Meat Oxidation Research Articles

Effects of n-3 and n-6 feeding sources on the quality and lipid oxidation of meat from feedlot-finished Bos indicus steers

This study was conducted to evaluate the fatty acid profile, sensory properties and lipid oxidation of meat on retail display (RD) from Nellore steers (n = 96) fed diets containing soybean (SOY), sunflower (SUN), or linseed (LIN) oil or a control diet (CON). After slaughtering, samples of the Longissimus muscle were collected for sensory properties (1 day), fatty acid composition (1 day) and oxidation stability (3 days under RDC) evaluations. No differences in total lipids, cholesterol, TBARS, and total SFAs, MUFAs, PUFAs, and PUFA/SFA were observed. However, meat from animals fed vegetable oil had more CLA than that of the CON samples. The flavour, juiciness and overall acceptability were affected by the treatments (P < 0.05), but no consistent effect of a specific oil source was observed. Meat colour was not affected by diets or days under RD, and 7-ketocholesterol was not detected in any sample. The oil sources used in this work were not effective in consistently changing meat properties.

Effect of vitamin E sources and inclusion levels in diets on growth performance, meat quality, alpha-tocopherol retention, and intestinal inflammatory cytokine expression in broiler chickens

Water-miscible vitamin E (WVE) has been known to be more bioavailable than conventional lipid-soluble vitamin E (LVE) in human foods because of its greater solubility in the gastrointestinal tract. However, no data regarding the comparison of the efficacy of WVE to LVE were available in poultry diets. The objective of the current experiment was to investigate the effect of vitamin E (VE) sources and inclusion levels in diets on growth performance, meat quality, alpha-tocopherol retention, and intestinal inflammatory cytokine expression in broiler chickens. A total of 420 6-d-old broiler chicks were allotted to 1 of 7 dietary treatments with 6 replicates in a completely randomized design. The corn-soybean meal-based basal diet was formulated without inclusion of supplemental VE. Additional 6 diets were prepared by supplementing the basal diet with either WVE or LVE at the inclusion levels of 33, 65, or 100IU/kg in diets. Diets were fed to birds for 26 d. Results indicated that different VE sources and inclusion levels from 33 to 100IU/kg in diets had no effects on growth performance in broilers. The VE sources did not affect lipid oxidation in both breast and thigh meat. However, increasing inclusion levels of VE decreased (linear and quadratic, P < 0.05) lipid oxidation in breast meat. Regardless of VE sources, increasing inclusion levels of VE increased (linear, P < 0.01) alpha-tocopherol concentrations in breast meat. Dietary WVE showed a greater reduction in the expression of both pro- and anti-inflammatory cytokine genes in the jejunum than dietary LVE. Increasing inclusion levels of both VE sources decreased (linear and quadratic, P < 0.05) the expression of both pro- and anti-inflammatory cytokine genes in the jejunum. The efficacy of dietary WVE for growth performance, meat quality, lipid oxidation, and alpha-tocopherol retention in broilers chickens is similar to that of dietary LVE. However, it is likely that dietary WVE is more effective in decreasing intestinal inflammatory responses than dietary LVE in broilers.

LIPID DISTRIBUTION IN THE MEAT OF JAU (Zungaro jahu) AND THE INFLUENCE OF STORAGE TEMPERATURE ON ITS FAT STABILITY

The aim of this study was to determine the total lipid content in nine different body regions of jau catfish ( Zungaro jahu ), and evaluate the nutritional composition, energy value and lipid oxidation of jau meat during 15 days at 4°C, before (T1) and after freezing (T2) for 105 days at –20°C. The body regions were divided into anterior-dorsal (P1), anterior-medial (P2), anterior-ventral (P3), central-dorsal (P4), central-medial (P5), central-ventral (P6), posterior-dorsal (P7), posterior-medial (P8), and posterior-ventral (P9). Jau catfish contained high protein (20.17%), low lipid (0.60%) and low energy value (88.36 kcal 100g -1 ). The increase of malondialdehyde - MDA (0.2 to 2.5 mg MDA/kg) was more pronounced (P<0.05) after freezing period (T2). Among all body regions analyzed, ventral portions (P3, P6 and P9) presented highest total lipid content (P<0.05). Our study revealed that total lipid varies depending on body regions. Moreover, both refrigerated and frozen storage did not avoid MDA formation.

