Thirty-two Merino lambs fed barley straw and a concentrate alone (CONTROL) or enriched with vitamin E (VITE006) or carnosic acid (CARN006; CARN012) were used to assess the effect of these antioxidant compounds on meat quality attributes. The animals were slaughtered after being fed for at least 5weeks with the experimental diets. The longissimus lumborum samples of VITE006, CARN006 and CARN012 groups showed higher values (P<0.001) of L* (lightness) through the complete storage period under modified atmosphere when compared to the CONTROL group. Moreover, the VITE006 and CARN012 samples revealed lower discoloration when compared to the CONTROL group, these differences being more apparent in a less color stable muscle such as gluteus medius (P<0.05 for hue after 14days of refrigerated storage). Meat sensory traits were not significantly affected by carnosic acid and microbiological analyses were not conclusive at the doses administered.
Thirty-two Merino lambs fed barley straw and a concentrate formulated either with palm oil (CTRL group) plus quercetin (QCT group) or flaxseed (FS group) plus quercetin (FS-QCT group) were used to assess the effects of this flavonoid on meat quality attributes. The animals were slaughtered after being fed for at least 5weeks with the experimental diets. Chemical composition of longissimus thoracis (LT) muscle was not different among treatments. The longissimus lumborum (LL) samples of QCT and FS-QCT groups revealed lower discolouration (hue angle) when compared to the CTRL and FS lambs (P<0.05), whereas extract release volume (ERV) and microbiological data jointly suggest that flaxseed and quercetin may reduce the growth of microbial populations responsible for meat spoilage in quadriceps femoris (QF).
Case-ready fresh beef is typically packaged in a modified-atmosphere with approximately 80% oxygen and 20% carbon dioxide. Recently, USDA approved distribution of fresh meats in a master bag system using 0.4% carbon monoxide (CO). This study compared effects of packaging system (vacuum, 80% oxygen, 0.4% carbon monoxide), fresh meat storage time (7-21 days) and cooking temperature (49-79 °C) on extent of myoglobin denaturation, color and rancidity in cooked top sirloin steaks. Steaks packaged in 80% oxygen or CO retained desirable red color for 14 and 21 days storage, respectively. Steaks stored in 80% oxygen exhibited the greatest TBA values and myoglobin denaturation at all storage times and cooking temperatures. Steaks stored in high oxygen developed brown interior color at internal temperatures as low as 57 °C, the premature browning effect. Premature browning and rancidity associated with steaks packaged in 80% oxygen was prevented by packaging in 0.4% CO or vacuum.
Changes in the ultrastructure of myofibrillar protein as a result of 1,5-glucono-δ-lactone-induced gelation at chilled temperatures were investigated using transmission electron microscopy. The myofibril structure appeared to have completely disintegrated at pH 4.0 resulting in a granular, amorphous appearance. It was suggested that as the pH was lowered to about 4.5, partial extraction of the A-band proteins occurred. A composite system of a myosin gel network reinforced by the residual myofibrillar structure was proposed to have formed. As the pH was lowered further, complete depolymerisation of actomyosin was suggested to have resulted in the formation of a predominantly myosin gel. The inclusion of sodium chloride resulted in swelling of the myofibrillar protein and retention of the myofibrillar structure to pH 3.8.
The effects of salt level and high pressure processing on cook loss, emulsion stability, colour, textural and sensory characteristics of frankfurters were investigated. Two salt levels (1.5 and 2.5%) and two pressure treatments (150 and 300 MPa) were examined. For each batch a control was set up which was non-pressure treated. Cook loss values were significantly decreased in 150 MPa products at the 2.5% salt level compared to controls. Significantly lower cook losses were recorded at the lower salt level after the application of 150 MPa pressure. The stability of the meat emulsions was significantly increased at the lower salt level, especially after 150 MPa pressure. Sensory analysis results for overall flavour acceptability after pressure application of 150 MPa and 300 MPa were similar to control products and panellists preferred products formulated at 1.5% salt after pressure treatment (150 MPa). Hardness, cohesiveness, gumminess and chewiness were also improved after pressure treatment. The results demonstrate that high pressure technology is a viable process that partially compensates for the reduction of salt levels in frankfurters.
