Effect of glycolysis on water holding capacity during postmortem aging of Jersey cattle-yak meat

BACKGROUND

Postmortem muscle moisture loss leads to a decrease in carcass weight and can adversely impact overall meat quality. Therefore, it is critical to investigate water holding capacity (WHC) to enhance meat quality. Current research has primarily focused on examining the correlation between signaling molecules and meat quality in relation to the glycolysis effect on muscle WHC. But there exists a significant knowledge gap regarding the mechanism of WHC in Jersey cattle-yak meat.

RESULTS

Jersey cattle-yak meat pH decreased and then increased during postmortem aging. Lactate content, cooking loss, pressing loss, drip loss and centrifuging loss of Jersey cattle-yak meat increased and then decreased during postmortem aging. The glycogen content of Jersey cattle-yak meat was significantly higher than that of yak meat at 6-120 h, being 8.40% higher than that of yak meat at 120 h. The activity of key glycolytic enzymes hexokinase (HK), pyruvate kinase (PK), phosphofructokinase (PFK) and lactate dehydrogenase (LDH) in Jersey cattle-yak meat was lower than that in yak meat. Correlation analysis showed that Jersey cattle-yak meat WHC was positively correlated with the activity of HK, PK, PFK and LDH.

CONCLUSIONS

The WHC of Jersey cattle-yak meat was higher than that of Gannan yak meat, and it was significantly positively correlated with the activity of key enzymes of the glycolytic signaling pathway. Therefore, the glycolysis rate can be reduced by inhibiting enzyme activity to improve Jersey cattle-yak meat WHC and meat quality. © 2023 Society of Chemical Industry.

The Content of Bioactive Compounds and Technological Properties of Matcha Green Tea and Its Application in the Design of Functional Beverages

Matcha is a powdered green tea obtained from the Camellia sinensis L. plant intended for both "hot" and "cold" consumption. It is a rich source of bioactive ingredients, thanks to which it has strong antioxidant properties. In this research, an organoleptic evaluation was carried out, and the physical characteristics (i.e., instrumental color measurement (L*a*b*), water activity, water solubility index (WSI), water holding capacity (WHC) of 10 powdered Matcha green teas, and in the 2.5% Matcha water solutions, pH, °Brix and osmolality were tested. Also, the content of phenolic ingredients, i.e., selected phenolic acids, flavonoids and total polyphenols, was assessed. The content of chlorophyll, vitamin C and antioxidant potential were also examined. Matcha M-4 was used to design two functional model beverages, in the form of ready-to-use powdered drinks, consisting of Matcha green tea, protein preparations, inulin, maltodextrin and sugar. The obtained powdered drink, when dissolved in the preferred liquid (water, milk, juice), is regenerative, high-protein and rich in bioactive ingredients from the Matcha drink, with prebiotic properties derived from the added inulin. The beverage is also characterized by low osmolality. It can be recommended as a regenerating beverage for a wide group of consumers, athletes and people with deficiencies, among others protein, and elderly people, as well as in the prevention and supportive treatment of bone and joint tissue diseases.

The Impact of Premortality Stress on Some Quality Parameters of Roe Deer, Wild Boar, and Red Deer Meat

The specifics of meat production from free-ranging animals include the killing of animals in the wild with firearms. This type of uncontrolled killing sometimes leads to the phenomenon that the game does not die immediately but after a certain time from the shot to death, which may ultimately affect the quality of the meat. During one hunting year on free-ranging red deer (Cervus elaphus) (RD), roe deer (Capreolus capreolus) (RoD), and wild boar (Sus scrofa) (WB), the effect of time from shot to death on final pH, water-holding capacity (WHC), water content, and colour (L*, a*, b*) was investigated. All analyses were performed on Musculus biceps femoris (BF). After shooting, the animals were divided into two categories (A = time from shot to death ≤ 1 min; B = time from shot to death > 1 min). In RD, group B had significantly lower (p < 0.05) water content. In RoD, group B had significantly lower (p < 0.05) values of L* and b*. In WB, group B had significantly lower (p < 0.05) L* value and significantly higher (p < 0.05) pH value. The study proves that in BF of the three studied game species, the time extension from shot to death significantly affects the final water content values in RD, L* and b* in RoD and pH and L * in WB.