A Comprehensive Review on Lipid Oxidation in Meat and Meat Products.

Meat and meat products are a fundamental part of the human diet. The protein and vitamin content, as well as essential fatty acids, gives them an appropriate composition to complete the nutritional requirements. However, meat constituents are susceptible to degradation processes. Among them, the most important, after microbial deterioration, are oxidative processes, which affect lipids, pigments, proteins and vitamins. During these reactions a sensory degradation of the product occurs, causing consumer rejection. In addition, there is a nutritional loss that leads to the formation of toxic substances, so the control of oxidative processes is of vital importance for the meat industry. Nonetheless, despite lipid oxidation being widely investigated for decades, the complex reactions involved in the process, as well as the different pathways and factors that influenced them, make that lipid oxidation mechanisms have not yet been completely understood. Thus, this article reviews the fundamental mechanisms of lipid oxidation, the most important oxidative reactions, the main factors that influence lipid oxidation, and the routine methods to measure compounds derived from lipid oxidation in meat.

Antioxidant capacity, lipid oxidation status and expression of specific selenoprotein mRNA in Longissimus dorsi muscle of lambs (Ovies aries) supplemented with supranutritional selenium

Selenium is known to play a key role in maintenance of redox status of tissues, immunity, reproduction, thyroid and muscle functions. The present investigation was carried out to understand the effect of supranutritional dietary Se supplementation on antioxidant capacity, lipid oxidation and expression of specific selenoprotein mRNA in Longissimus dorsi muscles of growing lambs. Twenty male lambs of 5–6 months of age were fed basal diet supplemented with 0.5, 1.5 or 4.5 ppm Se-yeast (organic Se) or without Se (control) for 90 days. The antioxidant capacity, lipid oxidation of meat during different days of storage and the mRNA expression of GPX1, GPX2, GPX3, TXNRD1, TXNRD3, DIO1, DIO2, DIO3, SEPP1, SEP15 and SEPW1 were studied in Longissimus dorsi muscles of sheep. The results indicated improvement in antioxidant status by supplementation of 1.5 and 4.5 ppm Se, and reduction in meat lipid oxidation status on day 0 without any further reduction after 3 and 7 days of storage in all the Se supplemented lambs. A selective change in expression of GPX2, GPX3, TXNRD1, DIO2, DIO3, SEPP1, SEP15 and SEPW1 mRNA was observed by supranutritional Se while GPX1, TXNRD3, DIO1 and expressions remained unaffected by supplementation. In conclusion, supranutritional Se supplementation in lambs increased antioxidant status, reduced lipid oxidation status with limited effect on oxidative stability of meat during storage and regulated Longissimus dorsi muscle selenoprotein mRNA expression differentially depending on the Se feeding levels. Our results thus provided new insights into the regulation of selenoprotein gene expression by supranutritional levels of dietary Se.

Antioxidant Effect of Extracts from Native Chilean Plants on the Lipoperoxidation and Protein Oxidation of Bovine Muscle.

The present study investigated the antioxidant potential and the ability to inhibit lipid and protein oxidation in bovine meat of four native Chilean species: canelo (Drimys winteri), nalca (Gunnera tinctoria), tiaca (Caldcluvia paniculata), and ulmo (Eucryphia cordifolia). Phenolic acids (gallic, chlorogenic, caffeic, and coumaric) and flavonoids (catechin, epicatechin, and rutin) were identified and quantified by HPLC-MS/MS. Drimys winteri extract exhibited the highest antioxidant capacity evaluated by oxygen radical absorption capacity-red pyrogallol method (ORAC-PGR) and ferric ion reducing antioxidant power (FRAP) assays. All extracts decreased lipid oxidation induced by 2,2’-azo-bis(2-amidinopropane) dihydrochloride (AAPH) derived peroxyl radicals by anywhere between 30% and 50% the. In addition, canelo and nalca extracts decreased spontaneous oxidation by around 57% and 37% in relation to the control group, being even more efficient than butylated hydroxyanisole (BHT) a synthetic antioxidant. Protein oxidation in the myofibrillar proteins was evaluated by the formation of protein carbonyls and loss of protein thiols. The canelo, ulmo, and nalca extracts decreased the formation of carbonyls by around 30%. Plant extracts and BHT did not show an antioxidant effect on protein thiol loss. However, tiaca and ulmo extracts exerted a pro-oxidant effect, favoring the oxidation of sulfhydryl groups. The oxidizing system induced structural changes in myofibrillar protein (SDS−PAGE). A protective effect on protein structure from the canelo extract can be observed during the incubation when compared to samples incubated with AAPH.

