RESUMO
This study was commissioned to assess if there are regional differences in the acceptability of beef between consumers from Northern Ireland (NI), Republic of Ireland (ROI) and Great Britain (GB). Palatability traits were affected by socioeconomic and behavioural factors such as preferred cooking endpoint, animal welfare, value, health aspects of beef product, ease of preparation as well as consumption frequency for specific cuts. "Willingness to pay" (WTP) was influenced by income, preferred cooking endpoint, value of beef product, ease of preparation and consumption frequency for frying steak. Results showed that GB consumers scored higher for the same striploin steak compared to NI and ROI consumers. This may be due to differences in the motivation for beef choice and/or consumption habits. GB consumers were less concerned about the healthiness of beef product and beef origin. In addition, a higher consumption frequency for rump was reported in GB, which may explain the higher sensory scores observed among GB consumers for striploins.
Assuntos
Comportamento de Escolha , Comportamento do Consumidor , Carne Vermelha/economia , Carne Vermelha/normas , Animais , Bovinos , Culinária/métodos , Feminino , Humanos , Masculino , Irlanda do Norte , Fatores Socioeconômicos , Paladar , Reino UnidoRESUMO
This paper reviews recent research into predicting the eating qualities of beef. A range of instrumental and grading approaches have been discussed, highlighting implications for the European beef industry. Studies incorporating a number of instrumental and spectroscopic techniques illustrate the potential for online systems to non-destructively measure muscle pH, colour, fat and moisture content of beef with R 2 (coefficient of determination) values >0.90. Direct predictions of eating quality (tenderness, flavour, juiciness) and fatty acid content using these methods are also discussed though success is greatly variable. R 2 values for instrumental measures of tenderness have been quoted as high as 0.85 though R 2 values for sensory tenderness values can be as low as 0.01. Discriminant analysis models can improve prediction of variables such as pH and shear force, correctly classifying beef samples into categorical groups with >90% accuracy. Prediction of beef flavour continues to challenge researchers and the industry alike, with R 2 values rarely quoted above 0.50, regardless of instrumental or statistical analysis used. Beef grading systems such as EUROP and United States Department of Agriculture systems provide carcase classification and some indication of yield. Other systems attempt to classify the whole carcase according to expected eating quality. These are being supplemented by schemes such as Meat Standards Australia (MSA), based on consumer satisfaction for individual cuts. In Australia, MSA has grown steadily since its inception generating a 10% premium for the beef industry in 2015-16 of $187 million. There is evidence that European consumers would respond to an eating quality guarantee provided it is simple and independently controlled. A European beef quality assurance system might encompass environmental and nutritional measures as well as eating quality and would need to be profitable, simple, effective and sufficiently flexible to allow companies to develop their own brands.
Assuntos
Bovinos/fisiologia , Comportamento do Consumidor , Suplementos Nutricionais , Carne Vermelha/normas , Animais , Cor , Análise Discriminante , Ingestão de Alimentos , Europa (Continente) , Ácidos Graxos/análise , Músculos , PaladarRESUMO
The Meat Standards Australia (MSA) grading scheme has the ability to predict beef eating quality for each 'cut×cooking method combination' from animal and carcass traits such as sex, age, breed, marbling, hot carcass weight and fatness, ageing time, etc. Following MSA testing protocols, a total of 22 different muscles, cooked by four different cooking methods and to three different degrees of doneness, were tasted by over 19 000 consumers from Northern Ireland, Poland, Ireland, France and Australia. Consumers scored the sensory characteristics (tenderness, flavor liking, juiciness and overall liking) and then allocated samples to one of four quality grades: unsatisfactory, good-every-day, better-than-every-day and premium. We observed that 26% of the beef was unsatisfactory. As previously reported, 68% of samples were allocated to the correct quality grades using the MSA grading scheme. Furthermore, only 7% of the beef unsatisfactory to consumers was misclassified as acceptable. Overall, we concluded that an MSA-like grading scheme could be used to predict beef eating quality and hence underpin commercial brands or labels in a number of European countries, and possibly the whole of Europe. In addition, such an eating quality guarantee system may allow the implementation of an MSA genetic index to improve eating quality through genetics as well as through management. Finally, such an eating quality guarantee system is likely to generate economic benefits to be shared along the beef supply chain from farmers to retailors, as consumers are willing to pay more for a better quality product.
