Heme Pigment Content Research Articles

Desempenho tecnológico de cortes diferentes de carne de coelho no processamento de produtos cárneos curados cozidos prontos para consumo

Abstract There is a worldwide demand for new protein sources through environmentally responsible production, and rabbit farming is a sustainable activity. Therefore, this study aimed to characterize meat from different cuts of rabbit carcasses and evaluate their use in the processing of restructured cured cooked ready-to-eat (RTE) products. Rabbit raw meats from different cuts were technologically characterized, and the RTE products were processed from the meats of the entire carcass (RABB), hind legs (RHIND), loin (RLOIN), and foreleg, thoracic cage, and flank (RBACK). Restructured pork cooked ham (PHAM) was used as the reference. Rabbit raw meat from different anatomical parts difered in proximate composition, total collagen and heme-pigment content, water-holding capacity, and CIE color, afecting the characteristics of processed products. RBACK products had higher fat content (5.46%), cooking and reheating losses (7.50% and 5.61%), and poor hardness and chewiness (11.1 N and 17.37 N×mm). Higher values of lightness (L* ~70.27), hue (h ~68.61°), and a slight cured color were observed in RLOIN, with a pale yellowish color described by sensory evaluation. RABB and RHIND were correlated with the sensory attributes of traditional PHAM, being preferred more often and with greater purchase intent than RLOIN and RBACK. It is concluded that cooked ham development from whole carcass meat (RABB) is a potential opportunity for the rabbit industry to ofer value-added technological products of high quality to consumers.

Quantitative and qualitative properties of giblets from conventional, organic, and wild ducks

The aim of the study was to evaluate selected properties of giblets (liver, heart, and gizzard) from conventional (C), organic (O), and wild (W) ducks. A total of 24 giblets (24 of each organ) were analysed in each bird group. Production properties, colour indicators, haem pigment content and chemical composition were compared. The heaviest organ with the highest yield was the liver in C and W ducks and the gizzard in O ducks (P < 0.05). The liver and gizzard of W and O ducks were darker (P < 0.05) compared to the same organs in C ducks. The redness of the heart of O ducks was higher (P < 0.05) than that of the heart of both other groups of ducks (C and W). All W duck organs contained (P < 0.05) more haem pigment. The livers of reared ducks (C and O) contained more protein (P < 0.05) than the livers of W birds. The liver of C reared poultry was about 3–4 × fattier (P < 0.05) compared to the liver of the remaining two groups of ducks. The heart of wild ducks had the highest protein and lowest fat content, the heart of ducks from the C breeding system had the least protein, whereas ducks bred organically had the highest amount of fat in the heart. Ducks from the O system had a fattier gizzard compared to other birds (P < 0.05). The highest protein percentages were found in the gizzards of W ducks, the smallest in the gizzards of C poultry.

Spectrophotometric evaluation of hemolysis in plasma by quantification of free oxyhemoglobin, methemoglobin, and methemalbumin in presence of bilirubin.

Severe intravascular hemolysis leads to the simultaneous presence of free heme pigments (oxyhemoglobin, methemoglobin, and methemalbumin) and bilirubin in human plasma. Standard spectrophotometric methods used to assess in vivo hemolysis inadequately address this complex analytical situation. Thus, we propose a novel quantification algorithm to ensure the highest analytical specificity. A corresponding second-derivative fitting algorithm was validated according to the guideline of bioanalytical method validation from the European Medicines Agency using plasma specimens (n = 1759) spiked with different concentrations of oxyhemoglobin and methemoglobin. The results were compared to standard spectrophotometric quantification methods described by Harboe, Noe, and Fairbanks. Based on the second-derivative method, simultaneous quantification of oxyhemoglobin and methemoglobin/methemalbumin in samples with total bilirubin concentrations ≤4.9 mg/dL (83.8 μmol/L) provided robust results (inaccuracy ≤20%, imprecision ≤16%). Analyzing UV/VIS spectra of plasma from patients with confirmed severe intravascular hemolysis evidenced an underestimation of up to 33% for the combined free heme pigment content. The employed second-derivative algorithm allows for automated and highly specific quantification of the free heme pigment content in diluted human plasma, which cannot be realized with standard spectrophotometric evaluation methods. An Excel-based tool readily applicable to clinical datasets accompanies this manuscript.

