Dietary supplementation with quercetin: an ideal approach for improving meat quality and oxidative stability of broiler chickens.

This study aimed to improve the eating quality of yellow-feathered broiler chicks by feeding them corn-soybean meal diets supplemented with 250, 500, and 1,000 mg/kg quercetin. we examined the impact of varying doses of dietary quercetin on the sensory quality of chicken breast meat as well as on the antioxidant enzymes, antioxidant-related signaling molecules, structure and thermal stability of myofibrillar protein (MPs), and microstructure of myogenic fibers in the meat during 24 h of postslaughter aging. Additionally, we investigated the potential correlations among antioxidant capacity, MP structure, and meat quality parameters. The results indicated that dietary supplementations with 500 and 1,000 mg/kg quercetin improved the physicochemical properties and eating quality of yellow-feathered broiler chicken breast meat during 12 to 24 h postslaughter. Additionally, quercetin improved the postslaughter oxidative stress status and reduced protein and lipid oxidation levels. It also increased hydrogen bonding interactions and α-helix content during 6 to 12 h postslaughter and decreased ß-sheet content during 12 to 24 h postslaughter in chicken breast MP. This resulted in improved postslaughter MP structure and thermal stability. The correlation results indicated that the enhancement of antioxidant capacity and MP structure enhanced the physicochemical and edible qualities of yellow-feathered broiler chicken breast meat. In conclusion, the current findings suggest that dietary supplementation with quercetin is an ideal approach for improving the eating quality of chicken meat, thereby broadening our understanding of theoretical and technological applications for improving the quality of chicken.

Quantitative Proteomics Reveals the Relationship between Protein Changes and Volatile Flavor Formation in Hunan Bacon during Low-Temperature Smoking.

This study aimed to investigate the changes in proteins and volatile flavor compounds that occur in bacon during low-temperature smoking (LTS) and identify potential correlations between these changes. To achieve this, a combination of gas chromatography-mass spectrometry and proteomics was employed. A total of 42 volatile flavor compounds were identified in the bacon samples, and, during LTS, 11 key volatile flavor compounds with variable importance were found at a projection value of >1, including 2',4'-dihydroxyacetophenone, 4-methyl-2H-furan-5-one, Nonanal, etc. In total, 2017 proteins were quantified at different stages of LTS; correlation coefficients and KEGG analyses identified 27 down-regulated flavor-related proteins. Of these, seven were involved in the tricarboxylic acid (TCA) cycle, metabolic pathways, or amino acid metabolism, and they may be associated with the process of flavor formation. Furthermore, correlation coefficient analysis indicated that certain chemical parameters, such as the contents of free amino acids, carbonyl compounds, and TCA cycle components, were closely and positively correlated with the formation of key volatile flavor compounds. Combined with bioinformatic analysis, the results of this study provide insights into the proteins present in bacon at various stages of LTS. This study demonstrates the changes in proteins and the formation of volatile flavor compounds in bacon during LTS, along with their potential correlations, providing a theoretical basis for the development of green processing methods for Hunan bacon.

Low-protein diets supplemented with glycine improves pig growth performance and meat quality: An untargeted metabolomic analysis.

For the purpose to improve meat quality, pigs were fed a normal diet (ND), a low protein diet (LPD) and a LPD supplemented with glycine (LPDG). Chemical and metabolomic analyses showed that LPD increased IMF deposition and the activities of GPa and PK, but decreased glycogen content, the activities of CS and CcO, and the abundance of acetyl-CoA, tyrosine and its metabolites in muscle. LPDG promoted muscle fiber transition from type II to type I, increased the synthesis of multiple nonessential amino acids, and pantothenic acid in muscle, which should contributed to the improved meat quality and growth rate. This study provides some new insight into the mechanism of diet induced alteration of animal growth performance and meat quality. In addition, the study shows that dietary supplementation of glycine to LPD could be used to improved meat quality without impairment of animal growth.

Metabolic perturbations and health impact from exposure to a combination of multiple harmful Maillard reaction products on Sprague-Dawley rats.