Assuntos
Bovinos/fisiologia , Comportamento do Consumidor , Carne Vermelha/normas , Animais , Austrália , Cruzamento , Culinária , Ingestão de Alimentos , Europa (Continente) , Músculos , Fenótipo , PaladarRESUMO
The beef industry must become more responsive to the changing market place and consumer demands. An essential part of this is quantifying a consumer's perception of the eating quality of beef and their willingness to pay for that quality, across a broad range of demographics. Over 19 000 consumers from Northern Ireland, Poland, Ireland and France each tasted seven beef samples and scored them for tenderness, juiciness, flavour liking and overall liking. These scores were weighted and combined to create a fifth score, termed the Meat Quality 4 score (MQ4) (0.3×tenderness, 0.1×juiciness, 0.3×flavour liking and 0.3×overall liking). They also allocated the beef samples into one of four quality grades that best described the sample; unsatisfactory, good-every-day, better-than-every-day or premium. After the completion of the tasting panel, consumers were then asked to detail, in their own currency, their willingness to pay for these four categories which was subsequently converted to a proportion relative to the good-every-day category (P-WTP). Consumers also answered a short demographic questionnaire. The four sensory scores, the MQ4 score and the P-WTP were analysed separately, as dependant variables in linear mixed effects models. The answers from the demographic questionnaire were included in the model as fixed effects. Overall, there were only small differences in consumer scores and P-WTP between demographic groups. Consumers who preferred their beef cooked medium or well-done scored beef higher, except in Poland, where the opposite trend was found. This may be because Polish consumers were more likely to prefer their beef cooked well-done, but samples were cooked medium for this group. There was a small positive relationship with the importance of beef in the diet, increasing sensory scores by about 4% in Poland and Northern Ireland. Men also scored beef about 2% higher than women for most sensory scores in most countries. In most countries, consumers were willing to pay between 150 and 200% more for premium beef, and there was a 50% penalty in value for unsatisfactory beef. After quality grade, by far the greatest influence on P-WTP was country of origin. Consumer age also had a small negative relationship with P-WTP. The results indicate that a single quality score could reliably describe the eating quality experienced by all consumers. In addition, if reliable quality information is delivered to consumers they will pay more for better quality beef, which would add value to the beef industry and encourage improvements in quality.
Assuntos
Bovinos/fisiologia , Comportamento do Consumidor/estatística & dados numéricos , Culinária/métodos , Carne Vermelha/normas , Adolescente , Adulto , Animais , Austrália , Demografia , Feminino , França , Humanos , Irlanda , Masculino , Pessoa de Meia-Idade , Polônia , Inquéritos e Questionários , Paladar , Adulto JovemRESUMO
Quantifying consumer responses to beef across a broad range of demographics, nationalities and cooking methods is vitally important for any system evaluating beef eating quality. On the basis of previous work, it was expected that consumer scores would be highly accurate in determining quality grades for beef, thereby providing evidence that such a technique could be used to form the basis of and eating quality grading system for beef. Following the Australian MSA (Meat Standards Australia) testing protocols, over 19 000 consumers from Northern Ireland, Poland, Ireland, France and Australia tasted cooked beef samples, then allocated them to a quality grade; unsatisfactory, good-every-day, better-than-every-day and premium. The consumers also scored beef samples for tenderness, juiciness, flavour-liking and overall-liking. The beef was sourced from all countries involved in the study and cooked by four different cooking methods and to three different degrees of doneness, with each experimental group in the study consisting of a single cooking doneness within a cooking method for each country. For each experimental group, and for the data set as a whole, a linear discriminant function was calculated, using the four sensory scores which were used to predict the quality grade. This process was repeated using two conglomerate scores which are derived from weighting and combining the consumer sensory scores for tenderness, juiciness, flavour-liking and overall-liking, the original meat quality 4 score (oMQ4) (0.4, 0.1, 0.2, 0.3) and current meat quality 4 score (cMQ4) (0.3, 0.1, 0.3, 0.3). From the results of these analyses, the optimal weightings of the sensory scores to generate an 'ideal meat quality 4 score (MQ4)' for each country were calculated, and the MQ4 values that reflected the boundaries between the four quality grades were determined. The oMQ4 weightings were far more accurate in categorising European meat samples than the cMQ4 weightings, highlighting that tenderness is more important than flavour to the consumer when determining quality. The accuracy of the discriminant analysis to predict the consumer scored quality grades was similar across all consumer groups, 68%, and similar to previously reported values. These results demonstrate that this technique, as used in the MSA system, could be used to predict consumer assessment of beef eating quality and therefore to underpin a commercial eating quality guarantee for all European consumers.
