Meat Antioxidant Research Articles

Assessing the Influence of Cumulative Chlorella vulgaris Intake on Broiler Carcass Traits, Meat Quality and Oxidative Stability.

The impacts of cumulative Chlorella vulgaris intake (proportion of microalga in the diet multiplied by the total feed consumed by each bird) on broiler carcass traits, meat quality and oxidative stability were reviewed to identify the optimal intake levels for maximising benefits. Our findings indicate that a cumulative intake of 8.73 g/bird significantly enhances thigh yield, while levels ranging from 8.73 to 401 g/bird optimise carcass weight and overall meat quality. However, higher cumulative levels may reduce carcass dressing percentage due to metabolic inefficiencies. Furthermore, C. vulgaris intake improves the oxidative stability of broiler meat by increasing antioxidant levels and balancing pro- and antioxidants. Including C. vulgaris in broiler diets boosts total carotenoid content, and antioxidant assays confirm that it enhances meat oxidative stability, with low to moderate cumulative intake levels (8.73 to 401 g/bird) providing the best balance of benefits. Optimal oxidative stability and antioxidant properties were observed at a cumulative intake level of 401 g/bird, showing significant improvements in meat antioxidant capacity. Higher levels may lead to diminishing returns or potential negative effects due to the digestibility issues of the microalga. Future research should refine intake models, understand the bioavailability of C. vulgaris nutrients and explore cost-effective methods to enhance its digestibility, to ensure its viability and sustainability as a feed additive.

Suitability of raw and heat-treated Amaranthus spinosus in broiler diets: Effects on growth performance, meat antioxidant capacity, haemato-biochemical parameters, intestinal histomorphometry, and cecal volatile fatty acid profile

This study aimed to examine the effects of incorporating amaranth (Amaranthus spinosus, either raw or heat-treated) into broiler diets on growth performance, meat antioxidant capacity, haemato-biochemical parameters, intestinal histomorphometry, and cecal volatile fatty acid profile. A total of 210 male Ross 308 broiler chicks were allocated to five dietary treatments in a completely randomized design, with each treatment comprising six replicates of seven birds each. The control group received a diet based on maize and soybean meal, while the remaining dietary groups were formulated to be isonitrogenous and isocaloric to the control, with exact levels of 10% and 20% raw or heat-treated amaranth in the diet. Body weight and feed intake were monitored on days 0, 10, 24, and 39 of the study. On day 39, two birds per replicate were randomly selected for blood sampling, followed by slaughtering for further parameter examination. Incorporating A. spinosus up to 20% in broiler diets had no adverse effect on body weight gain compared to the control. However, higher levels of amaranth led to a negative impact on the feed conversion ratio, attributed to increased feed intake. Furthermore, amaranth supplementation did not negatively influence carcass yield or various organ weights, except for the gizzard, which was heavier in the amaranth-fed groups. Notably, amaranth supplementation reduced abdominal fat, enhanced meat antioxidant status, and had no detrimental effects on blood biochemical or hematological indices. Additionally, amaranth feeding resulted in decreased blood triglyceride levels but had no effect on cholesterol levels. While heat treatment of amaranth did not significantly alter the performance of broiler chickens, it enhanced the beneficial effects of amaranth feeding on the histomorphological features of the duodenum and ileum, and increased blood IgG levels. The cecal volatile fatty acid profile remained largely unaffected by amaranth inclusion, although heat-treated amaranth led to increased levels of branched-chain fatty acids and valerate. Overall, the findings suggest A. spinosus as a promising alternative feed ingredient for broilers when included at 10% of the diet. However, further research is needed to investigate the effect of various amaranth species, processing methods and enzyme supplementation on poultry nutrition to expand its inclusion rate.

