TENDERNESS ANALYSIS AND CONSUMER SENSORY EVALUATION OF OSTRICH MEAT FROM DIFFERENT MUSCLES AND DIFFERENT AGING TIMES1

Six ostrich carcasses were split and aged for 1 h, 1 day, or 1 week, roasted to 75 C and evaluated for tenderness and sensory attributes. Shear values for aged ostrich meat were 10.1, 10.0, 10.0, and 14.1 kg/g for 1 h, 1 day, 1 week, and the beef control, respectively. The most tender ostrich muscles identified were: M. iliofibularis, M. iliofemoralis, and M. oburatorius lateralis. Tenderness was affected by fiber orientation of the meat after slicing. Shear values were higher (p<0.05) for the longitudinal fiber orientation (11.5 kg/g) compared with the transverse fiber orientation (7.4 kg/g). A 9–point hedonic scale and a consumer sensory panel were used to evaluate tenderness, flavor, and overall acceptance of selected cuts. Ostrich meat aged for 1 week provided higher (p<0.05) liking scores for flavor compared with lesser aged ostrich or the beef control. This study suggests that prepared ostrich meat provides a good alternative compared with a similar beef product.     

Electrochemical profiling using copper nanoparticle-plated electrode for identification of ostrich meat and evaluation of meat grades

Electrochemical (EC) profiling employing copper nanoparticle-plated screen-printed electrode (Cuⁿ-SPE) exhibited specific selectivity and sensitivity to peptides that could efficiently differentiate ostrich meat from pork, beef and chicken, and to evaluate grades and freshness of ostrich meat. The four meats were differentiated in 5 min by characteristic chromatographic profiles consisting only four major peaks. Peak identification by LC/MS/MS suggested that while lysine and glutamine were shown as common components, anserine were the avian-specific and carnosine was the ostrich-missing peptide in the EC profile. Statistical analysis (ROC curve) demonstrated that peak ratios could be used to evaluate ostrich meat grades with high sensitivity (up to 95%) and specificity (up to 100%). The effects of storage temperature and time were studied for potential use of Cuⁿ-SPE to evaluate meat freshness. This HPLC-EC method appeared to be superior to UV detection in terms of profile simplicity and devoid of derivatisation process or complex sample extraction procedures, rendering it a suitable method for routine rapid differentiation of ostrich meat from common meat species with the ability to simultaneously differentiate ostrich meat grades.     

Species identification in meat products using real-time PCR.

One of the most convenient methods for the identification of animal species in processed meat products is the examination of DNA sequences. Real-time polymerase chain reaction (qPCR) techniques are particularly suitable because even small fragments of DNA formed during heat processing of the meat can be amplified and identified. A real-time PCR method has been developed and evaluated for the identification of processed meat products. In test mixtures containing beef, pork, horse, mutton, chicken and turkey, it was possible to identify these species down to a level of 0.05%. By adjusting the number of cycles, it was possible to detect levels as low as 0.01% of these species. Cross-reactivity between these species was not found, except for pure horsemeat (250 ng DNA) in the assay for turkey meat. Cross-reactivity of deer, roe, ostrich, kangaroo, goat, domestic duck, mallard, goose, pigeon, guinea fowl, quail and pheasant was also investigated and it was found that amounts as high as 250 ng DNA of these species in the reaction vial did not result in (false) positive signals except for amounts higher than 125 ng deer DNA and higher than 50 ng pigeon DNA in the determination of chicken and beef, respectively. More than 150 meat samples were examined using DNA hybridization and real-time PCR. A comparison of the results showed a better performance of the real-time procedure compared to DNA hybridization.     

Physical, Chemical, and Sensory Properties of Bologna Sausage Made with Ostrich Meat

Three formulations of bologna were prepared, differing only by the lean meat used: (1) ostrich meat from Iliofibularis muscle (fan thigh), (2) ostrich meat from Femorotibialis medius muscle (tip thigh), and (3) beef meat from Subscapularis muscle (shoulder). Physical, chemical, and sensory analyses were made. The final products formulated with ostrich meat, although having a dark appearance, were acceptable in chemical composition and other sensory characteristics. The low fat and high protein content for ostrich bolognas will help to ensure that, if marketed in sufficient quantities, ostrich meat can successfully compete with other healthy meat products. The ostrich meat (Iliofibularis muscle) formula reached the highest general quality scores in the sensory evaluation.     

