Myoglobin and lipid oxidation interactions: Mechanistic bases and control

The Impact of Herbal Additives for Poultry Feed on the Fatty Acid Profile of Meat

Researchers often found that herbal additives to chicken feed can favorably alter the fatty acid profile of the meat. The most desirable effects of diet modification comprise an increased content of polyunsaturated fatty acids (PUFA) and monounsaturated fatty acids (MUFA) and a reduced content of saturated fatty acids (SFA) in the breast and thigh muscles. A modified fatty acid profile contributes to improvement in the quality of poultry meat, which is reflected in its increased consumption. However, it may be problematic that PUFAs are oxidized easier than other lipids, which can have a negative impact on the sensory traits of meat. By contrast, herbs and herbal products contain antioxidants that can prevent the oxidation of unsaturated fatty acids and cholesterol present in animal-origin products and increase the antioxidant potential of the consumer’s body. This paper aims to review the influence of herbal additives for broiler chicken diets on the fatty acid profile of poultry meat. Special attention was paid to changes in the content of SFAs, MUFAs, and PUFAs, but also alterations in the omega-6:omega-3 ratio. The presented reference literature supports the statement that herbs and bioactive components of herbs added to chicken diets can improve the quality of broiler chicken meat by altering the content of fatty acids.

Potential Mechanism and Effects of Different Selenium Sources and Different Effective Microorganism Supplementation Levels on Growth Performance, Meat Quality, and Muscle Fiber Characteristics of Three-Yellow Chickens

A trial was conducted to investigate the effects of different Se sources, including sodium selenite (S-Se) and selenium yeast (Y-Se) and different effective microorganism (EM) addition levels on growth performance, meat quality, and muscle fiber characteristics of three-yellow chickens and its potential mechanism. A total of 400 birds were randomly distributed into 4 groups (S-Se, S-Se + EM, Y-Se, and Y-Se + EM groups) consisting of a 2 × 2 factorial arrangement. The main factors were the source of Se (I_Se = inorganic Se: 0.2 mg/kg S-Se; O_Se = organic Se: 0.2 mg/kg Y-Se) and the level of EM (H_EMB = high EM: 0.5% EM; Z_EMB = low EM: 0% EM). Each treatment had 5 replicates and each replicate consisted of 20 broiler chickens. The trial lasted for 70 days. The results showed that, in breast muscle, the broiler chickens fed O_Se source decreased the pH_24h, drip loss, shear force, perimeter, cross-sectional area, and diameter, but increased the a24h* and density compared with the broiler chickens fed I_Se source (p < 0.05); broiler chickens supplied with H_EMB level decreased the cross-sectional area and diameter, but increased the pH_24h, a24h,* and density compared with the broiler chickens supplied with Z_EMB level (p < 0.05). In thigh muscle, O_Se source and H_EMB level also could improve the meat quality and change muscle fiber characteristics of broiler chickens (p < 0.05). Meat quality was correlated with the muscle fiber characteristics (p < 0.05). O_Se source and H_EMB level could regulate the expression levels of muscle fiber-relative genes in the breast and thigh muscles (p < 0.05). In conclusion, O_Se source and H_EMB level could improve the meat quality of the breast and thigh muscles of three-yellow chickens by changing the muscle fiber characteristics, and they changed the muscle fiber characteristics by regulating the expression levels of muscle fiber-relative genes.

Applications of algae to obtain healthier meat products: A critical review on nutrients, acceptability and quality

Meat constitutes one the main protein sources worldwide. However, ethical and health concerns have limited its consumption over the last years. To overcome this negative impact, new ingredients from natural sources are being applied to meat products to obtain healthier proteinaceous meat products. Algae is a good source of unsaturated fatty acids, proteins, essential amino acids, and vitamins, which can nutritionally enrich several foods. On this basis, algae have been applied to meat products as a functional ingredient to obtain healthier meat-based products. This paper mainly reviews the bioactive compounds in algae and their application in meat products. The bioactive ingredients present in algae can give meat products functional properties such as antioxidant, neuroprotective, antigenotoxic, resulting in healthier foods. At the same time, algae addition to foods can also contribute to delay microbial spoilage extending shelf-life. Additionally, other algae-based applications such as for packaging materials for meat products are being explored. However, consumers' acceptance for new products (particularly in Western countries), namely those containing algae, not only depends on their knowledge, but also on their eating habits. Therefore, it is necessary to further explore the nutritional properties of algae-containing meat products to overcome the gap between new meat products and traditional products, so that healthier algae-containing meat can occupy a significant place in the market.

Comparative phosphoproteomic provides insights into meat quality differences between slow- and fast-growing broilers

The selection of broilers for augmented growth rate and breast yield has been accompanied by deterioration in meat quality. To characterise the meat quality differences between slow- (SG) and fast-growing broilers (FG), Xueshan and Ross 308 chickens were employed to determine the mechanisms causing these differences. SG meat was found to display more redness and yellowness, higher shear force, pH_24h, and protein content, with lower intramuscular fat (IMF) content than FG meat. Further, based on comparative phosphoproteomic analysis (SG/FG), upregulated phosphorylated myofibrillar proteins resulted in larger fibres, which contributed to lower pressing loss and tenderness. The phosphoproteins of glycolytic enzymes, phosphorylase kinases, and calcium-related proteins were significantly downregulated, which reduced the acidity of the meat. SLC7A5 at Ser21, MRC2 at Ser1359 and CRAT at Ser341, AUP1 at Ser377 positively affected protein and IMF deposition, respectively. Together, these phosphoproteins elicit vital information for the genetic improvement of chicken meat quality.