Assuntos
Bovinos/fisiologia , Comportamento do Consumidor/estatística & dados numéricos , Culinária/métodos , Qualidade dos Alimentos , Carne Vermelha/normas , Adulto , Animais , Austrália , Feminino , França , Humanos , Irlanda , Masculino , Pessoa de Meia-Idade , Polônia , Paladar , Adulto JovemRESUMO
European conformation and fat grades are a major factor determining carcass value throughout Europe. The relationships between these scores and sensory scores were investigated. A total of 3786 French, Polish and Irish consumers evaluated steaks, grilled to a medium doneness, according to protocols of the ���Meat Standards Australia��� system, from 18 muscles representing 455 local, commercial cattle from commercial abattoirs. A mixed linear effects model was used for the analysis. There was a negative relationship between juiciness and European conformation score. For the other sensory scores, a maximum of three muscles out of a possible 18 demonstrated negative effects of conformation score on sensory scores. There was a positive effect of European fat score on three individual muscles. However, this was accounted for by marbling score. Thus, while the European carcass classification system may indicate yield, it has no consistent relationship with sensory scores at a carcass level that is suitable for use in a commercial system. The industry should consider using an additional system related to eating quality to aid in the determination of the monetary value of carcasses, rewarding eating quality in addition to yield.
Assuntos
Ingestão de Alimentos , Gorduras/análise , Qualidade dos Alimentos , Carne Vermelha/normas , Matadouros , Animais , Austrália , Bovinos , Comportamento do Consumidor , Ingestão de Alimentos/psicologia , Feminino , França , Humanos , Irlanda , Masculino , Músculos/anatomia & histologia , Músculos/química , PolôniaRESUMO
Delivering beef of consistent quality to the consumer is vital for consumer satisfaction and will help to ensure demand and therefore profitability within the beef industry. In Australia, this is being tackled with Meat Standards Australia (MSA), which uses carcass traits and processing factors to deliver an individual eating quality guarantee to the consumer for 135 different 'cut by cooking methods' from each carcass. The carcass traits used in the MSA model, such as ossification score, carcass weight and marbling explain the majority of the differences between breeds and sexes. Therefore, it was expected that the model would predict with eating quality of bulls and dairy breeds with good accuracy. In total, 8128 muscle samples from 482 carcasses from France, Poland, Ireland and Northern Ireland were MSA graded at slaughter then evaluated for tenderness, juiciness, flavour liking and overall liking by untrained consumers, according to MSA protocols. The scores were weighted (0.3, 0.1, 0.3, 0.3) and combined to form a global eating quality (meat quality (MQ4)) score. The carcasses were grouped into one of the three breed categories: beef breeds, dairy breeds and crosses. The difference between the actual and the MSA-predicted MQ4 scores were analysed using a linear mixed effects model including fixed effects for carcass hang method, cook type, muscle type, sex, country, breed category and postmortem ageing period, and random terms for animal identification, consumer country and kill group. Bulls had lower MQ4 scores than steers and females and were predicted less accurately by the MSA model. Beef breeds had lower eating quality scores than dairy breeds and crosses for five out of the 16 muscles tested. Beef breeds were also over predicted in comparison with the cross and dairy breeds for six out of the 16 muscles tested. Therefore, even after accounting for differences in carcass traits, bulls still differ in eating quality when compared with females and steers. Breed also influenced eating quality beyond differences in carcass traits. However, in this case, it was only for certain muscles. This should be taken into account when estimating the eating quality of meat. In addition, the coefficients used by the Australian MSA model for some muscles, marbling score and ultimate pH do not exactly reflect the influence of these factors on eating quality in this data set, and if this system was to be applied to Europe then the coefficients for these muscles and covariates would need further investigation.
