$60 million of funding invested in the past 5 years. Is now the time for increased use of Rubisco in food production as a nitrogen source, rather than just providing a carbon source?

A Comparison between the Egg Yolk Flavor of Indigenous 2 Breeds and Commercial Laying Hens Based on Sensory Evaluation, Artificial Sensors, and GC-MS

The focus of this study was to compare the yolk flavor of eggs from laying hens of Chinese indigenous and commercial, based on detection of volatile compounds, fatty acids, and texture characteristics determination, using sensory evaluation, artificial sensors (electronic nose (E-nose), electronic tongue (E-tongue)), and gas chromatography-mass spectrometry (GC-MS). A total of 405 laying hens (Hy-Line Brown (n = 135), Xueyu White (n = 135), and Xinyang Blue (n = 135)) were used for the study, and 540 eggs (180 per breed) were collected within 48 h of being laid and used for sensory evaluation and the instrument detection of yolk flavor. Our research findings demonstrated significant breed differences for sensory attributes of egg yolk, based on sensory evaluation and instrument detection. The milky flavor, moisture, and compactness scores (p < 0.05) of egg yolk from Xueyu White and Xinyang Blue were significantly higher than that of Hy-Line Brown. The aroma preference scores of Xinyang Blue (p < 0.05) were significantly higher, compared to Hy-Line Brown and Xueyu White. The sensor responses of WIW and W2W from E-nose and STS from E-tongue analysis were significantly higher foe egg yolks of Hy-Line Brown (p < 0.05), compared to that of Xueyu White and Xinyang Blue. Additionally, the sensor responses of umami from E-tongue analysis, was significantly higher for egg yolks of Xueyu White (p < 0.05), compared to that of Hy-Line Brown and Xinyang Blue. Besides, the contents of alcohol and fatty acids, such as palmitic acid, oleic acid, and arachidonic acid, in egg yolk were positively correlated with egg flavor. The texture analyzer showed that springiness, gumminess, and hardness of Hy-Line Brown and Xueyu White (p < 0.05) were significantly higher, compared to Xinyang Blue. The above findings demonstrate that the egg yolk from Chinese indigenous strain had better milky flavor, moisture, and compactness, as well as better texture. The egg yolk flavors were mainly due to presence of alcohol and fatty acids, such as palmitic acid, oleic acid, and arachidonic acid, which would provide research direction on improvement in egg yolk flavor by nutrition. The current findings validate the strong correlation between the results of egg yolk flavor and texture, based on sensory evaluation, artificial sensors, and GC-MS. All these indicators would be beneficial for increased preference for egg yolk flavor by consumers and utilization by food processing industry, as well as a basis for the discrimination of eggs from different breeds of laying hens.

Squid industry by-product hydrolysate supplementation enhances growth performance of Penaeus monodon fed plant protein-based diets without fish meal

The poor growth of aquatic animals fed with diets containing high plant proteins has been attributed to low diet acceptability and feed value. Supplementation of protein hydrolysate, with high contents of free amino acids and soluble low molecular weight peptides, may increase the acceptability and feed value of a plant protein-based diet. In the present work, squid processing by-products were enzymatically hydrolyzed and used as a supplement in a plant protein-based diet, without fish meal, of Penaeus monodon to fully maximize the utilization of this marine resource. The hydrolysate was incorporated at 0, 0.5, and 1% levels in P. monodon diets containing 0 and 10% fish meal levels. Growth, digestive enzyme activities, muscle growth-, gut pro-inflammatory and immune-related gene expressions, and muscle morphometric measurements were evaluated as biological indices in an 8-week feeding trial. The squid by-product hydrolysate produced in the present study contains 90.25% protein, 5.84% lipid, and 3.91% ash, and has a molecular weight of 3.76 kDa. Supplementation at 1% hydrolysate in the experimental shrimp diet without fish meal resulted in the highest growth performance associated with increased feed intake, efficient feed and nutrient conversion and retention, enhanced digestive enzyme activities, upregulation of muscle growth- and immune-related genes, and suppression of the gut pro-inflammatory gene. The growth promotion is also linked with a significant increase in muscle mean fiber area, which suggests hypertrophic growth in shrimp. Generally, the supplementation of 1% squid by-product hydrolysate supported the growth of P. monodon fed on a plant protein-based diet without fish meal.