Understanding the role of myoglobin content in Iberian pigs fattened in an extensive system through analysis of the transcriptome profile

Meat color is the first perceived sensory feature and one of the most important quality traits. Myoglobin is the main pigment in meat, giving meat its characteristic cherry‐red color, highly appreciated by the consumers. In the current study, we used the RNA‐seq technique to characterize the longissimus dorsi muscle transcriptome in two groups of Iberian pigs with divergent breeding values for myoglobin content. As a result, we identified 57 differentially expressed genes and transcripts (DEGs). Moreover, we have validated the RNA‐seq expression of a set of genes by quantitative PCR (qPCR). Functional analyses revealed an enrichment of DEGs in biological processes related to oxidation (HBA1), lipid metabolism (ECH1, PLA2G10, PLD2), inflammation (CHST1, CD209, PLA2G10), and immune system (CD209, MX2, LGALS3, LGALS9). The upstream analysis showed a total of five transcriptional regulatory factors and eight master regulators that could moderate the expression of some DEGs, highlighting SPI1 and MAPK1, since they regulate the expression of DEGs involved in immune defense and inflammatory processes. Iberian pigs with high myoglobin content also showed higher expression of the HBA1 gene and both molecules, myoglobin and hemoglobin, have been described as having a protective effect against oxidative and inflammatory processes. Therefore, the HBA1 gene is a very promising candidate gene to harbor polymorphisms underlying myoglobin content, whereby further studies should be carried out for its potential use in an Iberian pig selection program.

Effect of Aging and Retail Display Conditions on the Color and Oxidant/Antioxidant Status of Beef from Steers Finished with DG-Supplemented Diets

The aim of this work was to study the effect of finishing diets including distiller grains (DG) on color and oxidative stability of beef after being exposed to aerobic retail display conditions, with or without previous aging. For this purpose, beef samples from animals fed with finishing diets including 0%, 15%, 30%, and 45% DG (on a dry matter basis), which had been exposed to aerobic retail display conditions, with or without previous aging under vacuum packaging, were evaluated. The content of γ-tocopherol, β-carotene, and lutein in diet samples increased with the level of DG. Beef evaluated at 72 h post-mortem showed greater content of γ-tocopherol and retinol as the DG level increased. Meat color was not affected by DG inclusion, but color parameters decreased with retail conditions. Meat from animals fed with DG showed the lowest values of thiobarbituric acid reactive substances (TBARS), independently of the retail display conditions. However, all samples were below the threshold associated with rancid aromas and above the a* value related to meat color acceptance. Thus, feeding diets including up to 45% of DG improved the antioxidant status of meat, preserving the color, and delaying lipid oxidation in meat samples under the display conditions evaluated.

Small genetic variation affecting mRNA isoforms associated with marbling and meat color in beef cattle

The aim of this study was to identify mRNA isoforms and small genetic variants that may be affecting marbling and beef color in Nellore cattle. Longissimus thoracis muscle samples from 20 bulls with different phenotypes (out of 80 bulls set) for marbling (moderate (n = 10) and low (n = 10) groups) and beef color (desirable (n = 10) and undesirable (n = 9) group) traits were used to perform transcriptomic analysis using RNA sequencing. Fourteen and 15 mRNA isoforms were detected as differentially expressed (DE) (P-value ≤ 0.001) between divergent groups for marbling and meat color traits, respectively. Some of those DE mRNA isoforms have shown sites of splicing modified by small structural variants as single nucleotide variant (SNV), insertion, and/or deletion. Enrichment analysis identified metabolic pathways, such as O2/CO2 exchange in erythrocytes, tyrosine biosynthesis, and phenylalanine degradation. The results obtained suggest potential key regulatory genes associated with these economically important traits for the beef industry and for the consumer.

Quantitative proteomics reveals the relationship between protein changes and off-flavor in Russian sturgeon (Acipenser gueldenstaedti) fillets treated with low temperature vacuum heating

This study aimed to reveal the molecular mechanisms associated with off-flavor generation in sturgeon fillets treated by low temperature vacuum heating (LTVH). Label-free quantitative proteomics was used to identify 120 favor-related proteins, 27 proteins were screened as differentially expressed for bioinformatics analysis. 17 of KEGG pathways were identified. Particularly, proteins involved in proteasome and peroxisome were highly correlated with off-flavor formation. They were primarily implicated in the structures of proteins, including binding and proteasome pathways. The results indicated that the LTVH reduced the binding sites by down-regulating protease and superoxide dismutase expression. LTVH increased the myofibrillar protein and sulfhydryl content and decreased the total volatile basic nitrogen and thiobarbituric acid reactive substance, which confirmed that protein oxidation was related to off-flavor. This proteomics study provided new insights into the off-flavor of sturgeon with LTVH, and proposed potential link between biological processes and off-flavor formation.

Vacuum Packaging Can Extend Fresh Color Characteristics of Beef Steaks during Simulated Display Conditions

Packaging technology is evolving, and the objectives of this study were to evaluate instrumental surface color, expert color evaluation, and lipid oxidation (TBARS) on beef longissimus lumborum steaks packaged in vacuum-ready packaging (VRF) or polyvinyl chloride (PVC) overwrap packaging. Paired strip loins (Institutional Meat Purchasing Specifications # 180) were cut into 2.54-cm-thick steaks and assigned randomly to one of two packaging treatments, VRF or PVC. Steaks packaged in VRF were lighter in color (p < 0.05) as the display period increased, whereas steaks packaged in PVC became darker (p < 0.05). Redness (a*) values were greater (p < 0.05) for PVC steaks until day 5, whereas VRF steaks had a greater (p < 0.05) surface redness from day 10 to 35 of the display period. Calculated spectral values of red to brown were greater (p < 0.05) for steaks in VRF than PVC. In addition, expert color evaluators confirmed VRF steaks were less brown and less discolored (p < 0.05) from day 5 to 35 of the display. Nonetheless, lipid oxidation was greater (p < 0.05) for PVC steaks from day 10 through day 35 of the display. Results from this study suggest that the use of vacuum packaging for beef steaks is plausible for maintaining surface color characteristics during extended display periods.

