Consumers’ sensory acceptability of pork from immunocastrated male pigs

Boar taint is the off-odour or off flavour of cooked pork. Currently, the most common method of controlling boar taint is surgical castration. However, immunocastration has been used in some parts of the world as an alternative to surgical castration. The aim of this study was to evaluate the sensory acceptability of meat from immunocastrated pigs (IM) compared with meat from females (FE), surgically castrated (CM) and entire males (EM). Twenty animals of each type were evaluated by 201 consumers in 20 sessions. Longissimus thoracis muscle of the different animals was cooked in an oven at 180 °C for 10 min. Consumers scored the odour and the flavour of the meat in a 9-point category scale without an intermediate level. There were no significant differences in consumer’s evaluation of meat from IM, CM, and FE. In contrast, EM meat presented a higher percentage of dissatisfied scores and was significantly (P < 0.05) less accepted than meat from CM, IM and FE. Consumers’ acceptability of EM meat was always lower, independently of its androstenone levels. However meat with low levels of androstenone was more accepted that meat with medium or high levels of this substance. It can be concluded that immunocastration produced pork that was accepted by the consumers, and was indistinguishable from pork from CM or FE.     

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.     

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.     

Carcass and meat quality characteristics of immunocastrated male,surgically castrated male,entire male and female pigs

The aim of the study was to evaluate the effect of immunocastration on meat and carcass quality compared with meat from females, entire and surgically castrated males. One hundred and eighteen (Landrace × Duroc) × Pietrain crossbred pigs were assigned to four experimental groups: entire males (EM), females (FE), surgically castrated males (CM) and vaccinated males (IM). Pigs were reared in two pens per sex and slaughtered at an average of 180 days of age. Carcass and meat quality characteristics such as testis size and length, fat depth, lean content, proportion of the carcass represented by each joint, pH, colour and intramuscular fat were evaluated. There was a significant reduction in the size of these sexual organs in IM compared with EM. CM and IM were fatter than FE and EM in the loin area but, in the ham area, CM was the fattest and EM the leanest, while IM and FE were in between. Intramuscular fat of IM (2.1%) was no different from the other sexes evaluated, although it was higher in CM (2.5%) with respect to FE (1.7%) and EM (1.8%). There was no difference between the IM and other treatment groups in meat quality. Regarding ours results we can conclude that from the point of view of meat and carcass quality the immunocastration could be a good alternative to the surgical castration.     

Effect of vaccination against gonadotrophin-releasing factor on growth performance, carcass, meat and fat quality of male Duroc pigs for dry-cured ham production

The aim of this study was to compare production, carcass and meat quality parameters, boar taint compounds and fat composition of green and dry-cured hams, between immunocastrated (IM), surgically castrated (CM) and female (FE) Duroc purebred pigs (n=75, 138.7±8.27kg). Liveweight and fat and muscle thicknesses were measured and average daily gain was calculated during growth. Carcass, meat and fat quality parameters were measured. Immunocastrated grew faster than CM or FE after the second dose of vaccine. IM had the lowest dressing percentage but similar % of ham and carcass lean to FE and CM. The effect of the immunocastration on carcass fatness depended on the location, did not affect fat and meat quality and reduced skatole and androstenone levels. Both in green and dry-cured ham, immunocastration slightly altered FA composition. Thus, Duroc pigs vaccinated with Improvac are suitable for the production of high quality dry-cured ham.     