Observational and clinical evidence that plant-based nutrition reduces dietary acid load

Contemporary diets in Western countries are largely acid-inducing and deficient in potassium alkali salts, resulting in low-grade metabolic acidosis. The chronic consumption of acidogenic diets abundant in animal-based foods (meats, dairy, cheese and eggs) poses a substantial challenge to the human body's buffering capacities and chronic retention of acid wherein the progressive loss of bicarbonate stores can cause cellular and tissue damage. An elevated dietary acid load (DAL) has been associated with systemic inflammation and other adverse metabolic conditions. In this narrative review, we examine DAL quantification methods and index observational and clinical evidence on the role of plant-based diets, chiefly vegetarian and vegan, in reducing DAL. Quantitation of protein and amino acid composition and of intake of alkalising organic potassium salts and magnesium show that plant-based diets are most effective at reducing DAL. Results from clinical studies and recommendations in the form of expert committee opinions suggest that for a number of common illnesses, wherein metabolic acidosis is a contributing factor, the regular inclusion of plant-based foods offers measurable benefits for disease prevention and management. Based on available evidence, dietary shifts toward plant-based nutrition effectively reduces dietary-induced, low-grade metabolic acidosis.

Seaweed proteins are nutritionally valuable components in the human diet

The global population is expected to reach 11 billion people by the year 2100 and will require sustainable sources of dietary protein. Most dietary protein originates from animal and terrestrial plant agriculture, which leads to deforestation, water pollution, and greenhouse gas emissions. Discovering alternative protein sources that are nutritionally adequate for the human diet without harmful environmental effects is imperative. Seaweeds are a promising option as they produce abundant protein with a low carbon footprint. Experimental evidence shows that seaweeds contain high concentrations of the essential amino acids (EAAs) necessary for human consumption, but seaweeds have yet to be evaluated with standardized metrics to compare their nutritional value to other protein sources. In this technical note, independent literature describing the EAA content and protein digestibility of 3 commonly consumed species of seaweeds was evaluated alongside traditional protein sources using a novel hybrid protein quality (HPQ) metric. HPQ is derived from the protein digestibility-corrected amino acid score and digestibility indispensable amino acid score but includes modifications to address the lack of in vivo digestibility data for seaweeds. Seaweed proteins are similar in quality to common plant protein sources such as peas, soy, and tree nuts. Furthermore, seaweed proteins from different species have complementary EAA profiles and can be mixed to form protein blends that are nutritionally on par with animal products such as milk and whey. Thus, seaweeds may be viable protein sources with a reduced footprint that provide beneficial ecosystem services.

Rosehip (Rosa canina L.) Meal as a Natural Antioxidant on Lipid and Protein Quality and Shelf-Life of Polyunsaturated Fatty Acids Enriched Eggs

Eggs are a common food of animal origin, inexpensive, and rich in bioactive substances with high biological value. Eggs enriched in polyunsaturated fatty acids (PUFA) are extremely desired by the progressive consumer. However, during storage, eggs undergo some physiochemical changes, which decrease their value. In this regard, the effect of dietary rosehip meal and flaxseed meal on hens’ egg quality characteristics, amino acids, fatty acids, health-related indices, antioxidant capacity, total polyphenols content, and shelf life was examined. For this study 120 Tetra SL laying hens, 29 weeks of age, were fed, for 4 weeks, three diets that included control (basal diet—RF0), basal diet + 1.5% rosehip and 7% flaxseed meal (RF1), and basal diet + 3% rosehip and 7% flaxseed meal (RF2). Productive performance of hens were recorded. The content of essential amino acids (EAA), antioxidant amino acids (AAA), and sulfur amino acids (SAA) was higher in RF1 and RF2, compared with RF0. Eggs belonging to the RF1 and RF2 groups had significantly (p < 0.05) higher content of n-3 PUFAs, especially linolenic and docosahexaenoic acids. Total antioxidant capacity and polyphenol content increased in both rosehip supplemented groups, but especially in RF2. Moreover, eggs from RF1 and RF2 groups maintained significantly higher egg quality parameters after storage for 14 and 28 days in the refrigerator (5 °C) and ambient temperature (21 °C), compared with those from the RF0 group. In the Haugh unit, yolk and albumen pH presented better values in RF1 and RF2 eggs compared to the RF0 eggs.

