The effects of method of castration,rearing condition and diet on sensory quality of pork assessed by a trained panel

Beside surgical castration possible alternatives helping to reduce the incidence of boar taint in cooked pork are rearing conditions, immunocastration and feeding strategies for entire males known to lower the skatole levels. The goal of this study was to assess the effects of these alternatives on the sensory acceptability of pork. In experiment 1, carcasses from barrows, entire males (EM) and entire males fed raw potato starch (EM+) 7 d before slaughter were selected based on the androstenone (≤ 2 µg/g) and skatole (≤ 0.32 µg/g) levels. In experiment 2, carcasses from barrows, immunocastrates (IC), entire males either group-penned (EMG) or individually penned (EMP) were selected based on the aforementioned criteria. Boar odour and boar flavour intensities of longissimus dorsi (LD) and neck chops were evaluated by trained panellists. Boar odour and flavour scores were higher (P < 0.01) in neck than LD chops. Although skatole tissue levels in barrows and EM+ were similar (P > 0.05), boar odour and flavour scores were greater (P < 0.05) in EM+ than barrows. In experiment 2, scores for boar odour and flavour were lower (P < 0.05) in pork from barrows and IC than EMP, with intermediate values for EMG. In conclusion, we observed a discrepancy between the known boar taint compounds androstenone and skatole and sensory acceptability, which indicates that other factors influenced the perception of boar taint. Thus, surgical castration with or without anesthesia or immunocastration are still the safest methods to avoid boar taint.     

Consumer acceptance of fermented sausages made from boars is not distracted by respective information

This study investigated the impact of two information conditions and two androstenone concentrations on the acceptability of fermented sausages made from boar meat. Two batches of salamis were produced by mixing bellies and lean meat resulting in average androstenone levels of 0.408 μg/g vs. 1.585 μg/g melted fat, respectively. Skatole levels were kept below 0.05 μg/g melted fat in the final products. The consumers were provided with either the information that the products consisted of 100% pork or 100% boar meat. In total, 478 visitors of an animal husbandry fair, assumed to be familiar with the consequences of not castrating male piglets, evaluated the salami following a monadic between-subject design. The information did not significantly affect the hedonic scores. The percentage of dislikes was very low, i.e. 3 vs. 6% (p = 0.24) for salami LOW and HIGH, respectively. The batch with lower androstenone content was liked slightly but significantly better (p = 0.03).     

Effect of dietary chicory on boar taint

Following preliminary screening and feeding trials on farms supplying a commercial abattoir, 360 entire male pigs were used to evaluate the effects of different percentages of chicory (Cichorium intybus L.) on levels of boar taint compounds and sensory aspects in backfat. Pigs were fed 0, 3, 6 or 9% chicory in the diet, 30 pigs being sampled at 3 different times: initially to measure basal levels of skatole and androstenone and after 1 and 2 weeks on the test diets. Cooked samples of backfat were presented to a trained sensory panel for "sniff" tests. Chicory fed at 9% for 2 weeks reduced skatole levels significantly (P<0.001), with 0.55 of pigs below 0.05 μg/g, typical of levels in castrated males. Abnormal odour scores were significantly lower for pigs in this group compared with 0% pigs (P<0.001), however, androstenone concentration was significantly higher in this group after the 2 week feeding period (P<0.005). Thus, feeding 9% chicory for 2 weeks was effective in reducing backfat skatole concentrations and abnormal odour scores of cooked fat but not androstenone concentration.     

Use of serial ultrasound measures in the study of growth- and breed-related changes of ultrasonic measurements and relationship with carcass measurements in lean cattle breeds

The growth and breed-related changes of rib and rump characteristics in lean beef cattle and the ability of ultrasound to predict carcass traits were investigated. Three hundred bulls from three breeds were scanned monthly (6–7 times) using real-time ultrasound with final scans taken < 7 days prior to harvest. The rib and rump ultrasound measurements, except intramuscular fat content, increased (P < 0.05) with live weight. Breed affected most of traits. The 12th rib ultrasound measurements showed a weak to high positive correlation (0.131 to 0.976, P > 0.05 to P < 0.001) with 12th rib measurements in the carcass. Regression equations developed with the ultrasound measurements, explained 97% of the variation in longissimus muscle area, 88% of the variation in fat thickness and 57% of the variation in intramuscular fat content. When last ultrasound scan measurements were excluded from prediction equations, the R² significantly decreased. Ultrasound measures “in vivo” are viable options for assessing carcass attributes of lean cattle.     