Microencapsulated procyanidins by extruding starch improved physicochemical properties, inhibited the protein and lipid oxidant of chicken sausages

Microencapsulated procyanidins by extruding starch (MPS) were used in meat and meat products as an antioxidant for their simple production process and high stability. This study investigated the controlled released properties of MPS and their effect on antioxidant capacity, physicochemical properties, and sensory qualities of chicken sausages during 4°C storage within 28 days. Antioxidant capacity, particle size analysis, and simulated digestion in vitro demonstrated that microencapsulation by extruding starch delayed the procyanidins release. The reduced crystal structure of MPS was determined by the morphology observation (SEM) and the decrease of the typical diffraction peak at 2θ of 20.9° (XRD). The MPS-added sausage had a higher (p < 0.05) ABTS and DPPH radical scavenging ratio (97.6% and 67.3%) and sulfhydryl contents (114.69 nmol/g protein) than other groups. Moreover, lower (p < 0.05) thiobarbituric acid reactive substances (TBARS) (0.67 mg MDA/kg sausage) and carbonyl values (3.24 nmol/mg protein) were detected in MPS-added sausages than others at the end of storage. The MPS addition increased redness (a* value) and decreased the lightness (L* value). The sensory analysis suggested that the sausage with the increased redness was favorable. These results denominated that MPS was an alternative antioxidant in chicken sausages. Practical Application: In this study, microencapsulated procyanidins were prepared by extrusion technology, and the effect on the quality of chicken sausages was investigated, which provides an alternative natural antioxidant for meat and meat products.

Quality and Shelf-Life Stability of Pork Meat Fillets Packaged in Multilayer Polylactide Films

In the present study, the effectiveness of a multilayer film of polylactide (PLA), fully bio-based and compostable, was ascertained to develop a novel sustainable packaging solution for the preservation of fresh pork meat. To this end, the multilayer PLA films were first characterized in terms of their thermal characteristics, structure, mechanical performance, permeance to water and aroma vapors and oxygen, and optical properties and, for the first time, compared with two commercial high-barrier multilayer packaging films. Thereafter, the multilayers were thermosealed to package fillets of fresh pork meat and the physicochemical changes, lipid oxidation levels, and microbiological counts were monitored in the food samples during storage under refrigeration conditions. Results showed that the meat fillets packaged in PLA developed a redder color and showed certain indications of dehydration and oxidation, being more noticeably after 11 days of storage, due to the higher water vapor and oxygen permeance values of the biopolymer multilayer. However, the pH changes and bacterial growth in the cold-stored fresh pork meat samples were minimal and very similar in the three tested multilayer films, successfully accomplishing the requirements of the food quality and safety standards at the end of storage.

Retail Packaging Affects Colour, Water Holding Capacity, Texture and Oxidation of Sheep Meat more than Breed and Finishing Feed

This study investigated the CIELab colour, water holding capacity, texture and oxidative stability of sheep meat from different breeds, finishing feeds, and retail packaging methods. Leg primal cuts from a subset of Composite wether lambs (n = 21) and Merino wether yearlings (n = 21) finished on a standard diet containing grain and cereal hay, a standard diet with camelina forage, or a standard diet with camelina meal, were used in this study. Semimembranosus and Vastus lateralis were packaged in vacuum skin packaging (VSP), or modified atmosphere packaging with 80% O₂ and 20% CO₂ (HioxMAP), or with 50% O₂, 30% N₂, and 20% CO₂ (TrigasMAP). Packaging had a greater effect (p < 0.001) on L*, a*, b*, hue, and chroma than the effects from breed and finishing feed. Purge loss was affected by packaging. Cooking loss was affected by breed for Semimembranosus and packaging for both muscle types. HioxMAP and TrigasMAP increased WBSF and Texture Profile Analysis hardness of the meat compared to VSP. Lipid oxidation, assessed by TBARS, were lower in camelina forage or camelina meal supplemented diets and TrigasMAP compared to standard diet and HioxMAP, respectively. Total carbonyl and free thiol content were lower in VSP. Thus, supplementing feed with camelina forage or meal and lowering oxygen content in retail packaging by TrigasMAP or VSP are recommended to ensure optimal sheep meat quality.

Effects of ultrasound pretreatment on the quality, nutrients and volatile compounds of dry-cured yak meat

The objective of the present study was to assess the effects of ultrasound pretreatment on the quality of dry-cured yak meat. The ultrasonic power with 0, 200, 300 and 400 W (ultrasonic frequency of 20 kHz) were used to assist processing of dry-cured yak meat. The meat quality, nutrient substances, sensory quality, electronic nose, electronic tongue and volatile compounds of dry-cured yak meat were determined. The results indicated that the moisture content and hardness value of ultrasonic treatment group was significantly lower compared to the control group (P < 0.05). Ultrasonic treatment increased the value of b*, and decreased the value of L*, a*, pH, chewiness, melting temperature and enthalpy. Springiness value significantly increased from control group to 300 W of ultrasonic power group. Shear force significantly decreased with the increase of ultrasonic power (P < 0.05). Ultrasonic treatment had no effect on the TVB-N content, but it could increase the TBARS content. Ultrasonic treatment could significantly increase the essential FAA (EFAA) and total FAA (P < 0.05). In addition, the saturated fatty acid (SFA) content significantly increased with the increase of ultrasonic power (P < 0.05). Ultrasound treatment negatively affected the meat's color, smell, and taste but increased its tenderness and the overall acceptability. It also significantly increased alcohols and aldehydes contents (P < 0.05), which were consistent with the measurement of electronic nose and electronic tongue. The results demonstrated that the the appropriate ultrasonic power assisted in the processing improves quality of dry-cured yak meat, particularly for the power of 300 W.

Effect of multi-frequency ultrasound assisted thawing on the quality of large yellow croaker (Larimichthys crocea)

The effects of mono-, dual- and tri-frequency ultrasound-assisted thawing (UAT) on the physicochemical quality, water-holding capacity, moisture migration and distribution and myofibrillary structure of frozen large yellow croaker (Larimichthys crocea) were detected. The results indicated that multifrequency UAT treatment significantly increased the thawing rate, maintained the stability of myofibrils and reduced the lipid oxidation. The multifrequency UAT samples had better water-holding capacity (higher water-holding capacity values, lower thawing loss and cooking loss) and physicochemical quality (higher hardness, springiness, resilience, chewiness and lower total volatile basic nitrogen (TVB-N) values, thiobarbituric acid reactive substances (TBARS) values), higher immobilized water content, and lower free water content. Therefore, the results provide a further understanding of the quality stability of frozen large yellow croaker treated by the multifrequency UAT.

