A Survey of the Vitamin and Mineral Content in Milk from Yaks Raised at Different Altitudes.

In this study, the content of vitamins and of toxic and beneficial (macro- and micro-) minerals in milk from yaks raised at different altitudes (3,215, 4,340, and 5,410 m) was investigated. For comparison, the components in cow's milk were also measured. At higher altitudes, a significant (P < 0.05) increase in vitamin A and vitamin E was observed in the yak's milk, whereas the opposite was observed for vitamin B1 and vitamin B2. No significant statistical difference in vitamin C, Ca, P, Na, K, and Mg concentrations was observed in milk from yaks raised at different altitudes. The concentrations of Zn in milk from yaks raised at different altitudes showed no statistical difference, whereas the Mn and Fe concentrations in milk from yaks raised at 3,215 m were lower than those raised at higher altitudes. The concentrations of Pb and Cd in yak's milk did not exceed the maximum permissible concentrations (Codex Alimentarius Commission), whereas their concentrations were higher in milk from yaks raised at 3,215 m than at higher altitudes. These findings indicated that the contents of vitamins and minerals in yak milk varied in different altitudes.

Rosemary and Tea Tree Essential Oils Exert Antibiofilm Activities In Vitro against Staphylococcus aureus and Escherichia coli.

ABSTRACT: The purpose of the present study was to determine the bioactive compounds in rosemary essential oil (REO) and tea tree essential oil (TEO) and to investigate their antibacterial and antibiofilm activities against Staphylococcus aureus and Escherichia coli in vitro. The MIC and MBC assays were performed to assess the antibacterial activity of these two EOs against S. aureus and E. coli with the broth microdilution method. A crystal violet assay was used to ascertain the effects of EOs on the biofilm formation of the test strains, and a tetrazolium bromide (MTT) assay was used to measure the level of inactivation of mature biofilms by EOs. Gas chromatography-mass spectrometry revealed 15 compounds in REO and 27 compounds in TEO, representing 97.78 and 98.13% of the total EO, respectively. Eucalyptol and α-pinene were found in high concentrations in REO, and the two major compounds in TEO were 4-terpineol and terpinolene. The MICs of REO for the two S. aureus and E. coli test strains were both 0.5 mg/mL, and the MICs of TEO for the two strains were both 0.25 mg/mL. Therefore, these EOs can significantly inhibit the formation of biofilms and induced morphological biofilm changes, as verified by scanning electron microscopy. Both EOs had destructive effects on the mature biofilm of the two test strains. TEO was more inhibitory than REO for biofilm formation by the two test strains.

In-depth mapping of the proteome of Tibetan pig tenderloin (longissimus dorsi) using offline high-pH reversed-phase fractionation and LC-MS/MS.

In recent years, Tibetan pig breeding and meat processing have developed rapidly. However, the basic physiological and biochemical characteristics of Tibetan pork have not been systematically explored. The present study conducted a high-throughput analysis of the tenderloin (longissimus dorsi) proteome of the Tibetan pigs and performed a functional annotation and bioinformatics analysis of the identified proteins. Based on offline two-dimensional liquid chromatography fractionation and MS/MS identification, a total of 1,723 proteins were identified in the tenderloin of Tibetan pigs. Gene ontology analysis and pathway enrichment analysis revealed that the proteins involved in respiration (oxidative phosphorylation, glycolysis/gluconeogenesis, citric acid cycle, and pyruvate metabolism) and protein synthesis and metabolism (proteasome, amino acid biosynthesis, endoplasmic reticulum protein processing, and ribosomes) were significantly enriched, indicating that the energy production and protein metabolism are the most important physiological processes in Tibetan pig tenderloin. Practical applications The in-depth mapping of the tenderloin (longissimus dorsi) proteome of the Tibetan pigs gives a panoramic perspective at the protein molecular level and provides important information on the mechanisms of postmortem muscle physiology and meat quality formation. Furthermore, the development of Tibetan pork storage and processing technologies would also benefit from the characterization of the biochemical properties of Tibetan pork.

Proteome analysis using iTRAQ reveals the differentiation between Tibetan and ordinary ovalbumin peptides.

Ovalbumin peptides are food protein-derived fragments comprised of amino acid residues. The bioactive properties of the peptides are determined by the inherent amino acid composition and sequence of the peptide. The objective of this study was to evaluate the proteomics characteristics in Tibetan chicken egg ovalbumin peptides, compared to ordinary eggs, using isobaric tags for the relative and absolute quantification labelling technique (iTRAQ). The results showed that 165 proteins were identified and 56 proteins were significantly changed including 34 significantly upregulated and 22 significantly downregulated proteins. The more abundant proteins of the Tibetan ovalbumin peptides included vitellogenin-2, vitellogenin-1, vitellogenin, apolipoprotein A-I, and serum albumin, which were upregulated. A Gene Ontology (GO) analysis showed that these proteins mostly participated in biological processes and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that they may be associated with the peroxisome proliferator-activated receptor (PPAR) pathway, which is related to lipid metabolism. The Protein-Protein Interaction (PPI) analysis showed that these proteins significantly interacted.

Optimization of Antioxidant Hydrolysate Produced from Tibetan Egg White with Papain and Its Application in Yak Milk Yogurt.

The objective of the present study was to produce antioxidant hydrolysate from Tibetan egg white protein hydrolyzed with papain, and to investigate the effect of added papain egg white hydrolysate (PEWH) on the quality characteristics and amino acid profiles of yak milk yogurt. A response surface methodology (RSM) was utilized to analyze the effects of hydrolysis time (X1), the ratio of enzymes to substrates, and enzyme dosage (X3) on the superoxide anion radical (O2-) scavenging activity of hydrolysates. The predicted maximum value of O2- scavenging activity (89.06%) was obtained an X1 of 2.51 h, X2 of 4.13%, and X3 of 4500 U/g of substrate, almost approaching the experimental value (88.05 ± 1.2%). Furthermore, it was found that the addition of PEWH to yak milk can enhance acidification, sensory score, the number of lactic acid bacteria (LAB), and the amino acid content in yak milk yogurt. The results suggested that PEWH displayed an exceptional potential to be developed as a functional food ingredient that could be applied during the manufacturing process of yak milk yogurt.