Species identification in meat products using real-time PCR

One of the most convenient methods for the identification of animal species in processed meat products is the examination of DNA sequences. Real-time polymerase chain reaction (qPCR) techniques are particularly suitable because even small fragments of DNA formed during heat processing of the meat can be amplified and identified. A real-time PCR method has been developed and evaluated for the identification of processed meat products. In test mixtures containing beef, pork, horse, mutton, chicken and turkey, it was possible to identify these species down to a level of 0.05%. By adjusting the number of cycles, it was possible to detect levels as low as 0.01% of these species. Cross-reactivity between these species was not found, except for pure horsemeat (250 ng DNA) in the assay for turkey meat. Cross-reactivity of deer, roe, ostrich, kangaroo, goat, domestic duck, mallard, goose, pigeon, guinea fowl, quail and pheasant was also investigated and it was found that amounts as high as 250 ng DNA of these species in the reaction vial did not result in (false) positive signals except for amounts higher than 125 ng deer DNA and higher than 50 ng pigeon DNA in the determination of chicken and beef, respectively. More than 150 meat samples were examined using DNA hybridization and real-time PCR. A comparison of the results showed a better performance of the real-time procedure compared to DNA hybridization.     

Sensory profiles of breast meat from broilers reared in an organic niche production system and conventional standard broilers

BACKGROUND: Breast meat from broilers produced in very different production systems may vary considerable in sensory profile, which may affect consumer interests. In this study the aim was to evaluate differences in the sensory profiles of breast meat from five broiler products: two conventional standard products (A and B) and three organic niche genotypes (I657, L40 and K8) reared in an apple orchard. RESULTS: Thirteen out of 22 sensory attributes differed significantly between the products. The aroma attributes ‘chicken’, ‘bouillon’ and ‘fat’ scored highest and the ‘iron/liver’ aroma lowest for the niche products. The meat was more ‘tender’, ‘short’ and ‘crumbly’ and less ‘hard’ and ‘stringy’ in the standard products than in one or more of the niche products. Product ‘I 657’ was less ‘juicy’ than the rest. Products ‘I 657’ and ‘L 40’ were more ‘cohesive’ and tasted more ‘sourish’ and less of ‘sweet/maize’ than the standard products. The ‘overall liking’ score was significantly higher for the ‘K 8’ product than for the ‘Standard A’ and ‘L 40’ products. The ‘overall liking’ score was significantly correlated with the scores for aroma and taste of ‘chicken’, ‘umami/bouillon’, ‘iron/liver’ and ‘fat’ aroma. CONCLUSION: The sensory profiles differed particularly between conventional standard broilers and organic niche broilers, although differences were also found between breeds. The present study indicates that aroma and taste attributes were more important for the assessors than meat ‘tenderness’ for the overall liking of broiler meat. Copyright © 2011 Society of Chemical Industry     

Species identification in meat products using real-time PCR

One of the most convenient methods for the identification of animal species in processed meat products is the examination of DNA sequences. Real-time polymerase chain reaction (qPCR) techniques are particularly suitable because even small fragments of DNA formed during heat processing of the meat can be amplified and identified. A real-time PCR method has been developed and evaluated for the identification of processed meat products. In test mixtures containing beef, pork, horse, mutton, chicken and turkey, it was possible to identify these species down to a level of 0.05%. By adjusting the number of cycles, it was possible to detect levels as low as 0.01% of these species. Cross-reactivity between these species was not found, except for pure horsemeat (250 ng DNA) in the assay for turkey meat. Cross-reactivity of deer, roe, ostrich, kangaroo, goat, domestic duck, mallard, goose, pigeon, guinea fowl, quail and pheasant was also investigated and it was found that amounts as high as 250 ng DNA of these species in the reaction vial did not result in (false) positive signals except for amounts higher than 125 ng deer DNA and higher than 50 ng pigeon DNA in the determination of chicken and beef, respectively. More than 150 meat samples were examined using DNA hybridization and real-time PCR. A comparison of the results showed a better performance of the real-time procedure compared to DNA hybridization.     

白切鸡食用品质评定方法研究

目的建立一套客观评定白切鸡产品食用品质的标准方法。方法以色差法、剪切力法、离心和压榨损失法以及主观评分法测定样品的色泽、嫩度、保水性和感官评定。结果取样位置、样品尺寸和测定条件的变化对白切鸡的食用品质评定具有显著影响。最终选取鸡胸肉进行颜色评价、选取背部进行pH值评定、将鸡胸肉切成尺寸为1 cm×1 cm×4 cm的体积进行嫩度评定、转速为5000 g/min和加压条件为35 kg/5 min进行保水性评定,在上述条件下变异系数最小,结果最为稳定;白切鸡的感官特征复杂而多变,任何单一描述词都无法对其准确描述。结论成功构建出白切鸡感官评定判定方法,可为传统白切鸡的生产现代化改造提供技术支撑。     

Comparison of glutathione peroxidase activity,and of total and soluble selenium content in two muscles from chicken,turkey, duck,ostrich and lamb