Antimicrobial PLA-PVA multilayer films containing phenolic compounds

Multilayer materials with good interlayer-adhesion were obtained by thermocompression for laminating an internal poly (vinyl alcohol) (PVA) layer with two external poly (lactic acid) (PLA) layers. Carvacrol or ferulic acid were incorporated into the PVA sheet to obtain active materials. The multilayer films were characterised as to their microstructure, thermal behaviour, tensile and barrier properties. Furthermore, the antimicrobial capacity of the materials was analysed in packaged beef meat samples for 17 days at 5 °C. The laminates exhibited tensile properties close to those of the PLA films, but with enhanced stretchability. Compared to the monolayers, the barrier capacity of multilayers was much improved by combining polyester and PVA layers, which provide the laminate with water vapour and oxygen barrier capacity, respectively. Active multilayers were effective at controlling microbial growth in beef meat during cold storage. Therefore, the materials developed were functionally adequate for food packaging purposes and successfully promoted the meat preservation.

Effects of dietary betaine supplementation on growth performance, meat quality, muscle fatty acid composition and antioxidant ability in slow-growing broiler chickens

1. This study investigated the effects of dietary betaine supplementation on growth performance, meat quality, muscle fatty acid composition and antioxidant ability in slow-growing broiler chickens.2. In total, 400, one-day-old female Xueshan broiler chicks were randomly divided into five groups with eight replicates of ten chickens each for 102 d. Broilers were fed a basal diet supplemented with 0, 125, 250, 500 or 1,000 mg/kg betaine.3. Broilers fed betaine had better feed conversion efficiency and weight gain (P < 0.05) and increased meat redness and yellowness 24 h after slaughter. Supplementation linearly decreased cooking loss and drip loss from breast muscle (P < 0.05). Muscular resilience was improved and tenderness increased (P < 0.05). Intra-muscular saturated fatty acids decreased, while total monounsaturated fatty acids and polyunsaturated fatty acids increased (P < 0.05). Betaine increased activities of glutathione peroxidase (GPx) and total superoxide dismutase (SOD), glutathione (GSH) level, ratio of reduced glutathione/oxidised glutathione, and activity of scavenging hydroxyl radicals. It increased the activity of total antioxidant capacity (T-AOC) in the breast muscle (P < 0.05). Moreover, supplementation up-regulated (P < 0.05) mRNA expression levels of blood and antioxidant markers.4. In conclusion, 1000 mg/kg betaine can be recommended as a supplement for slow-growing, Xueshan chicken.

Formation of Zn-protoporphyrin during the elaboration process of non-nitrified serrano dry-cured hams and its relationship with lipolysis

This study assessed the ZnPP content, heme content, salt content, and instrumental color in the biceps femoris and semimembranosus muscles during the elaboration of Serrano dry-cured ham manufactured without the addition of nitrate and nitrite for 15 months. The effects of lipolysis and lipid oxidation on the content of Zn-protoporphyrin were also investigated in the biceps femoris. We found that the maximum formation of Zn-protoporphyrin occurred between end of resting and 6 months of processing, which coincides with temperature increase during processing and the end of salt equalization. Zn-protoporphyrin further increased in the biceps femoris until 9 months of processing but remained unchanged in the semimembranosus. Free fatty acid content increased till 6 months and then remained unchanged until the end of the process. These findings and those from an in vitro study reinforced the idea that the release of free fatty acids can promote the activity of the endogenous enzyme ferrochelatase and contribute to the formation of Zn-protoporphyrin from heme. However, the content of Zn-protoporphyrin decreased at the end of the processing, which may be due to the progression of lipid oxidation.

Impact of frozen storage on oxidation changes of some components in goose meat

The objective of this study was to investigate the oxidation activity and lipid oxidation changes in breast (BM) and leg (LM) muscles from 17-wk-old female White Kołuda geese packaged in a vacuum, and stored in freezing conditions at −20°C. The geese were fed ad libitum during the experimental period (up to 17 wk) on the same complete feed. The samples of LM (n = 18) and BM (n = 18) from the right carcass were stored for 30, 90, 80, 270, and 365 d. Lipid oxidation was described by determining changes in: TBARS value expressing the amount of malondialdehyde (MDA), total antioxidant capacity (TAC) measured by DPPH and ABTS methods and total reduction potential (TRP) measured by FRAP method. Moreover, total heam pigments pigment (THP), relative concentration of myoglobin (Mb), oxymyoglobin (MbO₂), and metmyoglobin (MMb) were determined in this study. Time of storage affected the TAC, TRP, TBARS, and the color stability of BM and LM. The THP concentration and Mb proportion decrease gradually during the 365 d of frozen storage, while the relative concentration of MMb increase in BM and LM. It was noted that the shares of MMb in both analyzed types of muscles stored for 365 d did not exceed 0.4. This value is considered to be the limit, after which the meat takes on an intense gray-brown color not accepted by the consumer. The oxidation processes occurring during frozen storage caused an increase of TBARS and a decrease of DPPH^•, ABTS^•+, FRAP values in both kinds of muscles. The amounts of TBARS during frozen storage of muscles did not exceed 2.0 mg MDA/kg of meat. A higher value of TBARS than 2.0 causes a lack of acceptance by consumers of the flavor profile. Based on the results concerning changes in the heam pigments, as well as changes related to the oxidation of lipids, we cannot unequivocally state in which types of muscles the changes had a more intense course.

