Eating quality of lamp meat
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  • 1. Meat Science 60 (2002) 379–387 www.elsevier.com/locate/meatsci Eating quality of lamb meat: effects of breed, sex, degree of maturity and nutritional management G. Arsenos*, G. Banos, P. Fortomaris, N. Katsaounis, C. Stamataris, L. Tsaras, D. Zygoyiannis Department of Animal Husbandry, School of Veterinary Medicine, Aristotle University of Thessaloniki, 54006 Thessaloniki, Greece Received 28 January 2001; received in revised form 16 June 2001; accepted 16 June 2001Abstract The eating quality of lamb meat of three indigenous Greek dairy breeds of sheep, reared under different nutritional managementconditions, was assessed by Taste Panel Tests (TPT). Lean samples from the leg joints of 69 lamb carcasses of the Boutsko (B),Serres (S) and Karagouniko (K) breed were used. For the first TPT, 24 lambs (four males and four females of each breed) werereared in individual pens on a concentrate ration fed ad libitum. For the second TPT, 27 individual penned male lambs were fed onLucerne hay ad libitum and on three different levels of concentrate: High (H), Medium, (M) and Low (L). For the third TPT, 18male lambs were used; initially the groups were fed indoors for 63 days on three different levels of concentrate (H, M and L)together with ad libitum Lucerne hay, and subsequently finished on irrigated, sown pasture. For TPT 1, leg joints were obtainedfrom lambs that had been slaughtered at 30, 45, 60 or 90% of mature weight (PMW) for each breed. For TPT 2, lambs wereslaughtered at 23, 28 or 33 kg target slaughter live weights (TSLW), common for all breeds. For TPT 3, lambs were slaughtered at48 or 55% of PMW for each breed. Panellists assessed warm, roasted lean samples of leg joints and rated Flavour, Juiciness, Ten-derness and Overall Acceptability. In TPT 1, degree of maturity significantly affected Flavour, Tenderness and Overall Accept-ability whereas sex affected only Flavour. In TPT 2, breed and concentrate level significantly affected the quality characteristics, butconcentrate level had no significant effect in TPT 3. Effects associated with slaughter weight were significant for most characteristicsin all TPT, with decreasing acceptability for older/heavier lambs. Significant interactions were found between breed and the otherfactors in TPT 2 and TPT 3 for most quality characteristics. Results from these studies suggest changing traditional productionsystems may enhance the eating quality of lamb meat. # 2002 Elsevier Science Ltd. All rights reserved.Keywords: Lamb; Meat; Quality; Taste panel1. Introduction at low weight has led to considerable research effort over the past few years (Arsenos, 1997; Arsenos, Quality of lamb meat is of great interest to producers, Zygoyjannis, Kufidis, Katsaounis, & Stamataris, 2000;consumers and scientists. There were a large amount of Boutonnet, 1999; Dransfield et al., 2000; Rubino, Mor-studies carried out in the UK, Australia and New Zeal- and-Fehr, Renieri, Peraza, & Sarti, 1999; Sanudo,and several years ago (e.g. Cramer, Barton, Shorland, & Alfonso, Sanchez, Delfa, & Texeira, 2000; Sanudo,Czochanska, 1967; Kemp, Johnson, Stewart, Ely, & Fox, Sanchez, & Alfonso, 1998b; Wood, Enser, Fisher, Nute,1976; Park, Corbett, & Furnival, 1972; Purchas et al., Richardson, & Sheard, 1999; Zygoyiannis, Katsaounis,1986; Rhodes, 1971). The fact that the carcass and meat Stamataris, Arsenos, Tsaras, & Doney, 1999;qualities of lamb types produced across Member States Zygoyiannis, Kyriazakis, Stamataris, Friggens, & Kat-of the EU are diverse, and the dearth of information saounis, 1997). The theme is important on severalparticularly from the Mediterranean regions where counts. First, it is important for the future of sheepconsumers prefer meat from milk fed lambs slaughtered production. Sheep producers operate in a competitive market and their survival is threatened because sheep * Corresponding author. Tel.: +30-31-999988; fax: +30-31- meat is continually facing challenges to maintain/999892. increase its market share (Boutonet, 1999; Morand-Fehr E-mail address: arsenosg@vet.auth.gr (G. Arsenos). & Boyazoglu, 1999). Second, it relates to the emergence0309-1740/02/$ - see front matter # 2002 Elsevier Science Ltd. All rights reserved.PII: S0309-1740(01)00147-4
