Effect of slaughter age and postmortem aging time on tenderness and water-holding capacity of yak (Bos grunniens) longissimus thoracis muscle

Transcriptomic analysis of different intramuscular fat contents on the flavor of the longissimus dorsi tissues from Guangling donkey

BACKGROUND

In this study, researchers aimed to explore the impact of intramuscular fat (IMF) concentration on the flavor of donkey meat, specifically in the longissimus dorsi muscle of Guangling donkeys. The internal volatile organic compounds that cause the flavor differences between donkey muscles are not clear at present. Transcriptomic technologies were utilized to analyze gene expression and its relationship to donkey meat flavor.

METHOD

Thirty Guangling donkeys had their IMF content evaluated in the longissimus dorsi muscle. Based on IMF content, 16 donkeys of similar ages were divided into two groups: low-fat (L) and high-fat (H). Headspace solid-phase microextraction Gas chromatography-mass spectrometry (HS-SPME-GC-MS) and headspace solid phase microextraction mass spectrometry were used to identify potential flavor components that differed between the two groups.

RESULTS

Five key volatile substances were identified, and WGCNA and KEGG analysis was conducted to analyze the genes associated with these substances. The results showed that pathways like PPAR signaling, nucleotide excision repair, glucagon signaling, arachidonic acid metabolism, and glycolysis/glycogenesis were involved in lipid deposition. Additionally, a gene-gene interaction network map was constructed, highlighting the importance of hub genes such as EEF2, DDX49, GAP43, SNAP25, NDUFS8, MRPS11, RNASEH2A, POLR2E, POLR2C and ALB in regulating key flavor substances.

CONCLUSION

This study provided valuable insights into the regulation of genes and protein expression related to flavor substances in donkey meat. It also deepened understanding of the influence of IMF on flavor and laid a foundation for future molecular breeding improvements in Guangling donkeys.

A short-term of starvation improved the antioxidant activity and quality of African catfish (Clarias gariepinus)

Clarias gariepinus is an important freshwater fish with high economic value and breeding potential in China. It is a fast-growing and adaptable catfish, but the main problems facing the current market are its low price and poor taste, although starvation is a good solution to these problems. In this study, the effects of starvation on the physiology, biochemistry, and muscle quality of C. gariepinus were investigated. The results showed that compared with the control group, the weight gain rate and specific growth rate of the starvation group were significantly different. Body weight, visceral weight, condition factor, viscerosomatic index, hepatosomatic index, and viscera fat index all decreased, while visceral weight and hepatosomatic index decreased significantly after starvation for 30 days. The hardness and crude protein of muscle increased significantly and crude lipid decreased significantly. Taste-enhancing amino acids increased slightly, and fatty acids increased significantly. Compared with the control group, starvation led to changes in antioxidant defense parameters. The level of malondialdehyde (MDA) in liver increased significantly; the activities of superoxide dismutase (SOD) increased in serum after 30 days; the activities of glutathione peroxidase (GSH-Px) increased considerably in the serum and liver after 15 days; the activities of alanine aminotransferase (ALT) increased considerably in the serum and liver after 30 days. The in-depth study of changes in physiological, biochemical, and nutritional components of fish under starvation is helpful to understand the ecological strategy of fish to adapt to starvation and of great guiding significance for fishery resource management and aquaculture production.

Improving the texture attributes of squid meat (sthenoteuthis oualaniensis) with slight oxidative and phosphate curing treatments

This study aimed to improve the pasty texture of squid meat by oxidative and phosphate curing (OPC) treatment, and elucidate the underlying mechanism. The shear force, springiness, weight gain, water-holding capacity (WHC), color and sensory evaluation of squid meat samples treated with a mild OPC approach (OPC_2, 10 mM H2O2 solution with complex phosphate solution) were significantly improved. However, the samples subjected to over-oxidized (20 and 30 mM H2O2 solution with complex phosphate solution) treatment did not obtain favorable outcomes. Microstructure analysis revealed that muscle fibers aggregated after moderate OPC treatments, leading to an increased spacing between muscle fiber bundles. This gap facilitated a more uniform distribution and restriction of water, according to low-field nuclear magnetic resonance (LF-NMR) results. The results from in vitro simulated oxidation of myofibrillar proteins (MPs) demonstrated that increased H2O2 led to formation of carbonyl groups and decreased sulfhydryl groups, and even secondary structure changes, according to fourier transform infrared spectroscopy (FT-IR). Particle size, zeta potential and sodium dodecyl sulfate-polyacryl amide gel electrophoresis (SDS-PAGE) results showed that oxidation caused protein aggregation into larger molecules. This study presents a novel approach to improve pasty texture of squid meat.

LF-NMR determination of water distribution and its relationship with protein- related properties of yak and cattle during postmortem aging

The water distribution have a profound influence on meat quality, and proteins play a critical role in water distribution. The water distribution detected with proton NMR and its relationship with protein related properties were investigated. Three populations of water were detected: bound water (T21, P21), immobilized water (T22, P22), and free water (T23, P23). The decreased T22 and T23 indicated an increase in water-holding capacity in both muscles from 3 days of aging. The P22 in cattle was higher than that in yak and the P23 in cattle was lower than that in yak, suggesting that cattle exhibited a greater water-holding capacity compared to yak. Moreover, postmortem aging affected muscle protein oxidation, denaturation, and degradation. Correlation analysis suggested that protein oxidation and denaturation caused muscle water loss and protein degradation could allow the muscle to retain water. It provides a basis for the optimization of quality of meat and products.