Development of a method to manufacture uncured,no-nitrate/nitrite-added whole muscle jerky

“Natural curing” is accomplished by use of vegetable juice/powder high in naturally occurring nitrates combined with a nitrate reducing starter culture to result in indirectly “cured” products. Since the starter culture used is not water soluble, making “naturally cured” whole muscle jerky with current manufacturing techniques has been found ineffective. The objective was to investigate processes for whole muscle beef jerky that might provide cured meat characteristics similar to those of a nitrite-added control. Treatments where jerky was placed in a barrier bag during incubation were found to be the least similar to the nitrite-added control. Jerky placed in a 40.6 °C smokehouse during incubation resulted in significantly more (P < 0.05) converted cured pigment than the barrier bag treatments but less (P < 0.05) than the control. The processing methods investigated to manufacture “naturally cured” whole muscle jerky in this study were ineffective in resulting in products similar to those cured with sodium nitrite.     

Sensory characterization of meat from pigs vaccinated against gonadotropin releasing factor compared to meat from surgically castrated,entire male and female pigs

Boar taint is a sensory defect mainly due to androstenone and skatole. The most common method to control boar taint is surgical castration at an early age. Vaccination against gonadotropin releasing factor (also known as immunocastration) is an alternative to surgical castration to reduce androstenone content. In this experiment, loins from 24 female (FE), 24 entire male (EM), 24 vaccinated males (IM) and 23 surgically castrated males (CM) were evaluated by eight trained panellists in 24 sessions. Loins were cooked in an oven at 180 °C for 10 min. Furthermore loins were evaluated by consumers and its androstenone and skatole content were also chemically determined. Meat from EM had higher androstenone and skatole odour and flavour than meat from FE, IM and CM and lower sweetness odour scores. High correlations were found between androstenone and skatole levels assessed by trained panelists, chemical analysis and consumers’ acceptability. Moreover meat from EM is mainly related to androstenone and skatole attributes.     

Effect of low voltage electrical stimulation on protein and quality changes in bovine muscles during postmortem aging

This experiment was conducted to determine the influence of low voltage electrical stimulation (ES) on the tenderness development of beef round muscles. Eight steers were slaughtered, and ES applied to one side of each carcass within 90 min of exsanguination. Steaks from M. longissimus dorsi, semimembranosus, adductor, and gracilis were vacuum packaged and aged at 4 °C for 9 d. Star probe, sensory evaluation, Western blot assays of troponin-T and μ-calpain autolysis and 2D-DIGE were conducted. ES resulted in accelerated (P < 0.05) pH decline of the longissimus in the first 24 h postmortem. ES did not influence (P > 0.05) proteolysis and tenderness, but did alter the predominance of metabolic proteins in the soluble fraction of muscle. Aging for 9 d improved tenderness (P < 0.05). The data confirmed that low voltage ES at 90 min of exsanguination had no effect on proteolysis and tenderness development in the longissimus dorsi, semimembranosus, adductor or gracilis in beef.     

Effects of phosphine and methyl bromide fumigation on the volatile flavor profile and sensory quality of dry cured ham

In separate experiments, randomized complete block designs with three replications were utilized to evaluate the effects of phosphine (PH₃) (0, 200 and 1000 ppm for 48 h) and methyl bromide (MB) (0, 4, 8, 16, and 32 mg/L for 48 h) fumigation concentration on the volatile flavor compound concentrations in dry cured ham. Minimal differences existed (P > 0.05) in the presence and concentration of aroma active compounds in both PH₃ and MB fumigated hams but sulfur and oxidation compounds were more prevalent (P < 0.05) in the fumigated treatments when compared to the control. As phosphine fumigation concentration increased, the residual concentration of phosphine also increased in the hams (P < 0.05), but all samples contained levels that are lower than the legal limit of phosphine allowed in stored food products (0.01 ppm) in the United States. A triangle test (n = 56) indicated that consumers could not discriminate (P > 0.75) between the control hams and those that were fumigated with PH₃. Minimal aroma/flavor differences existed among MB, PH3 and control hams, and dry cured ham that was fumigated with PH₃ was safe for consumption based on residual phosphine concentrations in the meat tissue.     