  • 2. 380 G. Arsenos et al. / Meat Science 60 (2002) 379–387of specific market needs and trends, implying a product 2.2. Joints and sample preparationmade in a specific area with specific characteristics. Ifsheep production is to remain competitive lamb should The experimental procedures regarding preparationmeet the demand of individual markets (Rubino et al., and presentation were identical for all samples used for1999; Sanudo, Santolaria, Maria, Osorio, & Sierra, TPT. All lambs were weighed at the start of each1996; Sanudo et al., 1998a,b). Further, markets require experiment and subsequently at 7-day intervals (everya constant volume of quality foods and, at the same Monday). Those found to be approaching pre-definedtime there is a great variation in the perception and live weights were then weighed daily until the nomi-definition of sheep meat quality amongst consumers (see nated live weight was reached. Lambs were thenreviews by Dransfield et al., 1999; Sanudo et al., 1998b; slaughtered on the same day. After slaughter, hot car-Wood et al., 1999). cass weight was determined and the carcasses were then The prevailing view is that quality is one of the major left at ambient temperature (around 12  C) for 6 h tofactors that determine the consumer’s acceptability and avoid cold-shortening. Subsequently, all carcasses werechoice amongst meat from different animal species placed in a refrigerator at +1  C and were kept at this(Homer, Cuthbertson, Homer, & McMenamin, 1997; temperature overnight. These carcasses were then sawnLucke, 1998; Wood et al., 1999). It has been further down at the middle line through the centre of the ver-suggested that detailed information could be helpful in tebral column. The left hand side (LHS) of each carcassdesigning feeding systems and adopt strategies that will was jointed into leg, chump, loin, best end, breast,guarantee good quality and hence assure the market- shoulder, middle neck and, neck joints, following aability of lamb meat. Examples include manipulating standard procedure (MLC, 1989). The leg joints werepost-weaning nutritional management and live weight at weighed (mean weights were 0.75–1.90 kg), sealed intoslaughter to avoid unwanted traits in lamb meat quality polyethylene bags under vacuum conditions and storedin traditional production systems (Arsenos, 1997; in a freezer (À25  C) until taste panel evaluation.Arsenos et al., 2000; Rubino et al., 1999; Sanudo et al., Before taste panel evaluation, all frozen joints were1998b; Wood, Enser, Fischer, Nute, Richardson, & allowed to thaw for 72 h at 3  C. After thawing, theSheard, 1998; Wood et al., 1999; Zygoyiannis et al., joints were weighed and sealed into cooking bags. All1999) and by addressing ecological concerns (i.e. joints were cooked at a maximum of 200  C in a fan-organic farming systems, Enser, Kurt, Chiles, Nute, & assisted electric oven, fitted with external temperatureWood, 1996; Gibon et al., 1999; Lucke, 1998; Matthes, controllers, until an internal temperature of 75  C wasHillmann, Demise, & Mohring, 1998). reached. Temperature was monitored by a probe, inser- This study was part of a project designed to assess the ted periodically into the centre of each joint. Cookingquality and marketability of sheep meat produced in the time of each sample was estimated to be 50 min per kgless favoured areas of the European Community plus 25 min. Following cooking, the cooking bag was(Arsenos et al., 2000; Zygoyiannis et al., 1997, 1999). removed and each joint was re-weighed, wrapped inThe objective of the study was to assess, in a series of aluminium foil and placed in a warming cabinet (55  C).Taste Panel Tests (TPT), the eating quality of lamb Thereafter, joints were removed from the warmingmeat of three indigenous Greek dairy breeds of sheep cabinet and treated similarly to chops in strict rotationreared under different nutritional management and to reflect the order that they were placed in the cabinet.slaughtered at different live weights using standard Lean cubes, 2Â2Â2 cm in size, subject to panel tastecommercial procedures. evaluation were cut from M. adductor (n=9), M. femoris (n=5) and M. semitendinosus (n=6). These muscles were trimmed of exterior fat and cut into cubes2. Materials and methods that were subsequently foil wrapped and kept warm prior to serving for taste panel evaluation.2.1. Source of carcasses 2.3. TPT 1 The study was carried out using lean samples from theleg joints of 69 lamb carcasses. They belonged to three The first Taste Panel Test (TPT 1) was performedindigenous dairy breeds of sheep, which are the most using lean samples from the leg joints of 24 lambs, 12representative breeds in Greece: the Boutsko breed male and 12 female, of each of the B, S and K breeds.(B), the Serres breed (S), and the Karagouniko breed They were reared on ad libitum fresh concentrate feed(K). For details on the growth and meat production (pellets) together with 100 g/day of unchopped Lucernepotential of these breeds see Zygogiannis et al. (1997). hay (Zygoyiannis et al., 1997). Lambs were slaughteredAll lambs were weaned at approximately 42 days of at four different live weights, corresponding to fourage and were then reared under different nutritional proportions of the estimated mature weight (PMW) ofmanagement. each breed, specifically at 30, 45, 60 and 90% of mature