Meat tenderness is an important characteristic in terms of consumer preference and satisfaction. However, each consumer may have his/her own criteria to judge meat tenderness, because consumers are neither selected nor trained like an expert sensory panel. This study aimed to characterize consumer tenderness using descriptive texture profiles such as chewiness and hardness assessed by a trained panel. Longissimus muscles cooked at four different end-point temperatures were subjected to a trained sensory panel (n=18) and consumer (n=107) tenderness tests. Multiple regression analysis showed that consumer tenderness was characterized as 'low-chewiness and low hardness texture.' Subsequently, consumers were divided into two groups by cluster analysis according to tenderness perceptions in each participant, and the two groups were characterized as 'tenderness is mainly low-chewiness' and 'tenderness is mainly low-hardness' for tenderness perception, respectively. These results demonstrate objective characteristics and variability of consumer meat tenderness, and provide new information regarding the evaluation and management of meat tenderness for meat manufacturers.
Investigations have been made into possible spectral interferences at fat, protein and water wavelengths of the Super-Scan (infra-red meat analyser) due to absorbance by phosphorus (a natural constituent of bone) at the carbohydrate wavelength. Instrument calibration for boneless meat resulted in the need for correction factors to results for bone-in meat of × 0·96, × 1·05 and × 0·97 for % fat, % protein and % water, respectively, to bring them in line with those by standard chemical methods. Comparisons between Super-Scan results for boneless meat to which tricalcium phosphate (the major constituent of bone) has been added showed an interference proportional to the amount of phosphate present and varied in size depending on sample fatness. Calibration with bone-in meat controlled interference adequately for % fat and % water, but still required an empirical correction factor of × 0·97 for protein.
Heifers (n = 70) were slaughtered and hung conventionally in an industrial meat plant. Near infrared (NIR) spectroscopy was studied for its ability to predict selected meat quality attributes, i.e. Warner-Bratzler shear force (WBSF), sensory tenderness, texture, flavour and acceptability. Freshly cut steaks (2.5 cm thick) were taken from the longissimus dorsi (LD) muscle at 1, 2, 7 and 14 days post mortem for NIR analysis. Other samples (also 2.5 cm thick) were taken at 2, 7 and 14 days post mortem, vacuum-packaged in plastic bags and stored at -20 °C for WBSF measurement and sensory analysis. Heifers were slaughtered in two groups; between slaughterings, replacement of the spectrophotometer lamp and lamp assembly was necessitated by a bulb failure. Using principal component regression (PCR), correlation coefficients of 0.82 and 0.73 were obtained for the prediction of WBSF in sample sets 1 and 2, respectively. On merging both sample sets, this value was lowered slightly (r = 0.61). Correlation coefficients obtained for the prediction of tenderness, texture, flavour and acceptability were 0.67, 0.53, 0.51 and 0.46 respectively (set 1); 0.72, 0.71, 0.45 and 0.67 (set 2); 0.53, 0.54, 0.24 and 0.42 (combined sets).
Biopreservation has been proven to be a promising natural preservation technique, but the impact of protective cultures on the sensory properties of cooked meat products (CMP) is not well documented. This work presents a case study on the protective culture Lactobacillus sakei 10A to obtain a clear view on the real consequences of using protective cultures on the sensory quality of CMP. A preliminary screening study on 13 different CMP and more elaborate application trials at 7°C on vacuum packaged pâté, cooked ham, cooked sausage and two cooked poultry products demonstrated that L. sakei 10A inhibits the endogenous LAB-flora, Leuconostoc mesenteroides, Brochothrix thermosphacta and Listeria monocytogenes. Despite these promising antagonistic effects, the application of L. sakei 10A to CMP was in some cases limited by a significant acidification resulting in an acid taste of the product. This was most obvious in pâté and cooked sausage and less obvious in cooked turkey fillet. From the results a hypothesis could be derived that high buffering capacity and low glucose content are key elements to avoid sensory deviations when applying protective cultures on CMP.