Influence of irradiation and moringa leaf powder on the amino acid and fatty acid profiles of chicken meat stored under various packaging materials

This study was carried out to observe the changes causes by irradiation doses (0, 1.5, and 3 kGy) on oxidation stability, amino acids, and fatty acids in chicken meat incorporated with or without moringa leaf powder (MLP) during refrigerator storage of 14 days under aerobic and vacuum packaging. The results revealed that Thiobarbituric acid reactive substances (2.10 ± 0.02 MDA/kg) and Peroxide value (1.13 ± 0.01 meq peroxide/kg) were higher in aerobic as compared to vacuum in treatment with 3 kGy + 2% MLP. However, MLP decreased the said values. The negligible reduction in amino acids and fatty acid profile in meat samples were also observed after being irradiated at high dose during storage period but the addition of MLP enhances the content of amino acids and fatty acids in meat samples regardless of the irradiation dose. In nutshell, 1.5 kGy + 2% MLP could be beneficial for the quality of chicken meat during storage. Practical applications This research indicates the significance of gamma irradiation and natural antioxidants in meat processing and their influence on meat products during storage in different types of packaging. Gamma Irradiation has strong penetration power and high energy which is helpful in killing microbes in food. High dose of irradiation causes meat oxidation which could be maintained by adding different natural antioxidants and good packaging as it could help in enhancing and maintaining the sensory attributes of the product.

Effects of dietary inclusion of sunflower soap stocks on colour, oxidation and microbiological growth of meat from light fattening lambs

SummaryThirty‐two lambs were finished on a total mixed ration (TMR) pelleted alone (00SS) or including sunflower soap stock (SS): 15SS (15 g SS per kg TMR), 30SS (30 g SS per kg TMR) and 60SS (60 g SS per kg TMR). Lambs (8 per group) were slaughtered at 27 kg live weight. Colour evolution, lipid oxidation, microbial growth and detection of diarrhoeagenic Escherichia coli were studied in meat samples. SS in the diet reduced meat lipid oxidation (P &lt; 0.05), but had no significant effect (P &gt; 0.05) on the cholesterol oxidation products. Meat from 60SS and control animals (00SS) revealed greater discoloration (P &lt; 0.05) than 15SS. SS supplementation did not affect the microbiological populations, whereas high doses of SS seemed to increase the proliferation of diarrhoeagenic E. coli on day 14 (P &lt; 0.10). These results suggest that the rate of SS inclusion in the diet of fattening lambs should not be above 15 g SS per kg TMR.

The effect of aging and muscle type on the quality characteristics and lipid oxidation of lamb meat.

The research carried out on meat from 45 ram lambs of the Polish merino breed allowed to determine the effect of meat aging and muscle type on physicochemical characteristics and oxidative stability of lipids. Analysis of physicochemical traits (pH, meat color, expressed juice, cooking loss, shear force, moisture, protein, fat and total collagen content) was performed on fresh and meat aged for 14 d in the longissimus lumborum (LL) and gluteus medius (GM) muscles. The meat aging determined all physicochemical characteristics except protein and fat content. More changes in pH and meat color parameters were defined in the GM muscle compared to the LL muscle. The increase in the tenderness of meat expressed as a reduction () of shear force values was observed in both muscles aged for 14 d. A lower value () of the shear force, despite the higher content of collagen, was determined in the GM muscle compared to LL. The investigated muscles differed in the degree of lipid peroxidation expressed as thiobarbituric acid-reactive substances (TBARS) in both fresh and aged meat. The TBARS value was lower () in the LL muscle than in GM. In the longissimus lumborum muscle, the significantly lower content of polyunsaturated fatty acids (PUFAs) and PUFA n-6 has been recorded. The oxidation stability was not influenced by the meat aging.