Carcass Characteristics, Meat Antioxidative State, and Gut Microbiota of Broilers Fed With a Mixture of Bitter Melon and Basil Leaves Powder

The impact of a mixture of bitter melon leaf and basil leaf powder (BBLPB) on the carcass characteristics, meat antioxidant state, and gut microbiota of broilers was investigated. Three hundred one-day-old Cobb 500 broiler chicks were allocated to five diets: diet 1 (negative control), diet 2 (positive control; 0.1% blend of probiotic, prebiotic, and acidifier (BPPA) supplementation), diets 3 (0.25% BBLPB), 4 (0.5% BBLPB), and 5 (0.75% BBLPB) randomly. The 0.25% BBLPB supplementation improved (P < 0.05) slaughtered weight, dressed weight, dressing %, and growth rate of broilers, while organ weights remained unchanged (P > 0.05). Slaughtered weight recorded in diets 2 and 3 was higher (P

Effects of turmeric meal supplementations on performance, carcass traits and meat antioxidant enzymes of broilers fed diets containing monosodium glutamate

The use of monosodium glutamate (MSG) as a potential taste enhancer in poultry nutrition is discouraged due to its perceived adverse effects. Hence, this study evaluated the impacts of turmeric powder (TP) on performance and some meat qualities of chickens fed MSG. Three hundred broilers were divided into four diets: T1 (control), T2 (1.25 g MSG/kg), T3 (1.25 g MSG/kg and 1.25 g TP/kg), and T4 (1.25 g MSG/kg and 2.50 g TP/kg). Results indicated increased (P

Bioaccessibility of condensed tannins and their effect on the physico-chemical characteristics of lamb meat.

The bioaccessibility of tannins as antioxidants in meat is essential to maximise their effectiveness in protecting the product. This property determines the amount of tannins available to interact with meat components, inhibiting lipid and protein oxidation and, consequently, prolonging shelf life and preserving the sensory quality of the product. The objective of this study was to evaluate the bioaccessibility of condensed tannins (CT) from Acacia mearnsii extract (AME) and their effect on the physico-chemical characteristics of fattened lamb meat. Thirty-six Dorset ×Hampshire lambs (3 months old and 20.8±3.3 kg live weight) were used. The lambs were distributed equally (n=9) into four treatments: T1, T2, T3 and T4, which included a basal diet plus 0%, 0.25%, 0.5% and 0.75% of CT from AME, respectively. At the end of the fattening period, bioaccessibility was evaluated, the animals were slaughtered and a sample of the longissimus dorsi (LD) muscle was collected to assess colour, lipid oxidation, cooking weight loss and shear force on days 1, 4, 7 and 14 of shelf-life, in samples preserved at -20°C. In addition, the long chain fatty acid profile was analysed. A completely randomised design was used, and the means were compared with Tukey's test (P<0.05). The mean lightness (L*), yellowness (b*) and hue (H*) values were higher for T3 and T4. The addition of CT did not affect (P>0.05) redness (a*), cooking weight loss (CWL) or shear force (SF). T4 decreased (P<0.05) stearic acid and increased cis-9 trans-12 conjugated linoleic acid (CLA). Bioaccessibility was higher in the supplemented groups (T1<T2, T3 and T4). In conclusion, supplementing CT from AME in the diet of lambs did not reduce lipid oxidation, but T3 or T4 improved some aspects of meat colour and CLA deposition.

Green tea catechin prevents oxidative stress-regulated autophagy and apoptosis signaling, and inhibits tenderness in postmortem bovine longissimus thoracis et lumborum muscle.

Although green tea catechin has been reported to be an antioxidant and preservative in meat, the extent to which it affects the tenderization of bovine muscle remains largely unknown. This study seeks to evaluate the effect of catechin on the interplay between apoptosis and autophagy, and subsequently, the development of bovine muscle tenderness. The results indicate that catechin significantly alleviated oxidative stress. A concomitant reduction of autophagic markers LC3-II/LC3-I ratio, Beclin-1, and Atg7 levels were caused by catechin. Besides, aforementioned autophagy inhibition was further augmented by PI3K/Akt/mTOR activation. Additionally, catechin protected against mitochondrial dysfunction and inhibited mitochondria-dependent caspase apoptosis pathway. Furthermore, there was a reciprocal inhibition between autophagy and apoptosis. Ultimately, tenderness at 24 and 120h, an increase in the gap between muscle fiber bundles, and disintegration of myofibrillar architectures were all inhibited by catechin. Therefore, despite alleviating oxidative stress, catechin may hamper tenderization pattern of postmortem bovine muscle.

