Selenium-enriched yeast, a selenium supplement, improves the rheological properties and processability of dough: From the view of yeast metabolism and gluten alteration.

This study investigated the effect mechanism of selenium (Se)-enriched yeast on the rheological properties of dough from the perspective of yeast metabolism and gluten alteration. As the yeast Se content increased, the gas production rate of Se-enriched yeast slowed down, and dough viscoelasticity decreased. The maximum creep of Se-enriched dough increased by 29%, while the final creep increased by 54%, resulting in a softer dough. Non-targeted metabolomics analyses showed that Se inhibited yeast energy metabolism and promoted the synthesis of stress-resistance related components. Glutathione, glycerol, and linoleic acid contributed to the rheological property changes of the dough. The fractions and molecular weight distribution of protein demonstrated that the increase in yeast Se content resulted in the depolymerization of gluten. The intermolecular interactions, fluorescence spectrum and disulfide bond analysis showed that the disruption of intermolecular disulfide bond induced by Se-enriched yeast metabolites played an important role in the depolymerization of gluten.

Protective Effect of Selenium-enriched Peptide from Cardamine violifolia on Ethanol-induced L-02 Hepatocyte Injury.

In this study, we investigated the protective effect of selenium (Se)-enriched peptide isolated from Cardamine violifolia (SPE) against ethanol-induced liver injury. Cell proliferation assays show that different concentrations of SPE protect human embryonic liver L-02 cells against ethanol-induced injury in a dose-dependent manner. Treatment with 12 µmol/L Se increases the cell survival rate (82.44%) and reduces the release of alanine aminotransferase, aspartate transaminase, lactate dehydrogenase, and apoptosis rate. SPE treatment with 12 µmol/L Se effectively reduces the concentration of intracellular reactive oxygen species and increases the contents of intracellular superoxide dismutase (51.64 U/mg), catalase (4.41 U/mg), glutathione peroxidase (1205.28 nmol/g), and glutathione (66.67 µmol/g), thereby inhibiting the effect of ethanol-induced oxidative damage. The results of the transcriptomic analysis show that the glutathione metabolism and apoptotic pathway play significant roles in the protection of L-02 hepatocytes by SPE. Real-time qPCR analysis shows that SPE increases the mRNA expression of GPX1 and NGFR. The results of this study highlight the protective effects of SPE against ethanol-induced liver injury.

Investigation of selenium and selenium species in Cardamine violifolia using in vitro digestion coupled with a Caco-2 cell monolayer model.

Inadequate Se intake can enhance vulnerability to certain health risks, with supplementation lessening these risks. This study investigated the bioavailability of Se and Se species in five Se compounds and in Se-rich Cardamine violifolia using in vitro digestion coupled with a Caco-2 cell monolayer model, which enabled the study of Se transport and uptake. Translocation results showed that SeCys2 and MeSeCys had high translocation rates in C. violifolia leaves (CVLs). The uptake rate of organic Se increased with time, and MeSeCys exhibited a higher uptake rate than that for SeCys2 and SeMet. The translocation mechanisms of SeMet, Se(IV), and Se(VI) were passive transport, whereas those of SeCys2 and MeSeCys were active transport. The bioavailability of organic Se was higher than that of inorganic Se, with a total Se bioavailability in CVLs of 49.11 %. This study would provide a theoretical basis for the application of C. violifolia in the functional food.

The Effect of Co-Fermentation with Lactobacillus plantarum HLJ29L2 and Yeast on Wheat Protein Characteristics in Sourdough and Crackers.

Sourdough fermentation has been widely used in food products. However, there has been limited study of the effect of co-fermentation with lactic acid bacteria and yeast on the dough and cracker products. In this study, the influence of co-fermentation with Lactobacillus plantarum HLJ29L2 (LP HLJ29L2) and yeast on wheat protein digestibility of cracker was studied, and the mechanism of the protein changes in sourdough during fermentation was further explored. Co-fermentation with LP HLJ29L2 and yeast (DN-1) strongly improved the protein digestibility of cracker. At the same time, the content of free amino acids in DN-1 crackers increased by 20%. Co-fermentation also had significant effect on the sourdough during fermentation. The SDS-soluble protein content in sourdough was increased, and large molecule proteins were significantly reduced in the DN-1 sourdough. This was due to the fact, that LP HLJ29L2 grew rapidly during co-fermentation and produced more organic acids, which led to an increase in protease activity in sourdough and promoted the degradation of protein by proteases. The results of this study provide an important theoretical basis for the application of lactic acid bacteria and yeast co-fermentation in crackers.

Antioxidant Activity of Selenium-Enriched Peptides from the Protein Hydrolysate of Cardamine violifolia.

Cardamine violifolia is a selenium (Se)-enriched plant found in China. In this study, the Se-enriched peptides of C. violifolia (CP) were isolated using a 1 kDa ultrafiltration membrane after enzymatic hydrolysis by alkaline and neutral proteases. The peptides were separated by DEAE-Sepharose FF anion-exchange chromatography and purified using preparative high-performance liquid chromatography (prep-HPLC). The component with the highest antioxidant activity, CPR13, was identified by comparing the 1,1-diphenyl-2-picrylhydrazyl (DPPH•), hydroxyl (•OH), 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+ •), and superoxide ( O 2 - · ) radical scavenging ability of each fraction. At a concentration of 0.1 mg/mL, the DPPH•, •OH, O 2 - · , and ABTS+ • scavenging activities of CPR13 were 89.2%, 26.3%, 40.6%, and 42.9%, respectively. Amino acid sequences were obtained by liquid chromatography combined with mass spectrometry as follows: GRVGSSSC, GRAGGSYM, GHPNFKLNCSGG, GTKSCKA, ASSNARDMI, TAGGCYIPI, and KNCALQ. The seleno-amino acids were identified as selenomethionine, methylselenocysteine, and selenocysteine. Correlation analysis among organic Se content, peptide content, and antioxidant activity revealed that organic Se plays a greater role in free radical scavenging than peptides, and that the organic Se content of the Se-enriched peptides was positively correlated with their antioxidant ability (P < 0.05). It indicated that CP has a great potential as natural functional materials for dietary supplement.