Effect of Edible Onion (Allium cepa L.) Film on Quality, Sensory Properties and Shelf Life of Beef Burger Patties

The production of edible film from onion (Allium cepa L.) to be applied as packaging is attractive, due to its chemical properties and biodegradable characteristics. Thus, we tested the hypothesis that edible onion film can positively influence the sensory properties, quality and increasing shelf life of beef burgers patties. The experiment was designed in a 4 × 2 factorial scheme, with two treatments (beef burgers patties with or without edible onion film) at an interval of four storage times (0, 3, 6 and 9 days) at 4 °C. The uncoated burger patties (control) suffered the most intense color modifications during the storage (p < 0.05). The luminosity index was higher (p < 0.05) in the control at all storage times, except at day 6, and redness, yellowness and chrome were higher (p < 0.05) in the edible onion film patties at all storage times. The pH of the beef burger patties was lower (p < 0.05) at all storage times when the edible onion film was applied. For the texture profile, only the chewiness was affected, as the inclusion of the edible onion film improved the chewing of the beef burgers patties over the storage time (p < 0.05). Additionally, there was an inhibition of the microbial growth of mesophiles and psychrophiles with the application of the edible onion film in beef burgers patties. The use of edible onion film improved the perception of panelists for the variables texture, color, flavor, odor and overall appearance, and increased the preference of panelists. The edible onion film is recommended for preserving beef burgers patties, as it delays the proliferation of unwanted microorganisms, stabilizes and improves the color parameters and sensory attributes, and increases the overall acceptance of the consumer.

Effect of Fresh Citrus Pulp Supplementation on Animal Performance and Meat Quality of Feedlot Steers

The use of fruit by-products such as citrus pulp represents a feeding ingredient that deserves to be evaluated as an energy source in animal rations. Thirty-six British breed steers were allotted to one of the three feeding treatments (12 steers/treatment): 0%, 15% and 30% of fresh citrus pulp inclusion in the ration in a randomized complete block design to evaluate animal performance and carcass and meat quality traits. In the present study, the inclusion of fresh citrus pulp up to 30% of the diet did not affect the animal average daily gain (p > 0.05) but steers that were fed the pulp consumed less feed (p < 0.05) and presented a lower feed conversion ratio (p < 0.05) than their counterparts without citrus pulp in their diet. No effect of fresh citrus pulp was observed on carcass and meat quality (p > 0.05). A greater lipophilic antioxidant capacity (p < 0.05) in meat was observed when fresh citrus pulp was offered at 15% of the diet. Fresh citrus pulp used up to 30% as a feed ingredient in feedlot rations does not negatively affect animal performance or meat quality but, rather, has a positive effect on dry matter intake and a better feed conversion ratio.

Processing Characteristics of Freeze-Dried Pork Powder for Meat Emulsion Gel

The processing characteristics of freeze-dried pork powder as raw meat for comminuted meat products were compared with those of freeze-thawed pork. The tertiary structural properties, oxidation, and solubility of proteins in the freeze-dried pork powder were investigated. In addition, the properties of the emulsion gels manufactured with freeze-dried pork powder (GFD) and freeze-thawed pork (GFT) at 1.5% and 2.0% NaCl were evaluated. The surface hydrophobicity and intrinsic tryptophan fluorescence intensity of myofibrillar proteins between the freeze-dried pork powder and freeze-thawed pork were similar. However, freeze-dried pork powder had higher carbonyl compounds and lower solubility of sarcoplasmic and myofibrillar proteins than freeze-thawed pork (p<0.05). GFD had higher cooking loss than GFT in 2.0% NaCl, and lower hardness and a* value of GFD were observed regardless of NaCl level (p<0.05). Moreover, GFD had higher malondialdehyde content than GFT at the two NaCl concentrations (p<0.05). Therefore, our study demonstrated that freeze-dried pork powder has lower functional properties than freeze-thawed pork as raw meat for comminuted meat products.

Variations in intramuscular fat content and profile in Angus x Nellore steers under different feeding strategies contribute to color and tenderness development in longissimus thoracis

Muscle from cattle reared under different finishing regime (grain vs. forage) and growth rate may have divergent metabolic signatures that are reflective of their inherent differences in biochemical processes that may impact its subsequent transformation into high quality beef. Differences in muscle lipid profiles were characterized in Angus x Nellore crossbred steers, using multiple reaction monitoring (MRM)-profiling, to identify potential metabolic signatures correlated to beef color and tenderness in the longissimus thoracis muscle of cattle fed in either a feedlot- or pasture-based system programmed to achieve either a high or low growth rate. A total of 440 MRMs were significant, which were related mainly to triglycerides and phosphatidylcholine lipids. Distinct clusters between feeding strategies for the lipid dataset were revealed, which affected glycerolipid metabolism (P = 0.004), phospholipid metabolism (P = 0.009), sphingolipid metabolism (P = 0.050) and mitochondrial beta-oxidation of long chain saturated fatty acids (P = 0.073) pathways. Lipid content and profile differed to feeding strategies, which were related to L*, a*, and tenderness. These findings provide a comprehensive and in-depth understanding of lipidomic profiling of beef cattle finished under different feeding strategies and provides a basis for the relationship between lipid content and profiles and beef quality development.

Correlation between CIELAB colour coordinates and malondialdehyde eqiuvalents in sausage with paprika stored under refrigerated conditions

Sensory properties of foods mainly affect purchasing decisions. In case of sausages, deterioration of pigments of meat and spices cause discolouration, while lipid oxidation leads to the formation of off-odours, and these two processes are connected. Lipid oxidation promotes the conversion of pigments, while the formation of metmyoglobin accelerates lipid oxidation. The scope of the study was to investigate the relationship between the amount of malondialdehyde equivalents (MDA) and CIELAB colour coordinates in a Hungarian sausage with paprika, sliced and stored under refrigerated conditions for 10 weeks. We detected negative correlation (P < 0.001) between the MDA-level and a* and b*; and positive correlation (P < 0.001) between the MDA-level and L*. The observed correlation between MDA level and colour coordinates supports the assumption that the oxidation of lipids and pigments are interrelated in the case of sausage with paprika.