Effect of the exposure to oxidation and malondialdehyde on turkey and rabbit meat protein oxidative stability.

The present study aimed at evaluating the effect of the exposure to a strong oxidative environment (100mM NaClO) and the concurrent incubation with different malondialdehyde (MDA) concentrations (0 to 5mM) on protein carbonylation, free thiol groups, total heme pigments, and on the relative concentration of the different myoglobin (Mb) derivatives in turkey thigh and rabbit hind leg meat to elucidate their eventual role in inducing oxidative modifications on the protein fraction. With regard to turkey meat, the addition of a strong oxidant resulted in remarkably higher (P < 0.001) carbonyls along with a reduction in free thiol groups (which become undetectable). The relative concentration of MbO2 and MetMb was significantly affected (P < 0.001) and total heme pigment was reduced by 62% when fresh meat is compared to its oxidized counterpart. The addition of MDA 2.5mM (or greater) resulted in a 1.4-fold increase in carbonyls and a tendency (P = 0.07) has been observed for free thiol groups whose content decreased as the MDA level increased. Overall, the aforementioned results are in agreement with those obtained on rabbit hind leg meat in which a three-fold increase (P < 0.001) in carbonyls and a remarkably higher (P < 0.001) MetMb content coupled with a 53% reduction in free thiol groups were found. No significant differences ascribable to MDA addition were found. In conclusion, exposing turkey and rabbit meat to the same environment resulted in distinctive oxidative changes that might be related to the compositional traits and a species-specific susceptibility of the meat toward oxidation. PRACTICAL APPLICATION: Protein and lipid oxidation have been investigated in different meat types; nevertheless, the knowledge concerning the interaction between these two phenomena is limited. According to their compositional traits (high Polyunsaturated fatty acids (PUFA) and heme pigment content), turkey and rabbit leg meats are particularly susceptible to oxidation. Providing information concerning the oxidative stability of turkey thigh and rabbit hind leg meat exposed to strong oxidative conditions and to a concurrent increasing content of a secondary product of lipid oxidation, the findings of the present study can be useful when proper processing strategies and storage conditions have to be implemented for manufacturing processed products.

Research to lessen the amounts of curing agents in processed meat through use of rock salt and carbon monoxide

This study was carried out to examine the reddening of meat products due to the addition of natural yellow salt (YS) and carbon monoxide (CO). Following YS or NaCl addition at 2% to pork subsequent to nitrite (0∼100 ppm) treatment, color development due to this addition was analyzed visually. Heme pigment content in the meat was also determined spectrophotometrically. YS was found to bring about greater reddening than NaCl, indicating residual nitrite and nitrate content to be significantly higher in meat containing YS, through the amount of either was quite small. The amount of nitrite required for a red color to develop was noted to vary significantly from one meat product to another. CO treatment of pork caused the formation of carboxy myoglobin (COMb) with consequent reddening of the meat. COMb was shown to be heat-stable and form stably at pH 5.0 to ∼8.0 and to be extractable with water, but was barely extractable at all with acetone. Nitric oxide was found to have greater affinity toward myoglobin (Mb) than CO. Nitrosyl Mb was noted to be stable in all meat products examined. CO was seen to be capable of controlling the extent of lipid oxidation.

Effects of substituting finely ground sorghum for finely ground corn on feed digestion and meat quality in lambs infected with Haemonchus contortus

