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1.
Meat Sci ; 96(1): 633-9, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24056406

RESUMO

This study investigated effects of high pressure (HP) treatment of pork meat at 150 or 300 MPa for 5 min before manufacturing sausages on the reduction of phosphate levels and compared to sausages manufactured with untreated pork meat (control sausages). Improvement in perceived saltiness, juiciness and overall flavour was observed in sausages manufactured using HP-treated meat at 150 MPa and 0% phosphate, compared to control sausages. Sausages manufactured using meat HP-treated at 150 MPa and 0.25% phosphate (P<0.05) improved hardness of sausages. HP-treated meat at 300 MPa and 0% phosphate decreased juiciness and adhesiveness, while at 0.25% phosphate, adversely affected emulsion stability and sensory attributes. HP treatment did not affect significantly the lightness of the sausages; however, elimination of phosphate reduced (P<0.05) the yellowness, while HP treatment at 150 MPa with 0.25 or 0.5% phosphate increased (P<0.05) redness. HP reatment at 150 MPa has potential for reducing phosphate levels in sausages without significant changes in their functionality and improved acceptability.


Assuntos
Manipulação de Alimentos/métodos , Produtos da Carne/análise , Fosfatos/análise , Pressão , Animais , Desjejum , Fenômenos Químicos , Cor , Emulsões/química , Humanos , Suínos , Paladar
2.
Food Chem ; 134(2): 1137-40, 2012 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-23107739

RESUMO

The ability of brown seaweed extracts, Ascophyllum nodosum, Laminaria hyperborea, Pelvetia canaliculata, Fucus vesiculosus and Fucus serratus to protect against tert-butyl hydroperoxide (tert-BOOH) induced stress in Caco-2 cells was investigated. Oxidative stress was determined by measuring alteration in the enzymatic activity of catalase (CAT) and superoxide dismutases (SOD) and cellular levels of glutathione (GSH). L. hyperborea, P. canaliculata and F. serratus significantly protected against tert-BOOH induced SOD reduction but did not protect against the reduction in CAT activity or the increased cellular levels of GSH. The ability of F. serratus and F. vesiculosus to protect against H(2)O(2) and tert-BOOH induced DNA damage was also assessed. The DNA protective effects of the two seaweed extracts was compared to those of three metal chelators; deferoxamine mesylate (DFO), 1,10-phenanthroline (o-phen) and 1,2-Bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetrakis (BAPTA-AM). F. serratus and F. vesiculosus significantly protected (P<0.05) against H(2)O(2) (50 µM) induced DNA damage but not tert-BOOH induced damage.


Assuntos
Células/efeitos dos fármacos , Dano ao DNA/efeitos dos fármacos , Peróxido de Hidrogênio/toxicidade , Phaeophyceae/química , Substâncias Protetoras/farmacologia , Alga Marinha/química , terc-Butil Hidroperóxido/toxicidade , Células CACO-2 , Catalase/metabolismo , Células/enzimologia , Células/metabolismo , Glutationa/metabolismo , Humanos , Estresse Oxidativo/efeitos dos fármacos , Superóxido Dismutase/metabolismo
3.
Meat Sci ; 86(1): 214-26, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20579814

RESUMO

The relationship between consumer perception of quality and the food industry's drive to satisfy consumer needs is complex and involves many different components. Science and innovation play a major role in equipping the industry to respond to consumer concerns and expectations. This paper examines the main elements of consumer perception of meat with focus on the red meat sector. Emphasis is placed on perception at point of sale particularly the intrinsic quality cues of colour, packaging and degree of visual fat. The state of the art developments in increasing consumers' perception at this point are discussed. Experienced quality cues such as tenderness and flavour are well known as being of immense importance to consumers at point of consumption. The latest technological developments to enhance the quality experienced by consumers are discussed. The use of pre-rigor restraining techniques offers the industry a method for changing its conventional procedures of processing beef for instance. Background cues of safety, nutrition, animal welfare and sustainability are also discussed. Finally opportunities and challenges facing the industry are outlined. It is concluded that the meat industry needs to invest in and embrace an innovation agenda in order to be sustainable. It must utilise emerging scientific knowledge and take a more proactive role in setting out a research agenda.