  • 3. G. Arsenos et al. / Meat Science 60 (2002) 379–387 381weight (Zygoyiannis et al., 1997). Eating quality char- 2.6. Assessment of eating qualityacteristics of meat from these lambs was assessed in a totalof 480 lean samples from roasted leg joints representing Eating quality characteristics were assessed in a seriesall possible combinations of sex, PMW and breed. of TPT. The panellists involved in those tests were typical consumers (30 to 55 years old) of lamb meat and2.4. TPT 2 were selected on a voluntary basis. Ten panellists were involved in TPT 1 and 20 in TPT 2 and TPT 3, respec- The second Taste Panel Test (TPT 2) was performed tively. A common scoring system was used in all assess-using lean samples from the leg joints of totally 27 male ments. The eating quality was evaluated with an eight-lambs of the B, S and K breed. They were reared con- point descriptive scale (1–8) with larger scores indicatingcurrently, under the same conditions, with the lambs in a more favourable rating. Four attributes were rated:the experiment reported by Zygoyiannis et al. (1999). Flavour, Juiciness, Tenderness, and Overall Accept-The lambs were randomly allocated to three target ability, which summarised the previous three attributes.slaughter live weights (TSLW), specifically at 23, 28 and For example, Flavour was described as: 1=extremely33 kg, common to all breeds. The TSLWs were selected undesirable, 2=very undesirable, 3=moderately unde-to correspond with the carcass weights at which the B, S sirable, 4=slightly undesirable, 5=slightly desirable,and K lambs, respectively, were found to produce the 6=moderately desirable, 7=very desirable, 8=extre-most marketable carcasses (Zygogiannis et al., 1997). mely desirable. Similarly, Juiciness was assessed asAll lambs were offered ad libitum Lucerne hay and were 1=extremely dry to 8=extremely juicy, whereas Ten-further allocated to three feeding treatments (FT; one derness was assessed from 1=extremely tough tolamb per treatment). Concentrate allowances dis- 8=extremely Tender and Overall Acceptability wastinguished between these FT and were set at high (H), personally rated from 1=extremely undesirable tomedium (M) and low (L) levels (Zygoyiannis et al., 8=extremely desirable. Panellists were given instruc-1999). The lambs were slaughtered when they had tions for completing the score sheet and were alsoreached their respective TSLW. Eating quality char- trained in standard attribute assessment. In order toacteristics of meat from these lambs was assessed in a ensure that the panellists would not receive the samplestotal of 540 lean samples from the leg joint, representing in the same order we used the statistical designs descri-all possible combinations of TSLW, FT and breed. bed by Nute (1986). Hence, the order of sample pre- sentation in each session was balanced representing all2.5. TPT 3 factors studied. The samples were offered warm (approximately 30  C) at intervals of 10 min between The third Taste Panel Test (TPT 3) was performed consecutive sample assessments. Panellists were instruc-using lean samples from the leg joint of totally 18 male ted to eat a small piece (3Â3 cm) of unsalted whitelambs of the B, S and K breed. They were reared in two bread and to rinse their mouth with water between eachphases: an indoor and a grazing phase. During the sample assessment. This was considered necessary inindoor phase the lambs were randomly allocated to order to remove any traces of the previous sample fromthree FT common for each breed. The design of such their mouth. The panelling room was kept free of non-treatments was similar to that of lambs used for TPT 2 sample odours. Artificial lighting was used and thewith differences only accounting for the levels of con- temperature was kept constant (about 18  C). Eightcentrate allowances (Zygoyiannis et al., 1999). Within samples were served per session during TPT 1 and ninethe