Protein Quality Evaluation of Some Commonly Consumed Bird Egg Varieties Using Amino Acid Scores

Objective

Food proteins provide amino acids (AAs) and serve as building blocks of all vital organs, muscles, hormones, and biological fluids such as blood. Eggs are known as a good source of protein. This study compared the protein quality of bird eggs (raw and boiled), using their AA scores since some individuals consume raw eggs for various reasons. Research Methods. Eggs studied were exotic chicken, local chicken, turkey, quail, and guinea fowl eggs. The eggs were shelled and their contents (boiled and raw) lyophilized. The standard AOAC method (Kjeldahl) was used to determine protein content, while the amino acid composition was measured using an AA analyzer. The total AA scores were calculated based on the whole hen's egg AA profiles. Statistical significance was accepted at p < 0.05.

Results

The Guinea fowl egg had the highest total amino acid score (TAAS) of 0.92. The other scores ranged as follows: 0.82 (quail) >0.81 (turkey) >0.75 (exotic chicken), and the lowest score was 0.65 (local chicken). The least scores were phenylalanine: 0.34 (exotic chicken), phenylalanine and serine: 0.36 (local chicken), leucine and aspartic acid: 0.41 (turkey), methionine: 0.31 (quail), and glutamic acid: 0.33 (guinea fowl). Also, guinea fowl egg had the highest total essential amino acid (TEAA) (49.6 g/100 g protein), i.e., % TEAA (55.1%), while exotic chicken egg had the lowest (41.1%), but the highest % NEAA (58.9%).

Conclusion

Guinea fowl eggs had the highest EAA and TAA content. Its consumption should particularly be encouraged for children as this can significantly reduce the risk of protein-energy malnutrition and prevent protein deficiencies.

Exploring the association between habitual food intake and the urine and blood metabolome in adolescents and young adults: a cohort study

SCOPE

Habitual diet may be reflected in metabolite profiles that can improve accurate assessment of dietary exposure and further enhance our understanding of their link to health conditions. We aimed to explore the relationship of habitual food intake with blood and urine metabolites in adolescents and young adults.

METHODS

The study population comprised 228 participants (94 male and 134 female) of the DONALD study. Dietary intake was assessed by yearly repeated 3d-food records. Habitual diet was estimated as the average consumption of 23 food groups in adolescence. Using an untargeted metabolomics approach, we quantified 2638 metabolites in plasma and 1407 metabolites in urine. In each sex, we determined unique diet-metabolite associations using orthogonal projection to latent structures (oPLS) and random forests (RF).

RESULTS

We observed 6 metabolites in agreement between oPLS and RF in urine, 1 in females (vanillylmandelate to processed/ other meat) and 5 in males (indole-3-acetamide, and N6-methyladenosine to eggs; hippurate, citraconate/glutaconate, and X - 12111 to vegetables). We observed no association in blood in agreement.

CONCLUSION

We observed a limited reflection of habitual food group intake by single metabolites in urine and not in blood. The explored biomarkers should be confirmed in additional studies. This article is protected by copyright. All rights reserved.