Assuntos
Bovinos/anatomia & histologia , Qualidade dos Alimentos , Carne Vermelha/análise , Carne Vermelha/normas , Caracteres Sexuais , Animais , Austrália , Cruzamento , Bovinos/classificação , Comportamento do Consumidor , Culinária , Feminino , França , Humanos , Irlanda , Masculino , Músculos/química , Fenótipo , Polônia , PaladarRESUMO
Ossification score and animal age are both used as proxies for maturity-related collagen crosslinking and consequently decreases in beef tenderness. Ossification score is strongly influenced by the hormonal status of the animal and may therefore better reflect physiological maturity and consequently eating quality. As part of a broader cross-European study, local consumers scored 18 different muscle types cooked in three ways from 482 carcasses with ages ranging from 590 to 6135 days and ossification scores ranging from 110 to 590. The data were studied across three different maturity ranges; the complete range of maturities, a lesser range and a more mature range. The lesser maturity group consisted of carcasses having either an ossification score of 200 or less or an age of 987 days or less with the remainder in the greater maturity group. The three different maturity ranges were analysed separately with a linear mixed effects model. Across all the data, and for the greater maturity group, animal age had a greater magnitude of effect on eating quality than ossification score. This is likely due to a loss of sensitivity in mature carcasses where ossification approached and even reached the maximum value. In contrast, age had no relationship with eating quality for the lesser maturity group, leaving ossification score as the more appropriate measure. Therefore ossification score is more appropriate for most commercial beef carcasses, however it is inadequate for carcasses with greater maturity such as cull cows. Both measures may therefore be required in models to predict eating quality over populations with a wide range in maturity.
Assuntos
Envelhecimento/fisiologia , Carne/normas , Animais , Composição Corporal/fisiologia , Bovinos/fisiologia , Colágeno , Feminino , Músculos , PaladarRESUMO
In this study, important eating quality attributes that influence consumer liking for grilled lamb loin have been identified using preference mapping techniques. The eating quality attributes identified as driving the consumer liking of lamb loin steaks were "tenderness", "sweet flavour", "meaty aftertaste", "roast lamb flavour" and "roast lamb aftertaste". In contrast, the texture attribute "rubbery" and the flavour attributes "bitter flavour" and "bitter aftertaste" had a negative influence on consumer perceptions. Associations were observed between eating quality and a number of instrumental and chemical measurements. Warner Bratzler Shear Force showed an association with "rubbery" texture and a negative association with "tenderness" and consumer liking scores. The compounds, glucose, glucose-6-phosphate, inosine, inosine monophosphate and adenosine monophosphate were associated with the attributes, "sweet flavour","meaty aftertaste", "roast lamb flavour", "roast lamb aftertaste" and with consumer scores for liking of lamb which is probably caused by the role some of these compounds play as precursors of flavour and as taste compounds.
