Zefu Wang,Zhifei He,Dong Zhang,Xiaosi Chen,Hongjun Li
Summary Frozen storage is chosen to be the preferred method in meat preservation. However, multiple freeze-thaw (F-T) cycles will occur during the transfers or distribution processes under poor cold-chain conditions. This study investigated the effects of multiple freeze-thaw (F-T) cycles on water mobility, microstructure damage, protein oxidation and lipid oxidation in rabbit meat during seven F-T cycles through 56 days. Scanning electron microscopy results indicated that the increase of F-T cycles induced the rupture of endomysia and the increase of gaps between fibres. Low-field nuclear magnetic resonance (LF-NMR) results showed that the peak area of T 21 and T 22 decreased with increasing number of repeated F-T cycles, indicating that immobile water shifted to free water, and free water mobility increased. During repeated freeze-thaw process, the peroxide value, thiobarbituric acid-reactive substances, non-haem iron content and carbonyl groups of rabbit meat gradually increased, whereas haem content, haem iron content and sulfhydryl content of rabbit meat gradually decreased. In addition, the results of Fourier transform infrared, sodium dodecyl sulphate polyacrylamide gel electrophoresis, and intrinsic fluorescence spectroscopy indirectly proved that multiple F-T cycles could cause α-helix structure disruption, protein aggregation and degradation, and tryptophan oxidation of rabbit meat myofibrillar protein (MP). Overall, multiple repeated F-T cycles changed moisture migration, damaged microstructure and promoted lipid and protein oxidation of rabbit meat.
Zefu Wang,Zhifei He,Dong Zhang,Xiaosi Chen,Hongjun Li
This study aimed to assess the protective effects of the main components of Zanthoxylum bungeanum Maxim. essential oil (ZBMEO) on the characteristics of rabbit meat myofibrillar protein (MP) under MDA (malondialdehyde) induced oxidation. The MP suspensions were mixed with various concentrations (5 mM, 25 mM and 50 mM) of linalool, limonene, sabinene under MDA-induced oxidation. The retained MDA contents were determined, and the thermal stability and structure of rabbit meat myofibrillar protein were analyzed. Linalool, limonene and sabinene can prevent MDA from binding to MP effectively. The addition of linalool, limonene and sabinene led to the increase in the sulfhydryl and free amine contents, and the decrease in the carbonyl content and surface hydrophobicity compared to control MP. Also, the addition had protective effects on maintaining the secondary structure and morphology of MP under MDA-induced oxidation. The Differential scanning calorimetry (DSC) and SDS-PAGE analysis indicated that linalool, limonene, sabinene had an obvious protective effect on MHC and actin. The above results suggest that linalool, limonene and sabinene could reduce the oxidative damage of MDA to MP, which might have the potential in protecting the structure and physicochemical properties of the protein in foods .
Junbo Chen,Xiaodong Yu,Wangxiang Huang,Chen Wang,Qiyi He
Bioactive peptides exhibiting angiotensin-converting enzyme (ACE) inhibitory effects and extracted from natural foods have potential as healthy and safe therapeutics for high blood pressure. The aim of this study was to isolate and purify ACE inhibitory peptides from rabbit meat protein hydrolysate, to explore the underlying mechanisms by molecular docking, and to evaluate the antihypertensive effects in vivo. A novel ACE inhibitory tetrapeptide Trp-Gly-Ala-Pro (WGAP) was identified and purified from a bromelain hydrolysate. WGAP acted against ACE in a non-competitive manner with an IC50 of 140.70 ± 4.51 μM. It was resistant to enzymatic degradation by pepsin and trypsin in vitro. Molecular docking analysis indicated that WGAP formed stable hydrogen bonds with ACE residues His353, Ala354 and ALA356. In vivo, 100 mg kg−1 WGAP significantly reduced systolic and diastolic blood pressure in hypertensive rats by up to 42.66 ± 2.87 and 28.56 ± 2.71 mmHg, respectively, 4 h after oral administration. ACE inhibitory peptides derived from rabbit meat have potential antihypertensive effects and provide a new route for the exploration of novel hypertension inhibitors and the utilization of rabbit meat.
危险品化学品经营许可证（带存储）