Effect of simultaneous application of antioxidants in oil and in chicken on heterocyclic aromatic amine formation in deep-fat fried chicken breast

This study aimed to estimate the effects of simultaneous application of antioxidants in meat and in oil on heterocyclic aromatic amine (HAA) formation in fried chicken during 40 deep-fat frying cycles. The experiment was carried out by adding Adinandra nitida leaf extract (ANE) (200 mg/100 g) to chicken while adding tea polyphenols (TP) (40 mg/100 g), sesamol (SL) (40 mg/100 g), or rosemary extract (RE) (40 mg/100 g) to soybean oil. It was found that the addition of TP, SL or RE in oil reduced the lipid oxidation and the formation of total HAAs in meats. Adding ANE alone to meat reduced total HAA contents in meats by 11.98%–38.00%; simultaneously adding TP, SL or RE to oil reduced total HAA contents in meats by 33.98%–61.46%, 15.86%–44.94%, and 25.22%–48.01%, respectively, during 40 frying cycles. Pearson correlation analysis revealed significant correlations (all absolute values of correlation coefficients > 0.53) between HAA formation and oxidation indices. This research supplies evidence that adding antioxidants to both meat and oil inhibits HAA formation during deep-fat frying.

Effect of dietary inulin on the antioxidant profile of broiler chickens’ meat raised in heat stress conditions

Abstract The study aimed to assess the effect of dietary inulin (1% dietary inclusion) supplements on broiler chickens’ meat antioxidant compounds. The experiment was carried out under heat-stress conditions, on 60 Ross 308 broiler chickens. The study took place in an experimental hall with digestibility pens and controlled humidity, ventilation and light regime. Each treatment (2 groups, C and E) was replicated 6 times with 5 chicks per replicate pen with ad libitum feeding and free water access. At 42 days old, 6 birds from each group were slaughtered and breast and thigh meat samples were collected. The presence of inulin in broiler chickens’ diets had a beneficial effect by increasing the iron and zinc concentrations in thigh samples. Regarding liposoluble antioxidants, the presence of inulin in diets from tissue samples had an antagonistic effect: increased concentrations of xanthophylls were registered in thigh meat and an adverse effect was noticed in breast meat while an inverse effect was noticed for vitamin E. At the thigh meat level, the antioxidant capacity was significantly improved under inulin influence. In conclusion, the nutritional quality of broilers meat (thigh meat) was improved, for the group fed with inulin-supplemented diets.

Novel Antioxidant Insights of Myricetin on the Performance of Broiler Chickens and Alleviating Experimental Infection with Eimeria spp.: Crosstalk between Oxidative Stress and Inflammation.

In the modern poultry industry, the application of novel phytogenic bioactive compounds with antioxidant potential aims to enhance productivity and quality and to minimize the stress of associated diseases. Herein, myricetin, a natural flavonoid, was evaluated for the first time on broiler chickens' performance, antioxidants and immune modulating functions, and tackling avian coccidiosis. A total of 500 one-day-old chicks were divided into five groups. The negative (NC) and infected control (IC) groups were fed a control diet without additives, and the latter was infected with Eimeria spp. Groups supplemented with myricetin (Myc) were fed a control diet of Myc (200, 400 and 600 mg/kg diet each). On d 14, all chicks except those in NC were challenged with oocysts of mixed Eimeria spp. Significant improvements in the overall growth rate and feed conversion ratio were detected in the group that was fed 600 mg/kg, unlike the IC group. Notably, groups that were fed 400 and 600 mg/kg showed higher total meat antioxidant capacity with an inverse reduction in oxidative and lipid peroxidation biomarkers (hydrogen peroxide: H2O2; reactive oxygen species: ROS; Malondialdehyde: MDA). Of note, the upregulation of glutathione peroxidase; GSH-Px, catalase; CAT, superoxide dismutase; SOD, heme oxygenase-1; HO-1 and NAD(P)H dehydrogenase quinone 1 NQO1 genes in jejunum and muscle were prominently observed with increasing levels of supplemental Myc. At 21 dpi, the severity of coccoidal lesions (p < 0.05) induced by mixed Eimeria spp. and oocyst excretion were greatly reduced in the group that was fed 600 mg/kg of Myc. In the IC group, higher serum levels of C-reactive protein; CRP and nitric oxide; and NO and the upregulated expression of inflammatory biomarkers (interleukin-1β; IL-1β, interleukin-6; IL-6, tumor necrosis factor-α; TNF-α, chemotactic cytokines; CCL20, stromal cell-derived factor-1; CXCL13, and avian defensins; AvBD612) were subsided in higher levels in the Myc-fed groups. Taken together, these findings indicate the promising antioxidant role of Myc in modulating immune responses and reducing growth depression associated with coccidia challenges.