three feeding treatments, lambs of each breed were samples per session during TPT 2 and TPT 3. Each ses-assigned to reach two pre-defined live weights after sion was conducted on a daily basis. TPT1 and TPT 2turnout to the grazing phase, corresponding to 48 and were each completed in 3 days and TPT 3 in two.55% of the estimated mature weight of each breed. Theirrigated sown pasture, used in the grazing phase, con- 2.7. Statistical analysissisted of tetraploid ryegrass (Lolium perenne) and whiteclover (Trifolium repens) in a proportion of 10:1. Pas- All statistical analyses were performed using GEN-ture management was based on maintaining a relatively STAT version 5 (Lawes Agricultural trust, 1993). Dataconstant sward surface height (mean Æ S.D.: 6 Æ 2 cm) were analysed separately for each TPT by using anthroughout the grazing period either by changes in analysis of variance (ANOVA) model. The model usedgrazing area or by adding non-experimental lambs when for data analysis of each TPT accounted for possiblerequired. Lambs were to be slaughtered off pasture differences between the panellists (Horgan & Sward,when they reached their pre-defined live weight. Eating 1995). Random effects were also fitted for panellistsquality of meat from these lambs was assessed in a total within session. For eating quality characteristics ofof 360 samples representing all possible combinations of lambs assessed in TPT 1, the model included the effectsFT, PMW and breed. of breed, sex, PMW and all possible interactions. The
  • 4. 382 G. Arsenos et al. / Meat Science 60 (2002) 379–387model used for the analysis of TPT 2 data included the the other hand, there were several statistically significanteffects of breed, FT, TSLW and all possible interac- interactions between breed and FT and between breedtions. Similarly, for TPT 3 data, the model included the and slaughter weight (Table 1). Such interactions mighteffects of breed, FT, PMW and all possible interactions. have considerable practical relevance to lamb meat production systems. As shown in Table 2 the differences in the overall3. Results scores of all four eating quality traits were such as to be detected by consumers eating the lamb in their own3.1. General homes. A summary of the ANOVA results regarding effects 3.2. TPT 1on the four eating quality characteristics (Flavour, Jui-ciness, Tenderness and Overall Acceptability) of lamb Table 3 shows marginal means and standard errorsmeat assessed in the three TPT is given in Table 1. R- (S.E.) of scores for the four eating quality characteristicssquared values of all analyses ranged from 0.43 to 0.58. of lamb meat assessed in TPT 1. Results are shown by Average scores of the four eating quality character- sex and PMW, collectively for the three breeds.istics of lamb meat from the B, S and K breed, across Slaughter weight, as a proportion of the estimatedthe three TPT, are shown in Table 2. mature weight, had significant effects on Flavour, Ten- Significant differences (P < 0.05–P < 0.01) between derness and Overall Acceptability, with the largestbreed effects on Flavour, Juiciness, Tenderness and PMW (90% of estimated mature weight) receiving con-Overall Acceptability were detected in TPT 2, indicating siderably lower scores. The weight at slaughter corre-preference for lamb meat from the Karagouniko breed. sponded to a commercial range of live weight fromHowever, such differences were not significant for sam- 13.3–70 kg (with carcass weight ranging from 6.2 to 31.2ples assessed in TPT 1 and TPT 3 (Tables 1 and 2). On kg). Across sex and breed, Flavour mean scores wereTable 1Summary of analysis of variance (ANOVA) results regarding effects on four eating quality characteristics (Flavour, Juiciness, Tenderness andOverall Acceptability) of lamb meat assessed in three Taste Panel Tests (TPT)aFactors Flavour Juiciness Tenderness Overall acceptabilityTPT 1Breed NS NS NS NSSex * NS NS NSSlaughter weight (PMW)b * NS ** *BreedÂSex NS NS NS NSBreedÂPMW NS NS NS NSSexÂPMW * NS NS NSBreedÂSexÂPMW NS NS NS NSTPT 2Breed *** *** ** **Feeding treatment (FT) NS * ** ***Target slaughter live weight (TSLW) NS NS NS ***BreedÂFT ** NS NS NSBreedÂTSLW NS NS NS NSFTÂTSLW NS * * ***BreedÂFTÂTSLW *** * * *TPT 3Breed NS NS NS NSFeeding treatment (FT) NS NS NS NSSlaughter weight (PMW)b ** * * *BreedÂFT *** NS NS NSBreedÂPMW * * * *FTÂPMW NS NS NS NSBreedÂFTÂPMW NS NS NS *** a NS, non significant. b The slaughter weight was estimated as a proportion of mature weight of each breed. * P<0.001. ** P <0.01. *** P< 0.05.