Lipid oxidation and its implications to meat quality and human health.

Lipid oxidation not only negatively influences the sensory characteristics but also the functional characteristics of meat. During the process, various primary and secondary by-products are formed depending upon the types of fatty acids, oxygen availability, and the presence of pro- and antioxidants. Some of the lipid oxidation products only influence the quality of meat but others are implicated to various diseases and human health. Therefore, prevention of lipid oxidation in meat is important for meat quality and for human health as well. The imbalance of oxidants and antioxidants that favors oxidants in the biological system is called oxidative stress in the body. Although the body is equipped with defense enzymes and antioxidant compounds, there are many sources of oxidants or free radicals that can destroy the oxidants/antioxidants balance. Therefore, supply of extra antioxidants through food can help maintaining the balance in favor of antioxidants and help preventing various diseases and malfunctions of our body.

Evaluation of lipid oxidation and volatile compounds of traditional dry‐cured pork belly: The hyperspectral imaging and multi‐gas‐sensory approaches

AbstractThis study examined the feasibility of using hyperspectral imaging (HSI) to predict thiobarbituric acid reactive substances (TBARS) values as by‐products of lipid oxidation during traditional processing of dry‐cured meat. Using the spectral data of HSI and reference values of TBARS, models based on partial least square regression were tested. Prediction outcomes, Rp = 0.71, RMSEP = 1.10 and Rp = 0.77, RMSEP = 0.97 were obtained after preprocessing with first and second derivatives (second‐order polynomial), respectively. Preprocessing with standard normal variate, and multiplicative scatter correction yielded lower values, Rp = 0.64, RMSEP = 1.21 and Rp = 0.52, RMSEP = 1.40, respectively. Results obtained indicated that the HSI was capable of monitoring TBARS values as a lipid oxidation index during meat processing. Volatile fingerprint results for all processing phases were also obtained following analysis by gas chromatography (GC) coupled to ion mobility spectrometry (IMS) and a mass spectrometry (MS) detector. The MS was deployed to provide names and proportions of the volatile components while IMS was used to visualize the topographic maps of the individual volatile components. The GC‐IMS proved to be very versatile considering the little time it required to identify the volatile fingerprints of the various samples.Practical applicationsThe conventional methods for determining lipid oxidation in meat are highly destructive and time‐consuming and require the use of hazardous chemicals. This study evaluated the feasibility of the hyperspectral imaging (HSI) and gas chromatography coupled to ion mobility spectrometry (GC‐IMS) and a mass spectrometry detector to rapidly predict thiobarbituric acid reactive substances (TBARS) and analyze volatile components during lipid oxidation. The HSI was successful in predicting TBARS values as by‐products of oxidation. The results obtained proved that the methods presented can be useful for industries to simultaneously estimate various quality attributes of samples to save time, labor, and cost, which reflects economic importance. Additionally, the recurrence of hexanal during analysis volatile compounds means industries should be mindful of it as it acts as a marker for lipid oxidation in muscle food products. Finally, the topographic plots generated by the GC‐IMS are also very useful for easy differentiation of samples.

Superabsorbent food packaging bioactive cellulose-based aerogels from Arundo donax waste biomass

A.donax waste biomass has been valorized for the extraction of cellulosic fractions with different purification degrees, as well as aqueous bioactive extracts, which were then combined to develop superabsorbent bioactive aerogels. All the developed aerogels presented excellent water and oil sorption capacities; however, the presence of hemicelluloses yielded more porous and hydrophilic aerogels, capable of absorbing more water. With regards to the aqueous extracts, the hot water treatment (HW) of A. donax stems promoted the extraction of polysaccharides and polyphenols, producing the extract (S-HW) with the highest antioxidant capacity. This extract was then incorporated into the aerogels produced from the less purified stem fractions (F2A and F3A), which were chosen due to their good water sorption capacity, higher antioxidant potential and lower production costs and environmental impact. The hybrid aerogels showed a great potential to be used as bioactive pads for food packaging. In particular, the F2A + S-HW aerogel would be the most optimum choice since it provides a complete release of the extract in hydrophilic media, as demonstrated by in-vitro release and β-carotene bleaching inhibition studies, and it is able to reduce the colour loss and lipid oxidation in red meat upon refrigerated storage to a greater extent.