Astragalus membranaceus Alters Rumen Bacteria to Enhance Fiber Digestion, Improves Antioxidant Capacity and Immunity Indices of Small Intestinal Mucosa, and Enhances Liver Metabolites for Energy Synthesis in Tibetan Sheep

Simple Summary

Astragalus membranaceus is a widely used traditional Chinese herb that has been used by humans for hundreds of years. The Qinghai-Tibetan plateau (QTP) is regarded as one of the remaining ‘Green’ places in the world. With the fast-developing intensive livestock production, sustainable and environmentally-friendly practices are required urgently on the QTP. In the current study, Tibetan sheep were supplemented with the root of Astragalus membranaceus (AMT) to reduce the use of chemical veterinary drugs and antibiotics, and to examine the effect on rumen bacteria, the antioxidant capacities and immunity indices of small intestinal mucosa and meat tissue, and the liver metabolome responses.

Abstract

Natural, non-toxic feed additives can potentially replace chemical medications and antibiotics that are offered sheep to improve performance. In the present study, Tibetan sheep were supplemented with the root of Astragalus membranaceus (AMT), a traditional herb used widely in China. Twenty-four male Tibetan sheep (31 ± 1.4 kg; 9-month-old) were assigned randomly to one of four levels of supplementary AMT: 0 g/kg (A₀), 20 g/kg (A₂₀), 50 g/kg (A₅₀) and 80 g/kg (A₈₀) dry matter intake (DMI). The A₅₀ and A₈₀ groups increased the diversity of rumen bacteria on d 14 and the relative abundances of fiber decomposing bacteria. Supplementary AMT upregulated the metabolism of vitamins, nucleotides, amino acids and glycan, and downregulated the metabolism of lipids and carbohydrates. In addition, supplementary AMT enriched rumen bacteria for drug resistance, and reduced bacteria incurring cell motility. In general, AMT supplementation increased the concentrations of catalase (CAT), superoxide dismutase (SOD) total antioxidant capacity (T-AOC) and secretory immunoglobulin A (sIgA) in the small intestinal mucosa and CAT and SOD in meat tissue. The liver tissue metabolome response showed that AMT in the A₈₀ lambs compared to the A₀ lambs upregulated the metabolites for energy synthesis. It was concluded that supplementary A. membranaceus increased the relative abundances of fiber decomposing bacteria and improved the antioxidant capacities and immunity indices of small intestinal mucosa and meat tissue in Tibetan sheep.

Concentrations of HSP27 and αβ-crystallin in Oula Tibetan sheep meat and their relationship with meat quality during postmortem aging

HSP27 and αβ-crystallin are molecular chaperones participating in multiple cellular processes. Their roles in the development of postmortem meat quality remain unclear. The current study was designed to investigate the relationship between the concentrations of HSP27 and αβ-crystallin with meat quality during postmortem aging. Specifically, cooking loss, color, pH, and the myofibril fragmentation index (MFI) of Oula Tibetan sheep meat were determined, and changes in the concentrations of HSP27 and αβ-crystallin were evaluated. The results indicated that HSP27 concentration significantly decreased in 0-3 days (p < 0.05), presenting a positive correlation with pH (p < 0.05) and a negative correlation with L*, b*, cooking loss, and MFI (p < 0.05, p < 0.05, p < 0.01, p < 0.01). Besides, αβ-crystallin concentration significantly decreased in 0-2 days (p < 0.05), exhibiting a significant positive correlation with pH (p < 0.05) and a negative correlation with L*, b*, cooking loss, and MFI (p < 0.01, p < 0.01, p < 0.01, p < 0.01). The results suggested that the HSP27 and αβ-crystallin may participate in the development of meat quality in Oula Tibetan sheep during postmortem early aging. PRACTICAL APPLICATION: Tenderness, color, and water holding capacity (WHC) are crucial quality attributes of meat. The relationship between the concentrations of HSP27 and αβ-crystallin and meat quality reveals that HSP27 and αβ-crystallin may contribute to the development of meat quality in Oula Tibetan sheep during postmortem aging. Therefore, HSP27 and αβ-crystallin are effective research objects for regulating meat quality during postmortem aging.

Detection of previously frozen poultry through plastic lidding film using portable visible spectral imaging (443-726 NM)

The objective of this study is to use a portable visible spectral imaging system (443–726 nm) to detect poultry thawed from frozen at the pixel level using multivariate analysis methods commonly used in machine learning (decision tree, logistic regression, linear discriminant analysis [LDA], k-nearest neighbors [KNN], support vector machines [SVM]). The selection of the most suitable method is based on the amount of data required to build an accurate model, computational speed, and the robustness of the model. The training set consists of pixel spectra from packages of chicken thighs without plastic lidding to evaluate the robustness of the models when implemented on the test set with and without plastic lidding. Data subsets were created by randomly selecting 1, 5, 10, 20, and 50% of the pixel spectra of each sample for both the training and test data sets. The subsets of pixel spectra and the full training set were used to train the machine learning algorithms to evaluate how the amount of data influences computational time. Logistic regression was found to be the best algorithm for detecting poultry thawed from frozen with and without plastic lidding film. Although logistic regression and SVM both performed with the same high accuracy and sensitivity for all training subset sizes, the computational time needed to implement SVM makes it the less suitable algorithm for detecting poultry thawed from frozen with and without plastic lidding film.