Assuntos
Comportamento do Consumidor , Glucose-6-Fosfato/análise , Glucose/análise , Carne/análise , Purinas/análise , Estresse Mecânico , Paladar , Monofosfato de Adenosina/análise , Animais , Culinária/métodos , Humanos , Inosina/análise , Inosina Monofosfato/análise , Músculo Esquelético , Percepção , OvinosRESUMO
Proximate data, consumer palatability scores and volatile compounds were investigated for four beef muscles (Longissimus lumborum, Psoas major, Semimembranosus and Gluteus medius) and five USDA quality grades(Prime, Upper 2/3 Choice, Low Choice, Select, and Standard). Quality grade did not directly affect consumer scores or volatiles but interactions (P < 0.05) between muscle and grade were determined. Consumer scores and volatiles differed (P < 0.05) between muscles. Consumers scored Psoas major highest for tenderness, juiciness, flavor liking and overall liking, followed by Longissimus lumborum, Gluteus medius, and Semimembranosus (P < 0.05). Principal component analysis revealed clustering of compound classes, formed by related mechanisms. Volatile n-aldehydes were inversely related to percent fat. Increases in lipid oxidation compounds were associated with Gluteus medius and Semimembranosus, while greater quantities of sulfur-containing compounds were associated with Psoas major. Relationships between palatability scores and volatile compound classes suggest that differences in the pattern of volatile compounds may play a valuable role in explaining consumer liking.
Assuntos
Comportamento do Consumidor , Carne/análise , Músculo Esquelético/química , Paladar , Compostos Orgânicos Voláteis/análise , Aldeídos/análise , Animais , Bovinos , Comportamento de Escolha , Gorduras na Dieta/análise , Aromatizantes , Qualidade dos Alimentos , Humanos , Peroxidação de Lipídeos , Carne/classificação , Carne/normas , Compostos de Enxofre , Estados Unidos , United States Department of AgricultureRESUMO
The effect of fat content and carbohydrate fat-replacers on the release of volatile odor compounds from beefburger, salami, and frankfurter has been investigated. The reduction in fat content in any of the three meat products studied resulted in a tendency toward an increase in the quantities of volatiles released in the headspace. Tapioca starch and maltodextrin appear to delay the release of certain classes of compounds selectively; for instance, tapioca starch appears to slow the release of some Maillard products while maltodextrin has a similar effect on terpenes. In contrast, oat fiber decreases the release of most of the compounds analyzed. Thus, the addition of carbohydrate fat-replacers to low-fat meat products could assist the flavor qualities of low-fat meat products by slowing down the release of odor compounds.
Assuntos
Gorduras na Dieta , Produtos da Carne/análise , Odorantes , VolatilizaçãoRESUMO
More than 100 volatile compounds have been identified in the headspace of frankfurter sausages. Most abundant were the terpene hydrocarbons, monoterpene alcohols, phenyl propanoids, and phenols. Separate analyses of solutions of spices and smoke demonstrated that most of the terpenes were derived from the spices, whereas the phenols originated mostly from the smoke ingredients. Many of the compounds contributing to the overall odor of the frankfurters have been identified. Some odors, characteristic of the smokiness and spiciness of frankfurters, were caused by phenols and terpenes, whereas others were due to compounds derived from the meat fraction; these compounds included aldehydes, ketones, furanthiols, and alicyclic sulfur compounds.
Assuntos
Produtos da Carne/análise , Odorantes/análise , Paladar , Animais , Bovinos , Cromatografia Gasosa , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Suínos , VolatilizaçãoRESUMO
The effect of fat content on the release of volatile aroma compounds from frankfurters has been investigated. Although the release of most n-alkanals, alcohols, ketones, and furans was little affected by changes in the fat content of frankfurters, that of monoterpene hydrocarbons, sesquiterpene hydrocarbons, terpenes containing oxygen, cyclopentenones, phenyl propanoids, and phenols was greatly increased when the fat content was decreased. Some odors were also detected more frequently in the low-fat than in the full-fat sausages. These included smoky odors, due to phenols, spicy, synthetic, and floral odors due to terpenes, and meaty, roasted odors caused by sulfur-containing heterocyclic compounds. The release of aroma compounds from frankfurters appears to be closely related to the solvation of these compounds in the lipid phase.