Inovasi Pakan Organik pada Ternak Ayam Kampung Super

Public nutrition is essential to obtain a healthy and fit body condition, especially during a pandemic like today. The content of vitamins A, C, magnesium, gelatin, phosphorus, and antioxidants in chicken meat can help build the immune system to fight viruses. Besides that, the content of amino acids derived from chicken protein can form antibodies to fight infections. Therefore, raising free-range chickens can be a good business opportunity to fulfill the need for healthy meat from free-range chickens. In addition, it is indicated that the demand for chicken meat in Kendari has yet to be fulfilled, so it must be supplied from other regions. Therefore, raising super free-range chickens can be a promising solution and business opportunity with a maintenance pattern that is not too complicated, where even a not-too-large area of ​​land can be used as a place for its maintenance. Even so, the obstacle free-range chicken breeders face is the slow growth of free-range chickens, which can take 4-6 months to produce 1 kg body weight. But now, this problem can be overcome by the presence of super-free-range chickens or super Javanese chickens, which are the result of crosses between male local native chickens and breeder breeders that have fast growth characteristics. With a maintenance pattern that is not too complicated, where even a not-too-large area of ​​land can be used as a place for its maintenance. The body and flesh still show the type of free-range chicken but with organic care, without drugs, and with organic feed.

Essential Oil and Plant Extracts as Preservatives and Natural Antioxidants Applied to Meat and Meat Products: A Review.

The meat and meat product industry has evolved according to the needs of the market. Consumers are increasingly seeking quality in food. Thus, the concern regarding the excessive use of additives such as preservatives and antioxidants has driven research towards natural, healthy and safe substitutes. Essential oils and plant extracts have been shown to be a good option for resolving this problem. They are completely natural with biological activity, which mainly includes prevention of oxidation and the proliferation of microorganisms, thus arousing the interest of the industry and consumers. This review will present studies published in the last five years regarding the potential of essential oils and plant extracts to act as preservatives and antioxidants in meat and meat products. The forms of application, innovations in the area, alternatives to the incorporation of essential oils and extracts in meat products, effects caused in food, and limitations of applications will be detailed and discussed.

Isolation, Bioactive Potential, and Application of Essential Oils and Terpenoid-Rich Extracts as Effective Antioxidant and Antimicrobial Agents in Meat and Meat Products.

Using food additives (e.g., preservatives, antioxidants) is one of the main methods for preserving meat and meat product quality (edible, sensory, and technological) during processing and storage. Conversely, they show negative health implications, so meat technology scientists are focusing on finding alternatives for these compounds. Terpenoid-rich extracts, including essential oils (EOs), are remarkable since they are generally marked as GRAS (generally recognized as safe) and have a wide ranging acceptance from consumers. EOs obtained by conventional or non-conventional methods possess different preservative potentials. Hence, the first goal of this review is to summarize the technical-technology characteristics of different procedures for terpenoid-rich extract recovery and their effects on the environment in order to obtain safe, highly valuable extracts for further application in the meat industry. Isolation and purification of terpenoids, as the main constituents of EOs, are essential due to their wide range of bioactivity and potential for utilization as natural food additives. Therefore, the second goal of this review is to summarize the antioxidant and antimicrobial potential of EOs and terpenoid-rich extracts obtained from different plant materials in meat and various meat products. The results of these investigations suggest that terpenoid-rich extracts, including EOs obtained from several spices and medicinal herbs (black pepper, caraway, Coreopsis tinctoria Nutt., coriander, garlic, oregano, sage, sweet basil, thyme, and winter savory) can be successfully used as natural antioxidants and antimicrobials in order to prolong the shelf-life of meat and processed meat products. These results could be encouraged for higher exploitation of EOs and terpenoid-rich extracts in the meat industry.

Comparative analysis of the use of natural and synthetic antioxidants in chicken meat: an update review.