Alternative protein sources of plant, algal, fungal and insect origins for dietary diversification in search of nutrition and health

This review aimed to compare alternative protein sources in terms of nutritional composition and health benefits with the purpose of disseminating up-to-date knowledge and contribute for diversification of the food marked and consumers decision-making. Plant-based is the most well-established category of alternative proteins, but there is still room for diversification. Less conventional species such as chia seeds are prominent sources of ω-3 (∼60% total lipids), while hempseed and quinoa are notable sources of ω-6 (up to 58% and 61%, respectively). Edible insects and microalgae are alternative foods rich in protein (up to 70%), fibers (∼30%), as well as peptides and polysaccharides with antimicrobial, antioxidant, anti-hypertensive, antidiabetic, antidepressant, antitumor, and immunomodulatory activities. Additionally, lipid contents in insect larvae can be as high as 50%, on a dry weight basis, containing fatty acids with anti-inflammatory and antitumor properties. In contrast, edible fungi have low lipid contents (∼2%), but are rich in carbohydrates (up to 79%) and have balanced amino acid profiles. The results suggest that food formulations combining different alternative protein sources can meet dietary requirements. Further studies on flavoring and texturing processes will help to create meat and dairy analogs, thus helping to broaden acceptance and applicability of alternative protein sources.

Spray-Drying Hen Eggs: Effects of the Egg Yolk to Egg White Ratio and Sucrose Addition on the Physicochemical, Functional, and Nutritional Properties of Dried Products and on Their Amino Acid Profiles

Manufactured egg powders can be formulated to produce food products that vary in their properties. The present study aims to determine the effect of egg white content on the physicochemical characteristics and on the functionality and nutritional value of dried whole egg (WE), egg white (W), and an egg yolk/white mixture in a 1:3 ratio (M1:3). These fresh egg products were spray-dried using sucrose—an agent recognized for its effect of protecting the protein in the egg during the drying process. Experiments were conducted in a laboratory-scale spray dryer, operated under controlled conditions, with an air inlet temperature of 120 °C. In the dried products, water activity, water solubility index, color, and pH were affected significantly as a function of the fresh egg component ratio and the added sucrose. The wettability and dispersibility in water of egg powder were improved when sucrose was added to the WE. The water-holding capacity was highest in dried egg white, and higher in the M1:3 mixture without sucrose added than in the WE with 5% sucrose. The results suggest that modifying the ratio of fresh egg yolk to egg white could lend some control over the protein and fat contents of dried egg products and over their functional properties.

Yarrowia lipolytica as an Alternative and Valuable Source of Nutritional and Bioactive Compounds for Humans

Yarrowia lipolytica, an oleagineous species of yeast, is a carrier of various important nutrients. The biomass of this yeast is an extensive source of protein, exogenous amino acids, bioavailable essenctial trace minerals, and lipid compounds as mainly unsaturated fatty acids. The biomass also contains B vitamins, including vitamin B12, and many other bioactive components. Therefore, Y. lipolytica biomass can be used in food supplements for humans as safe and nutritional additives for maintaining the homeostasis of the organism, including for vegans and vegetarians, athletes, people after recovery, and people at risk of B vitamin deficiencies.

Yeast Protein as an Easily Accessible Food Source

In recent years, the awareness and willingness of consumers to consume healthy food has grown significantly. In order to meet these needs, scientists are looking for innovative methods of food production, which is a source of easily digestible protein with a balanced amino acid composition. Yeast protein biomass (single cell protein, SCP) is a bioavailable product which is obtained when primarily using as a culture medium inexpensive various waste substrates including agricultural and industrial wastes. With the growing population, yeast protein seems to be an attractive alternative to traditional protein sources such as plants and meat. Moreover, yeast protein biomass also contains trace minerals and vitamins including B-group. Thus, using yeast in the production of protein provides both valuable nutrients and enhances purification of wastes. In conclusion, nutritional yeast protein biomass may be the best option for human and animal nutrition with a low environmental footprint. The rapidly evolving SCP production technology and discoveries from the world of biotechnology can make a huge difference in the future for the key improvement of hunger problems and the possibility of improving world food security. On the market of growing demand for cheap and environmentally clean SCP protein with practically unlimited scale of production, it may soon become one of the ingredients of our food. The review article presents the possibilities of protein production by yeast groups with the use of various substrates as well as the safety of yeast protein used as food.