Absence of an effect of dietary fibre or clinoptilolite on boar taint in entire male pigs fed practical diets

This study aimed to evaluate the possibility of reducing boar taint in boars (Piétrain × Hybrid) by addition of different feed ingredients (raw potato starch (RPS) 10%, raw potato starch 10% + wheat bran 5% (RPS + WB), lupins 10%, inulin 5%, clinoptilolite 1%) to a standard diet over a period of 4–6 weeks before slaughter. Control boars (CBOAR) as well as barrows were fed the standard diet. Efficacy of the different feed ingredients was evaluated by different boar taint detection methods: hot iron method, consumer panel, expert panel and laboratory analysis. According to all detection methods, clear differences were noticeable between boars and barrows. No differences in boar taint incidence were found between the boars on the different dietary treatments as assessed by consumers, experts, hot iron method or the concentration of skatole in fat. A significant effect on indole level was found, but no further differentiation could be made. The concentration of backfat androstenone was significantly higher for the inulin and control boar group compared to the lupin group.     

Interrelationship between measures of collagen,compression, shear force and tenderness

This study examined the relationship between collagen content as determined by hydroxyproline assay with other measures of connective tissue, shear force and tenderness in lamb muscle. Samples were taken from both m. longissimus lumborum (LL, loin) and the m. semimembranosus (SM, topside) of 99 lambs. Sensory tenderness and compression of the LL were not correlated to any measure of collagen or connective tissue, with one exception where compression was correlated (r = − 0.28; P < 0.05) to the percentage of connective tissue determined by imaging. Intramuscular fat (IMF) was linearly correlated (P < 0.05) to sensory tenderness and compression, such that a 1% increase in IMF increased the tenderness score by 2.3 ± 0.83 units and reduced compression by 0.73 ± 0.21 N. There was no correlation between SM shear force and collagen concentration. The data suggest that measurement of collagen concentration did not explain the variation in shear force and sensory tenderness observed in the meat from lambs.     

Mitochondrial respiratory activity in porcine longissimus muscle fibers of different pig genetics in relation to their meat quality

The pig genetics of Duroc, Pietrain (MHS homozygote negative, PiNN), Pietrain (MHS homozygote positive, PiPP) and a F2-Duroc-Pietrain cross-breed were analyzed. The animals had comparable (P > 0.05) carcass weights, but the PiPP pigs had higher carcass yield and lean meat values (P < 0.05). Considering the meat quality characteristics, the PiPP showed a faster pH drop and higher electrical conductivity, drip loss, shear force as well as lightness and redness values (P < 0.05). The PiPP animals had less slow-twitch-oxidative (STO) and more fast-twitch-glycolytic (FTG) muscle fibers, whereas the results of the Duroc animals were converse (P < 0.05). The STO and FTG fibers of the PiPP animals were larger than those of the other genetics (P < 0.05). The analysis of the mitochondrial respiratory activity (MRA) using permeabilized longissimus muscle fibers resulted in no differences between the pig genetics before and immediately after slaughter. During chilling the MRA decreased in all pigs but to a higher extent in the PiPP pigs (P < 0.05).     