The objective of this study was to determine the effects of substituting different levels of finely ground sorghum (FGS) for finely ground corn (FGC) on feed digestion and meat quality in lambs infected with Haemonchus contortus. Twenty-four male Ujumqin lambs at 90±6.3 days of age were randomly assigned to receive one of four dietary treatments for 8 weeks prior to slaughter. The four diets contained 0g/kg FGS and 400g/kg FGC (CON), 100g/kg FGS and 300g/kg FGC (LFGS), 200g/kg FGS and 200g/kg FGC (MFGS), and 400g/kg FGS and 0g/kg FGC (HFGS). Before feeding, all lambs were dewormed and experimentally infected with 10,000 H. contortus third stage larvae. After a 28-day adaption to larvae infection, the feeding period was started. Fecal and blood samples were collected and lambs were weighed every 2 weeks. At the end of the feeding period, lambs were slaughtered, meat samples were collected, and the H. contortus burden in the abomasum was determined. The results demonstrated interaction effects between treatment and sampling time on fecal egg count (FEC; P<0.001) and packed cell volume (PCV; P<0.001) in lambs. The FEC decreased and the PCV increased significantly over the feeding period. As the dietary FGS content increased, the H. contortus burden in the abomasum, the abomasal mucosal surface (HBAM), and the abomasal contents (HBAC) decreased linearly (P<0.001). In addition, the ratio of HBAM to HBAC decreased numerically but not linearly (P=0.196) and the ratio of male to female H. contortus increased linearly (P=0.016). Although dry matter intake decreased linearly (P=0.001) as the dietary FGS content increased, no differences in the average daily weight gain and feed conversion ratio were observed between lambs in the FGS substitution groups and CON group. The apparent digestibility of all feed nutrients in the MFGS diet was numerically higher than those in other diets. As the dietary FGS content increased, the dressing percentage of lambs (P<0.001), total heme pigment content (P<0.001), and amount of tannins in meat increased linearly (P<0.001). Diets containing 100–400g/kg FGS did not affect total amino acids levels in meat, although levels of some individual essential amino acids increased as the FGS in diets increased. In conclusion, substitution of 100–400g/kg FGS inclusion for equal amounts of FGC in diets is not only beneficial for protection of lambs against H. contortus infection but also for improving the meat color in lambs by increasing the deposition of antioxidant tannins in the meat.

Effect of acid whey on nitrosylmyoglobin concentration in uncured fermented sausage

The objective of this study was to investigate the effect of acid whey on the nitrosylmyoglobin formation of organic sausage. The oxidation–reduction potential (ORP), total haem pigment concentration, haem iron, L∗, a∗, b∗ colour parameters were analyzed after ripening (0) when sausages had the status of “ready-to-eat” and after 90 and 180 days of chilling storage (4 °C). The reflectance spectra and ratios were analyzed after ripening (0) and 180 days of chilling storage. At the end of the storage period nitrosylmyoglobin (NO-MbFe2+) were analyzed and then sausages were heat treated. After that L∗, a∗, b∗ with reflectance spectra and ratios were analyzed. The acid whey treatment affected significantly (P < 0.05) the ORP, colour parameter (a∗) and reflectance ratios. Uncured sample with acid whey have the lowest ORP value (320.98–359.75 mV) from all study sample. There were no significant differences between a∗ parameters and NO-MbFe2+ content (a∗ = 9.46, NO-MbFe2+ = 54.93 g/100 g) of sample with acid whey compared to cured sample (a∗ = 9.54, NO-MbFe2+ = 66.29 g/100 g). Sausages with acid whey developed red-pinkish colour characteristic for cured meat as indicated by the obtained results of reflectance ratios and spectra and the NO-MbFe2+ concentration. The formation of a desired colour could be achieved even after heat processing.

Characterisation of the lipid and protein fraction of fresh camel meat and the associated changes during refrigerated storage

Characterisation of protein and lipid fractions of fresh camel meat and their associated changes were investigated during 9 days of refrigerated storage. Camel meat lipids contained palmitic acid (C16:0) as dominant fatty acid followed by stearic acid (C18:0) and oleic acid (C18:1 n-9). Content of total saturated fatty acid (SFA) and unsaturated fatty acids were 58.46 and 41.5mg/100g, respectively. Total unsaturated fatty acids were reduced at the end of storage. Lipids underwent rapid oxidation as indicated by increase in peroxide value (PV) and thiobarbituric acid reactive substances (TBARS). Decrease in total haem pigment, myoglobin and haemoglobin content with concomitant decrease in redness (a* value) was noticed during the storage. Protein extractability, solubility, TCA-soluble peptides and drip loss increased during storage indicating proteolysis and degradation of structural proteins, which was also evident from SDS-PAGE pattern. This further corroborates with the decrease of textural parameters like hardness, cohesiveness, springiness and gumminess. Thus, the protein and lipid fraction of camel meat underwent considerable changes during refrigerated storage. Therefore, the behaviour of protein and lipid fraction in camel meat during refrigerated storage could provide better understanding of the processing and storage conditions.