Effects of Cathepsins on Gel Strength and Water-Holding Capacity of Myofibrillar Protein Gels from Bighead Carp (Aristichthys nobilis) under a Hydroxyl Radical-Generation Oxidizing System

This study investigates the effects of cathepsins on the gel strength and water-holding capacity (WHC) of myofibrillar protein gels from bighead carp (Aristichthys nobilis) under a hydroxyl radical-generation oxidizing system. The myofibrillar proteins were divided into control group (with cathepsins) and E64 group (without cathepsins). The changes of cathepsin B and cathepsin L activities, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), protein oxidation (total sulfhydryl and carbonyl contents), and chemical interactions (nonspecific association, ionic bonds, hydrogen bonds, hydrophobic interactions, and disulfides) of myofibrillar protein and gels, as well as the gel strength and WHC of two groups under 0–100 mM H₂O₂, were measured. The results indicated that mild oxidation (10 mM H₂O₂) made a better gel strength and WHC. Cathepsin B and L activities decreased with increasing H₂O₂ concentrations but their effects on myofibrillar protein degradation still existed during 0.1–50 mM H₂O₂, which was expressed by higher carbonyl contents and ionic bonds at 0.1 and 50 mM H₂O₂, higher total sulfhydryl contents at 0 mM H₂O₂, and a lower intensity of MHC and actin of the control group than the E64 group. Besides more protein degradation, cathepsin proteolysis also resulted in lower gel strength and WHC in control gels than E64 gels under mild oxidation, which could be explained by lower hydrophobic interaction and moderate disulfides bonds between gel protein molecules of control gels.

Injection of iodoacetic acid into pre-rigor bovine muscle simulates dark cutting conditions

The purpose of this study was to develop an in situ model for dark cutting beef. Iodoacetic acid (IAA) was injected at different concentrations (0, 0.625, 1.25, 2.5, 3.75, 5, or 10 μmol/g of muscle) into pre-rigor bovine longissimus thoracis et lumborum (LTL) muscle samples, and pH and color were evaluated over a 48 h period. Injection of IAA blunted muscle pH decline and lowered lightness (L*), redness (a*), and yellowness (b*) values (P ≤ 0.05) in a concentration dependent fashion. In a follow-up study, LTL muscle samples were injected with 5 μmol IAA/g of muscle to test whether IAA maintains its effect over a 336 h post-mortem storage period. In addition to inhibiting pH decline and decreasing color values, IAA increased LTL muscle water holding capacity (WHC) and firmness (P ≤ 0.05) throughout the 336 h post-mortem storage period. Collectively, these data suggest that pre-rigor injection of IAA generates beef with dark cutting-like characteristics.

Structural changes induced by direct current magnetic field improve water holding capacity of pork myofibrillar protein gels

The study was to investigate the role of direct current magnetic field (DC-MF) for water-holding capacity (WHC) of myofibrillar protein gels and to understand potential mechanisms. Samples were subjected to DC-MF with different intensities (3.5, 3.8, 9.5 and 10.4 mT), and DC-MF treatment significantly improved WHC compared with control (46.09%), reaching the maximum value of 50.36% at 3.8 mT. The main reason for the increase in WHC might be that DC-MF modified the protein structure via unfolding, re-crosslinking and aggregation of proteins, which was supported by the increased intensity of tyrosine, aliphatic and tryptophan residues, and reduced reactive sulfhydryl (2.97 to 1.94). And the re-crosslinking between molecules was maintained mainly through hydrophobic interactions and disulfide bonds. Besides, DC-MF treatment helped to generate a relatively loose and uniform microstructure to trap more water as shown by electron microscope image, which was consistent with the highest WHC at 3.8 mT.

Analysis of the physical meat quality in partridge (Alectoris chukar) and its relationship with intramuscular fat

This study was undertaken to assess the effect of various levels of intramuscular fat (IMF: <0.5%, 0.5-0.99%, 1.0-1.49%, 1.5-1.99%, 2.0-2.49%, and >2.5%) on the physical meat quality of partridge. Physical characteristics such as moisture, pH, shear force, water-holding capacity (WHC), and color, along with IMF, were measured on 414 partridges (pectoral muscle). In this study, partridge meat was described as a kind of tender and moderately juicy meat with a nice color. Additionally, tenderness was significantly different between IMF < 0.5% and IMF > 0.5% levels (P < 0.01). IMF >0.5% also obtained higher value of WHC than IMF <0.5% although the difference was statistically nonsignificant. IMF levels did not affect pH or color. The results showed that IMF content was not significantly correlated with physical meat quality. However, in terms of eating experience, the minimum IMF level for better meat quality for consumer was 0.5%. Pearson correlation coefficients indicated that IMF content had significant negative correlations with moisture content but not with pH (r = -0.066), shear force (r = -0.072), WHC (r = 0.085), or color (L*(r = -0.049), a*(r = -0.028) and b*(r = 0.045)). Besides, meat pH had significant negative correlations with WHC (r = -0.036; P < 0.01) and lightness (L*) (r = -0.292; P < 0.01). Consequently, we consider pH to be one of the most important factors in evaluating meat quality of partridge.