A comparative study of boar taint in cooked and dry-cured meat

A comparative study of boar taint in cooked and dry-cured pig meat products was performed. Forty-eight cooked loins and 48 dry-cured hams from entire males and castrates were studied. The samples were classified according to the androstenone (AN) and skatole (SK) fat content determined using HPLC. A trained sensory panel evaluated taste, aroma, boar odour, boar flavour, juiciness, tenderness and fatness in cooked and dry-cured samples. Threshold levels of AN and SK to separate (P<0.05) entire and castrate samples according to their boar odour and flavour were determined. The effects of castration and processing on the eating quality were studied. Finally, the relationships among boar taint and other sensory attributes in cooked and dry-cured meat were compared. Results from these studies show that the eating quality of processed meat was affected negatively by boar taint. Threshold values were higher in dry-cured ham (2 μg g(-1) AN and 0.12 SK) than cooked loin (0.5 AN and 0.1 SK). AN and SK had a synergistic effect on boar odour and flavour in both products. AN had a greater influence than SK on the aroma and taste, especially in cooked meat. Boar odour was perceived more intensely than boar flavour in both of the products studied. Castration favoured fatness and improved the aroma and taste of cooked and dry-cured meat. The loss of aroma and taste due to boar taint was more noticeable in cooking than drying and curing. In dry-cured meat boar taint was associated with less aroma, taste, juiciness and tenderness. However, in cooked meat, boar taint affected the aroma and taste more strongly, but was not related with juiciness and tenderness, probably because these attributes are influenced by cooking.     

Expected effects on carcass and pork quality when surgical castration is omitted — Results of a meta-analysis study

Alternatives to the common castration (C) practice of piglets are surgical castration under anaesthesia and rearing entire males (EM) or immunocastrates (IC). It is well established that boar taint hinders the breakthrough of these options. Less is known how avoiding surgical castration would affect carcass characteristics and pork quality. The objective of this meta-analysis was to estimate the impact of lack of castration on quality traits besides boar taint. The most marked effect of castration method and gender was found in lean meat and intramuscular fat percentage. Compared to EM, carcass leanness was estimated to be greater (P < 0.05) and intramuscular fat level lower (P < 0.05) than in C, IC and females. Regarding pork quality traits only the difference in shear force between IC and EM was of relevant magnitude. This meta-analysis revealed that the implementation of EM production should not be hindered by pork quality concerns.     

An international study on the importance of androstenone and skatole for boar taint: III. Consumer survey in seven European countries

There has long been debate over the relative importance for consumer acceptability of androstenone and skatole. The objective of this study was to investigate consumer reaction to pig meat of varying levels of androstenone and skatole in seven member states of the European Union. Over 4000 entire male pigs (and 233 gilts as a control) were produced in six European countries, and a sub-sample of 420 were selected to represent a range of androstenone and skatole levels. Loin samples from these pigs were distributed to the seven participating countries. Samples were prepared and cooked according to standardised procedures in each of the countries and presented to pork consumers. Each consumer rated samples from five pigs for liking of flavour and liking of odour. Although there were significant differences between country panels in their liking of meat from entire males generally, there was a greater degree of dislike as both androstenone and skatole increased. This reaction was stronger for skatole than androstenone and consumers reacted more negatively in terms of odour than flavour.     

Acceptability of entire male pork with various levels of androstenone and skatole by consumers according to their sensitivity to androstenone

Consumer acceptability of entire male pork at eating was assessed in three experiments. The 140 consumers involved in each experiment were classified as insensitive (INSENS) to the odor of pure androstenone or sensitive perceiving it as pleasant (SENS-PLEA) or unpleasant (SENS-UNPL). Entire male pork with very low skatole and androstenone levels (LS-LA) was as well accepted as gilt pork, whatever the consumer category. Entire male pork with elevated levels in both skatole and androstenone (HS-HA) was clearly differentiated from LS-LA pork by SENS-UNPL, but not by SENS-PLEA or INSENS consumers. Whatever the consumer category, entire male pork with elevated levels of androstenone and very low levels of skatole (LS-HA and LS-HHA) were not significantly differentiated from LS-LA pork. The results suggest that, in the conditions of the present experiment, androstenone and skatole totally explain boar taint at eating and that the acceptability threshold for androstenone, in the absence of skatole, is in the range of 2-3 μg/g liquid fat.     