Comparison of 2 commercial turkey hybrids: productivity, occurrence of breast myopathies, and meat quality properties

This study was undertaken to compare productive performance, occurrence of breast myopathies, chemical composition, and technological properties of the meat in 2 dominant commercial turkey hybrids. A total of 972 1-day-old male turkey poults (equally divided in hybrid A and B) were randomly distributed in 18 floor pens. Overall, productive performance resulted similar between the genotypes, although they showed different growth profile (turkeys from group B grew up faster up to 84 d). Regarding the occurrence of myopathies, the percentage of breasts affected by white striping was markedly higher in both genotypes (46 vs. 60% of severe lesions, respectively for A and B; P < 0.05), while the occurrence of spaghetti meat-like condition was negligible. The histological features of the different categories of meat abnormalities resulted similar to those previously described for chicken hybrids. The technological traits such as ultimate pH, lightness, redness, marinade uptake, cooking losses, and shear force were not significantly affected by the genotype. However, turkeys from group B exhibited lower yellowness (b*, 0.50 vs. 1.04; P < 0.05) and higher drip losses (1.34 vs. 1.26%; P < 0.05). The shelf-life test on thigh meat showed no significant changes in meat color over the storage time in both hybrids, whereas thigh meat from group A showed absolute lower values of lightness (L*) and yellowness (b*) (P < 0.05). Lipid oxidation of thigh meat significantly increased during storage, although no significant difference was found between the hybrids. Proximate composition and intramuscular collagen properties resulted similar between genetic lines with the exception of total fat content (1.55 vs. 1.21%, respectively for A and B; P < 0.05). The genotype had a moderate effect on fatty acid families of breast meat as only monounsaturated fatty acid content was significantly affected (31.7 vs. 29.8%, respectively for A and B). In conclusion, the overall productive traits of commercial turkeys, including the occurrence of muscle myopathies, as well as quality attributes of fresh and refrigerated meat were only slightly affected by the genotype.

Effects of cooking methods on changes in fatty acids contents, lipid oxidation and volatile compounds of rabbit meat

The effects of boiling, roasting and sous-vide on the cooking loss, lipid and water content, lipid oxidation, fatty acids (FAs) contents and volatile profile (VC) of rabbit meat were studied. Sous-vide resulted in lower cooking loss (20.12%) as compared with boiling (30.66%) and roasting (32.28%). Cooked meat (C-meat) contained higher amount of lipids: sous-vide (6.30%), boiling (5.91%), roasting (4.83%), as compared with raw meat (R-meat; 4.24%). Cooking increased saturated FAs content of C-meat, but decreased the atherogenic palmitic acid by 3–7%. Decreased content of polyunsaturated FAs in C-meat with more evidenced effect of roasting (14%) than boiling and sous-vide (7 and 6% respectively) resulted in formation lipid oxidation products (LOPs). Thus, cooking increased the contents of hydroperoxides: 13-, 6- and 7.5-fold after roasting, sous-vide and boiling, respectively, as compared with R-meat. Roasted meat contained about twice more secondary LOPs than boiled meat. Dominating VCs were aldehydes; their amounts increased 13-, 9- and 7-fold in roasted, boiled and sous-vide meat, respectively, compared with R-meat. Cooking resulted in increasing or generating new VCs in meat: eight hydrocarbons, 1-pentanol and 2-penthylpyridine in roasted meat, furans: 2-ethyl and 2-penthyl in boiled meat, three sulfur-containing compounds in sous-vide meat.