Comparison of iodine value equations among pork carcass fat depots of immunologically castrated pigs

cells transformed by a pET(21) plasmid containing the Shp gene and purified. Ability of apoShp to remove hemin from pork metHb was spectrophotometrically determined (n = 2) in solution by observing absorbance shifts from 405 nm (metHb peak) to 418 nm (holoShp peak) during incubation at 0.2 °C and pH 5.9. To investigate the significance of residual Hb in promoting lipid oxidation in pork muscle, the Semitendinosus was selected as a model muscle. The muscle was trimmed to select the red portion, ground with a 5 mm plate, and minced in a food processor. Heme content of the mince was determined by acid–acetone extraction. Lipid oxidation in stored mince (0.2 °C, pH 5.9, n = 2) with and without added apoShp was investigated by thiobarbituric acid reactive substances (TBARS) measurement. Statistical analysis employed the MIXED procedure of the SAS system. Results: Promotion of lipid oxidation in the mince was affected by the presence of 1.5% NaCl at 0.2 °C and pH 5.9. The 1.5% NaCl treatment achieved a significant increase in TBARS formation over the 0% treatment (P=0.0005). By 241 h of storage, TBARS in the 1.5% NaCl treatment reached 48.45 ± 2.45 μmol TBARS/kg mince, while TBARS in the 0% NaCl treatment reached 0.049 ± 0.069 μmol TBARS/kg mince, representing a 989-fold increase in TBARS formation (P b 0.0001). To determine the significance of residual Hb in promoting lipid oxidation in the mince, effect of a 2.5-fold excess of apoShp over total heme pigment content on TBARS formation in the mince was investigated in the presence of 1.5% NaCl. ApoShp significantly inhibited TBARS formation (P= 0.0019). By 131 h of storage, TBARS in the apoShp treatment reached 0.490 ± 0.690 μmol TBARS/kg mince, while TBARS in the apoShp-free treatment reached 9.129 ± 0.439 μmol TBARS/kg mince, representing a 95% inhibition of TBARS formation (P b 0.0001). To determine the ability of apoShp to remove hemin from pork metHb, a 4-fold excess of apoShp over metHb was incubated with pork metHb, in the presence of 1.5% NaCl. Evidenced by a shift in absorbance from 405 nm to 418 nm, apoShp removed increasing quantities of hemin from pork metHb over 91 h. Conclusion: These data suggest Hb, not Mb, as the primary promoter of lipid oxidation in pork Semitendinosus muscle, and reinforce the importance of residual blood in postmortem muscle as a target for antioxidant strategies.

Application of a computer vision system to classify beef as normal or dark, firm, and dry1

The purpose of this research was to evaluate the possibility of using computer vision systems (CVS) to detect DFD beef. The experimental material consisted of beef obtained from 60 carcasses (M. semimembranosus) that were 48 h postmortem. The beef was classified into 2 quality groups according to pH: normal (pH < 5.8) or DFD (pH ≥ 5.8). L*, a*, and b* color components were determined in the experimental materials using both CIELab and a CVS using 3 color models: RGB (red, green, blue), HSV (hue, saturation, value), and HSL (hue, saturation, lightness). The total heme pigment content also was determined. As determined by both CIELab and CVS, DFD meat was characterized by a darker color than normal beef. Color lightness, as determined using both CIELab and CVS, can also be used to detect DFD beef. A significant relationship was found between V (r = -0.79) and L (r = -0.77) using CVS and pH, which is an indicator of DFD beef. This finding indicates the possibility of using these color components to assess the pH level of beef.

Effect of production system on physical–chemical, antioxidant and fatty acids composition of Longissimus dorsi and Serratus ventralis muscles from Iberian pig

The effect of three production systems of Iberian pigs namely Montanera (free-range system and feeding based on acorns and grass), Recebo (free-range system and nutrition based in combination of acorns, grass and mixed feeds) and Intensive (confinement with mixed feeds) on some quality traits of Longissimus dorsi (LD) and Serratus ventralis (SV) muscles were studied. Muscles from pigs raised in the Montanera system showed significantly higher CIE L∗, a∗ and b∗ values and higher haem pigment content than those from Intensive system. Similarly, muscles from pigs raised in the Montanera system had significantly higher contents of α and γ-tocopherol and phenolic compounds contents and higher lipophilic and hydrophilic activity antioxidant than those from pigs raised in the Intensive system. Fatty acids profiles from Montanera pigs had significantly higher monounsaturated (MUFA) and polyunsaturated (PUFA) fatty acids and lower saturated fatty acids (SFA) than those from pigs raised in the Intensive system. In relation to muscle effect, LD showed lower intramuscular fat (IMF), α-tocopherol, phenolic compounds, lipid oxidation and PUFA, but higher MUFA than SV.