Data from 180 bulls from Charolais, Limousine and Retinta breeds were used to evaluate image analysis of cross-sections as method of predicting the physical composition of the 10th-11th-12th rib-cut. The site along the longissimus thoracis muscle (between either the 9th and10th ribs or the 12th and 13th ribs), and the breed had significant influence on most of the variables analyzed. The correlation coefficients between the rib composition obtained by image analysis and by dissection were low to moderate (r=0.18-0.59, P<0.01-P<0.001). The R(2) values of the composition components of the 12th-13th rib cross-section to 10th-11th-12th rib-cut composition were higher than those recorded from the 9th-10th rib cross-section (R(2)=0.535 to 0.759 vs. 0.148 to 0.502). The accuracy of the predictions of lean, longissimus thoracis m. and bone percentages improved significantly with the addition of carcass weight. Results indicate that image analysis can predict rib composition in lean cattle with moderate accuracy and precision.
Transmission infrared analysis, which has been successfully applied to milk analysis, was assessed for the quantitative analysis of fat and protein in meat products. Meats of varying fat and protein content were converted into milk-like emulsions, which were, in turn, analyzed by standard chemical methods and by a Multispec M infrared analyzer. The performance of the instrument for meat analysis using a standard milk calibration was also assessed and compared with the instrument set with a meat calibration. Both approaches provided a good estimate of the fat and protein content for a range of meat products, the meat calibration being more accurate than the milk calibration. The infrared method allowed for rapid and accurate analysis of meat and has future potential in the meat industry for quality control purposes.
The changes in electron micrographs of muscles frozen at -10, -22, -33, -78 and -115°C were analyzed. The ultrastructure of muscle successively changed with decreasing freezing temperature whereas light microscopy indicated anomalous behaviour at -22°C. It appeared that, in muscles frozen at -10°C, there was no freezing of water intracellularly; in those frozen at -22°C, water was frozen intracellularly (but only in the I-band region); whereas, in muscles frozen at -33°C, water was frozen inside the fibres, both in the I- and the A-bands. In muscles frozen at -78 and -115°C, water is frozen intracellularly. These findings can be explained on the basis that, in the I-band region, the major protein is actin, which has a relatively high proportion of non-polar residues and holds water weakly, whereas the predominant protein in the A-band is myosin, which contains many polar residues and has a high water-holding capacity.
To elucidate the relationship between the lowering of freezing temperature and the distribution of ice crystals in frozen muscle, samples of beef Longissimus dorsi muscle were frozen at -10, -22, -33, -78, -115 and -196°C. Histological preparations of these samples indicated that ice crystals were formed in muscles frozen at -10°C intercellularly, at -22°C inter- and intracellularly, at -33°C intercellularly and at -78, -115 and -196°C only intracellularly. In muscles frozen at -78°C, ice crystals in fibres were large; in those frozen at -115°C they were relatively smaller; and in those frozen at -196°C they were evenly distributed throughout the muscles. The greatest damage was caused at -22°C due to the simultaneous formation of the ice intra- and intercellularly. The results indicated that the pattern of distribution of ice crystals at the latter temperature deviates from that predicted from a linear progression of change with temperature of freezing.
The effects of gender (barrows; gilts) and terminal sire genotype (DD, Danish Duroc; PxLW, Pietrain×Large White) on performance and carcass and meat quality of pigs sacrificed at a fixed weight of 117 kg were studied. Barrows ate more feed, grew faster, and had poorer feed conversion and less yield of trimmed lean cuts than gilts. Castrates were fatter and had more intramuscular fat and more intense colour of the meat than females. Crossbreds from DD boars grew faster and had better feed conversion than crossbred from P×LW boars. Also, DD sired-pigs had smaller dressing percentages but more trimmed lean cuts proportion than P×LW sired-pigs. Meat from DD pigs was more tender, had more intramuscular fat, and presented lower a* value than meat from P×LW pigs. We conclude that DD boars are a good alternative to P×LW boars for production of heavy pigs destined for the dry-cured industry.