The search for healthy foods has attracted the industry's attention to developing products that use natural ingredients, including natural antioxidants. Antioxidants act as free radicals or oxygen scavengers, inhibiting lipid oxidation and adversely affecting meat products' sensory and nutritional quality. Several synthetic antioxidants have been used in the meat industry; however, studies point to health risks related to their consumption. Such fact drives research into natural antioxidants extracted from grains, oilseeds, spices, fruits, and vegetables, which may have a health-promoting effect. This manuscript evaluates the effectiveness of several natural antioxidants in improving the quality and shelf life of chicken meat products during processing, storage, and distribution. The potential effects of natural antioxidants widely used in chicken products are also discussed. It can be concluded that these natural antioxidants are possible substitutes for synthetic ones. However, their use can affect the product's characteristics.

Effects of ginger meal supplementation on performance and meat antioxidative enzymes of broilers fed monosodium glutamate

The ameliorative effects of ginger meal (GM) on the performance, carcass, and meat qualities of broilers fed diets containing MSG were examined. A total of 360 day – old broilers were randomly allotted into four diets: Diet A (control), Diet B (basal + 1.25 g MSG/kg diet), Diet C (Diet B + 1.25 g GM/kg diet) and Diet D (diet B +&nbsp; 2.50 g GM/kg diet). The birds were fed starter and finisher diets and water ad – libitum. At 6 weeks old, growth performance, carcass and meat qualities were assessed. Broilers on Diets B to D significantly (P &lt; 0.05) recorded increased weight, feed, energy, and protein intakes with those on Diet D having the best feed conversion ratio. The dressed weight and dressing percentage of broilers on the experimental diets were better than the control diet. The inclusion of GM significantly (P &lt; 0.05) ameliorated the negative impacts of MSG on relative weights of the heart, liver, and bile. Meat catalase and glutathione peroxidase were significantly (P &lt; 0.05) reduced while lipid peroxidation and meat cholesterol were significantly (P &lt; 0.05) elevated among the birds fed Diet B when compared with the control. However, the inclusions of GM played a restorative role by significantly (P &lt; 0.05) improving the meat antioxidant enzymes and reducing lipid peroxidation and cholesterol. Therefore, the inclusion of MSG at 1.25 g/kg with an inclusion of 1.25 to 2.50 g GM/kg was beneficial for feed palatability enhancement with resultant improvement on performance, carcass, and meat qualities. Keywords: Chicken, Carcass quality, Ginger, Haematology, Lipid peroxidation

Reactivity of Vitamin E as an Antioxidant in Red Meat and the Stomach Medium.

The stomach is a bioreactor and an important intersection of biochemical reactions that affect human health. Lipid peroxidation of meat in the stomach medium generates malondialdehyde (MDA), which is absorbed from the gut into human plasma and modifies low-density lipoprotein (LDL) to MDA-LDL. We found in the stomach medium (pH 3.0) a high antioxidant activity of vitamin E against meat lipid peroxidation, almost 35-fold higher than at pH 6.3. In the stomach medium, the antioxidant activity of vitamin E on meat lipid peroxidation was 20-fold higher than that of catechin. Vitamin E, at pH 3.0, acts synergistically with metmyoglobin (MbFe+3), as a peroxidase/antioxidant couple. The synergistic effect of MbFe+3/vitamin E was almost 150-fold higher than the antioxidant effect achieved by MbFe+3/catechin. The meat antioxidant activity was maintained continuously by addition of a low concentration of vitamin E, catechin, and vitamin C, preventing the propagation of lipid oxidation, reactive aldehyde generation, and the loss of vitamin E.

The anti-oxidative potential of ginger extract and its constituent on meat protein isolate under induced Fenton oxidation