Assuntos
Comportamento do Consumidor/economia , Difusão de Inovações , Tecnologia de Alimentos/métodos , Indústria de Embalagem de Carne/métodos , Carne/análise , Carne/economia , Papel Profissional , Criação de Animais Domésticos/tendências , Bem-Estar do Animal , Animais , Fenômenos Químicos , Microbiologia de Alimentos , Tecnologia de Alimentos/economia , Tecnologia de Alimentos/tendências , Humanos , Carne/microbiologia , Indústria de Embalagem de Carne/economia , Indústria de Embalagem de Carne/tendências , Ciências da Nutrição/tendências , Valor Nutritivo , Papel Profissional/psicologia , Sensação
4.
Meat Sci ; 79(1): 86-97, 2008 May.
Artigo em Inglês | MEDLINE | ID: mdl-22062601

RESUMO

The objective was to determine the effect of pre-slaughter growth rate on feed efficiency, components of body growth and on the tenderness of longissimus muscle from steers reared to a common age and carcass weight. Sixty Friesian steers were group-housed and offered grass silage ad libitum and 3.5kg concentrates per animal daily for 5 months and then 5kg concentrates and 1kg grass hay for 1month before the experiment began. The animals were then weighed and in a randomised block were assigned to one of 5 groups, for slaughter at the beginning of the experiment or to be offered concentrates and hay (900 and 100g/kg total diet, respectively) to achieve target growths of: 0.72kg/day continuously for 17 weeks, 0.36kg/day for the first 8 weeks and 1.08kg/day for the final 8 weeks (low-high), 1.08kg/day for the first 8 weeks and 0.36 for the final 8 weeks (high-low) or 0.36kg/day for the first 2 weeks, 0.72kg/day during weeks 4 and 14 and 1.08kg/day for the final 2 weeks (pulse). One week was allowed for transition to the different dietary allowances within each energy supply pattern. The mean age at the beginning and end of the study was 18 and 22.5 months, respectively. After slaughter, the weight of the carcass and kidney+channel fat depot were recorded, the pistola hind quarter was dissected into fat, lean and bone and the tenderness of the m. longissimus thoracis et lumborum (LTM) muscle was measured instrumentally and using a trained taste panel after 2, 7 or 14 days ageing. The pattern of energy supply did not affect carcass weight, fat score or kidney+channel fat weight. The pistola hind quarter from animals offered the low-high energy pattern had a similar composition to the continuously-fed animals but contained more muscle than that from animals offered high-low or pulse energy patterns. After 14 days ageing, LTM from the continuously-fed animals was more tender than that from animals offered the other energy supply patterns but shear force did not differ between supply patterns. The data do not support the hypothesis that pre-slaughter growth rate increases tenderness but suggest that energy supply pattern can influence body composition of finishing cattle.

5.
Meat Sci ; 79(2): 355-64, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22062764

RESUMO

Steers were offered grass silage ad libitum and 6.4 kg concentrates daily for 126 days or silage ad libitum for 35 days, followed by concentrates ad libitum (Experiment 1). Steers were offered grass silage ad libitum and 6 kg concentrates daily for 154 days, concentrates ad libitum or grass silage ad libitum for 112 days followed by concentrates ad libitum (Experiment 2). All treatments received the same total concentrate allowance. In Experiment 1, there was no difference in any measurement of meat quality. In Experiment 2, ad libitum concentrate feeding per se, decreased redness and increased shear force of muscle at 2 days post-mortem. Delaying concentrate feeding decreased fat yellowness, decreased shear force at 7 and 14 days post-mortem and increased muscle redness at 14 days post-mortem. Modifications of the beef production system examined had minor effects on beef quality which are unlikely to be of commercial significance.

6.
Meat Sci ; 75(4): 551-7, 2007 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22064018

RESUMO

The objective of this study was to determine if there is an association between tenderness in bovine M. longisimus dorsi (LD) and polymorphisms in the bovine calpain I (exons 9 & 14), calpain II (regulatory subunit) or growth hormone (intron 3) genes. Genomic DNA was isolated from bovine LD (n=281) on which quality attributes (Warner Bratzler shear force (WBSF), sarcomere length and composition) were also characterised. DNA polymorphisms were analysed using polymerase chain reaction (PCR) and restriction fragment length polymorphism analysis. Association analyses were performed between genotypes at the four polymorphic loci and day 14 WBSF values. It was found that the calpain 1 exon 9 genotypes had an association with WBSF such that animals with the GA genotype exhibited decreased WBSF and increased tenderness when compared to animals with the GG genotype (P<0.05). This observation concurs with that of earlier studies, suggesting that this polymorphism is a functional marker for beef tenderness.

