RESUMEN
This study evaluated the effects of varying levels of malondialdehyde (MDA) on the structural and foaming properties of the egg yolk proteins (EYPs), and the interaction between them was explored by molecular docking. The results showed that oxidative modification due to MDA increased the carbonyl content of EYPs by 4.49 times. Simultaneously, the total sulfhydryl content was reduced by 21.47%, and the solubility of EYPs was significantly decreased (p < 0.05). Continuous oxidation disorders the previously ordered structure of EYPs. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated that some proteins underwent crosslinking and aggregation with increased MDA oxidation, aligning with changes in particle size and zeta-potential. Moderate oxidation (<1 mmol/L) enhanced the foaming capacity and foam stability of EYPs. Additionally, molecular docking results uncovered favorable interactions between MDA and specific EYPs, primarily through hydrogen bonding. This research offers valuable insights into managing the functional and quality changes of yolk products during processing.
Asunto(s)
Pollos , Proteínas del Huevo , Malondialdehído , Simulación del Acoplamiento Molecular , Malondialdehído/química , Malondialdehído/metabolismo , Proteínas del Huevo/química , Proteínas del Huevo/metabolismo , Animales , Yema de Huevo/química , Oxidación-Reducción , Solubilidad , Tamaño de la Partícula , Enlace de HidrógenoRESUMEN
A multi-residue analytical method based on solid-phase extraction (SPE) with multiwalled carbon nanotubes (MWCNTs) as adsorbent was developed. The determination of 6 organochlorine pesticides and 7 pyrethroid pesticides in vegetables (including cucumber, cherry tomato, cabbage, lettuce, purple cabbage, leek, shallot and onion) was carried out by gas chromatography-electron capture detection (GC-ECD). The GC-ECD method used two columns (HP-50 and HP-1) and two ECD detectors. The HP-50 column was used for the analysis and the HP-1 column for validation. The clean-up conditions were optimized. The analytes were extracted by acetonitrile, and the extract was cleaned up by the MWCNTs SPE cartridge. The extract was re-dissolved by hexane, eluted with acetone-hexane (7:3, v/v) from the columns. The recoveries were over 70% for the 11 pesticides in the 13 pesticides. The results indicated that the MWCNTs SPE cartridge was efficient for 8 vegetable samples, because it reduced the contamination of the coloring materials to GC-ECD. The experimental results showed the MWCNTs SPE cartridge can adsorb the coloring materials and the eluant was nearly colorless.
Asunto(s)
Cromatografía de Gases/métodos , Hidrocarburos Clorados/análisis , Residuos de Plaguicidas/análisis , Piretrinas/análisis , Verduras/química , Insecticidas/análisis , Nanotubos de Carbono , Extracción en Fase Sólida/métodosRESUMEN
A rapid ultra-performance liquid chromatographic (UPLC) method was developed for the separation and determination of 18 amino acids in soy sauce by using 6-aminoquinolyl-N-hydroxyl-succinimidyl-carbamate (AQC) as pre-column derivatization reagent. The 18 amino acids were separated within 12 min using a BEH C18 column, ultraviolet (UV) detection at 260 nm, ammonium acetate-acetic acid-acetonitrile-water and acetonitrile-acetic acid as the mobile phases with combined gradient elution and gradient flow-rate. A linear relationship between the UV absorbance and the concentration of each amino acid was obtained with the correlation coefficient (r2) above 0.999. The detection limits were ranged from 0.032 mg/L to 0.12 mg/L for different amino acids, and the overall relative standard deviations from 0.72% to 4.05%. The recoveries of 18 analytes in a spiked soy sauce were from 90.2% to 103.7%. With simple pretreatment of the samples and shorter analysis time, the proposed method can be applied to determine amino acids in soy sauce.
Asunto(s)
Aminoácidos/análisis , Cromatografía Líquida de Alta Presión/métodos , Alimentos de Soja/análisis , Aminoácidos/aislamiento & purificación , Aminoquinolinas/química , Carbamatos/químicaRESUMEN
To investigate the effects of different states of donor cells on the development of reconstructed sheep embryos, we designed five treatments of donor cells, including cell passage, cell size, serum starvation, colchicine treatment and gene transfection. Results are as follows: (I) Compared with 16-18 passage cells, the morula/blastocyst rate of 5-7 passage cells as donor nuclei was significantly higher (17.3% vs. 4.9%, P<0.05), suggesting the advantage of short-time cultured cells in supporting the development of reconstructed embryos. (II) The mourla/blastocyst rate of reconstructed embryos derived from medium cells (15-25 microm) as donor nuclei was higher than that from large cells (25-33 microm) and small cells (8-15 microm)(20.0% vs. 8.0%, 9.7%), indicating that reconstructed embryos from medium cells had a greater potentiality to develop into morula/blastocysts than those from small or large ones. (III) The morula/blastocyst rate of reconstructed embryos from donor cells of SS (serum starvation) was lower than that from donor cells of NSS (non-serum starvation), but no significant difference was detected between SS and NSS(11.8% vs. 18.6%, P>0.05). (IV) Fetal fibroblasts treated with 0.05 micromol/L colchicine exhibited a higher morula/blastocyst rate of reconstructed embryos than those treated with 0.10 micromol/L colchicine and untreated ones (27.5% vs. 12.1%, 17.1%), however, no significant difference among the three treatments was detected (P>0.05). (V) The morula/blastocyst rate of reconstructed embryos from fetal fibroblasts transfected with GFP gene only was 3.1%, significantly lower than that from non-transgenic cells (3.1% vs. 20.4%, P<0.05). In conclusion, our results demonstrated that fetal fibroblasts of fewer passages, medium size could ensure a higher morula/blastocyst rate of reconstructed embryos. Serum starvation of donor cells might be unnecessary to the development of reconstructed embryos. Donor cells treated with 0.05 micromol/L colchicine could facilitate the development of reconstructed embryos. Additionally, as cells transfected with GFP gene were used as donor nuclei, adverse effect on the development of reconstructed embryos was observed. Therefore, the developmental efficiency of reconstructed embryos could be improved if proper treatments to donor cells were used.