Expected effects on carcass and pork quality when surgical castration is omitted - Results of a meta-analysis study

Alternatives to the common castration (C) practice of piglets are surgical castration under anaesthesia and rearing entire males (EM) or immunocastrates (IC). It is well established that boar taint hinders the breakthrough of these options. Less is known how avoiding surgical castration would affect carcass characteristics and pork quality. The objective of this meta-analysis was to estimate the impact of lack of castration on quality traits besides boar taint. The most marked effect of castration method and gender was found in lean meat and intramuscular fat percentage. Compared to EM, carcass leanness was estimated to be greater (P<0.05) and intramuscular fat level lower (P<0.05) than in C, IC and females. Regarding pork quality traits only the difference in shear force between IC and EM was of relevant magnitude. This meta-analysis revealed that the implementation of EM production should not be hindered by pork quality concerns.     

Threshold Detection of Boar Taint Chemicals Using Parasitic Wasps

Abstract: Surgical castration has been long used to prevent consumers from experiencing taint in meat from male pigs, which is a large problem in the pig husbandry industry. Due to obvious animal welfare issues, the EU now wants an alternative for castration, suggesting an urgent need for novel methods of boar taint detection. As boar taint is only a problem when taint chemicals exceed a well‐defined threshold, detection methods should be concentration‐specific. The wasp, Microplitis croceipes’ ability to learn and respond to particular concentrations of the boar taint compounds, skatole, androstenone, and indole was tested. Also tested was the wasps’ ability to discriminate between known concentrations of indole, skatole, and androstenone in real boar fat samples at room temperature. Wasps were trained using associative learning by providing food‐deprived wasps with sucrose–water in the presence of specific odor concentrations. Trained wasps’ responses were tested to a range of concentrations of 3 compounds. Wasps showed unidirectional generalization of learned concentration responses, whereby the direction of concentration generalization was shown to be chemical‐dependent. Through both positive (sucrose) and negative feeding experiences (water only) with varying compound concentrations, the wasps can also be conditioned to respond to concentrations exceeding a defined threshold, and they were successful in reporting low, medium, and high concentrations of indole, skatole, and androstenone in boar fat at room temperature. The need for threshold detection rather than simple detection of absence/presence applies to many food quality issues, including the detection of spoilage or pest damage in crops or stored foods. Practical Application: An inexpensive and reliable means of detecting boar tainted pork at slaughter to avoid tainted meat on the market and dissatisfied consumers.     

Acceptability of boar meat by consumers depending on their age, gender, culinary habits, and sensitivity and appreciation of androstenone odour

Sensitivity of the consumers to androstenone, evaluated as the degree of smell (strong/weak) perceived by smelling the pure compound, is important in determining their acceptability of pork with different levels of androstenone and skatole. However, 8% (3.3% women and 16.2% men) of highly sensitive consumers like this odour, and 12.7% (9.1% women and 15.9% men) of mildly sensitive/insensitive consumers dislike it. The effect of the appreciation (like/dislike) of the smell in the acceptability of pork samples has not been reported previously. The aim of this paper is to ascertain if this liking for androstenone odour affects pork acceptability as well as the gender, age, and culinary habits of the consumers. Consumers evaluated the flavour and odour of five cooked and reheated samples, and recorded their acceptability on a 7-step scale. Results showed that acceptability of pork increases when the frequency of cooking and eating fresh pork are higher. The acceptability also differed depending on the sensitivity of the consumer within each age group. Appreciability of androstenone odour discriminates more than sensitivity in consumers’ acceptance of pork.     

Marinating as a technology to shift sensory thresholds in ready-to-eat entire male pork meat

This study investigated the effect of marinades in improving the eating quality in ready-to-eat boar meat. Neck chops with fat content below 18.9%, skatole 1.1 ppm (range 0.03–1.1) and androstenone 5.6 ppm (range 0.01–5.6) were used. In a screening experiment different marinades were tested for their ability to mask boar taint (defined as manure and urine odour and flavour). Liquid smoke and oregano extracts appeared to have the best potential for masking, and were studied in detail. Results from the study indicated that marinated chops with skatole content of approximately 0.4 ppm appeared similar to castrates in boar taint. Chops with skatole contents above 0.7 ppm remained unmasked despite the use of strongly flavoured marinades. Unmarinated chops served at 60 °C were more tainted than those served at 15 °C, but scored lower for boar taint when reheated, although the concentrations of androstenone and skatole remained the same. The fat content of the chops was not well correlated to the perception of boar taint. The attributes manure and urine were correlated with the level of skatole, but urine attribute was not a good indicator of the androstenone level.     