7.
Meat Sci ; 72(3): 380-6, 2006 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22061721

RESUMO

Pork loins were pumped to 110% of original weight with solutions containing 5.5% salt and 3.3% sodium tripolyphosphate, 5.5% salt and 3.3% ß-lactoglobulin (ß-lg) enriched fraction or 5.5% salt and 3.3% whey protein concentrate 80% (WPC80) for comparison with non-enhanced control loins. The enhancement of pork loins significantly increased (p<0.001) the tenderness and juiciness. Warner-Bratzler shear force values were lower (p<0.001) in enhanced then in non-enhanced control chops. The enhanced pork chops had a slightly higher overall flavour and overall acceptability to the control pork chops. Sensory analysis showed that ß-lg enriched fraction and WPC80 can be used as replacement ingredients to reduce the amount of phosphate used in enhancement solutions, as they were comparable to salt/sodium tripolyphosphate (salt/STPP) enhancement solution. Consumers rated the tenderness, juiciness and taste of the enhanced chops significantly (p<0.001) higher then the control chops.

8.
Meat Sci ; 73(1): 132-43, 2006 May.
Artigo em Inglês | MEDLINE | ID: mdl-22062062

RESUMO

The effect of supplementation of beef cattle diets with tea catechins (TC) (1000mg/animal/day) and rosemary extract (RE) (1000mg/animal/day), for 103 days preceding slaughter, on the oxidative stability of M. longissimus dorsi (LD) steaks was evaluated. Dietary supplementation with TC and RE did not increase plasma total antioxidant status (TAS), LD α-tocopherol concentrations or pH. In LD steaks stored aerobically or in modified atmosphere packs (80% O(2):20% CO(2)) (MAP) for up to 8 days at 4°C, surface redness (CIE 'a' redness value) and lipid stability (TBARS, mg MDA (malondialdehyde)/kg muscle) were not significantly improved as a result of supplementation with TC and RE. Similarly no improvement in the sensory properties and lipid stability of cooked LD slices, stored aerobically or in 30% CO(2):70% N(2) for up to 11 days at 4°C, was observed. An in vitro fermentation study demonstrated that TC and RE were not fermented to any great extent under simulated rumen conditions. Direct addition of TC (1000ppm) and RE (1000ppm) significantly (P<0.05) improved the colour and lipid stability in LD patties stored in 80% O(2):20% CO(2) for up to 8 days at 4°C, thus, demonstrating the antioxidant potential of TC and RE supplements employed in the present study.

9.
Meat Sci ; 73(1): 151-6, 2006 May.
Artigo em Inglês | MEDLINE | ID: mdl-22062064

RESUMO

The aim of this study was to monitor the effects of the alteration of the pre-rigor environment of the bovine LD muscle using controlled temperature regimes in order to gain an insight into the early post-mortem pH/temperature/time interactions which are important from the point of view of tenderness and to identify possible reasons for inconsistencies in beef tenderness. LD muscles (n=12) were hot-boned within 90min post-slaughter, cut into three pieces which were randomly placed in polyethylene bags and submerged in water baths pre-set at the following temperatures; 0, 5, 10, 15, 20 and 25°C for 8 h post-mortem then stored at 2°C for up to 14-days post-mortem. The rate of pH decline increased with increasing temperature. Muscles incubated at 0 and 5°C were cold shortened however not all of these muscles were tough as indicated by Warner Bratzler shear force values (WBSF). A pH range of 5.9-6.2 at 3 h post-mortem (pH(3)) produced consistently tender beef where cold-shortening was avoided. Cold shortened muscles showed the greatest variation in tenderness at 14 days post-mortem and underwent the greatest amount of tenderisation (ΔWBSF) and proteolysis between days 2 and 14 post-mortem. Proteolysis of cold shortened muscle may induce variation in tenderness in these muscles.