Growth Performance, Meat Quality and Antioxidant Status of Sheep Supplemented with Tannins: A Meta-Analysis

The objective of this study was to evaluate the effects of dietary supplementation with tannins (TANs) on productive performance, carcass characteristics, meat quality, oxidative stability, and blood serum antioxidant capacity of sheep through a meta-analysis. Using Scopus, Web of Science, ScienceDirect, and PubMed databases, a systematic search was performed for studies published in scientific journals that investigated the effects of TANs supplementation on the variables of interest. Only studies with weaned or older sheep were included. The data analyzed were extracted from 53 peer-reviewed publications. The sheep included in the present study were between 2 and 6 months old, and between 12 and 31 kg of body weight. The effects of TANs were analyzed using random-effects statistical models to examine the standardized mean difference (SMD) between treatments with TANs and control (no TANs). Heterogeneity was explored by meta-regression and a subgroup analysis was performed for covariates that were significant. Supplementation with TANs did not affect dry matter intake, pH, color (L* and b*), Warner-Bratzler shear force, cooking loss and meat chemical composition (p > 0.05). Supplementation with TANs increased daily weight gain (SMD = 0.274, p < 0.05), total antioxidant capacity (SMD = 1.120, p < 0.001), glutathione peroxidase enzyme activity (SMD = 0.801, p < 0.001) and catalase (SMD = 0.848, p < 0.001), and decreased malondialdehyde (MDA) concentration in blood serum (SMD = -0.535, p < 0.05). Supplementation with TANs decreased feed conversion rate (SMD = -0.246, p < 0.05), and the concentration of MDA (SMD = -2.020, p < 0.001) and metmyoglobin (SMD = -0.482, p < 0.05) in meat. However, meat redness (SMD = 0.365), hot carcass yield (SMD = 0.234), cold carcass yield (SMD = 0.510), backfat thickness (SMD = 0.565) and the Longissimus dorsi muscle area (SMD = 0.413) increased in response to TANs supplementation (p < 0.05). In conclusion, the addition of tannins in sheep diets improves productive performance, antioxidant status in blood serum, oxidative stability of meat and some other characteristics related to meat and carcass quality.

Effect of modified atmosphere packaging and vacuum packaging on quality characteristics of lamb meat

The aim of the study was to evaluate the effect of vacuum packaging and modified atmosphere packaging (80 % N2 + 20 % CO2) on the microbial and physicochemical parameters of lamb meat and the sensory properties of cooked meat. Musculus longissimus thoracis et lumborum samples were examined at 10 d intervals (0, 10, 20 and 30 d) during storage at 4 ∘C. There was no significant effect of the packaging method and storage time used on cooking loss, natural drip loss, lightness, yellowness, and intensity of taste and aroma. An interaction between storage time, packaging method, and mesophilic aerobic bacteria and coliform counts was observed. Storage time significantly affected the number of aerobic psychrotrophic bacteria, redness, pH (P≤0.001), shear force value (P=0.006), and the desirability of aroma (P<0.026) and taste (P<0.01). During the storage time, an increase in red saturation from 11.92 to 13.33 and pH value from 5.69 to 5.80 was recorded. Moreover, the storage method affected sensory properties. Vacuum-packed meat was characterized by higher scores in juiciness, tenderness and taste desirability in comparison to MAP. The obtained results suggest that both packaging methods allow for maintaining high-quality lamb meat during a long period of storage under refrigeration conditions.

Feeding, Muscle and Packaging Effects on Lipid Oxidation and Color of Avileña Negra-Ibérica Beef

In order to increase the economic profitability of Avileña-Negra Ibérica beef production, the inclusion of corn silage in total mixed rations was proposed during the fattening period. Twenty-four Avileña-Negra Ibérica breed entire young bulls were used to evaluate the effects of two feeding systems-concentrate (CON) and corn silage (SIL)-and two packaging systems-vacuum (VAC) and modified atmosphere (MAP)-on the lipid oxidation, color evolution and visual color acceptability of meat throughout display with either oxygen-permeable film (FILM) or modified atmosphere (MAP). Two muscles were assessed: Longissimus thoracis (LT) and Semitendinosus (ST). Meat from SIL-fed animals had higher TBA values than CON-fed animals after 7 days in MAP packaging. Lipid oxidation was prevented more effectively by VAC packaging than MAP. Display time highly influenced lipid oxidation, since oxidation rates were lower with VAC than MAP packaging. After 14 days of display in MAP, the LT from CON was lighter than the ST. Meat discoloration after 7 days of display was significantly different between packaging systems. Vacuum-packaged meat kept the same color throughout the storage time. Visual color acceptability for the LT was higher throughout display than for the ST. Samples from the MAP were well accepted by consumers, especially the meat from the SIL group. Alternatively, feeding with corn silage could be used for this type of animals without affecting important aspects of meat quality.

Effects of Modified Atmospheric Packaging on Ground Chicken Color and Lipid Oxidation

The objective of the current study was to evaluate the color changes and lipid oxidation of ground chicken patties packaged in polyvinyl chloride (PVC) film, high-oxygen (HiOx)–modified atmospheric packaging (MAP; 80% oxygen + 20% carbon dioxide [CO2]), and carbon monoxide (CO)-MAP (0.4% CO + 19.6% CO2 + 80% nitrogen) and stored at 2°C. Surface color was measured using a HunterLab MiniScan spectrophotometer on days 0, 1, 2, and 4. Lipid oxidation, pH, and aerobic plate count were determined on days 0 and 4 of storage. Fatty acid profiles were determined on day 0 to characterize saturated and unsaturated fatty acids. Patties packaged in PVC had greater (P &lt; 0.05) pH than HiOx-MAP and CO-MAP. Gas chromatography analysis indicated that ground chicken has 72.8% unsaturated fatty acids and 27.2% saturated fatty acids (based on total lipids and fatty acid methyl ester). The formation of carboxymyoglobin on ground chicken patty surface was confirmed by peaks at 420 and 570 nm, whereas oxymyoglobin had peaks at 410 and 580 nm. Instrumental color analysis indicated both HiOx-MAP and CO-MAP had greater (P &lt; 0.05) redness (a* values) than PVC on day 4 of storage. Patties packaged in HiOx-MAP had greater (P &lt; 0.05) chroma values than CO-MAP and PVC on day 4 of storage. Visual panelists noted less (P &lt; 0.05) surface discoloration in CO-MAP than PVC and HiOx-MAP on day 4 of storage. Lipid oxidation was greater (P &lt; 0.05) in PVC and HiOx-MAP than CO-MAP. CO inclusion at 0.4% level effectively inhibited lipid oxidation and stabilized surface redness during refrigerated storage of ground chicken.