The Effect of L-Glutamine on Basal Albumen and Yolk Indices, and Albumen Amino Acids Composition

Simple Summary

At present, with increased consumers’ focus on eating healthy, it is expected that egg protein content and amino acids profile are among the components of eggs that play critical roles in egg selection. Thus, this research investigated the effect dietary L-glutamine supplementation has on basal albumen and yolk indices as well as albumen protein amino acid profile. The study shows a potential role of L-glutamine supplementation for enhancing nutritional values of eggs by the decrease of albumen lipid content and the change of amino acid profile.

Abstract

The current study tested the hypothesis that 1.0% dietary inclusion of L-glutamine (Gln), an non-essential amino acid that influences protein synthesis, can improve internal egg quality, including amino acids profile. Thirty-week-old Bovans Brown laying hens in their middle laying period were assigned to one of the two experimental groups (12 replicate cages, 2 hens/cage) with Gln in the form of alpha-ketoglutarate (10 g/kg) or without Gln inclusion. The experimental period lasted for 30 wks, from the 31st to the 60th week of age of hens, when eggs were collected and selected egg quality indices were determined. Gln supplementation had no effect on albumen and egg yolk share, albumen and yolk basal indices and composition, including yolk cholesterol content. However, Gln decreased the lipid content of the egg albumen (p < 0.001), and influenced albumen amino acid profile, increasing content of asparagine (p < 0.05), phenylalanine (p < 0.05), proline (p < 0.001), tryptophan (p < 0.01), and tyrosine (p < 0.05). In conclusion, the study shows a potential role of Gln supplementation for enhancing nutritional values of eggs by lower lipid content and higher amino acid profile.

Genotype affects free amino acids of egg yolk and albumen in Japanese indigenous breeds and commercial Brown layer chickens

Using a variety of genetic resources, the aim of this study is to see how genetic background affects egg traits in chickens. Three different chicken genotypes (a commercial Brown layer, BOR; 2 Japanese indigenous breeds, NGY and YKD) were investigated effects on genotype in 10 external and internal egg quality traits along with 20 yolk and albumen free amino acid traits. Significant effects on genotype in 10 external and internal egg quality traits and 18 yolk and 17 albumen amino acid traits were found (P < 0.05). In sizes and weights of egg and eggshell redness, there were significant differences among all combinations of genotype (BOR > NGY > YKD). In 14 yolk (Asn, Ser, Gln, Gly, His, Arg, Ala, Pro, Tyr, Val, Met, Leu, Phe, and Lys) and 8 albumen amino acid traits (Gln, Gly, His, Arg, Val, Ile, Leu, and Lys), BOR was significantly higher than NGY and YKD, while the opposite relations were seen in 2 amino acid traits (Cys and GABA). Moreover, phenotypic correlation analyses revealed that positive correlations among amino acid traits within each yolk and albumen were broadly seen (0.30 < r < 0.98, P < 0.05). However, there are almost no phenotypic correlations in amino acids between yolk and albumen in BOR and NGY, but negative correlations in YKD, which implying a potential use of untapped genetic resources for modifying amino acid balance. These results indicate genetic background affects not only sizes and weights of egg but also amino acid contents and their balance of yolk and albumen.

Genetic effect on free amino acid contents of egg yolk and albumen using five different chicken genotypes under floor rearing system