Glutathione peroxidase activity (GSHPx), total and soluble selenium in two muscles from five species were compared (chicken, duck, turkey, ostrich and lamb). The highest GSHPx activity, found in duck muscles (4.8 U/g; 3.0 U/g), was significantly higher than that in lamb (1.8 U/g; 1.4 U/g), turkey (1.2 U/g; 0.6 U/g), chicken (1.0 U/g; 0.7 U/g), and ostrich muscles (0.9 U/g; 0.8 U/g). GSHPx activities were significantly higher in the oxidative muscles from chicken (thigh), duck (breast), turkey (thigh) and lamb (PM) than those in the corresponding glycolytic muscles (breast, thigh, breast and LD, respectively). Also the total selenium content was higher in duck muscles (149 ng/g; 139 ng/g), than in lamb (171 ng/g /PM, M. psoas major/ and 86 ng/g /LD, M. longissimus dorsi/), chicken (117 ng/g; 109 ng/g), ostrich (106 ng/g; 103 ng/g) and turkey muscles (110 ng/g; 70 ng/g). The selenium content was significantly higher in the oxidative muscles of lamb and turkey than in the corresponding glycolytic muscles. The percentage of soluble selenium in lamb PM was lower (32%) than that in all other muscles (range 48–76%). The study thus showed considerable variation, among species, of glutathione peroxidase activity, total and soluble selenium content in muscle, which may be important for the oxidative stability and nutritional value of different meat products.     

Comparison of postmortem changes in goose cardiac and breast muscles at 5 °C

BACKGROUD: The tenderness of goose heart is an important consideration in its utilization as a popular meat product. It is generally thought that postmortem degradation of myofibrillar proteins may improved meat tenderness. Little information, however, is available regarding the postmortem changes in goose cardiac muscle. Therefore, the postmortem proteolysis between goose cardiac and breast muscles at 5 °C is compared. RESULTS: The pH is higher (P < 0.05) in cardiac samples than in breast samples. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis and western blots results indicate that postmortem degradation of titin and desmin and the appearance of the 28 and 30 kDa components are faster in breast muscle than in cardiac muscle. CONCLUSION: Our results may suggest that goose postmortem proteolysis occurs more rapidly in breast muscle than in cardiac muscle at 5 °C. Copyright © 2008 Society of Chemical Industry     

Biochemical and technological characteristics of hot chicken meat

In the hot breast and leg muscles of broiler chicken the level of ATP, the 'R' value, the lactic acid content, the pH value, the length of sarcomers, the water and fat retention capacity, the fat emulsion stability, thermal drip, and the extractability of protein fraction were investigated. It was found that in the breast muscles the onset of rigor mortis commenced within 30–60 min, and in the leg muscles as early as 15–30 min after killing of the birds. The deepest rigor mortis occurred between the first and fourth hour, and then gradually declined, sooner in the leg than in the breast muscles. The addition of sodium chloride (2.0–2.5%) to the minced pre-rigor meat not later than 40 min after slaughter, or better, an injection of NaCl brine into intact muscles 15 min after slaughter of birds, preserved their good technological properties.
The tenderness and the thermal drip of hot salted and chilled salted muscles showed no significant differences, but water retention and fat emulsifying capacity were better in the hot salted meat samples. The hot salted and cooked muscles were preferred by the sensory panel to corresponding samples of chilled muscles.
From the hot salted chicken meat more sarcoplasmic and myofibrillar proteins were extracted than from meat salted after chilling. However, after frozen storage the extractability of myofibrillar proteins were higher in the salted chilled meat.     

超高压技术对鹅肉嫩度的影响

研究超高压技术对鹅肉嫩化效果的影响,在室温(20℃)条件下,采用不同压力(0～500MPa)和不同时间(0～30min)对鹅肉进行嫩化处理,得出嫩化效果较好的压力和处理时间,并采用响应面优化超高压工作条件。单因素试验结果表明：压力300MPa、处理时间20min时,鹅肉的嫩化效果较好。通过响应面统计分析,压力和处理时间两因素具有交互作用,优化后的参数为：压力292MPa、高压处理时间19.75min条件下,失水率最低;压力246MPa、高压处理时间23.85min时持水率最高。超高压技术处理鹅肉可以明显增加其嫩度,具有较好的应用前景。     

黄羽肉鸡胴体冷藏时间对蒙山炒鸡食用品质的影响

研究黄羽肉鸡胴体冷藏时间（0～4 ℃,0、24、48 h）对蒙山炒鸡食用品质的影响。取蒙山炒鸡的鸡腿肉和鸡胸肉,测定其肉色、质地、pH值、系水率和挥发性物质含量等指标,并进行感官评定。结果表明：0 h组（对照组）和24 h组炒鸡鸡胸肉亮度值（L*）均显著高于48 h组（P＜0.05）;24 h组炒鸡的鸡腿肉L*显著高于0 h组和48 h组（P＜0.05）;0 h组和24 h组炒鸡的鸡腿肉和鸡胸肉硬度显著高于48 h组（P＜0.05）;感官评定结果表明,除48 h组香气评分显著降低（P＜0.05）、24 h组色泽评分显著升高（P＜0.05）外,各组滋味、组织形态评分及总分差异较小。因此,屠宰黄羽肉鸡后,宜冷藏24 h内炒制,以达到更好的食用品质。     