Assuntos
Gorduras na Dieta/análise , Produtos da Carne/análise , Odorantes/análise , Paladar , Animais , Bovinos , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Suínos , VolatilizaçãoRESUMO
A series of human androgen receptor (hAR) agonists based on 4-alkyl-; 4,4-dialkyl-; and 3,4-dialkyl-1,2,3,4-tetrahydro-8-pyridono[5,6-g]quinoline was synthesized and evaluated in competitive receptor binding assays and an androgen receptor cotransfection assay in a mammalian cell background. A number of compounds in this series demonstrated activity equal to or better than dihydrotestosterone in both assays and represent a novel class of compounds for use in androgen replacement therapy.
Assuntos
Androgênios , Quinolonas/síntese química , Quinolonas/farmacologia , Animais , Células COS , Di-Hidrotestosterona/farmacologia , Humanos , Concentração Inibidora 50 , Cinética , Ligação ProteicaRESUMO
A new nonsteroidal antiandrogenic pharmacophore has been discovered using cell-based cotransfection assays with human androgen receptor (hAR). This series of AR antagonists is structurally characterized by a linear tricyclic 1,2-dihydropyridono[5,6-g]quinoline core. Analogues inhibit AR-mediated reporter gene expression and bind to AR as potently as or better than any known AR antagonists. Several analogues also showed excellent in vivo activity in classic rodent models of AR antagonism, inhibiting growth of rat ventral prostate and seminal vesicles, without accompanying increases in serum gonadotropin and testosterone levels, as is seen with other AR antagonists. Investigations of structure-activity relationships surrounding this pharmacophore resulted in molecules with complete specificity for AR, antagonist activity on an AR mutant commonly observed in prostate cancer patients, and improved in vivo efficacy. Molecules based on this series of compounds have the potential to provide unique and effective clinical opportunities for treatment of prostate cancer and other androgen-dependent diseases.
Assuntos
Antagonistas de Androgênios/síntese química , Di-Hidropiridinas/síntese química , Compostos Heterocíclicos/síntese química , Quinolinas/síntese química , Receptores Androgênicos/metabolismo , Antagonistas de Androgênios/química , Antagonistas de Androgênios/farmacologia , Antagonistas de Receptores de Andrógenos , Animais , Células COS , Linhagem Celular , Di-Hidropiridinas/química , Di-Hidropiridinas/farmacologia , Di-Hidrotestosterona/farmacologia , Gonadotropinas/sangue , Compostos Heterocíclicos/química , Compostos Heterocíclicos/farmacocinética , Humanos , Indicadores e Reagentes , Masculino , Estrutura Molecular , Orquiectomia , Próstata/efeitos dos fármacos , Próstata/crescimento & desenvolvimento , Quinolinas/química , Quinolinas/farmacocinética , Quinolinas/farmacologia , Ratos , Ratos Sprague-Dawley , Receptores de Progesterona/biossíntese , Receptores de Progesterona/metabolismo , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/metabolismo , Glândulas Seminais/efeitos dos fármacos , Glândulas Seminais/crescimento & desenvolvimento , Relação Estrutura-Atividade , Testosterona/sangue , TransfecçãoRESUMO
A series of 2(1H)-pyrrolidino[3,2-g]quinolinones was prepared and tested for the ability to modulate the transcriptional activity of the human androgen receptor (hAR). The parent compound, 4-(trifluoromethyl)-2(1H)-pyrrolidino[3,2-g]quinolinone, displayed moderate interaction with hAR, but more substituted analogues, particularly 6,7-disubstituted compounds, were potent hAR agonists in vitro.