Characterization of protein changes and development of flavor components induced by thermal modulation during the cooking of chicken meat

With the development of new technology in the food industry, stewed chicken should now be prepared based on scientific processing parameters instead of traditional procedures. This study was designed to examine the effects of cooking temperature (75, 80, 85, 90, 95, and 100°C) and cooking time (10, 20, 30, 40, 50, 60, 90, and 120 min) on protein degradation, protein oxidation, and flavor formation in stewed chicken meat. Significantly greater nonprotein nitrogen and total free amino acid concentrations were observed when cooking at 80 and 90°C for 50 and 60 min. Cooking for 90–100 min resulted in a stable flavor profile according to e-nose data. The results suggest that with a cooking temperature of 80–90°C and a cooking time of 50–60 min, protein degradation and protein oxidation are each maximized, indicating a critical point for increasing stewed chicken flavor formation. Practical applications Heating of meat modifies its eating quality, including texture, color, and flavor. The rate and extent of these changes are dependent on the amount of heat that is transferred to the meat and on the heating rate. The ability to exert control over these variables will define to what extent the meat becomes more palatable to the consumer after cooking, with tenderness, juiciness, and flavor being the main factors influencing choice and acceptance of cooked meat. Therefore, a continuing aim of the meat industry is to discover improvements in processing that ensure and enhance these desirable sensory attributes while still yielding a product that is safe to consume.

Incorporation of probiotic strain in raw minced beef meat: Study of textural modification, lipid and protein oxidation and color parameters during refrigerated storage

The aim of this work was to evaluate the effect of different concentrations of probiotic strain Lactobacillus plantarum TN8 on the quality and safety of raw minced beef after 10 days of refrigerated storage. The obtained results showed that the incorporation of the probiotic strain can inhibit the proliferation of spoilage microorganisms, such Listeria monocytogenes and Salmonella spp., delay the lipid oxidation, improve texture parameters, and extend the shelf life of these products during storage. We also examined the correlations between protein and lipid oxidation, texture profile and color parameters of raw minced beef meat inoculated with L. plantarum TN8. The incorporation of strain at 108 CFU/g resulted in better quality inclusive color, lipid oxidative stability, and texture parameters notably cohesiveness, adhesiveness, hardness and chewiness. Overall, the findings demonstrated that TN8 can be used as a biopreservative agent for extending the safety and quality of refrigerated raw minced beef meat.

Use of apple pomace in animal feed as an antioxidant of meat

The experiment was aimed to evaluate the effects of dietary inclusion of fermented apple pomace (FAP) in lamb diet on physicochemical and lipid oxidation of meat during storage at 4 °C. Twenty-four crossbred sheep were randomly assigned to two experimental diets with or without 11% (dry matter basis) FAP for 56 d. The lambs were then slaughtered, and the longissimus dorsi muscle was removed 24 hours after slaughter to measure meat quality. The inclusion of FAP in the diet of sheep did not change lightness and redness of meat, but greater yellowness was observed with increased storage time. Diet did not have any influence on the pH, water-holding capacity (WHC), drip loss (DL) and shear force of meat. Storage time increased yellowness and tenderization of meat. Oxidation of lipids in stored meat from sheep that were fed FAP was lower than that in the control group. It is concluded that the use of fermented apple pomace in the diet of sheep decreased meat oxidation during storage, without affecting other quality characteristics of the meat. Keywords: Diet, fermented, longissimus dorsi , sheep, storage

Dietary omega-3 and antioxidants improve long-chain omega-3 and lipid oxidation of broiler meat