10.
Meat Sci ; 73(2): 196-203, 2006 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22062289

RESUMO

The objective of this study was to determine the effects of hot-boning, low voltage electrical stimulation (ES) and chilling temperature on the tenderness of bovine M. longissimus dorsi (LD) and M. semimembranosus (SM) muscles. LD (n=32) and SM (n=32) muscles were subjected to different post-mortem treatments; hot-boning (before 90min post-mortem), cold-boning (at 48h post-mortem), low voltage ES and rapid or slow chilling. Hot-boned muscles which were not electrically stimulated (NES) had higher Warner Bratzler shear force (WBSF) values (P<0.001) and shorter sarcomeres (P<0.001) than cold-boned muscles. Hot-boned muscles subjected to ES had lower pH values (P<0.001) post-stimulation and up to 8h post-mortem than NES muscles. At both chilling temperatures WBSF values were lower in ES hot-boned LD and SM muscles at days 2, 7 and 14 post-mortem than NES muscles. Hot-boned muscles subjected to slow chilling had longer sarcomeres (P<0.001) than those subjected to fast chilling. In hot-boned SM muscles, ES resulted in longer sarcomere lengths (P<0.001). However, ES did not have a significant effect on the sarcomere length of LD muscles. As indicated by WBSF values all muscles tenderised during ageing, including muscles which were 'cold shortened'. Proteolysis was not the main reason for differences in WBSF values between ES and NES muscles as judged by qualitative sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). A combination of slow chilling and ES had a positive effect on hot-boned muscles with respect to WBSF values.

11.
Meat Sci ; 73(2): 204-8, 2006 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22062290

RESUMO

The objective of this study was to evaluate the importance of proteolysis and sarcomere length in determining the tenderness of bovine M. longissimus dorsi (LD) muscle over a 21-day period. This was done by altering the pre-rigor glycolytic behaviour of hot-boned LD muscles using different early post-mortem temperature regimes. Hot-boned LD muscles (n=8) were cut in two, randomised, placed in polythene bags and submerged in a water bath set at 5°C (rapidly chilled) and 15°C (slowly chilled) for 8h post-mortem. All muscles were then stored at 2°C for up to 21 days post-mortem. The temperature regimes altered the glycolytic behaviour of the muscles in the pre-rigor period. The slowly chilled muscles exhibited a faster (P<0.01) pH fall than rapidly chilled muscles. Cold shortening was induced in rapidly chilled muscles as they had shorter (P<0.01) sarcomere lengths than slowly chilled muscles up to day 21 post-mortem. Warner Bratzler shear force values (WBSF) deemed cold-shortened muscles as tougher than noncold shortened up to day 14 post-mortem. Both cold-shortened and noncold-shortened muscles tenderised over time to an extent where there was no significant difference in WBSF values by day 21 post-mortem. SDS-PAGE protein profiles indicated that the rate of proteolysis was faster in slowly chilled muscles when compared to rapidly chilled muscles. However by day 21 post-mortem it appeared that rapidly and slowly chilled muscles underwent proteolysis to the same extent.

12.
Meat Sci ; 71(2): 238-43, 2005 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22064221

RESUMO

Four Beta-lactoglobulin (ß-lg) enriched fractions containing different mineral contents were prepared and evaluated in frankfurters. Frankfurters were assessed for cook loss, water holding capacity (WHC), textural and sensory characteristics. The addition of the ß-lg fractions reduced the cook loss (p<0.001) in comparison to the control (6.63% vs 3.98%). The fractions (ß-lg 1 and 2) with the lowest calcium level significantly reduced WHC (p<0.01). The ß-lg fractions had no detrimental effect on the sensory characteristics (p>0.05). All of the fractions increased the TPA value of hardness in comparison to the control (p<0.001) while the springiness decreased in the fractions (p<0.001) with the lowest mineral level. This study showed that the mineral composition of the ß-lactoglobulin fractions affected cook loss, tenderness and hardness (TPA) of the frankfurters and the addition of the ß-lactoglobulin enriched fraction did not affect the organoleptic quality of frankfurters in comparison to the control. This study shows the potential for next generation whey protein fractions and their application in meat products.