  • 5. G. Arsenos et al. / Meat Science 60 (2002) 379–387 3836.07, 5.93, 5.64 and 4.08, (S.E.D. 0.092, P < 0.001) for TPT 2. Results are shown by FT and TSLW, collec-PMW 30, 45, 60 and 90% of mature weight, respec- tively for the three breeds.tively. Similarly, Tenderness means were 5.23, 5.14, 4.99 Feeding treatment affected significantly Juiciness,and 4.80 (S.E.D 0.128, P < 0.01), for the four PMW, Tenderness and Overall Acceptability. Panellists seemedrespectively. Overall Acceptability means were 6.18, to prefer samples from medium and low levels of con-6.04, 5.92 and 5.71 (S.E.D. 0.106, P < 0.01). centrate. Average scores, across breed and TSLW, for Sex of the lamb had a significant effect on Flavour. In H, M and L feeding treatments, respectively were: 5.04,general, the panellists seemed to prefer samples from 5.56, 5.39 (S.E.D. 0.111, P < 0.001) for Juiciness; 5.42,female lambs, especially when heavier carcasses were 5.77, 5.79 (S.E.D. 0.128; P < 0.01) for Tenderness andbeing assessed. Across breed and PMW, Flavour scores 5.61, 5.93, 5.86; S.E.D. 0.130; P < 0.05) for Overallwere 5.18 vs. 5.69 (S.E.D. 0.093, P < 0.001) for male and Acceptability.female lambs, respectively. Sex differences for the other The interaction between FT and TSLW was significantcharacteristics were non-significant. for Juiciness (P < 0.001), Tenderness (P < 0.01) and Sex by PMW interaction was also significant for Fla- Overall Acceptability (P < 0.05). This indicates that con-vour, mainly because of the large difference between centrate levels in the diet of lambs had a significant effectsexes at the largest PMW (90% of the estimated mature on the eating quality characteristics of meat produced atweight). All other interactions were non-significant. different TSLW. Samples from lambs fed medium levels of concentrate were rated highest except for those from3.3. TPT 2 lambs slaughtered at 28 kg, where highest scores were observed on feeding low levels of concentrate. Table 4 shows marginal means and S.E. of scores for Breed had a significant effect on all characteristics ineating quality characteristics of lamb meat assessed in TPT 2 (Tables 1 and 2) with meat samples fromTable 2Overall means and standard errors of difference (S.E.D.) of four eating quality characteristics (Flavour, Juiciness, Tenderness and Overall Accept-ability) of lamb meat from the Boutsko (B), Serres (S) and Karagouniko (K) breeds, assessed in three Taste Panel Tests (TPT 1, TPT 2 and TPT 3)a TPT 1 S.E.D. TPT 2 S.E.D. TPT 3 S.E.D. B S K B S K B S K (n=160) (n=160) (n=160) (n=180) (n=180) (n=180) (n=120) (n=120) (n=120)Flavour 5.44 5.41 5.44 0.11 5.52 5.83 6.09 0.19 5.49 5.41 5.48 0.24Juiciness 4.49 4.44 4.49 0.11 5.09 5.22 5.69 0.21 5.17 5.21 5.17 0.22Tenderness 5.11 4.96 5.05 0.11 5.27 5.72 6.00 0.18 5.34 5.35 5.18 0.25Overall acceptability 6.04 5.91 5.94 0.09 5.48 5.80 6.12 0.19 5.47 5.37 5.32 0.23 a An eight-point rating scale (1–8) was used with higher scores indicating more favourable rating.Table 3Marginal means and standard errors (in parentheses) of four eating quality characteristics (Flavour, Juiciness, Tenderness and Overall Acceptability)of lamb meat assessed in Taste Panel Test 1, by sex (M=Males, F=Female) and slaughter weight (PMW—defined as proportion of mature weight)a PMW 30% 45% 60% 90% M F M F M F M FFlavour 6.10 6.03 5.97 5.90 5.57 5.72 3.07b 5.10 (0.17) (0.16) (0.16) (0.14) (0.16) (0.16) (0.12) (0.14)Juiciness 4.57 4.58 4.53 4.52 4.47 4.47 4.35 4.33 (0.16) (0.16) (0.16) (0.16) (0.17) (0.16) (0.16) (0.15)Tenderness 5.23 5.22 5.17 5.12 5.00 4.98 4.77 4.83 (0.17) (0.18) (0.16) (0.16) (0.16) (0.16) (0.16) (0.16)Overall 6.18 6.18 6.03 6.05 5.92 5.92 5.67 5.75Acceptability (0.16) (0.16) (0.17) (0.16) (0.16) (0.15) (0.14) (0.14) a An eight-point rating scale (1–8) was used with higher scores indicating more favourable rating. b Indicates that means in the same row with different letters differ significantly (P<0.05).
