Characterization of Meat from Pecora Dell'amiata and Pomarancina Light
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Tocci_imp_ok 26/07/18 09:57 Pagina 131 R. Tocci et al. Large Animal Review 2017; 23: 131-140 131 Characterization of meat from Pecora dell’Amiata and Pomarancina light l lamb slaughtered at 20 kg of live weight R. TOCCI, E. PIPPI, M. CAMPOSTRINI, A. MARTINI, R. BOZZI, D. BENVENUTI, A. BONELLI, A. PEZZATI, C. SARGENTINI Dipartimento di Scienze delle Produzioni Agroalimentari e dell’Ambiente (DISPAA) - Sez. Scienze animali Università degli Studi di Firenze. Via delle Cascine, 5 - 50144 Firenze, Italy SUMMARY In this study, the slaughtering performances and the meat quality of lambs slaughtered at 20 kg of live weight were consid- ered. The lambs belonged to two Tuscan local breeds, the Pecora dell’Amiata sheep and the Pomarancina sheep. In this study on the longissimus thoracis+lumborum samples the physical-chemical and nutritional characteristics were considered. Data were analysed to Analysis of Variance through the least squares method. On the fatty acid composition and on the Health In- dices a Principal Component Analysis (PCA) was performed. The Amiata lambs have reached later the weight at slaughter- ing (88±3.5 vs 66.5±3.3 d). The carcass weight (11264.0±482.0 vs 9007.0±533.0 g) and the dressing percentage (52.91±0.87 vs 47.55±0.95) were higher in Pomarancina lamb meat. The free water (16.29±0.47 vs 12.47±0.65 cm2) and the texture val- ues (35.97±2.24 vs 18.79±3.25 N) were higher in Pomarancina lamb meat. Amiata lamb meat had a higher Saturated Fatty Acids (SFA) (49.91±1.29 vs 46.05±0.96) and PUFA ω6 (9.14±0.55 vs 7.64±0.41) percentage, while Pomarancina lamb meat had higher Monounsaturated Fatty acids (MUFA) percentage (38.82±0.85 vs 31.72±1.14). The health Indices indicated as both meats are favourable in human diet; ω6/ω3 ratio was 2.78±0.10 vs 2.20±0.08 in Amiata lamb meat and in Pomaranci- na lamb meat respectively. The PCA for the single fatty acids indicated two different groups for Amiata lamb meat and Po- marancina lamb meat in the PC1; the first group was identified by SFA. The PCA for the fatty acids categories and Healthy Indices subdivided both meats in the PC2 that identified the Amiata lamb meat for SFA and the Pomarancina lamb meat for MUFA, MUFA/SFA and UFA (Unsaturated Fatty Acids)/SFA. KEY WORDS Pecora dell’Amiata, Pomarancina, lamb meat quality, fatty acids, PCA. INTRODUCTION Comune Toscana “Nostrale” or “Vissana”, and has merinized breeds as ancestors (Maremmana or Spagnola Bastarda). It In Italy, the ovine meat production is represented by 65% of shows a typical white fleece evenly distributed over the body, suckling lamb meat, and 25% of light lamb meat. The re- and the rams are often horned. The adult females have a maining percentage is represented by meat deriving from at mean height at withers of 70.6 cm and a mean live weight of the end of career ewes and heavy lambs. The suckling lambs 50 kg, while the mean height at withers of the males is 73.8, derive mainly from dairy breeds, in particular Sarda breed, and the weight is 60 kg. There are currently about 1300 indi- having a live weight less than 12 kg at 40 days. The market viduals of this breed3;4. Pomarancina sheep derives from the trend shows an increase of meat deriving from heavier Pisa province and has as ancestor the Appenninica sheep. It sheep1,2. shows white fleece. Live weight of adult males is around 70 In this study the physical-chemical and nutritional charac- kg, while the live weight of adult females is around 60 kg. teristics of the meat deriving from light lambs belonging to This breed, having meat as main production, was crossed in two Tuscan breeds, Pecora dell’Amiata and Pomarancina, the past with Merinos, Bergamasca and Ilê di France5. There were considered. These animals were slaughtered at 20 kg of are currently about 1300 individuals of this breed4. average live weight, unusual live weight for the Tuscan con- sumer that prefers suckling lamb meat. Amiata sheep, recently enrolled in the “Registro anagrafico MATERIALS AND METHODS delle popolazioni ovine e caprine autoctone a limitata diffu- sione” (D.M. 17444/2014), is a not specialized breed, having Animals meat and milk as main productions. It derives from the This work dealt with the post mortem results of 21 Po- mount Amiata area in Tuscany. It derives from the “Pecora marancina (10 females and 11 males) and 12 Amiatina (6 fe- males and 6 males) lambs. The lambs were reared with their dams on the pasture; lambs were fed with milk until 30 days of age, then a daily rate of 100 g/head (on average) of a mix- Autore per la corrispondenza: ture of maize, barley and faba bean, in addition to the suck- Roberto Tocci ([email protected]). led milk, was supplied. Ewes, reared