Quantitative determination of the boar taint compounds androstenone,skatole, indole, 3α-androstenol and 3β-androstenol in wild boars (Sus scrofa) reveals extremely low levels of the tryptophan-related degradation products

The major boar taint compounds androstenone and skatole as well as the minor compounds indole, 3α-androstenol and 3β-androstenol were determined in back fat samples of 23 male wild boars by applying a recently published SIDA–HS-SPME–GC/MS method. The boar pheromones androstenone, 3α-androstenol and 3β-androstenol were found in extraordinary high concentrations, resulting in mean values of 3329 ng/g androstenone, 1273 ng/g 3α-androstenol and 545 ng/g 3β-androstenol. Interestingly, skatole was not detectable in about 50% of the boars and negligibly low in all other samples as expressed by a mean skatole value of only 14 ng/g. Indole was also found in every sample, but again in low concentrations with a mean value of 40 ng/g. Possible factors explaining this remarkably low skatole deposition in wild boars such as intestinal flora and anatomy, dietary composition, housing or genetic predisposition are discussed in this paper.     

Physical and sensory characteristics of pork sausages from enzymatically modified blends of lard and rapeseed oil during storage

Physical and sensory characteristic of pork sausages produced from enzymatic interesterified blends of lard and rapeseed oil during storage were evaluated. All three enzymatic interesterified blends (IE90, IE70 and IE50) had ratios of unsaturated to saturated fatty acids within the range of 1.47–2.84 which is favourable for cardiovascular disease risk reduction. Blends of IE90 and IE70 were found to have suitable solid fat content, melting and crystallization profile suitable for sausages production. Sausages were produced from blends of IE90 and IE70 with different muscle types (musculus longissimus dorsi and musculus sternomandibularis) and processing conditions such as cooling rates and final processing temperature. Cooling rate was found to have no significant (P > 0.05) effect on hardness of the sausages throughout storage. Both musculus longissimus dorsi and high final processing temperature of 20 °C increased the hardness of the sausages during storage. In terms of fat particle size distribution, it was found that sausages IE70 had significantly (P < 0.05) lower amount of small fat particles (<4 μm) and higher amount of big fat particles (4–500 μm). This is in agreement with the findings on softer texture of sausages IE70. All the sausages produced from interesterified blends of lard and rapeseed oil had no apparent fat excretion and were rated as having acceptable sensory attributes as compared to reference sausage which was produced from pure lard.     

Eating quality of beef from biotypes included in the PGI “Ternera Asturiana” showing distinct physicochemical characteristics and tenderization pattern

Different biotypes of the Protected Geographical Indication (PGI) “Ternera Asturiana” were studied to determine if their differences in physicochemical characteristics and tenderization pattern during maturation (3 to 21 days) had an effect on the consumer evaluation of beef palatability. Biotype affected significantly pH, water holding capacity, chemical composition (P < 0.001) and meat lightness (P < 0.05). Ageing time affected significantly (P < 0.05) colour, meat toughness and sensory attributes in a different way within each biotype. Multivariate analysis showed two different meat groups: 1) meat from mh-genotypes, characterized by high juice losses, lightness (L*), protein content and high sensory acceptability at intermediate (7 and 14 days) ageing times; 2) meat from rustic (AM) breed and biotypes free of myostatin mutation (AV (+/+) and AV × AM), showing higher intramuscular fat, myoglobin content, and instrumental toughness and requiring longer storage times (21 days). This should be taken into account for the proper post-mortem management and commercialization of each product to achieve its best sensory quality.     

Consumer assessment of beef palatability from four beef muscles from USDA Choice and Select graded carcasses

Consumer sensory analysis was conducted to determine differences in beef palatability between two quality grade categories [Upper 2/3 (Top) Choice and Select] and four muscles [longissimus lumborum (LL), gluteus medius (GM), serratus ventralis (SV), and semimembranosus (SM)]. Generally, tenderness, flavor, and overall liking scores were more desirable for Top Choice compared to Select, regardless of muscle. Consumers rated LL as more tender (P < 0.05) than SV and SM, but similar to GM (P = 0.52). Overall and flavor acceptability were similar (P > 0.05) between LL, GM, and SV, regardless of quality grade. Consumer overall liking was most highly correlated with flavor liking (r = 0.85). When tenderness was acceptable, flavor and juiciness played a major role in determining overall acceptability. Overall liking of GM and SV from Top Choice carcasses was superior to LL from Select carcasses and comparable to LL from Top Choice carcasses.     