Effect of freeze–thaw cycles on physicochemical properties and color stability of beef semimembranosus muscle

The effects of freeze–thaw cycle on the physicochemical properties and color stability of beef semimembranosus muscle during cold storage were investigated. Meat was tested for effects on color (CIE L ⁎, a ⁎, b ⁎), myoglobin content (%), metmyoglobin reducing ability (MRA), thiobarbituric acid reactive substances (TBARS), heme pigment content (ppm), SDS-PAGE profile, and tissue microstructure. Fresh meat showed significantly ( p < 0.05) higher values of CIE a ⁎, CIE b ⁎, and oxymyoglobin content (%) compared to freeze–thawed meat during cold storage. However, metmyoglobin content (%) was higher in freeze–thawed meat than in fresh meat during 7 days of cold storage. There were no significant differences ( p > 0.05) in MRA among the treatments during cold storage. The TBARS value (0.387 mg/kg) of fresh meat was significantly ( p < 0.05) higher than those of freeze–thawed meats after 5 days of cold storage. These results suggest that the freeze–thaw process could accelerate the deterioration of meat color.

FACTORS AFFECTING LIPID OXIDATION IN BREAST AND THIGH MUSCLE FROM CHICKEN, TURKEY AND DUCK

ABSTRACT Lipid oxidation occurred rapidly in turkey muscle, intermediate in duck and slowest in chicken. pH was lowest in turkey muscle. Chicken muscle had a lower content of polyunsaturated fatty acids compared with turkey and duck muscles. The aqueous fraction of duck breast inhibited hemoglobin-mediated lipid oxidation in washed muscle more effectively than aqueous fractions from turkey and chicken muscle. α-Tocopherol content was highest in duck muscle, intermediate in chicken and lowest in turkey. Depletion of tocopherols during frozen storage was more rapid in turkey and duck compared with chicken. It was thought that the elevated tocopherol level in chicken muscle may be caused by less efficient catabolism via the omega hydroxylation pathway. However, tocopherol hydroxylase activity was similar in chicken compared with turkey liver microsomes. Heme pigment content was around sixfold higher in duck breast compared with chicken and turkey breast. Duck thigh had especially elevated pH. PRACTICAL APPLICATIONS This work describes a number of factors that explain the wide variation in oxidative stability (chicken > duck > turkey) when comparing muscle tissues from the three avian species. These factors include muscle pH, concentration of heme pigments, fatty acid unsaturation, inhibitors of lipid oxidation in the aqueous fraction of the muscle, tocopherol content in lipid phases and depletion rates of tocopherol. These factors should be considered when developing strategies to inhibit lipid oxidation in muscle foods. The relatively high content of α-tocopherol in chicken muscle compared with turkey should be a subject of further research to better understand the mechanisms by which certain animal species preferentially deposit the molecule into muscle.

Effect of dietary tea catechins supplementation in goats on the quality of meat kept under refrigeration

Liuyang black male goats were used to examine the effects of TC inclusion on lipid oxidation and fresh meat quality of goats. Forty goats were randomly divided into four equal groups (ten animals in each group) and assigned to four experiment diets with TC supplementation at four levels (0, 2000, 3000 and 4000 mg TC/kg feed). After 60 days of feeding period, all goats were slaughtered and sampled. The results showed that dietary TC supplementation had significant ( P < 0.05) effect on plasma total antioxidant status (TAS) at days 40 and 60, lipid oxidation of M. longissimus dorsi (LD), gluteus medius (GM) and semimemberanosus (SM), pH value of GM and SM at 24 h postmortem, intramuscular fat (IMF) of SM, drip loss percentage of GM and SM, and total haem pigment content (THP) of LD and SM. In conclusion, suitable dietary TC level could inhibit lipid oxidation, decrease drip loss of fresh meat and improve meat colour stability in goat, moreover, dietary TC inclusion influences muscle pH values and IMF at some degree, but different muscle types showed different trend to change, and the quality of LD was relatively stable according to overall evaluation.