under a pasture-based Tocci_imp_ok 26/07/18 09:57 Pagina 132 132 Characterization of meat from Pecora dell’Amiata and Pomarancina light lamb slaughtered at 20 kg of live weight semi-extensive system, during lactation period, received a cell. The Warner-Bratzler shear test (WB-shear force) con- supplementation of hay from mixed meadow ad libitum and sisted of a 3 mm thick steel blade which had a 73° V cut in- 400 g/head of a mixture of maize, barley and faba bean. to it. The cut was perpendicular to the muscle fibre direc- Lambs were slaughtered when reached 20 kg of live weight, tion. The samples were placed on the table, under the V of in order to meet the new market requirements. the blade, and was cut through as the blade moved with a constant speed through the slit of the table (crosshead Slaughter parameters speed of 30 mm/min). The resistance of the samples to All animals were slaughtered following the actual UE shearing was recorded every 0.01 seconds and plotted by a 1099/2009 regulation6. Before slaughtering all animals of the computer in a force deformation. Maximum shear force, trial were weighed. On the carcasses the following parame- defined as maximum resistance of the sample to shearing17 ters were also considered: carcass weight, carcass weight after was determined. Two raw and two cooked cores from each 24 hours, left and right half carcass weight, front and hind sample were submitted to WB-Shear force; the mean val- quarter weight, net live weight, carcass length, thigh length, ue of both measures was considered. croup length, thorax width, trunk length, thorax depth. The dressing percentage and the net dressing percentage were al- Chemical analyses were carried out on each sample of Mus- so considered. The weight of thoracic internal organs, stom- culus longissimus thoracis+lumborum determining dry mat- achs, intestines, gastrointestinal content, skin, head, genitals, ter, ether extract, crude protein and ash18. right front and hind cannons, tail was also taken. The car- casses were weighed, measured, and valuated following the The samples were analysed for total lipid concentration by slaughter procedures of ASPA7; carcasses were classified, ac- gravimetric determination of total lipid extract according to cording to the EU Mediterranean grid, for carcass colour and Folch et al.19. The tissue was homogenized with chloro- fatness score by experienced evaluators8. form/methanol (2/1) to a final volume 20 times the volume of the tissue sample (1 g in 20 ml of solvent mixture). After Laboratory analysis dispersion, the whole mixture is agitated during 15-20 min- Four days after slaughtering, on the carcasses stored at 4 °C utes in an orbital shaker at room temperature. The ho- in a refrigerator, samples from the Musculus longissimus tho- mogenate was either filtrated (funnel with a folded filter pa- racis+lumborum, were taken9 in order to evaluate the physi- per) to recover the liquid phase. The solvent was washed with cal-chemical and nutritional characteristics of the meat. 0.2 volume (4 ml for 20 ml) of water or better 0.9% NaCl so- The physical parameters were the following: lution. After vortexing some seconds, the mixture was cen- – pH: The measurement of pH was performed in triplicate trifuged at low speed (2000 rpm) to separate the two phases. on Musculus longissimus thoracis+lumborum samples, us- After centrifugation and siphoning of the upper phase, the ing Mettler Toledo DevenGo SG2™ pH-meter (Novate lower chloroform phase containing lipids was evaporated Milanese, Milano, Italy) equipped with an Inlab punc- under vacuum in a rotary evaporator or under a nitrogen ture electrode (Mettler-Toledo, Ltd). The mean value was stream if the volume is under 2-3 ml19. The samples were al- utilized. so analysed for quantitative fatty acid composition of total – Water holding capacity (WHC), determined using three lipids by gas chromatographic separation of methyl esters, different methods: comprising C19:0 as internal standard, on capillary column ✓ filter paper press Grau and Hamm method10, ex- oven temperature ranging from 164°C and 200°C with pressed as the ratio M/T, where M is the area (cm2) of 3°C/min heat increment. the Musculus Longissimus thoracis+lumborum and T is The following health indices were also calculated: the total wetted area (cm2)11;12. A cuboidal sample of MUFA/SFA, UFA/SFA, PUFA/SFA, ω6/ω3 PUFA. 300 ± 5 mg was kept for four minutes under a pressure of 50 kg/cm2. Statistical analysis ✓ drip loss on cubic Musculus Longissimus thoracis+lum- Data were submitted to Analysis of Variance through the least borum samples of 30 grams kept at 4 °C for 48 h in a squares method, using JMP 10 statistical software20, and con- plastic container with double bottom; sidering as source of variance the breed.