BackgroundThis study aimed to investigate the possibility of producing broiler meat rich in long-chain n-3 polyunsaturated fatty acids especially eicosapentaenoic acid (EPA, C20:5 n-3) and docosahexaenoic acid (DHA, C22:6 n-3) with preventing lipid oxidation of the produced meat by supplementing the diets with linseed oil or fish oil along with vitamin E (Vit. E) or sweet chestnut tannins (SCT) as antioxidants. A total of 144 1-day-old Cobb broiler chicks were divided into six treatments with three replicates, eight chicks each. The treatments were basal diets containing 2 g linseed oil/100 g (T1), 2 g linseed oil/100 g + 200 mg Vit. E/kg (T2) and 2 g linseed oil/100 g + 2 g SCT/kg (T3), 2 g fish oil/100 g (T4), 2 g fish oil/100 g + 200 mg Vit. E/kg (T5), and 2 g fish oil/100 g + 2 g SCT/kg (T6) for 5 weeks. Fatty acid composition, thiobarbituric acid (TBA), and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity were determined.ResultsDietary 2 g fish oil/100 g elevated (P ≤ 0.001) long-chain omega-3 polyunsaturated fatty acids in broiler meat mainly EPA and DHA. At the same time, dietary fish oil resulted in a significant decrease (P ≤ 0.001) in α-linolenic acid in broiler meat (6%). However, total omega-3 fatty acids in meat were higher (P ≤ 0.001) with dietary fish oil than with dietary linseed oil. The ratio of n-6:n-3 PUFA was decreased (P ≤ 0.001) in the meat of broilers fed diets containing 2 g fish oil/100 g compared with broilers fed diets containing 2 g linseed oil/100 g. The two sources of antioxidant decreased (P ≤ 0.05) TBA value and increased (P ≤ 0.05) the DPPH radical scavenging activity in broiler meat compared to the diet without antioxidant. No significant differences observed between chicks fed 2 g SCT/kg or 200 mg Vit. E/kg on TBA and DPPH radical scavenging activity.ConclusionsIt is concluded that inclusion of 2 g fish oil/100 g in broiler diets elevated levels of long-chain omega-3 PUFA mainly EPA and DHA, but decreased n-6:n-3 ratio. Moreover, the addition of 2 g SCT/kg diet or 200 mg Vit. E/kg diet as antioxidant sources inhibited lipid oxidation and enhanced antioxidant activity value in broiler meat, and each of them had the same effect.

Effects of malondialdehyde as a byproduct of lipid oxidation on protein oxidation in rabbit meat

The effects of malondialdehyde (MDA) as a byproduct of lipid oxidation on myoglobin and myofibrillar proteins (MP) oxidations in muscle homogenates containing components native to rabbit muscle were investigated. For myoglobin, MDA could lead to increase in metmyoglobin percentage. For MP, MDA could promote protein carbonylation and loss of tryptophan fluorescence. In addition, MDA could affect reactive oxygen species (ROS)-generating system by promoting the formation of hypervalent myoglobin species and release of non-heme iron. The result of MDA-MP adducts fluorescence intensity indicated that ROS-generating systems may be the main reason for protein carbonylation at the later of incubation treatment. SDS-PAGE analysis revealed that the ability of ROS-generating systems to facilitate protein oxidation was enhanced with MDA, which was responsible for the formation of protein cross-linking throughout incubation treatment. Taken together, the ability of MDA on promoting the oxidation of MP in rabbit muscle homogenates may be relied on both adduct reactions and the influence on ROS-generating system.

The influence of dietary chestnut and quebracho tannins mix on rabbit meat quality.

Tannins were recently evaluated as feed additives in order to increase antioxidant compounds in animal diet, mainly to enhance resistance to lipid oxidation in meat. Rabbit meat is one of the most susceptible animal products, thus the main aim of this study was to evaluate the capacity of tannins to elongate shelf life of rabbit meat. Ninety hybrid rabbits were fed with three different diets: basal diet (control, C) and basal diet supplemented with 0.3% or 0.6% of tannins mix. Meat samples were refrigerated as raw at 4°C up to 11 days and analysed both as raw and cooked for physical-chemical characteristics, fatty acids profile, lipid oxidation and antioxidant capacity. Results showed that dietary tannins affected meat colour of raw samples (mostly yellowness). Lipid peroxidation (TBARS) of raw samples was lower in tannins group than C group; a further inhibition of peroxidation was showed also in cooked samples only by the highest dose of tannins mix. Moreover, antioxidant capacity (ABTS) of raw samples increased with the percentage of tannins. In conclusion, supplementation with 0.6% of tannins mix seems to positively affect the lipid peroxidation and antioxidant capacity of meat without modifying the intrinsic characteristics of rabbit meat.