高强度超声对鹅胸肉嫩度及品质的影响

为了解超声技术对鹅胸肉品质的影响,采用高强度超声（超声功率800 W,超声总时间42 min,工作时间 2 s、停歇时间3 s）对鹅胸肉进行处理。测定未超声和超声处理的鹅胸肉于4 ℃下放置不同时间（0、6、12、24、 36、48 h）的pH值、肌原纤维小片化指数、蒸煮损失率、剪切力、表面微观结构、肌原纤维蛋白降解情况、肉品 的热力学性质等指标。结果显示：与未经超声处理的鹅胸肉相比,超声处理后随着放置时间的延长,肉品pH值升 高,肌原纤维小片化指数显著增大,蒸煮损失率和剪切力显著减小（P＜0.05）;表面微观结构发生明显变化,肌 动蛋白和肌球蛋白热敏性增大,导致更多肌原纤维蛋白降解,游离肌动蛋白含量显著增加（P＜0.05）,从而显著 改善鹅胸肉的嫩度。因此,超声处理可破坏鹅胸肉肌原纤维的完整结构,缩短宰后肉品成熟所需时间,进一步提高 鹅胸肉的品质。     

鸡肉冷藏成熟过程中新鲜度和嫩度与肽含量关系

为研究冷藏成熟过程中鸡肉新鲜度和嫩度与肽含量的关系,以刚屠宰的鸡胸肉为研究对象,探究宰后鸡肉常规冷却与快速冷却过程中的肽含量与其感官评分、新鲜度和嫩度的相关性。结果表明：鸡肉中肽含量随冷藏时间的延长先下降后上升,在冷藏0.5 d时达到最低值,冷藏3 d后逐渐上升,且常规冷却组鸡肉肽含量极显著高于快速冷却组（P＜0.01）;鸡肉中总游离氨基酸含量与肽含量变化趋势相反;冷藏0.5 d后,随着冷藏时间的延长,鸡肉中肽含量与pH值、菌落总数及挥发性盐基氮（total volatile basic nitrogen,TVB-N）含量同步上升,而剪切力及感官评分逐渐降低。快速冷却能够延长成熟的时间,有利于鸡肉贮藏保鲜。冷藏期间,2 组鸡肉中的肽含量与菌落总数、pH值和TVB-N含量呈显著或极显著正相关（P＜0.05、P＜0.01）,肽含量可用于评价鸡肉的新鲜度。     

Ostrich meat: Physico-chemical characteristics and comparison with turkey and bovine meat

In several European countries ostrich breeding has now become quite common. In Italy this has also given rise to the need for regulations for the slaughtering of Ratites. The present work studies and compares the physico-chemical characteristics of the meat from the thigh of the ostrich with the same anatomical cuts of turkey and bovine. The ostrich meat muscle of the thigh was imported vacuum packed from Israel and France, the muscles considered were m. flexor cruris and m. iliofibularis. The turkey thighs were from the domestic market (supermarket) and the bovine muscle m. pectineus was from spent milking animals from an EEC slaughterhouse. Needless to say that the breeding, the feeding and the system of slaughtering could influence some parameters of the different kinds of meat; however these factors could not be assessed. Due to its tenderness, low fat content and cholesterol levels ostrich meat is, in accordance with modern-day nutritional principles, a valid alternative to other kinds of meat.     

Biochemical and sensorial evaluation of intact and boned broiler breast meat tenderness during ageing

Meat tenderness is the main characteristic demanded by consumers and is affected by rigor mortis development and proteolysis activities, both of which occur during carcass refrigeration. In this work, we demonstrate that broiler breast fillet tenderness can be further increased and its extension depends on whether or not meat is excised from the carcass. Post-harvest samples taken from 0 to 72 h after slaughtering and kept refrigerated at 2 ± 2 °C were evaluated for tenderness by myofibrillar fragmentation index determination, shear force analysis and sensorial testing. The 24 h post-harvested intact samples were 30.6% more tender than excised samples and 41.7% more tender than control samples (p ? 0.05). The myofibrillar fragments index was 13.2% higher in intact samples than in deboned fillet (p ? 0.05) and a sensory test showed that the 24 h intact samples were of major acceptability. Our results demonstrated that tenderness was best achieved with intact breast fillet samples stored at 2 ± 2 °C for 24 h.