An international study on the importance of androstenone and skatole for boar taint: IV. Simulation studies on consumer dissatisfaction with entire male pork and the effect of sorting carcasses on the slaughter line, main conclusions and recommendations

An international study has been conducted in order to determine the respective contributions of androstenone and skatole to boar taint and their possible variations according to production systems and consumer populations. The presentation of the study and the main results concerning skatole and androstenone levels and data from sensory evaluation or consumer surveys are reported in companion papers. The present paper summarises the main conclusions of the study and gives tentative recommendations. A simulation study was conducted, based on the skatole and androstenone levels currently observed in European populations of entire male pigs and on the results of the consumer surveys. The first part of the simulation study demonstrated that, overall, 6.5% (odour) and 3.0% (flavour) more consumers were dissatisfied with entire male than with gilt pork. The differences were, however, very variable according to countries. Consumer dissatisfaction for the odour of entire male pork was mostly associated with high skatole levels, while androstenone had little influence on it. On the other hand, androstenone and skatole had similar contributions to the level of dissatisfaction for flavour. From the present study it is not possible to determine clear cut-off levels for androstenone/skatole. The regression equations presented in [Matthews, K. R., Homer, D. B., Punter, P., Béague, M. P., Gispert, M., Siret, F., Leask, H., Fonti i Furnols, M., & Bonneau, M. (2000). An international study on the importance of androstenone, skatole for boar taint: III. Consumer survey in seven European countries. Meat Science, 54, 271-283] provide a basis for decision making. However, due to methodological limitations, the results may underestimate consumer reaction to entire male pork. The second part of the simulation study demonstrated that sorting carcasses on the basis of androstenone/skatole would reduce, but not eliminate, differences in consumer dissatisfaction between entire male and gilt pork. For odour, taking androstenone into account did not improve the efficiency obtained from sorting using skatole only. For flavour, sorting using both compounds was more efficient than sorting using skatole only. Sorting out 15% of the entire males, on the basis of skatole only, would result in a difference in the proportion of dissatisfied consumers of 4.2% (odour) or 2.0% (flavour) between entire male and gilt pork. The results of the last part of the simulation study demonstrated that decreasing skatole in entire male pig populations, to levels as low as 0.10 ppm, would still result in a difference in the proportion of dissatisfied consumers of 3.2% (odour) or 1.6% (flavour). To reduce this difference further, the levels of both compounds would have to be reduced still further. The lowest difference that can be achieved is 2.3% (odour) or 0.4% (flavour). The conclusions of the present study may differ according to whether immediate commercial applications or long-term goals are considered. On the basis of the skatole and androstenone levels currently observed in entire male pig populations, sorting out procedures based on skatole is the easiest way to rapidly achieve a significant decrease in consumer dissatisfaction with entire male pork. In most countries, however, this will not be sufficient to obtain the same level of acceptability as with gilts. In the long term, a sharp reduction in both skatole and androstenone would have to be achieved in entire male pig populations to obtain low differences in acceptability between entire male and gilt pork.     

Influence of differences in sensitivity of Spanish and German consumers to perceive androstenone on the acceptance of boar meat differing in skatole and androstenone concentrations

The reactions of German (n=472) and Spanish (n=480) consumers of the European boar taint study to boar meat were evaluated according to their androstenone sensitivity. Consumers were checked with pure substance for their androstenone sensitivity. Eighteen per cent of the German and 31% of the Spanish participants were highly sensitive to androstenone, with a significantly higher proportion of women. For insensitive/mildly sensitive consumers, skatole level was the main determinant for the rating of flavour and odour of pork. For highly sensitive consumers, androstenone significantly influenced the rating of odour (Spain and Germany) and flavour (Germany) and is the predominant problem for that group, due to the high percentage of carcasses with high androstenone levels.     