Assuntos
Antagonistas de Androgênios/farmacologia , Pirrolidinas/farmacologia , Quinolinas/farmacologia , Quinolonas/farmacologia , Receptores Androgênicos/genética , Transcrição Gênica/efeitos dos fármacos , Antagonistas de Androgênios/síntese química , Antagonistas de Androgênios/química , Anilidas/química , Anilidas/farmacologia , Animais , Linhagem Celular , Desenho de Fármacos , Flutamida/química , Flutamida/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Estrutura Molecular , Nitrilas , Pirrolidinas/síntese química , Pirrolidinas/química , Quinolinas/síntese química , Quinolinas/química , Quinolonas/síntese química , Quinolonas/química , Proteínas Recombinantes/biossíntese , Relação Estrutura-Atividade , Compostos de Tosil , TransfecçãoRESUMO
A series of nonsteroidal human progesterone receptor (hPR) antagonists based on conformationally-restricted analogues of a 6-aryl-1,2-dihydro-2,2,4-trimethylquinoline pharmacophore were synthesized and evaluated for their ability to bind to the human progesterone receptor and inhibit progesterone-stimulated reporter gene expression in mammalian cells.
Assuntos
Quinolinas/química , Quinolinas/farmacologia , Receptores de Progesterona/antagonistas & inibidores , Humanos , Conformação Molecular , Relação Estrutura-AtividadeRESUMO
'Label Rouge' (LR) chickens are reputed to possess improved sensory characteristics compared with birds reared under intensive conditions. The effects on body weight, food utilisation, behaviour and carcass composition, of genotype (Ross I vs ISA '657'), diet (conventional UK broiler vs LR) and stocking density (17.0 birds m(-2),vs 4.25 birds m(-2)) were evaluated in a 2 × 2 × 2 experiment. ISA birds were grown to 83 days, and compared with Ross birds grown to 48 days; additionally ad libitum and control-fed Ross birds were grown to 83 days. Performance and behaviour parameters were assessed empirically. The effects on carcass composition were evaluated using standardised carcass dissection techniques and analysed by analysis of variance. ISA birds grown under LR conditions to 83 days had similar body weights to Ross birds grown under UK broiler conditions to 48 days, but LR birds consumed more food, and converted food into meat less efficiently. LR birds had no mortality, whilst UK broiler mortality was 11.3%. Under similar conditions, Ross birds had a faster body weight gain, a larger food intake, but more efficient food conversion ratio and higher incidence of mortality. Birds stocked 17.0 m(-2) had lower body weights, consumed less food and, when fed UK diets, converted food less efficiently than birds stocked 4.25 m(-2). Both genotypes had a faster growth rate on UK diets, similar food intakes, and, as a result, better food conversion than birds given LR diets. LR and UK broiler birds had similar carcass component weights, breast meat yields, and total meat yield, but LR birds had less meat on the frame, larger drumsticks and more meat on the wings. Under similar conditions, ISA birds had a larger percentage of wing and total bone, but a smaller percentage of breast meat and total meat yields. When Ross birds had controlled growth, total meat, bone and skin yields were similar to those of ISA birds. Birds stocked 4.25 m(-2) had more breast meat and larger frames than, but similar meat, bone and skin yields to, birds stocked 17.0 m(-2). Most carcass components were heavier in birds fed UK broiler diets, but, on a percentage basis, these birds had larger thighs, but smaller drumsticks.
RESUMO
French Label Rouge quality chickens are reputed to possess improved sensory characteristics compared with birds reared under intensive conditions. The effects of genotype, diet, stocking density and age on eating quality were evaluated in a 2 × 2 × 2 experiment. The results suggest that genotype, diet, age and, to a lesser extent, stocking density can influence eating quality. The most pronounced sensory differences between the two genotypes were in the appearance and texture of the cooked meat. In particular, scores for toughness were higher for breast meat from Ross than ISA birds, though the opposite effect was observed for the thigh meat. Diet and age also affected texture, with the breast meat from chickens on the Label Rouge diet, or from older birds, having lower scores for toughness. Effects on odour and flavour were generally small and subject to genotype × diet interactions. The odour and flavour intensity of breast meat increased with age, while the odour intensity of thigh meat was higher in birds reared at low stocking density.