13.
J Anim Sci ; 82(8): 2384-91, 2004 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-15318738

RESUMO

The objective of this study was to determine the effect of type of conserved forage and concentrate composition on the quality of beef held in overwrapped (aerobic) or modified atmosphere packaging under simulated retail display for 17 d. Friesian steers (n = 45) were assigned randomly to one of five dietary treatments: 1) extensively fermented grass silage plus silage concentrate (EFS); 2) restricted fermented grass silage plus silage concentrate (RFS); 3) starch-based concentrate plus wheat straw (SC); 4) nonstarch-based concentrate plus wheat straw (NSC); or 5) zero-grazed perennial ryegrass plus grass concentrate (RYE). Meat quality was determined by measuring color, lipid oxidation (TBARS), alpha-tocopherol concentrations, and fatty acid composition. In aerobically packaged beef, there was a display x diet interactive effect (P < 0.001) on Hunter a* values, with steaks from the EFS group having higher (P < 0.05) a* values than all other dietary groups from d 6 through d 17. Moreover, during the last 12 d of display, beef from the EFS group had the lowest (P < 0.01) proportion of metmyoglobin (display day x diet; P < 0.001). Under aerobic packaging, the SC and NSC groups produced steaks with higher (P < 0.05) TBARS values than RFS, EFS, and RYE groups, which did not differ from each other (display day x diet; P < 0.01). The SC and NSC groups had higher (P < 0.05) oxidation levels than RFS, EFS, and RYE groups, which did not differ from each other. Beef from the EFS group had (P < 0.05) higher concentrations of alpha-tocopherol than from the SC, NSC, and RYE groups. Beef from EFS-fed steers had a higher (P < 0.05) proportion of saturated fatty acids than the SC and NSC groups. It was concluded that the method of grass conservation influenced beef color, whereas concentrate composition did not. Color of aerobically packaged beef was improved by feeding animals silage that had undergone extensive fermentation. Conversely, oxidative stability was decreased by feeding animals starch- and nonstarch-based concentrate diets.


Assuntos
Ração Animal , Bovinos/metabolismo , Embalagem de Alimentos/métodos , Carne/normas , Oxigênio/metabolismo , Pigmentação , Fenômenos Fisiológicos da Nutrição Animal , Animais , Antioxidantes/análise , Antioxidantes/metabolismo , Ácidos Graxos/análise , Fermentação , Masculino , Metamioglobina/metabolismo , Poaceae , Distribuição Aleatória , Silagem , Substâncias Reativas com Ácido Tiobarbitúrico/análise , Fatores de Tempo , Triticum , alfa-Tocoferol/análise
14.
Meat Sci ; 66(4): 765-70, 2004 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22061006

RESUMO

Probes, which can be used on-line to rapidly and efficiently detect beef quality attributes (colour and tenderness), are currently being considered to predict ultimate beef quality. The contribution of the inherent sampling variability (due to factors such as muscle location) needs to be evaluated in order to optimise the sampling procedure for these measurements. The main objective of this trial was to monitor some sampling factors which may contribute to variation in pH and various quality attributes in bovine M. longissimus thoracis et lumborum (LTL). Location along the muscle did not impact on colour measurements (P⩾0.05). Location had no effect on cook loss, Warner Bratzler shear force (WBSF) and sarcomere length values (P⩾0.05). The moisture and intramuscular fat contents did vary (P⩾0.05); however, as the differences were very small this may not be of practical significance. Different models of pH meters/probes had a significant influence (P⩽0.01) on recorded pH values. However pH did not differ significantly (P⩾0.05) along the length of the LTL. The type of meter used also had a significant impact on colour readings and 1 h 'blooming' time was observed as optimal for measuring colour on beef.