Ginger extract has been reported to possess antioxidant properties. However, components isolated from ginger have been rarely reported to inhibit oxidation. Herein, the antioxidant properties of ginger and purified components derived from it (6-gingerol, zingerone, rutin, quercetin, and kaempferol) were confirmed by using HPLC and were further used to investigate its effect on lamb meat. Myofibrillar proteins isolated (MPI) from lamb meat were incubated with ginger and its constituents under induced Fenton oxidation (1.0 mmol/L FeCl3, 0.1 mmol/L Asc, and 20 mmol/L H2O2) for 1, 3,5, and 7 h. Incubating meat protein isolate in the absence of ginger extract or its components resulted in a substantial drop in sulfhydryl groups, an increase in protein carbonyl content, and a corresponding increase in TBARS content. However, ginger extract and its constituents demonstrated antioxidant properties, which might be attributed to their hydroxyl groups and suitable solubilizing side chains. Overall, ginger extract exhibited the highest antioxidant capabilities of all treated samples, suggesting that ginger extracts may be used as a natural antioxidant in meat and lipid/protein-containing processed products. Significance of the studyGinger extract is also frequently used as a herbal medicine due to its anti-inflammatory, anti-cancer, and antibacterial qualities. Nonvolatile pungent chemicals found in ginger, such as gingerol, shogaols, paradols, and zingerone, as well as kaempferol, rutin, and other phenolic compounds, have been confirmed in ginger extract and have been shown to have antioxidant action driven by free radical elimination. Despite these findings, ginger extract and its pure constituent components have seldom been shown to have the ability to slow protein and lipid oxidation in meat and meat-related products. The effect of ginger extracts on the oxidative stability of myofibriller protein isolate has never been investigated. Exploiting the phenolic content of ginger extract may result in a discovery that would have a huge influence on both the ginger and meat industries as well as other food processing sectors. The first aim of our study was to confirm the presence of six selected phenolic compounds (rutin, kaempferol, 6-gingerol, zingerone, naringenin, and quercetin) in ginger as reported by literature, and the second objective was to determine the efficacy of ginger extracts and its purified constituents on myofibrillar protein isolate treated under induced Fenton oxidation.

The effect of varying levels of purified condensed tannins on performance, blood profile, meat quality and methane emission in male Bapedi sheep fed grass hay and pellet-based diet

This study determined the effect of purified condensed tannin inclusion levels in a diet on production, haematological indices, blood biochemical components, meat quality and methane emission by yearling indigenous male Bapedi sheep on a grass hay and sheep pellet-based diet in a 28-day trial. The diets contained similar (P > 0.05) nutrients but with different (P < 0.05) purified condensed tannin supplementation levels. A complete randomized design was used. Twenty-four yearling male Bapedi sheep were assigned to four dietary treatments having different purified condensed tannin levels of 0 (GH80P20PCT0), 30 (GH80P20PCT30), 40 (GH80P20PCT40) and 50 (GH80P20PCT50) g/kg DM. A quadratic type of equation was also used to determine condensed tannin supplementation levels for optimal performance and methane emission reduction by sheep. Supplementing diets with purified condensed tannins did not affect (P > 0.05) diet intake, digestibility and live weight gain of male Bapedi sheep. Supplementing diets with purified condensed tannins did not affect (P > 0.05) blood components of male Bapedi sheep. Inclusion of condensed tannins in the diets did not affect (P > 0.05) Bapedi sheep meat pH and sensory attributes. However, supplementing diets with purified condensed tannins decreased (P < 0.05) methane emission by 51 to 60%. A 49.08 g supplementation level with purified condensed tannins per kg DM diet was calculated, with the use of quadratic equations, to result in the lowest methane emission by male Bapedi sheep. The meat of male Bapedi rams on diets containing 30, 40 or 50 g of purified condensed tannins per kg DM contained higher (P < 0.05) antioxidant activities than those from rams fed a diet without purified condensed tannins. These results indicate that purified condensed tannin supplementation levels of 0, 30, 40 or 50 g/kg DM diet had no adverse effects on growth performance, blood profiles and meat sensory attributes of male Bapedi sheep. However, supplementation levels of 30, 40 or 50 g of purified condensed tannins per kg DM diet reduced methane emission by 51 to 60%, and increased sheep meat antioxidant activity values. Supplementing diets with purified condensed tannins has the potential to reduce methane production and emission by sheep. However, long-term studies are recommended to ascertain the present findings.

Antioxidative Reactivity of L-Ascorbic Acid and D-Isoascorbic Acid Species towards Reduction of Hexachloroiridate (IV)