This study evaluated the effects of the ovine c.*1232G>A myostatin mutation (MM) on carcass traits in heterozygous crossbred lambs sired by Texel and Poll Dorset rams using ultrasound, CT scanning, carcass classification and VIA. In experiment 1, MM was associated with increased loin depth (+2.8%) and area (+3.2%). MM-carriers had significantly higher CT-estimated lean weight and proportion (2 to 4%) and muscle to bone ratio (by ~3%), in both experiments, and muscle to fat ratio (28%) in experiment 2. Muscle areas in three cross-sectional CT scans, were higher (2 to 5%) in MM-carriers. In experiment 2, fat-related measurements were significantly lower in MM-carrier lambs but this was not seen in experiment 1. A significant increase in muscle density, indicative of lower intramuscular fat, in MM-carriers shows that meat quality characteristics need attention. Carrying MM significantly decreased carcass fat scores. VIA did not detect any significant MM effects.
Adulteration of high quality meat and meat products with their inferior/cheaper counterparts is a problem in the meat industry. The present study investigated the use of polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) of the mitochondrial 12S rRNA gene for identification of the origin of meats. PCR-RFLP was applied for species identification of beef, buffalo meat, mutton and chevon. PCR amplification yielded a 456-bp fragment in each of these species. The amplicons were digested with AluI, HhaI, ApoI and BspTI restriction enzymes resulting in a pattern that could identify and differentiate each of the above species. This technique did not yield satisfactory results with meat mixtures/meats. However, consistent results were obtained with both fresh and processed meat samples.
The verification of authenticity of meat products is relevant for economical, religious or public health concerning reasons. A molecular approach using terminal restriction fragment length polymorphism (T-RFLP) was developed to distinguish 12 common economically important meat species. The partial 12S rRNA gene was amplified with double-fluorescently labeled primers. The amplified fragments were digested with two endonucleases and only the terminal restriction fragment containing labeled primer was detected on capillary electrophoresis system ABI3100. AluI and Tru9I generated differently-sized terminal fragments in different species. Pig and buffalo can be separated by 3'-terminal fragment of AluI digestion. Horse, turkey, goat, sheep, deer, and cattle can be further separated by 5'-terminal fragment of Tru9I digestion. Dog and chicken, sturgeon and salmon can finally be separated by 5'-terminal fragment of AluI digestion and 3'-terminal fragment of Tru9I digestion. Our results demonstrated the potential feasibility and applicability of T-RFLP method for rapid and accurate identification of animal species.
In this study, sequence analysis of mitochondrial 12S rRNA has been applied for meat species identification. The procedure involves polymerase chain reaction (PCR) amplification of a fragment of mitochondrial (mt) 12S rRNA gene and sequencing of amplicons. Amplified product of mt 12S rRNA gene was 456 bp in size. Species sequenced include cattle (Bos indicus), buffalo (Bubalus bubalis), sheep (Ovis aries), goat (Capra hircus) and mithun (Bos frontalis). Sequences were compared with the reported sequences of low land anoa (Bubalus depressicornis), yak (Bos grunniens) and pig (Sus scrofa). There was no effect of routinely used additives or cooking temperature (72, 90, 120 and 180 °C) on the efficacy of PCR amplification. The closely related species like cattle and buffalo, sheep and goat could also be differentiated decisively by sequence analysis. Sequencing and analysis of mt 12S rRNA gene was, hence, found to be an ideal, authentic and unambiguous qualitative method for meat species identification.