15.
Meat Sci ; 63(3): 279-86, 2003 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22062378

RESUMO

Continental Limousin and Charolais crossbred steers (n=66) were assigned to one of six diets: (1) high herbage allowance (18 kg grass dry matter), zero concentrate (HH0C), (2) high herbage allowance and 2.5 kg concentrate (HHLC), (3) high herbage allowance and 5 kg concentrate (HHHC), (4) low herbage allowance (6 kg grass DM) and 5 kg concentrate (LHHC), (5) medium herbage allowance (12 kg grass DM) and 2.5 kg concentrate (MHLC) or (6) concentrates ad-libitum+1 kg straw (CON). Colour was assessed in steaks (n=5) chosen at random from each dietary group and held in overwrapped and/or modified atmosphere packaging (MAP) (80 O(2):20 CO(2)) under simulated retail display conditions for 17 days. When the HH0C and the CON groups were compared, there was no significant difference in colour under overwrapped conditions, however under MAP, surface redness was significantly (P<0.01) higher (greatest Hunter "a" values) in the HH0C group. When the other four diets were compared to the HH0C and CON groups, there was no significant difference in colour under both forms of packaging. Lipid oxidation was highest for the dietary group CON compared to all other dietary groups examined. There was no significant difference in vitamin E levels between the six dietary groups, levels ranged from 1.7 to 2.5 µg/g meat.

16.
Meat Sci ; 64(2): 105-11, 2003 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22062855

RESUMO

The conditions of PSE (pale, soft, exudative) and DFD (dark, firm, and dry) are significant causes for downgrading of pigmeat resulting in financial loss to the slaughter plant. The objective of this study was to document the variation in quality of pigmeat from one slaughter plant over a 15-month period, based on colour, appearance and pH. During 4 days of most weeks, 30 pigs were randomly selected from the slaughter line, resulting in a total number of 4560 pigs. Muscle pH between the third and fourth rib was measured 45 min, 90 min and 24 h after slaughter. Using a Minolta colorimeter (Hunter L, a, b scale), colour of the longissimus dorsi muscle was measured 24 h after slaughter. Muscle colour was also visually scored on a scale of 1-6. Carcass pH at 24 h post-mortem varied significantly with month of slaughter (P<0.04) as did colour (Hunter L, P<0.001; Hunter a, P<0.001; Hunter b, P<0.001). It was concluded that meat quality as measured by 24 h pH and colour was poorest during the months of November and December. While this may be at least partly related to weather, it is probable that the increased slaughtering rates at this time and variable resting period before slaughter had the biggest impact.

17.
Meat Sci ; 64(2): 113-8, 2003 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22062856

RESUMO

Meat quality comparisons were carried out on hams produced from pork legs showing evidence of PSE and normal pork legs. Quality measurements included drip loss, sliceability, cooking loss, TBARS analysis and colour evaluation (Hunter L, a, b). A total of 40 pork legs were selected from a commercial slaughtering plant, 20 from carcasses showing PSE and 20 from normal carcasses based on L, a, b, and pH values. Carcass pH taken between the third/fourth rib was measured 45 min, 90 min, and 24 h after slaughter. Using a Minolta colorimeter (Hunter L, a, b,), colour of the Longissimus dorsi muscle was measured 24 h after slaughter. PSE had an adverse effect on cooked hams in comparison to normal cooked hams with respect to driploss (P<0.01), cooking loss (P<0.01), sliceability (P<0.01), colour (P<0.05) and lipid oxidation (P<0.05). Cooked hams manufactured from severe PSE pork in this study had an estimated financial loss of 50% (IRL£4.90) in comparison to those manufactured from normal pork (IRL£9.80).

18.
J Anim Sci ; 80(6): 1556-63, 2002 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12078737

RESUMO

The effects of three preslaughter diets on heifer beef quality were investigated. Heifers (n = 45) were divided into three groups and fed for ad libitum consumption either maize silage, grass silage, or a 50:50 mixture of maize silage and grass silage. Meat quality was determined by measuring color, lipid oxidation, alpha-tocopherol levels, and fatty acid composition. Beef from the maize silage group had poorest color stability (P < 0.05), whereas beef from the grass silage diet had best (P < 0.05) color stability. The visual panel least preferred the maize silage group after 2 or more days of display, and lipid oxidation was significantly (P < 0.001) higher in this group compared to the 50:50 maize:grass silage and grass silage groups. There was a significant (P < 0.001) difference in the alpha-tocopherol levels detected in the meat from the three dietary groups. Alpha-tocopherol levels increased in the order: maize silage < 50:50 maize:grass silage < grass silage, at levels of 2.08, 2.95, and 3.84 microg/g meat, respectively. Fatty acid analysis indicated 18:3 was significantly (P < 0.001) lower in the maize silage-fed group than in the maize:grass silage and grass silage groups. However, 18:3 was significantly (P < 0.001) higher in the grass silage group than in the other two groups. There were no significant differences in all other fatty acids among the three dietary groups. It was concluded that beef from grass silage-fed animals had better overall quality in terms of color, lipid oxidation, and alpha-tocopherol levels than beef from maize silage fed animals.