Fatty acid composition of certified organic,conventional and omega-3 eggs

The objective of this study was to compare the fatty acid composition of commercially available conventional, certified organic, and omega-3 eggs. Egg components were assessed, and the fatty acid composition of yolk lipids was determined by gas chromatography. Organic egg yolk contained a higher percentage of palmitic and stearic acids than did conventional yolk (P < 0.05) with no differences observed in the monounsaturated or polyunsaturated fatty acid compositions. Compared with organic and conventional eggs, omega-3 egg yolk contained lower percentages of myristic and palmitic acids, and higher omega-3 fatty acids. In a sub-analysis of conventional egg types, the percent of stearic acid in “cage” egg yolk was significantly lower (P < 0.05) than those of “barn-laid” and “free-range” eggs. “Cage” eggs had a significantly lower percentage (P < 0.05) of arachidonic acid than had “barn-laid” eggs. Consumption of omega-3 eggs has the potential to confer health benefits through the increase in intake of omega-3 fatty acids. With regard to organic or conventional methods of production, the small differences in saturated fatty acids observed in the present study are unlikely to have any significant metabolic effect on the consumer.     

Qualitative effects of fresh and dried plum ingredients on vacuum-packaged,sliced hams

Boneless ham muscles (Semimembranosus + Adductor) were injected (20% w/w) with a curing brine containing no plum ingredient (control), fresh plum juice concentrate (FP), dried plum juice concentrate (DP), or spray dried plum powder (PP) at 2.5% or 5%. Hams were cooked, vacuum-packaged, stored at <4 °C and evaluated at 2-week intervals over 10 week. Evaluations were performed on sliced product to determine cook loss, vacuum-package purge, Allo–Kramer shear force, 2-thiobarbituric acid-reactive substances (TBARS), proximate analysis, objective color, sensory panel color and sensory attributes. FP, DP and 2.5% PP increased (P < 0.05) cook loss by 2% to 7% depending on treatment and level, but the highest cook loss (17.7%) was observed in hams with 5% PP. Shear force values increased as the level of plum ingredient increased (P < 0.05) from 2.5% to 5%, and the highest shear values were observed in hams containing 5% FP. There were no differences (P > 0.05) in lipid oxidation among treatments as determined by TBARS and sensory evaluation. FP and PP ham color was similar to the control, but DP had a more intense atypical color of cured ham. Minimal changes in physical, chemical and sensory properties were observed during storage of all treatments.     

Use of image analysis of cross-sectional cuts to estimate the composition of the 10th–11th–12th rib-cut of European lean beef bulls

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 R² 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 (R² = 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.     

Effects of murta (Ugni molinae Turcz) extract on gas and water vapor permeability of carboxymethylcellulose-based edible films

The effect of murta (Ugni molinae Turcz) leaves extract on water vapor permeability (WVP) and gas permeability (GP) of carboxymethylcellulose (CMC)-based films was studied. Two ecotypes of murta leaves “Soloyo Grande” (SG) and “Soloyo Chico” (SC), were analyzed for their composition (HPLC-MS) and SC extract revealed a higher concentration of flavonols than the SG extract. The film forming solution was prepared with 2 g of CMC, 0.4 ml of glycerol and 0.5 ml of sunflower oil in 100 ml of water (Control), 50 ml of water and 50 ml of each exctract (SC50 or SG50) and 100 ml of each extract (SC 100 or SG 100). The addition of murta leaves extract modified the WVP and GP of the films. The WVP decreased significantly (P?0.05) with the incorporation of SG extract in the film but not with the SC extract (P>0.05). The CO₂ and O₂ permeability of the films were influenced by the kind and concentration of murta leaves extract used. The CO₂ permeability, with SG extract was higher than without extract (P?0.05) and with SC extract was not modified. The O₂ permeability with murta leaves extract were lower than without extract. Therefore, it is possible to consider that films with SC acts only as barrier to the oxygen, but with SG the water vapor and gas barrier properties were modified, being more permeable to the CO₂ and acting as barrier to O₂ and water vapor.