Rheological properties and bread quality of frozen sweet dough with added xanthan and different freezing rate

In this paper the effects of frozen storage time, xanthan gum and rate of freezing on frozen sweet dough properties and unfermented bread quality was investigated. Results revealed that the water holding capacity, WHC, K₁ (stress decay rate) and K₂ (residual stress at the end of the stress relaxation experiment) values of frozen dough decreased with increasing frozen storage time and decreasing freezing rate; while the lowest values for these parameters were obtained for samples without xanthan gum. The amount of unfreezable water increased and freezable water decreased with addition of xanthan gum. Glass transition temperature for fresh or frozen sweet were around -37 and -39 °C, respectively. Addition of xanthan gum increased the glass transition temperature of fresh and fozen sweet dough. Firmness and gumminess of sweet bread increased during frozen storage which led to lower specific volume of frozen sweet bread. Increasing freezing rate and addition of xanthan gum to dough formulation improved the texture and specific volume of the final bread.

Genotoxic and phytotoxic risk assessment of fresh and treated hydrochar from hydrothermal carbonization compared to biochar from pyrolysis

Biochar is discussed as an option for climate change mitigation via C sequestration and may promote sustainable resource efficiency. Large-scale field trials and commercial business with char materials have already started. Therefore char materials have to be assessed for toxic compounds. We tested genotoxic effects of different hydrochars and biochars with the Tradescantia micronucleus test. For this purpose chromosomal aberrations in pollen cells of Tradescantia in the form of micronuclei were evaluated microscopically after defined exposition to extracts from char materials. Hydrochars from hydrothermal carbonization mostly exhibited significantly negative results. Additional germination experiments with hydrochar showed total germination inhibition at additions above five percent v/v in comparison to biochar. However, biological post-treatment of previously toxic hydrochar was successful and toxic effects were eliminated completely. Some post-treated hydrochars even showed growth stimulating effects. Our results clearly demonstrate the necessity of risk assessment with bioindicators. The chosen tests procedures can contribute to biochar and hydrochar characterization for safe application.

Lead immobilization and bioavailability in microbial and root interface

A range of both soluble and insoluble phosphate (P) compounds have been used to immobilize Pb in solution and soil. However, these compounds have limitations because of low solubility or leaching of P. Phosphate solubilizing bacteria (PSB) can be used to enhance the solubility of insoluble P compounds. The effects of PSB on the immobilization of Pb in the presence of phosphate rock (PR) and subsequent reduction in Pb uptake by Indian mustard (Brassica juncea) in nutrient agar medium and ryegrass (Lolium perenne) in soil under sterile condition were tested. Root colonization of PSB was confirmed by halo formation around the root in the medium containing tricalcium phosphate. Addition of PR in the presence of PSB immobilized Pb in both agar medium and soil, and reduced Pb translocation from root to shoot. Furthermore, shoot Pb concentrations of Indian mustard in agar medium and ryegrass in soil were decreased by 58.1% and 22.8%, respectively, compared to the control. Even though soluble P compound was the most effective in the immobilization of Pb, excess P may cause eutrophication. Therefore, PSB are suggested as a co-amendment to facilitate immobilization of Pb without causing any detrimental effect on the environment.

Glutathione S-transferase (GST) family in barley: identification of members, enzyme activity, and gene expression pattern

Barley (Hordeum vulgare) is one of the most important cereals in many developing countries where drought stress considerably diminishes agricultural production. Glutathione S-transferases (GSTs EC 2.5.1.18) are multifunctional enzymes which play a crucial role in cellular detoxification and oxidative stress tolerance. In this study, 84 GST genes were identified in barley by a comprehensive in silico approach. Sequence alignment and phylogenetic analysis grouped these HvGST proteins in eight classes. The largest numbers of the HvGST genes (50) were included in the Tau class followed by 21 genes in Phi, five in Zeta, two in DHAR, two in EF1G, two in Lambda, and one each in TCHQD and Theta classes. Phylogenetic analysis of the putative GSTs from Arabidopsis, rice, and barley indicated that major functional diversification within the GST family predated the monocot/dicot divergence. However, intra-specious duplication seems to be common. Expression patterns of five GST genes from Phi and Tau classes were investigated in three barley genotypes (Yusof [drought-tolerant], Moroc9-75 [drought-sensitive], and HS1 [wild ecotype]) under control and drought-stressed conditions, during the vegetative stage. All investigated genes were up-regulated significantly under drought stress and/or showed a higher level of transcripts in the tolerant cultivar. Additionally, GST enzyme activity was superior in Yusof and induced in the extreme-drought-treated leaves, while it was not changed in Moroc9-75 under drought conditions. Moreover, the lowest and highest levels of lipid peroxidation were observed in the Yusof and Moroc9-75 cultivars, respectively. Based on the achieved results, detoxification and antioxidant activity of GSTs might be considered an important factor in the drought tolerance of barley genotypes for further investigations.