Lipid and colour stability of meat from lambs fed fresh herbage or concentrate

Fourteen male Comisana lambs were divided into two groups at 45 days of age and were individually penned for 105 days. Over this period, seven lambs were fed a concentrate-based diet (C), whereas the remaining animals received vetch ( Vicia sativa; H) harvested daily and given fresh to the animals. Lipid oxidation was measured in both minced cooked meat ( semimembranosus muscle, SM) over 4 days of aerobic refrigerated storage and on minced raw meat stored over 14 days in a high oxygen atmosphere. Colour descriptors, haem pigment concentration, and metmyoglobin percentages were also determined during storage duration on the minced raw meat. Lipid oxidation increased over time in cooked and raw meat ( P < 0.0005), but lower TBARS values were found in both cooked and minced meat from lambs fed vetch compared to those given concentrates ( P = 0.001; P = 0.006, respectively). Higher a* values, lower b* values and lower hue angle values were observed in meat from H-fed animals as compared to meat from C-fed lambs ( P = 0.006; P = 0.02; P = 0.005, respectively). Metmyoglobin formation increased over time ( P < 0.0005), but the H diet resulted in lower metmyoglobin percentages than the C diet ( P = 0.006). Haem pigment concentration decreased over the 14 days of storage ( P < 0.0005). We conclude that, under conditions that promote oxidative stress in meat, a herbage-based diet can improve the oxidative stability of meat compared to a concentrate-based diet.

Dietary tannins improve lamb meat colour stability

Fourteen male Comisana lambs were divided into two groups at 45 days of age: lambs fed a concentrate diet (C), or lambs fed the same concentrate with the addition of quebracho ( Schinopsis lorentzii) tannins (T). Sheep were slaughtered at 105 days of age. Lipid oxidation, colour coordinates, haem pigment concentration, and metmyoglobin percentages were measured on minced semimembranosus muscle (SM) over 14 days of refrigerated storage in a high oxygen modified atmosphere. Tannin supplementation increased ( P < 0.01) a ∗ values and reduced ( P < 0.01) b ∗ values of the SM when compared to C. Lower hue angles ( P < 0.001) and metmyoglobin formation ( P = 0.07) were observed in lamb from T-fed compared to C-fed sheep during the 14-days storage period. Furthermore, feeding T resulted in greater ( P < 0.001) haem pigment concentrations in the SM during refrigerated storage; however, diet had no ( P = 0.28) effect on lipid oxidation. Therefore, including quebracho tannins in sheep diets can improve meat colour stability of fresh lamb during extended refrigerated storage.

Detection of quantitative trait loci for meat quality traits in cattle

A whole-genome scan was carried out to detect quantitative trait loci (QTL) affecting sensory, organoleptic, physical and chemical properties of meat. The study used phenotypic data from 235 second-generation cross-bred bull calves of a Charolais x Holstein experimental population. Loin muscle samples were evaluated for yield force, intramuscular fat and nitrogen contents, myofibrillar fragmentation index, haem pigment concentration, moisture content and pH at 24 h postmortem. A sensory assessment was performed on grilled loin and roasted silverside joints by trained panellists. A linear regression analysis based on 165 markers revealed 35 QTL at the 5% chromosome-wide significance level (20 for sensory traits and 15 for physical and chemical traits), five of which were highly significant (F-value: > or =9). The most significant QTL was located on chromosome 6 (with the best likely position at 39 cM) and affected haem pigment concentration. The Holstein allele for this QTL was associated with an increase of 0.53 SD in the haem scores. A QTL for pH(24h) was identified on chromosome 14 (at 40 cM) and a QTL for moisture content was identified on chromosome 22 (at 21 cM). Two highly significant QTL were identified for sensory panel-assessed traits: beef odour intensity (grilled sample) on chromosome 10 (at 119 cM), and juiciness (roast sample) on chromosome 16 (at 70 cM). The proportion of phenotypic variance explained by the significant QTL ranged from 3.6% (for nitrogen content on chromosome 10) to 9.5% (for juiciness, roast sample on chromosome 16).