Chicken eggs play an important role as food resources in the world. Although genetic effects on yolk and albumen contents have been reported, the number of chicken genotypes analyzed so far is still limited. To investigate the effect of genetic background on 10 egg traits, 19 yolk amino acid traits, and 19 albumen amino acid traits, we evaluated a total of 58 eggs from five genotypes: two Japanese indigenous breeds (Ukokkei and Nagoya) and three hybrids (Araucana cross, Kurohisui, and Boris Brown) under a floor rearing system. One-way ANOVA revealed significant effects of genotype on 10 egg traits, 8 yolk amino acids (Asp, Glu, Ser, Gly, Thr, Tyr, Cys, and Leu), and 11 albumen amino acids (Asp, Glu, Asn, Ser, Gln, His, Ala, Tyr, Trp, Phe, and Ile) contents. Moderate to strong positive phenotypic correlations among traits within each trait category (size and weight traits, yolk amino acid traits, and albumen amino acid traits), whereas there were basically no or weak correlations among the trait categories. However, a unique feature was found in the Araucana cross indicating moderate positive correlations of amino acids between yolk and albumen. These results suggest that genetic factors can modify not only the size and weight of the egg and eggshell color but also yolk and albumen free amino acids contents.

Analyses of free amino acid and taste sensor traits in egg albumen and yolk revealed potential of value-added eggs in chickens

To create high-quality eggs by using different breed and feed materials, we investigated free amino acid contents and taste sensor traits using two chicken breeds (Rhode Island Red; RIR and Australorp; AUS) fed two feeds (mixed and fermented feeds). Two-way ANOVA revealed significant breed and feed main and interaction effects on albumen bitterness and a significant interaction effect on yolk bitterness. Albumen from RIR fed mixed feed and AUS fed fermented feed was higher bitterness, whereas yolk from those groups was lower bitterness. Significant breed effects were detected in four albumen amino acid traits (His, Met, Ile, and Lys) and a yolk His, whereas significant feed effects were found in 15 albumen amino acid traits (Asp, Glu, Ser, His, Gly, Thr, Ala, Tyr, Val, Met, Trp, Ile, Leu, Lys, and Pro) and a yolk cystine trait. Compared to albumen amino acids, yolk amino acids had limited effects by breed and feed. The present results suggest that genetic and nutritional factors can alter not only amino acid contents but also sensor values of bitterness, indicating that selecting the combination of breed and feed enable us to make amino acids enriched and taste added designer eggs in future.

Amino acid requirements for laying hens: a comprehensive review

The main aim of this review is to consolidate the relevant published data examining amino acid requirements of layer hens and to reach a new set of recommendation based on these data. There are inconsistences in lysine, sulphur-containing amino acids, threonine, tryptophan, branched-chain amino acids, and arginine recommendations in data that have surfaced since 1994. This review finds that breed, age, basal diet composition, and assessment method have contributed toward inconsistencies in amino acid recommendations. Presently, the development of reduced-protein diets for layer hens is receiving increasing attention because of the demand for sustainable production. This involves quite radical changes in diet composition with inclusions of nonbound, essential and nonessential amino acids. Increasing inclusions of nonbound amino acids into layer diets modifies protein digestive dynamics, and it may influence amino acid requirements in layer hens. This review considers present amino acid recommendations for layer hens and proposes refinements that may better serve the needs of the layer industry in the future.

Impact on genetic differences among various chicken breeds on free amino acid contents of egg yolk and albumen

Eggs play important roles as food resources and nutraceuticals, to alleviate malnutrition and to improve health status in the world. Since free amino acids contribute to the nutritional values and food tastes, we investigated a total of 81 eggs from five chicken breeds, which are Australorp, Nagoya (NGY), Rhode Island Red (RIR), Shamo (SHA), Ukokkei, and two F₁ hybrids (NGYxRIR and SHAxRIR) to test impact on genetic differences in 10 egg traits, 20 yolk amino acid traits, and 18 albumen amino acid traits. One-way ANOVA revealed significant breed effects on 10 egg traits, 20 yolk amino acid traits, and 15 albumen amino acid traits. Moreover, a significant heterosis effect on yolk aspartic acid was identified. In addition, positive correlations were found broadly among traits within each trait category (egg traits, yolk amino acid traits, and albumen amino acid traits), whereas there were basically no or weak correlations among the trait categories. These results suggest that almost all traits can be dramatically modified by genetic factor, and there will be partially independent production systems of amino acids into yolk and albumen. Since there will be typical quantitative genetic architecture of egg contents, further genetic analyses will be needed.