  • 6. 384 G. Arsenos et al. / Meat Science 60 (2002) 379–387Karagouniko lambs scoring the highest. There was also Slaughter weight as proportion of the mature weighta significant three-way interaction between breed, had a significant effect on all characteristics. AverageTSLW and FT on all characteristics. scores, across breed and FT, for lambs slaughtered at 48 and 55% of the mature weight, respectively were: 5.293.4. TPT 3 and 5.63 (S.E.D. 0.140 P< 0.05) for Flavour; 4.92 and 5.44 (S.E.D. 0.122 P < 0.001) for Juiciness; 4.98 and 5.60 Table 5 shows marginal means and S.E. of scores for (S.E.D. 0.138 P < 0.001) for Tenderness; and 5.15 andeating quality characteristics of lamb meat assessed in 5.63 (S.E.D. 0.118 P < 0.001) for Overall Acceptability.TPT 3. The results are shown by breed and PMW, col- However, there was a significant interaction (P < 0.001)lectively for the three FT. between breed and PMW for all characteristics. SamplesTable 4Marginal means and standard errors (in parentheses) of four eating quality characteristics (Flavour, Juiciness, Tenderness and Overall Accept-ability), of lamb meat assessed in Taste Panel Test 2, by feeding treatment (defined by the level of concentrate in the diet; H=High, M=MediumL=Low) and target slaughter live weight (TSLW)aFeeding treatment TSLW 23 kg 28 kg 33 kg H (n=60) M (n=60) L (n=60) H (n=60) M (n=60) L (n=60) H (n=60) M (n=60) L (n=60)Flavour 5.63 a 5.97 a 5.95 a 5.70 a 5.70 a 5.95 a 5.68 a 5.95 a 5.80 a (0.18) (0.16) (0.16) (0.17) (0.17) (0.14) (0.18) (0.16) (0.15)Juiciness 4.77a 5.80b 5.35ab 5.07 ab 5.20 ab 5.60 b 5.30 ab 5.68 b 5.23 ab (0.18) (0.17) (0.21) (0.17) (0.17) (0.18) (0.20) (0.16) (0.17)Tenderness 5.17a 6.12b 5.85b 5.47 ab 5.37 ab 5.98 b 5.63 ab 5.82 b 5.55 ab (0.20) (0.18) (0.19) (0.17) (0.18) (0.19) (0.21) (0.20) (0.18)Overall 5.43a 6.13b 5.88 ab 5.63 ab 5.63 ab 6.02 b 5.77 ab 6.02 b 5.68 abAcceptability (0.17) (0.17) (0.19) (0.15) (0.15) (0.16) (0.18) (0.16) (0.16)a, b Indicate that means in the same row, with different letters differ significantly (P <0.05); letters ab is not statistically different to a and b. a An eight-point rating scale (1–8) was used with higher scores indicating more favourable rating.Table 5Marginal means and standard errors (in parentheses) of four eating quality characteristics (Flavour, Juiciness, Tenderness and Overall Acceptability)of lamb meat assessed in Taste Panel Test 3, by breed (B=Boutsko, S=Serres and K=Karagouniko) and slaughter weight (PMW–defined as pro-portion of mature weight)a Breed (PMW) B S K 48% (n=60) 55% (n=60) 48% (n=60) 55% (n=60) 48% (n=60) 55% (n=60)Flavour 5.17 a 5.82 b 5.57 ab 5.25 ab 5.15 a 5.82 b (0.20) (0.18 (0.17) (0.19) (0.20) (0.17)Juiciness 4.55 a 5.78 b 5.27 b 5.15 b 4.93 ab 5.40 b (0.23) (0.18) (0.19) (0.19) (0.19) (0.17)Tenderness 4.50 a 6.18 b 5.45 c 5.25 c 4.98 ac 5.38 c (0.24) (0.17 (0.19) (0.21) (0.22) (0.18)Overall 4.83 a 6.10 b 5.57 b 5.18 ab 5.05 ab 5.60 bAcceptability (0.23) (0.16 (0.17) (0.20) (0.20) (0.16)a,b,c Indicate that means in the same row, with different letters differ significantly (P <0.05); letters ab are not statistically different to a and b; lettersac are not statistically different to a and c. a An eight-point rating scale (1–8) was used with higher scores indicating more favourable rating.