Eating quality of young bulls from three Spanish beef breed-production systems and its relationships with chemical and instrumental meat quality

Sensory characteristics of longissimus thoracis muscle from three local Spanish beef breed-production systems and their relationships with chemical and instrumental meat quality traits were studied. Young bulls of Bruna dels Pirineus (BP; n = 69), Avileña-Negra Ibérica (A-NI; n = 70) and Morucha (MO; n = 70) breeds were reared in their own production systems. MO breed showed the highest water holding capacity and also the highest thawing loss and haem pigment content ( P < 0.001). No differences in moisture and protein contents were found among breeds. A-NI showed the highest intramuscular fat (IMF, P < 0.05) and total collagen ( P < 0.001) contents, whereas BP showed the lowest IMF content ( P < 0.05) and the highest collagen solubility ( P < 0.001). Beef flavour, tenderness and juiciness accounted for the eating quality differences among the three breed-production systems. Meat from A-NI was rated significantly higher ( P < 0.01) for beef flavour and tenderness than that from BP and MO animals. Furthermore, MO showed the lowest juiciness ( P < 0.001) which could be due to its higher thawing loss. Within the three breeds, thawing loss was negatively correlated with juiciness and, likewise cooking loss with juiciness and tenderness ( P < 0.05). The canonical discriminant analysis showed that the three breeds were significantly different ( P < 0.05) from each other according to sensory attributes, which justifies their involvement in different protected geographical indications (PGI).

Meat color evaluation and pigment levels in bullfrog ( Rana catesbeiana) slaughtered by different methods

This work aimed to evaluate the muscle color and heme pigment content of bullfrog muscles after electrical or thermal stunning and use or not of bleeding. Stunning method did not influence ( P>0.05) the instrumental color or the total heme pigment content of the meat or the relative chemical forms of heme pigments. However, muscle myoglobin content was lower in electrically stunned frogs ( P<0.05). Overall, the myoglobin content of bullfrog meat was similar to that of avian white muscles. Bleeding enhanced the final quality of the meat. Meat from bled animals was whiter and had an important contribution of the b* value (yellowness) to its color. Muscle hemoglobin content of bled frogs was lower ( P<0.05) than that of un-bled frogs, and negatively correlated ( P<0.05) with slaughter weight. Oxymyoglobin, reduced myoglobin, and metmyoglobin contents were, respectively, highly correlated with lightness ( L*), redness ( a*), and yellowness ( b*).

Characterisation of young bulls of the Bruna dels Pirineus cattle breed (selected from old Brown Swiss) in relation to carcass, meat quality and biochemical traits

Seventy-four young bulls of the Bruna dels Pirineus beef cattle breed were reared in a typical production system and slaughtered at an average age of 381 days and live weight of 541 kg. The animals were evaluated for productive traits, carcass quality, meat quality, eating quality and biochemical characteristics of m. longissimus thoracis (LT). Biochemical measurements included intramuscular fat (IMF) and collagen proportion, haem pigment concentration, lactate dehydrogenase and isocitrate dehydrogenase activities and type I (MHC I) fibre percentage determined by ELISA. Bruna dels Pirineus bulls achieved high growth rates during the fattening period (1.63 kg/day) and showed good carcass quality, with a high dressing-out proportion (607 g/kg, hot carcass), a good conformation score (U; EUROP) and a moderate fatness score (3;1–5). Carcass composition was estimated from the sixth rib joint dissection (682 g/kg lean proportion, 127 g/kg total dissectable fat and 163 g/kg bone). IMF (24.3 g/kg) and MHC I (27.9%) showed high variabilities (CV>30%). Sensory analysis of LT included beef and livery odour and flavour intensity, and overall tenderness and juiciness assessment of loin samples (14-day ageing). Beef odour and flavour were slightly positively correlated with IMF and carcass fatness score ( P<0.05). Fatness, MHC I, insoluble collagen and cooking losses tended to affect the livery flavour intensity positively. This variable was significantly higher in meat from bulls of lower carcass quality (i.e. lower conformation score, lower lean proportion; P<0.05) and higher type I fibre percentage. Loin overall tenderness and juiciness were not affected by the biochemical traits studied, however, they were negatively affected by cooking loss ( P<0.05).