Polymerase chain reaction (PCR) based on oligonucleotide primers targeting the mitochondrial 12S rRNA gene was applied to the specific identification of meats from red deer (Cervus elaphus), fallow deer (Dama dama), and roe deer (Capreolus capreolus). The use of a common reverse primer, together with forward specific primers for red deer, fallow deer, and roe deer, allowed the selective amplification of the desired cervid sequences. The specificity of each primer pair was verified by PCR analysis of DNA from various game and domestic meats. The assay can be useful for the accurate identification of meats from cervid species, avoiding mislabeling or fraudulent species substitution in meat products.
The 4-hydroxy-l-proline content of a variety of meats and meat products was determined both by carbon-13 pulsed Fourier transform nuclear magnetic resonance (FTNMR) spectroscopy and by a traditional colorimetric method. These two fundamentally different methods gave results which were in good agreement; both methods require chemically free 4-hydroxy-l-proline from hydrolysis which is the time-consuming experimental step. The relative merits are discussed with reference to specifity, operator time and sample throughput. Observation of 4-hydroxy-l-proline without time-consuming hydrolysis by (13)C-FTNMR spectroscopy was found to be possible with collagen and with carbohydrate-free meat samples. Direct observation without such hydrolysis could be useful as a rapid survey method if carbohydrate interferences can be eliminated.
Proton and carbon-13 NMR was used to investigate post-mortem metabolism in bovine muscles at 26°C during the first 10h after slaughter. WALTZ-16 decoupling was used to eliminate the proton couplings in the (13)C spectra and the 'jump and return' pulse sequence was used to suppress the water resonance in the (1)H-NMR experiments. With carbon-13 NMR the glycogen breakdown and the lactate development could be followed. This was compared with the lactate, creatine and phosphocreatine development as measured by proton NMR. The intracellular pH was estimated from the chemical shift of the abundant dipeptide, carnosine, as measured in the (1)H- and (13)C-NMR spectra. These were compared with similar measurements obtained earlier using phosphorus-31 NMR. The three independently determined pH profiles were in excellent agreement with one another, as well as with results obtained with the standard iodoacetate extraction method. In the course of these studies we observed that the post-mortem metabolism in cow and heifer was slow and that it took four more hours to complete compared to bull or young bull. After 10 h the pH was 5·9 in bull and 6·1 in cow. Phosphocreatine had completely disappeared after 3·5 h in bull samples while the lactate continued to increase even after 10h. The curves obtained by carbon-13 and proton NMR for the increase in lactate during the first 10 h post mortem were very similar. Moreover, plots for the increase in the lactate level versus the intracellular pH decrease showed a linear relationship, indicating that anaerobic glycolytic activity is the main determining cause for the intracellular pH decrease. Various other parameters, such as the ratio of unsatirated to saturated fatty acid side chains and the presence of amino acids and taurine, could be measured from the in vivo carbon-13 NMR spectra. However, no gross changes occured in any of these parameters during the first 10 h post mortem.
The effects of production system (SE: pasture based vs. IN: concentrate based) and slaughter age (12 vs. 14months) on chemical composition, vitamin E and myoglobin contents, lipid oxidation at 0, 3 and 6days of display, colour and cooking losses at 2 and 7days postmortem from thirty-three Tudanca calves were studied. SE animals showed lower IMF and greater vitamin E contents (1.2 vs. 2.9% and 4.1 vs. 1.8μg/g, respectively). Thiobarbituric acid reactive substances (TBARS) increased (p≤0.001) with display time and was greater in the IN system. After 6days display, IN animals presented twofold TBARS values (1.4 vs. 0.8mg malonaldehyde/kg meat). At 7days postmortem, SE groups presented greater (p≤0.05) L* and lower (p≤0.05) b* and H° than IN groups. Myoglobin increased with age (3.4 to 3.9mg/g meat), but differences (p≤0.05) on a* and C* values were observed only between 12 and 14months at 2days postmortem.