  • 7. G. Arsenos et al. / Meat Science 60 (2002) 379–387 385from heavier PMW scored higher for B and K but lower Nute, Hogg, & Walters, 1990; Ellis et al., 1997; Sanudofor S compared with samples from lighter carcasses. et al., 1998b). Further investigation of this effect was not feasible in the current study because the leg joints used for TPT 2 and TPT 3 were obtained from male4. Discussion lambs only. The main objective of this study was to investigate the 4.2. Effect of nutritional managementeffects of post-weaning nutritional management and liveweight at slaughter on the eating quality of lamb meat The prevailing view in the literature is that informa-produced by three Greek dairy breeds of sheep. This tion on how nutritional management affects eatingwas achieved by three taste panel tests. It has been sug- quality characteristics of meat would help to explain thegested that information on eating quality characteristics differences observed in such characteristics of lambof lamb meat produced by taste panel assessments could meat produced under different systems and, hence, pro-provide important insights on how such characteristics vide insights for the development of new strategies forare perceived and further evaluated by consumers more profitable production of sheep meat (Boutonnet,(Sanudo et al., 1996, 1998a,b; Wood et al., 1998). 1999; Sanudo et al., 1998b; Wood et al., 1999). Results Samples used for taste panel assessment represented from TPT 2 and 3 suggested that there is much toseveral combinations of breed, sex, nutritional manage- choose between breeds of lambs investigated here inment conditions and live weights at slaughter. These terms of eating quality of the meat they produce whenfactors are discussed next. manipulation of nutritional management is possible. In particular, results from TPT 2, where lambs were fed on4.1. Effect of breed and sex three different levels of concentrate throughout the course of the experiment, revealed a significant effect of Breed has been suggested as a complex source of var- such FT on Juiciness, Tenderness and Overall accept-iation of meat quality whose estimated effect may vary ability of roasted lean samples of their leg joints. Independing on the comparison criterion (Sanudo et al., contrast, when lambs were reared under a similar nutri-1998b). Results of the present study clearly demonstrate tional management for a preliminary period indoorsthat breed is a factor affecting the eating quality of lamb and, subsequently, finished on irrigated sown pasture,meat. Presence of significant interactions between breed there were no significant effects of the FT during theand the other factors studied in each TPT support the indoor period on any of the eating quality parametersview that the genetic potential of lambs determines, to a assessed in TPT 3. The latter would imply that thecertain extent, the quality of the meat they produce effects of nutritional management of lambs during the(Arsenos et al., 2000; Carson, Moss, Steen, & Kilpa- finishing period, here grazing, are likely to overshadowtrick, 1999; Ellis, Webster, Merrell, & Brown, 1997; any effect of previous FT. In this respect, Crouse, Field,Matthes et al., 1998; Sanudo, Campo, Sierra, Maria, Chant, Ferrell, Smith, and Harrison (1978) stated thatOlleta, & Santolaria, 1997). Results also confirmed pre- improvement of the quality characteristics of sheepvious suggestions that the indigenous Greek breeds of meat could be mainly achieved through manipulation ofsheep produced carcasses with a relatively high eating feeding. More recent studies, using taste panel assess-quality (Arsenos, 1997; Zygoyiannis, Stamataris, ments have also shown that there is a considerable effectKouimtzis, & Doney, 1990). However, the fact that of nutritional management in post-weaning nutrition ofbreed as a main effect was significant only for eating lambs on the quality of meat they produce (Sanudo etquality characteristics assessed in TPT 2 indicated that al., 1998b; Vipond, Marie, & Hunter, 1995).breed is not necessarily a dominant factor with respectto the eating quality of lamb meat. Alfonso (2000) and 4.3. Effect of live weight at slaughterNotter et al. (1991) suggested that the breed effect onmeat quality was not very important compared with The evidence in the literature regarding effects of livesuch factors as feeding treatment. weight at slaughter on the quality of lamb meat is not A question, addressed only in TPT 1, was whether the very conclusive (Hopkins, Beattie, & Pirlot, 1998;sex of lambs, slaughtered at different live weights repre- Keane & Allen, 1998; Sanudo et al., 1996, 1997, 1998b;senting different degrees of maturity, affected the eating Vergara, Molina, & Gallego, 1999; Zygoyiannis et al.,quality characteristics of meat. Results of TPT 1 did not 1999). Live weight at slaughter, defined either as targetreveal significant effects of sex on eating quality char- weight corresponding to marketable carcasses or asacteristics, except for Flavour, where female lambs gen- proportion of mature weight, affected significantly mosterally gave more desirable meat than males. This is in eating quality characteristics assessed by the taste panelagreement with the view that differences between sexes tests. For the range of PMW considered in this study,in meat quality are not very important (Dransfield, preferred samples were those of lambs slaughtered at
