Heat-induced gel properties and gastrointestinal digestive properties of egg white produced by hens fed with selenium-enriched yeast

Egg Yolk Selenopeptides: Preparation, Characterization, and Immunomodulatory Activity

In this study, egg yolk selenium peptides (Se-EYP) were prepared using double-enzyme hydrolysis combined with a shearing pretreatment. The properties of the selenopeptides formed were then characterized, including their yield, composition, molecular weight distribution, antioxidant activity, in vitro digestion, and immunomodulatory activity. The peptide yield obtained after enzymatic hydrolysis using a combination of alkaline protease and neutral protease was 74.5%, of which 82.6% had a molecular weight <1000 Da. The selenium content of the lyophilized solid product was 4.01 μg/g. Chromatography-mass spectrometry analysis showed that 88.6% of selenium in Se-EYP was in the organic form, of which SeMet accounted for 60.3%, SeCys2 for 21.8%, and MeSeCys for 17.9%. After being exposed to in vitro simulated digestion, Se-EYP still had 65.1% of oligopeptides present, and the in vitro antioxidant activity was enhanced. Moreover, Se-EYP exhibited superior immune detection indices, including immune organ index, level of immune factors in the serum, histopathological changes in the spleen, and selenium content in the liver. Our results suggest that Se-EYP may be used as selenium-enriched ingredients in functional food products.

Selenium- and/or Zinc-Enriched Egg Diet Improves Oxidative Damage and Regulates Gut Microbiota in D-Gal-Induced Aging Mice

Eggs, with their high nutritional value, are great carriers for enriching nutrients. In this study, selenium- and/or zinc-enriched eggs (SZE) were obtained and their effects on ameliorating oxidative stress injury, alleviating cognitive impairment, and maintaining intestinal flora balance in a D-gal-induced aging mice model were investigated. As determined by the Y-maze test, SZE restored the learning and memory abilities and increased the Ach level and AChE activity of aging mice (p < 0.05). Meanwhile, supplementation of low-dose SZE increased antioxidant levels and decreased inflammation levels (p < 0.05). High-dose SZE increased anti-inflammatory levels but were less effective than low dose. Additionally, SZE maintained the intestinal flora balance and significantly increased the ratio of Firmicutes and Bacteroidota. Blautia, as a probiotic, was negatively correlated with pro-inflammatory factors and positively correlated with antioxidant levels (p < 0.05). These results suggest that SZE might improve organ damage and cognitive function by attenuating oxidative stress and inflammatory response and maintaining healthy gut flora.

Structural property of extractable proteins and polysaccharides in wheat bran following a dual-enzymatic pretreatment and corresponding functionality

The current study applied dual-enzymatic treatment via alcalase and Bacillus velezensis hydrolase for enhancing extraction of proteins and polysaccharides from wheat bran and modifying their corresponding structure. Results indicated the aqueous extract by enzymatic pretreatment (referred as EHWB) had an increased content of soluble substance, in which 18.5 % increased for carbohydrates and 11.4 % increased for proteins in the extract compared to the aqueous extract without enzymes (labeled as AEWB). Furthermore, compositions with lower molecular weight of 130 kDa and < 21.1 kDa for polysaccharides and proteins, respectively, were found in EHWB. Interestingly, EHWB had a twice higher radicals scavenging than that of AEWB, and digestive property indicated EHWB had a greater peptides production although glucose release was lower in gastric phase. Importantly, this is the first study to reveal that gut microbiota fermentation of EHWB resulted in faster generation of short-chain fatty acids at initial fermentation stage (6 h), followed a higher generation of butyrate at final fermentation stage (24 h). This fermentation property might be associated with its presence of lower molecular weight substrates and even the changes in the molecular structure induced by the enzymes. This study highlights a novel approach for developing a value-added product from wheat bran.

The ionome and proteome landscape of aging in laying hens and relation to egg white quality