Meat Quality of Nellore Young Bulls-Effects of Different Days on Feed and Zilpaterol Hydrochloride Supplementation

Ninety-six Nellore young bulls were fed (90 or 117 day) diets containing ZH (8.33 mg/kg) for 0, 20, 30, or 40 days to evaluate the effects of days on feed (DOF) and length of zilpaterol hydrochloride (ZH) supplementation on meat quality. At the end of feeding period, animals were slaughtered, and samples of the Longissimus muscle were collected to evaluate the chemical composition, fatty acid profile, color stability, shear force, and sensory profile. DOF did not affect chemical composition, shear force, sensory tenderness, and most of fatty acids; however, animals fed for 90 d had lower redness (p < 0.01), sustained juiciness (p < 0.01), and more flavor (p = 0.03) than those fed for 117 d. The ZH supplementation decreased lipid content and redness (p < 0.01), initial and sustained tenderness (p < 0.01), initial and sustained juiciness (p < 0.01), but increased protein (p < 0.01) and shear force (p < 0.01) as compared to non-supplemented animals. The ZH supplementation increased total PUFA, c9,c12-18:2, and 20:4-n6, and decreased c9-20:1 (p < 0.05). Feeding ZH impairs meat quality attributes of Nellore young bulls, regardless of duration of supplementation, while DOF has a small effect on meat quality properties.

Strategies to increase the shelf life of meat and meat products with phenolic compounds

Oxidative reactions and microbial growth are the main processes involved in the loss of quality in meat products. Although the use of additives to improve the shelf life is a common practice in the meat industry, the current trends among consumers are pushing the researchers and professionals of the meat industry to reformulate meat products. Polyphenols are compounds with antioxidant and antimicrobial activity naturally found in several plants, fruits, and vegetables that can be used in the production of extracts and components in active packaging to improve the shelf life of meat products. This chapter aims to discuss the advances in terms of (1) encapsulation techniques to protect phenolic compounds; (2) production of active and edible packages rich on phenolic compounds; (3) use of phenolic-rich additives (free or encapsulated form) with non-thermal technologies to improve the shelf life of meat products; and (4) use of active packaging rich on phenolic compounds on meat products. Innovative strategies to encapsulated polyphenols and produce films are mainly centered in the use of innovative and emerging technologies (such as ultrasound and supercritical fluids). Moreover, the combined use of polyphenols and non-thermal technologies is a relevant approach to improve the shelf life of meat products, especially using high pressure processing. In terms of application of innovative films, nanomaterials have been largely explored and indicated as relevant strategy to preserve meat and meat products.

Quality and Oxidative Changes of Minced Cooked Pork Incorporated with Moringa oleifera Leaf and Root Powder

Consumers are currently demanding meat products produced using natural additives due to their potential health benefits. Consequently, there has been a progressive interest in the search for more natural antioxidant sources. The aim of this study was to evaluate the effect of varying levels of M. oleifera root and leaf powder on the oxidative stability and quality of cooked minced pork during eight days of refrigerated storage at 4 °C. The leaves contained significantly higher (p ˂ 0.05) concentrations of total phenols (50.08 ± 0.01 mg GAE/g), while the roots contained the highest amounts of flavonoids (375.15 ± 0.19 mg QE/g) and proanthocyanidins (132.62 ± 0.4 mg CE/g). Both plant parts demonstrated good 2,2-Diphenyl-2-picrylhydrazyl (DPPH) and 2,2 íazino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) free radical scavenging activity. Minced cooked pork incorporated with M. oleifera leaf and root powder had significantly lower pH and thiobarbituric acid-reactive substances (TBARS) values compared to the control (p < 0.05). The ferric reducing antioxidant power (FRAP) was also significantly higher in the samples that incorporated antioxidants compared to the control (p < 0.05). Findings from this study suggest that M. oleifera leaves and roots are potent antioxidant sources which can be incorporated in meat to improve quality attributes during storage.

The significant influences of pH, temperature and fatty acids on meat myoglobin oxidation: a model study

Colour is one of the important quality traits affecting the meat purchasing decision by consumers, and myoglobin is the principal heme protein responsible for the meat colour. This study aimed to investigate the effects of pH (5.3, 5.8, 6.4 and 7.4) and temperature (4 and 25 °C) on oxymyoglobin (OxyMb) oxidation in model reaction mixtures containing OxyMb, fatty acids (C18:2n-6 and C18:3n-3) and vitamin E. A decrease of the OxyMb concentration with increased acidity was observed for all the reaction mixtures with/without fatty acids and vitamin E. After 48 h of storage at 4 °C, the OxyMb concentration decreased by approximately 60-70%, 61-69%, 53.7-53.9% and 40.93-41.84% in the reaction mixtures containing [OxyMb + C18:2n-6 or C18:3n-3] at pH 5.3, 5.8, 6.4 and 7.4, respectively. While, after 48 h at 25 °C, the OxyMb concentration decreased by 95-98% in all the reaction mixtures containing [OxyMb + C18:2n-6 or C18:3n-3] under all the pH conditions. The presence of vitamin E significantly inhibited the OxyMb oxidation in the reaction mixtures containing fatty acids under acidic conditions, but a higher level of vitamin E may be required for meat(s) containing high n-3 fatty acids content that are stored at high temperature.

Use of alginate edible coating and basil (Ocimum spp) extracts on beef characteristics during storage

The effect of alginate edible coating and the addition of two levels of basil (Ocimum spp) on polyphenols, DPPH and ABTS activities, meat characteristics (lipid oxidation, pH, weight loss, texture, and color) during storage and on consumer acceptability were evaluated. Four treatments were developed: CON (control-without coating), AEC (with alginate edible coating), B01 (with alginate edible coating + 1% of basil extract) and B02 (with alginate edible coating + 2% of basil extract). The addition of basil increased the polyphenols and antioxidant activity of meat and reduced the lipid oxidation. The pH values were not altered by the addition of basil and ageing time. The meat with coating was darker, more red and yellow. The inclusion of basil extract in the alginate-based edible coating improved meat acceptability. Thus, edible coatings with natural sources of antioxidants improve meat stability during storage and can be used in the food industry.