Consumer studies on sensory acceptability of boar taint: A review

Boar taint can be found in meat from boars and affects consumer acceptability of pork. The aim of this review is: (1) to describe different aspects of the existing methodologies used in consumer studies when evaluating boar taint from a sensory point of view, (2) to draw conclusions on different studies regarding the acceptability of meat from entire males, and (3) to discuss a possible harmonization of the different aspects to be considered when performing consumer studies on boar taint. This paper focuses on different aspects of studies previously carried out such as the country of assessment, the location of the test, the cooking procedure, the type of meat samples evaluated, the attributes and scales used, consumer profile, the results obtained, and the effect of androstenone sensitivity of the consumers on boar meat acceptability. A discussion on the possibility of a harmonization of the different aspects is also performed and final remarks and considerations have been drawn.     

Consumer studies on sensory acceptability of boar taint: A review

Boar taint can be found in meat from boars and affects consumer acceptability of pork. The aim of this review is: (1) to describe different aspects of the existing methodologies used in consumer studies when evaluating boar taint from a sensory point of view, (2) to draw conclusions on different studies regarding the acceptability of meat from entire males, and (3) to discuss a possible harmonization of the different aspects to be considered when performing consumer studies on boar taint. This paper focuses on different aspects of studies previously carried out such as the country of assessment, the location of the test, the cooking procedure, the type of meat samples evaluated, the attributes and scales used, consumer profile, the results obtained, and the effect of androstenone sensitivity of the consumers on boar meat acceptability. A discussion on the possibility of a harmonization of the different aspects is also performed and final remarks and considerations have been drawn.     

Norwegian consumers' acceptability of boar tainted meat with different levels of androstenone or skatole as related to their androstenone sensitivity

The aim of work was to study Norwegian consumers' acceptance of pork meat with different levels of skatole and androstenone. One group of androstenone sensitive consumers (N = 46) and one group of non sensitive consumers (N = 55) participated in a home test and evaluated 11 samples with different skatole (range 0–0.35 ppm) and androstenone (range 0–9.0 ppm) levels. Liking of odour during frying and odour and flavour of the fried meat were evaluated. Results showed that the non sensitive consumers accepted all levels of androstenone in the samples. Sensitive consumers gave a significantly lower liking score for androstenone samples containing 3 ppm (and more) than the reference sample when evaluating these samples above the frying pan, but no significant difference were found between 3 ppm samples and reference samples when liking of fried meat was evaluated. This indicated that the sensitive consumers accepted 3 ppm in fried meat, but not if 3 ppm was present in the sample during the frying process. The same consumer's differentiated skatole samples with regard to flavour at 0.15 ppm. The Norwegian established practise with a threshold value of 0.21 ppm skatole is higher than the value accepted by the consumers.     

Marinating as a technology to shift sensory thresholds in ready-to-eat entire male pork meat

This study investigated the effect of marinades in improving the eating quality in ready-to-eat boar meat. Neck chops with fat content below 18.9%, skatole ⩽1.1 ppm (range 0.03–1.1) and androstenone ⩽5.6 ppm (range 0.01–5.6) were used. In a screening experiment different marinades were tested for their ability to mask boar taint (defined as manure and urine odour and flavour). Liquid smoke and oregano extracts appeared to have the best potential for masking, and were studied in detail. Results from the study indicated that marinated chops with skatole content of approximately 0.4 ppm appeared similar to castrates in boar taint. Chops with skatole contents above 0.7 ppm remained unmasked despite the use of strongly flavoured marinades. Unmarinated chops served at 60 °C were more tainted than those served at 15 °C, but scored lower for boar taint when reheated, although the concentrations of androstenone and skatole remained the same. The fat content of the chops was not well correlated to the perception of boar taint. The attributes manure and urine were correlated with the level of skatole, but urine attribute was not a good indicator of the androstenone level.