Assuntos
Bovinos/metabolismo , Carne/normas , Poaceae , Silagem , Zea mays , Animais , Antioxidantes/análise , Cor/normas , Ácidos Graxos/análise , Feminino , Metabolismo dos Lipídeos , alfa-Tocoferol/análise
19.
Meat Sci ; 61(3): 227-32, 2002 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22060844

RESUMO

Heifers (n=10) were randomly selected from the slaughter line of a local factory each month for a period of 21 months. Rib steak (sampled at the 10th rib) from the left side of each carcass was taken for analysis. The cattle breeds selected during this study were Friesian, Hereford and Charolais. The mean weight of the left side for all carcasses was 146.6 (S.E.M.= 1.0kg). Graded carcasses selected for sampling during this trial were classified using the EUROP scale and the specific heifer grades chosen were factory grades EO4L and EO4H. Initial Hunter 'a' values (on the day of arrival in the laboratory) of rib steak from heifers finished between November and March (overwintered) were significantly (P<0.001) higher than Hunter 'a' values from heifers finished between April and October (pastured). After storage at 4 °C under simulated retail display conditions for 6 days, the Hunter 'a' values for overwintered samples were also significantly (P<0.001) greater than those for pastured samples. Breed also had an effect on the colour of the meat. After storage for 6 days, Hunter 'a' values of rib steak from Charolais were significantly (P<0.05) higher than either Friesian or Hereford. Pastured heifers had significantly (P<0.05) higher levels of the monounsaturated fatty acid C16.1 in the total lipid fraction of rib steak (neutral and polar) than samples taken from overwintered heifers. Pastured heifers had significantly (P<0.01) higher levels of the polyunsaturated fatty acid (PUFA) C18.3 in the phospholipid fraction than those from overwintered cattle. However, Hereford had significantly (P<0.05) higher levels of C14.0, C16.1 and C18.0 in the phospholipid fraction than those found in Friesian and Charolais. The level of α-tocopherol in the muscle was not affected by either pasturing/overwintering or breed. However, Continental breeds had significantly (P<0.05) higher levels of α-tocopherol in adipose tissue than Friesian.

20.
Proc Nutr Soc ; 60(2): 221-9, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11681638

RESUMO

The perception of healthiness and/or safety, tenderness, juiciness and aroma or flavour are important quality criteria that influence the decision of a consumer to purchase beef. Beef production systems represent the combined and interacting effects of genotype, gender, age at slaughter and nutrition before slaughter. The present paper highlights recent information on how beef production systems can be modified to enhance the tenderness, flavour and healthiness of beef. Carcass management post-slaughter has a larger effect on meat tenderness than gender, genotype or feeding systems. Optimum 'pasture to plate' management systems are being established to ensure beef tenderness. The chemistry underlying beef flavour is complex, with in excess of 140 components identified in cooked beef volatiles. Flavour of beef is influenced by cattle diet, but assessment of flavour by a taste panel is subject to the previous experiences and preferences of the panellists. Modern lean beef can have an intramuscular fat concentration of 25-50g/kg and can be considered a low-fat food. As the quantity of grass in the diet of cattle is increased, there is a decrease in saturated fatty acid concentration, and an increase in the n-3 polyunsaturated fatty acid and conjugated linoleic acid concentrations. It is concluded that there is opportunity to exploit the diet of cattle to produce tender flavoursome beef that has an increased conjugated linoleic acid concentration, a lower fat concentration and a fatty acid profile more compatible with current human dietary recommendations.


Assuntos
Criação de Animais Domésticos/métodos , Manipulação de Alimentos/métodos , Carne/normas , Ração Animal , Fenômenos Fisiológicos da Nutrição Animal , Animais , Bovinos , Gorduras na Dieta/administração & dosagem , Humanos , Valor Nutritivo , Odorantes , Controle de Qualidade , Paladar
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