The ionome is essential for maintaining body function and health status by participating in diverse key biological processes. Nevertheless, the distribution and utilization of ionome among different organs and how aging impacts the ionome leading to a decline in egg white quality remain unknown. Thus, we used inductively coupled plasma mass spectrometry (ICP-MS) to analyze 35 elements and their isotopic contents in eight organs of laying hens at 35, 72, and 100 weeks. Moreover, the magnum proteome, amino acids in egg white, and egg white quality were analyzed in laying hens at three different ages using 4D proteomics techniques, an amino acid analyzer, and an egg quality analyzer. Across the organs, we identified varying distribution patterns among macroelements (Mg24, Ca43/44, K39, and P31), transition metals (Zn64/66, Cu63/65, Fe56/57, and Mn55), and toxic elements (Pb208, Ba137, and Sr86). We observed an organ-specific aging pattern characterized by the accumulation of toxic elements (Pb208, Ba137, and Sr86) and calcification in the small intestine. Additionally, a decrease in the utilization of essential trace elements selenium (Se78/82) and manganese (Mn55) was noted in the oviduct. By analyzing ionome in tandem with egg quality, egg white amino acids, and proteome, we unveiled that the reduction of selenium and manganese concentrations in the magnum during the aging process affected amino acid metabolism, particularly tryptophan metabolism, thereby inhibiting the amino acid synthesis in the magnum. Furthermore, it accelerated the senescence of magnum cells through necroptosis activation, leading to a decline in the albumen secretion function of the magnum and subsequently reducing egg white quality. Overall, this study provides insights into the evolution of 35 elements and their isotopes across 8 organs of laying hens with age. It also reveals the elemental composition, interactions, and utilization patterns of these organs, as well as their correlation with egg white quality. The present study highlights the significance of ionome and offers a comprehensive perspective on the selection of ionome for regulating the aging of laying hens.

Effects of Selenium Enrichment on Dough Fermentation Characteristics of Baker's Yeast

In this research, the effect of selenium (Se) enrichment on dough fermentation characteristics of yeast and the possible mechanisms was investigated. Then, the Se-enriched yeast was used as starter to make Se-enriched bread, and the difference between Se-enriched bread and common bread was investigated. It was found Se enrichment increased CO₂ production and sugar consumption rate of Saccharomyces cerevisiae (S. cerevisiae) in dough fermentation, and had positive impacts on final volume and rheological index of dough. The mechanism is possibly related to higher activity and protein expression of hexokinase (HK), phosphofructokinase (PFK), pyruvate kinase (PK), citrate synthase (CS), isocitrate dehydrogenase (ICD), and α-ketoglutarate dehydrogenase (α-KGDHC) in Se-enriched yeast. Moreover, Se-enriched bread (Se content: 11.29 μg/g) prepared by using Se-enriched yeast as starter exhibited higher overall acceptability on sensory, cell density in stomatal morphology, and better elasticity and cohesiveness on texture properties than common bread, which may be due to effect of higher CO₂ production on dough quality. These results indicate Se-enriched yeast could be used as both Se-supplements and starter in baked-foods making.

Effects of cadmium, lead, mercury, chromium, and selenium co-treatment on egg quality and fatty acids

This study aimed to reveal the effect of selenium (Se) and heavy metals (chromium (Cr), cadmium (Cd), lead (Pb), and mercury (Hg)) on the quality, fatty acids, and 13 kinds of ions in the egg yolk and albumen. Four experimental groups were established, including a control group (control; basal diet), Se group (basal diet + Se), heavy metals group (basal diet + CdCl₂ + Pb(NO₃)₂ + HgCl₂ + CrCl₃), and Se + heavy metal (HM) group (basal diet + Se + CdCl₂ + Pb(NO₃)₂ + HgCl₂ + CrCl₃). Se supplementation significantly increased the experimental egg yolk percentage since Se accumulation mainly occurred in the yolks of the eggs. The Cr content in the yolks of the Se + heavy metal groups decreased at 28 days, while a significant reduction was evident in the Cd and Hg levels of the Se + heavy metal yolks compared to the heavy metal group at 84 days. The complex interactions between the elements were analyzed to determine the positive and negative correlations. Se displayed a high positive correlation with Cd and Pb in the yolk and albumen, while the heavy metals minimally affected the fatty acids in the egg yolk.

A review on selenium-enriched proteins: preparation, purification, identification, bioavailability, bioactivities and application

Selenium (Se) deficiency can cause many diseases and thereby affect human health. Traditional inorganic Se supplements have disadvantages of toxicity and low bioavailability. Se-Enriched proteins exhibit good bio-accessibility and high biological activities. This review provides a comprehensive overview of the preparation, purification, identification, bioavailability, bioactivities and application of Se-enriched proteins. The method of extracting Se-enriched proteins from animals, microorganisms and plants mainly includes solvent extraction (water, salt, ethanol and alkali solution extraction) and novel extraction technologies (ultrasound-assisted and pulsed electric field assisted extraction). Se-Enriched proteins and their hydrolysates exhibit good bioactivities, mainly including antioxidant activity, immune regulation, neuroprotective activity, and inhibition of hyperglycemic activity, among others. Future research should focus on the relationship between Se-enriched protein metabolism and the selenium regulatory protein metabolic pathway by using multi-omics technology. In addition, it is necessary to comprehensively study the structure-activity relationship of Se-enriched proteins/hydrolysates from different sources, to further clarify their bioactive mechanism and to verify their health benefits in vivo.