Longissimus lumborum (LL) muscles from 117 steers plus LL, gluteus medius (GM), and triceps brachii (TB) muscles from 132 heifers were evaluated for effects of feeding duration of zilpaterol hydrochloride (Zilmax(R); ZH; 7.56g/907kg on a dry matter basis) and aging time on tenderness. Both genders were blocked by initial weight into six blocks of four pens. Pens were assigned to treatments of control (C), or 20, 30 or 40days on ZH, with a 3day withdrawal. Steaks from each subprimal were vacuum aged individually for 7, 14 or 21days, frozen, thawed, and cooked to 71 degrees C for Warner-Bratzler shear force (WBSF). All muscles from steers and heifers from ZH30 and ZH40 treatments had higher (P<0.05) WBSF than those of C. The WBSF of steer LL and heifer TB from the ZH20 treatment was higher (P<0.05) than C. There was a treatment by aging interaction (P>0.05) for WBSF of GM steaks from heifers. Percentage of intramuscular fat had little effect on tenderness. Percentages of steer LL and heifer TB steaks with WBSF values below thresholds of either 5.0 or 4.6kg from the ZH20 treatment were quite high, whereas percentages of heifer LL and GM muscles below 5.0kg (67%) and 4.6kg (57%) were low. Feeding ZH20days generally increased WBSF values, but mean WBSF values for steer LL and heifer TB were below 4.6kg. Feeding ZH 20days resulted in>40% of GM steaks with WBSF values above 4.6kg.
Raw samples of 14 muscles: Mm. biceps femoris (BF), quadriceps femoris (CF), diaphragm (DI), flexor digitorum (FD), gluteus medius (GM), infraspinatus (IE), longissimus lumborum (LL), longissimus thoracis (LT), psoas major (PM), pectoralis profundus (PP), semimembranosus (SM), semitendinosus (ST), sternomandibularis (STER) and triceps brachii (TB) from four Swiss Brown (485±15 days old) young bull carcasses and weighing approximately 300 kg were evaluated for some chemical and physical properties. PM (2.11 kg) and DI (2.24 kg) were the muscles which had the lowest Warner-Bratzler shear force values, while PP (6.66 kg) had the greatest shear force (P<0.05). FD and IE muscles had the highest concentration of total collagen content while PM and DI had the lowest (P<0.05) contents, TB and IE muscles presented the highest insoluble collagen concentration while PM and LT had the lowest (P<0.05) contents. High positive correlation between total collagen content and Warner-Bratzler shear force of raw samples was found (r=0.723; P<0.01) and between insoluble collagen content and Warner-Bratzler shear force was (r=0.661; P<0.01). Significant differences (P<0.05) were observed among muscles for differential scanning calorimetry, sarcomere length, pH and colour parameters.
A total of twenty two Large White X Landrace castrated males were slaughtered at 30, 70, 110 or 140kg BW. Carcasses were weighed and cut into four primal cuts (belly, ham, loin, and shoulder). Each cut was weighed and dissected into bone, muscle, skin, and intermuscular and subcutaneous adipose tissues. Kidney fat was also taken and weighed. Kidney fat grew more rapidly than subcutaneous or intermuscular fat averaged over all four cuts. In the shoulder and loin, about one third of total adipose tissue was in the intermuscular fraction. In the belly, there was as much (in 30-110kg BW pigs) or more (in 140kg BW pigs) intermuscular than subcutaneous adipose tissue. In the ham, the intermuscular fraction of adipose tissue grew more slowly than the subcutaneous one, so that it represented less than one fourth of total ham adipose tissue in 140kg BW pigs. Intermuscular adipose tissue exhibited a lower lipid content than subcutaneous adipose tissue, whatever the body weight, but the differences in lipid content between the adipose tissues decreased with increasing weight. These results show that the relative development of intermuscular and subcutaneous adipose tissues differs according to anatomical location.