The present study aimed to investigate the metabolic perturbations and health impact of the co-accumulation of Maillard reaction products (MRPs), including acrylamide, harmane, and Nε-(carboxymethyl)lysine (CML), via serum biochemical and histopathological examinations as well as metabolomic analysis. Sprague-Dawley rats were treated with acrylamide (2 mg per kg body weight [bw]), harmane (1 mg per kg bw), CML (2 mg per kg bw), and combinations of these MRPs. Harmane did not cause adverse effects on the health of rats, whereas acrylamide and CML resulted in significantly (P < 0.05) decreased insulin sensitivity (HOMA-IR > 1), increased oxidative stress levels, and pathological injuries to the pancreas, liver, and gastrocnemius. Owing to the antioxidant and anti-diabetic activities of harmane, the effects of the combination of the MRPs on oxidative stress levels, blood glucose metabolism, and pathological injuries to the pancreas and gastrocnemius were relieved. However, new health problems, including pathological injury of the kidneys and increased cancer risk, were observed. Metabolomic analysis revealed that this may be related to the effects of MRPs on the arginine biosynthesis pathway, which resulted in the abnormal metabolism of fumaric acid and the tricarboxylic acid cycle. These results indicated that the mechanisms of the combined effect of MRPs and their effects on health cannot be predicted from the effects of individual MRPs.

Antioxidant Activity and Sensory Quality of Bacon.

Effects of liquid smoke prepared from different woods on physicochemical parameters, sensory quality, and protein and lipid oxidation were determined in bacons during process and storage. The relationship between the antioxidant activity of smoked liquid and the quality of bacon was further explored through chemometric analysis. Results showed that liquid smoke prepared from different woods differed in phenolic and carboxyl compounds and antioxidant capacity. Bacon processed with different liquid smoke had different antioxidant capacity, lipid and protein oxidation during storage, and sensory quality. The concentration of phenols was positively highly correlated with the antioxidant capacity of both liquid smoke and fresh bacon, but negatively correlated with lipid and protein oxidation in bacon. Among the five woods, liquid smoke made from Punica granatum L. showed higher antioxidant capacity, but bacon smoked with Armeniaca vulgaris Lam had better overall eating quality. This study reveals that selection of woods to prepare antioxidant fumigant is a feasible approach to retard oxidative spoilage of meat products. Future study is need for the development of composite smoke flavorings to improve both oxidative stability and sensory quality of foods.

Duck breast muscle proteins, free fatty acids and volatile compounds as affected by curing methods.

The aim of this study was to investigate the effects of different curing methods on protein structure, protein and lipid oxidation, lypolysis and volatile compounds in duck breast meat. The results showed that compared to static brining and pulsed pressure salting, the vacuum tumbling curing significantly decreased the oxidation of proteins and lipids, and the surface hydrophobicity of proteins, increased α-helix structure but decreased the proportion of ß-sheet, and increased actomyosin dissociation, liplysis and the free fatty acid content in meat. Meanwhile, vacuum tumbling curing decreased the amount of volatile flavor compounds, hexanal, 2,3-octanone, and off-flavor compounds 1-octen-3-ol and 1-hexanol. This study suggests that concerns on healthiness and the sensory quality of processed meat products should be paid in the selection of curing methods and vacuum tumbling curing is superior in terms of both aspects.

Histone acetyltransferase inhibitors antagonize AMP-activated protein kinase in postmortem glycolysis.

OBJECTIVE: The purpose of this study was to investigate the influence of AMP-activated protein kinase (AMPK) activation on protein acetylation and glycolysis in postmortem muscle to better understand the mechanism by which AMPK regulates postmortem glycolysis and meat quality. METHODS: A total of 32 mice were randomly assigned to four groups and intraperitoneally injected with 5-Aminoimidazole-4-carboxamide1-ß-D-ribofuranoside (AICAR, a specific activator of AMPK), AICAR and histone acetyltransferase inhibitor II, or AICAR, Trichostatin A (TSA, an inhibitor of histone deacetylase I and II) and Nicotinamide (NAM, an inhibitor of the Sirt family deacetylases). After mice were euthanized, the Longissimus dorsi muscle was collected at 0 h, 45 min, and 24 h postmortem. AMPK activity, protein acetylation and glycolysis in postmortem muscle were measured. RESULTS: Activation of AMPK by AICAR significantly increased glycolysis in postmortem muscle. At the same time, it increased the total acetylated proteins in muscle 45 min postmortem. Inhibition of protein acetylation by histone acetyltransferase inhibitors reduced AMPK activation induced increase in the total acetylated proteins and glycolytic rate in muscle early postmortem, while histone deacetylase inhibitors further promoted protein acetylation and glycolysis. Several bands of proteins were detected to be differentially acetylated in muscle with different glycolytic rates. CONCLUSION: Protein acetylation plays an important regulatory role in postmortem glycolysis. As AMPK mediates the effects of pre-slaughter stress on postmortem glycolysis, protein acetylation is likely a mechanism by which antemortem stress influenced postmortem metabolism and meat quality though the exact mechanism is to be elucidated.