  • 8. 386 G. Arsenos et al. / Meat Science 60 (2002) 379–387low live weight when the nutritional management was tion of lambs and their live weight at slaughter. Givenad libitum concentrate feed (TPT 1). This is not sur- the results of the current study the expectation is thatprising given the overwhelming market desire for light consumers may be able to differentiate meat samples oncarcasses in Greece (Zygoyiannis et al., 1997) and most the basis of these qualities.likely across the Mediterranean countries, since it isbelieved that meat from animals slaughtered at lowweights is more tender than meat from heavier lambs Acknowledgements(Sanudo et al., 1997, 1998a,b; Vergara et al., 1999). Results from TPT 2 suggest that when concentrate The work was supported by the European Commu-allowances in the diet are restricted then it is possible to nity (DG VI) project No. CAMAR 8001 CT 91-0308) asproduce heavier carcasses that are still highly acceptable a part of a collaborative program between the UK,to consumers. However, it should be borne in mind that Greece and Spain. We are grateful to all those wholambs used in this study belong to breeds that differ participated in the various aspects of this study. Espe-significantly in their growth potential. For example, cially, we would like to thank the farmer Mr. G.Boutsko lambs were slaughtered after 70–158 days post- Zygoyiannis and his family for their essential assistanceweaning, depending on the concentrate level of the diet, on animal and pasture management.whereas the range was 41–130 days for Serres lambs and35–97 days for Karagouniko lamb, respectively. There-fore, although lambs were slaughtered at the same ReferencesTSLW, their carcasses might differ significantly in termsof the degree of maturity (Zygoyiannis et al., 1997), Alfonso, M. G. (2000). Caracterization sensorial y aceptabilitad de lawhich is closely associated with meat quality (Sanudo et carne de doce tipos ovinos representatives de distintos sistemas deal., 1998b) and consumer acceptability. production europeos. PhD thesis, University of Saragosa, Spain. Arsenos, G. (1997). The influence of genotype and method of production Results from TPT 3 suggest that the major factor on fatty acids composition of carcass fat of Boutsko, Serres and Kar-affecting the eating quality of lambs was their live agouniko lambs. PhD thesis, Aristotle University of Thessaliniki,weight at slaughter, irrespective of the feeding treatment Greece, pp. 125–126.prior to grazing. The interaction between post-weaning Arsenos, G., Zygoyjannis, D., Kufidis, D., Katsaounis, N., & Stama- taris, C. (2000). The effect of breed slaughter weight and nutritionalnutritional management and live weight at slaughter of management on cholesterol content of lamb carcasses. Small Rumi-lambs seemed to account for most of the variation in nant Research, 36, 275–283.scores of eating quality characteristics assessed in TPT 3. Boutonnet, J.-P. (1999). Perspectives of the sheep meat world market Consumers demand tender and flavoursome meat on future production systems and trends. Small Ruminant Research,(Boutonnet, 1999; Homer et al., 1997). Similarly, other 34, 189–195.published data, mainly from British and Spanish taste Carson, A. F., Moss, B. W., Steen, R. W. J., & Kilpatrick, D. J. (1999). Effects of the percentage of Texel or Rouge de l’Ouest genespanel tests (Sanudo et al., 1998a) indicate that lamb in lambs on carcass characteristics and meat quality. Meat Science,carcasses from non dairy sheep, were rated as low 69, 81–92.quality with respect to Tenderness and Juiciness and Cramer, D. A., Barton, R. A., Shorland, F. B., & Czochanska, Z.were not red. The relationship between Overall Accept- (1967). A comparison of the effects of white clover (Trifolium repens)ability and the other characteristics assessed in all TPT and of perennial ryegrass (Lolium perenne) on fat composition and flavour of lamb. Journal of Agricultural Science, 69, 367–373.conducted in the current study is consistent with the Crouse, J. D., Field, R. A., Chant, J. L., Ferrell, C. L., Smith, G. M.,findings of those latter studies. & Harrison, V. L. (1978). Effect of dietary energy intake on carcass In conclusion, this study extends previous findings composition and palatability of different weight carcasses from ewe(Arsenos et al., 2000; Zygoyiannis et al., 1999) regarding and ram lambs. Journal of Animal Science, 47, 1207–1218. Dransfield, E., Martin, J. F., Fisher, A., Nute, G. 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