The electrical properties of biological tissues have been researched for many years. Impedance measurements observed with increasing frequencies are mainly attributed to changes in membrane conductivity and ion and charged-molecule mobility (mainly Na(+), K(+), CL(-) ions). Equivalent circuits with passive electrical components are frequently used as a support model for presentation and analyses of the behavior of tissues submitted to electrical fields. Fricke proposed an electrical model where the elements are resistive and capacitive. The model is composed of a resistive element (Rp) representing extracellular fluids (ECF) placed in parallel with a capacitive element (Cs) representing insulating membranes in series and a resistive element (Rs) representing intracellular fluids (ICF). This model is able to describe impedance measurements: at lower frequencies, most of the current flows around the cells without being able to penetrate them, while at higher frequencies the membranes lose their insulating properties and the current flows through both the extracellular and intracellular compartments. Since meat ageing induces structural change, particularly in membrane integrity, the insulating properties of membranes decrease, and intracellular and extracellular electrolytes mix, thus driving changes in their electrical properties. We report a method combining the Fricke and Cole-Cole models that was developed to monitor and explain tissues conductivity changes in preferential directions during beef meat ageing.
Twenty-nine crossbred boars were used to evaluate the effects of live weight and processing on the sensory attributes and concentrations of androstenedione and androstenone (boar taint) in boar meat. Boars were stratified by litter across six weight group endpoints (90.9, 95.5, 100.0, 104.5, 109.1, and 113.6kg). Back fat and longissimus muscle from the lumbar region were used for androstenone determination, proximate analysis and sensory evaluation. Hams were cured for sensory analysis and were used to determine androstenone concentrations. Androstenone as an off-flavor did not differ (P>0.05) among treatments for longissimus lean or cured hams and was found to be in the "threshold" to "none detected" range. Back fat androstenone concentration was positively correlated (P<0.05) to hot carcass weight, however, lean androstenone concentration was not (P>0.05). No relationship was found (P>0.05) between androstenone concentration and days on feed, average daily gain or androstenedione concentration. Additionally, further processing decreased androstenone concentration by approximately 29%.
Androstenone (5α-androst-16-en-3-one) is a volatile steroid which is synthesized in boar testes and stored in high amounts in fat thus leading to an urine-like odor in pork. Whereas microtiter assays (MTA) exist for fat determination, measurement in blood with MTA was not yet possible. The system reported here is based on a specific antiserum and a horse radish peroxidase conjugate as tracer. For coating bovine serum albumin was avoided which otherwise would lead to unspecific binding. Blood plasma was extracted with n-hexane, solvent was evaporated in a vacuum centrifuge and the extract was taken up in buffer with 10% methanol. Assay sensitivity was 2.5pg/well (0.025ng/mL), specificity was confirmed by GC-MS (r=0.96; n=50) and inter- and intraassay variation were 4.9% and 5.9%, respectively. Thus an assay system is available for studies in pig production and in wildlife research due to pheromone activity also in other species.
Twelve (Large White×Landrace) gilts were randomly allotted in a 2×2 factorial design with the respective factor being dietary vitamin E (10 or 200 mg/kg feed) and dietary fishmeal (0 or 5%). Bacon was manufactured from the meat obtained from the animals after slaughter using wood smoke only or a combination of liquid and wood smoke. The oxidative stability of the bacon was examined over 16 weeks of frozen storage. Lipid oxidation in the product was measured by means of thiobarbituric acid reactive substances (TBARS) and fluorescence shift. Dietary fishmeal supplementation increased lipid oxidation in bacon, while dietary vitamin E supplementation reduced lipid oxidation in the product. Lipid oxidation in frozen bacon was successfully reduced when bacon was manufactured from pigs fed a diet supplemented with or without 200 mg of α-tocopherol per kilogram of feed and processed with a combination of liquid and wood smoke. It is concluded that bacon processed with a combination of liquid and wood smoke was significantly less (P<0.001) susceptible to lipid oxidation than bacon processed with wood smoke only.