The pair [IrCl6]2–/[IrCl6]3– has been demonstrated to be a good redox probe in biological systems while L-ascorbic acid (AA) is one of the most important antioxidants. D-isoascorbic acid (IAA) is an epimer of AA and is widely used as an antioxidant in various foods, beverages, meat, and fisher products. Reductions of [IrCl6]2– by AA and IAA have been analyzed kinetically and mechanistically in this work. The reductions strictly follow overall second-order kinetics and the observed second-order rate constants were collected in the pH region of 0 ≤ pH ≤ 2.33 at 25.0°C. Spectrophotometric titration experiments revealed a well-defined 1 : 2 stoichiometry, namely Δ[AA] : Δ[Ir(IV)] or Δ[IAA] : Δ[Ir(IV)] = 1 : 2, indicating that L-dehydroascorbic acid (DHA) and D-dehydroisoascorbic acid (DHIA) were the oxidation products of AA and IAA, respectively. A reaction mechanism is suggested involving parallel reactions of [IrCl6]2– with three protolysis species of AA/IAA (fully protonated, monoanionic, and dianionic forms) as the rate-determining steps and formation of ascorbic/isoascorbic and ascorbate/isoascorbate radicals; in each of the steps, [IrCl6]2– acquires an electron via an outer-sphere electron transfer mode. Rate constants of the rate-determining steps have been derived or estimated. The fully protonated forms of AA and IAA display virtually identical reactivity whereas ascorbate and isoascorbate monoanions have a significant reactivity difference. The ascorbate and isoascorbate dianions are extremely reactive and their reactions with [IrCl6]2– proceed with the diffusion-controlled rate. The species versus pH and the species reactivity versus pH distribution diagrams were constructed endowing that the ascorbate/isoascorbate monoanionic form dominated the total reactivity at physiological pH. In addition, the value of pKa1 = 3.74 ± 0.05 for IAA at 25.0°C and 1.0 M ionic strength was determined in this work.

Edible Films on Meat and Meat Products

In 2018, the worldwide consumption of meat was 346.14 million tonnes, and this is expected to increase in the future. As meat consumption increases, the use of packaging materials is expected to increase along with it. Petrochemical packaging materials which are widely used in the meat processing industry, take a long time to regenerate and biodegrade, thus they adversely affect the environment. Therefore, the necessity for the development of eco-friendly packaging materials for meat processing, which are easily degradable and recyclable, came to the fore. The objective of this review is to describe the application of natural compound-derived edible films with their antioxidant and antibacterial activities in meat and meat products. For several decades, polysaccharides (cellulose, starch, pectin, gum, alginate, carrageenan and chitosan), proteins (milk, collagen and isolated soy protein) and lipids (essential oil, waxes, emulsifiers, plasticizers and resins) were studied as basic materials for edible films to reduce plastic packaging. There are still high consumer demands for eco-friendly alternatives to petrochemical-based plastic packaging, and edible films can be used in a variety of ways in meat processing. More efforts to enhance the physiological and functional properties of edible films are needed for commercial application to meat and meat products.

Vitamin E Supplementation Enhances Lipid Oxidative Stability via Increasing Vitamin E Retention, Rather Than Gene Expression of MAPK-Nrf2 Signaling Pathway in Muscles of Broilers.

Dietary vitamin E (VE) supplementation is a method to produce VE-enriched meat and improve meat lipid oxidative stability. We aimed to study the effect of the VE supplementation duration on meat lipid oxidative stability, VE retention, and antioxidant enzymes’ activity, and explore its relationship with the mitogen-activated protein kinases (MAPK)-nuclear factor-erythroid 2-related factor 2 (Nrf2) signaling pathway in broilers slaughtered after electrical stunning. A total of 240 male 18-day-old Arbor Acres Plus broilers were distributed to four treatments, with six replicates in each treatment, and ten broilers per replicate. Broilers were fed with a basal diet (no supplementation of VE) or VE diet (200 IU/kg VE, DL-α- tocopherol) for one (W1), two (W2), or three (W3) weeks before electrical stunning (130 mA, 60 Hz, for 1s) and slaughter. The VE retention was positively and linearly affected (p < 0.01) by the VE feeding duration at one to three weeks before slaughter, and negatively (all p < 0.01) related to the thiobarbituric acid reactive substance (TBARS) content in both breast and thigh muscles at d 0, d 2, and d 6 postmortem. The VE retention was negatively (p < 0.05) related to the gene expression of c-Jun N-terminal kinases 1 (JNK1) and 2 (JNK2), Nrf2 in breast muscles, and JNK1 and p38 MAPK in thigh muscles. In conclusion, dietary vitamin E supplementation at 200 IU/kg for three weeks before electrical stunning and slaughter improved lipid oxidative stability via increasing VE retention, rather than the regulation by gene expression of the MAPK-Nrf2 signaling pathway in skeletal muscles of broilers.