Woody Breast短期贮藏中肉质的变化

为研究近年来速生型肉鸡鸡胸肉硬度缺陷(woody/wooden breast,WB)俗称"木质肉"在短期贮藏中生肉肉质参数的变化。实验选取68只42日龄Cobb 500肉鸡作为研究对象,经宰杀后人工分级为低(normal,NORM)、高(severe,SEV)两组(n=34只/组)。在不同时间节点下(1、3、8 d)对所有样本测定质量、挤压力(compression force,CF)、滴水损失(drip loss,DL)、肌节长度(sarcomere length,SL)及肉破碎化指数(gravimetric fragmentation index,GFI)。对所有参数进行组间(不同WB等级间,不同时间节点)显著性分析,同时对各参数与WB等级间进行相关性分析。结果表明:SEV样本质量、CF、SL、GFI在贮藏时间节点处都显著高于NORM样本(P0.05),DL在1 d时NORM与SEV间无差异,在3~8 d时显著上升(P0.05)。CF、SL、GFI在1~3 d时,所有样本都显著减小(P0.05),3~8 d时CF无显著变化(P0.05),SL、GFI在NORM样本间无差异但在SEV样本间继续减小(P0.05)。相关性分析表明,CF、累积DL与WB等级极显著相关(P0.01),SL、GFI随时间变化与WB硬度减小存在联系。综上可知,SEV生肉肉质较NORM差,WB硬度随贮藏时间变长而减小,但其生肉品质并不会发生改变,因此对WB检测应在宰杀当天在线进行,且WB硬度由多种原因共同作用导致。     

Application of multivariate statistical analysis to quality control systems. Relevance of the stages in poultry meat production

The poultry meat production includes several stages. In this study, the whole process has been evaluated in order to determine the stages or processes which must be specially taken into account in the control system, and which other could be out of the routine controls. The study has been carried out in reverse by studying the relevance of every stages starting from the end of the process towards the initial point.A sequence of operations and consecutive statistical analyses has been performed to finally state the stages and/or operations that must be controlled.Based on the result of statistical studies, the plucking, gutting, washing and classifying stages should be considered Process Control Points. Air chilling and packaging stages are not considered checkpoints in the process verification system, although they should be included within the Good Hygiene Practices, since factors such as temperature, time, cleaning, disinfection or appropriate conditions of handling should be monitored.     

Intensive sheep and beef production from pasture — A New Zealand perspective of concerns,opportunities and challenges

This paper details current production trends for sheep and beef cattle production in New Zealand and gives some insight into the opportunities for improvement based on New Zealand research at Massey University. Further it outlines some of the challenges the industries face in the near future. The New Zealand climate favours pasture growth and this is the key to sheep and beef cattle production with over 95% of the diet being grazed pasture or crop. Exports are the focus of the industry with 95% of sheep meat and wool, and 80% of beef exported. There have been considerable gains in production over the last 20 years but there still remains a huge opportunity for further intensification through breeding sheep at an earlier age, increasing the weight of lambs weaned per ewe per year and improving beef production systems. These improvements need to occur within a framework of minimal environmental footprint and produce products that are in demand in the high end international markets.     

Level of natural hepatotoxin (Indospicine) contamination in Australian camel meat

Camel meat production for human consumption and pet food manufacture accounts for a relatively small part of overall red meat production in Australia. Reliable statistical data for the Australian production and consumption of camel meat are not available; however, it is estimated that 300,000 feral camels roam within the desert of central Australia, with an annual usage of more than 3000 camels for human consumption, 2000 for pet food manufacture and a smaller number for live export. Despite a small Australian camel meat production level, the usage of camel meat for pet food has been restricted in recent years due to reports of serious liver disease and death in dogs consuming camel meat. This camel meat was found to contain residues of indospicine, a non-proteinogenic amino acid found in certain Indigofera spp., and associated with mild to severe liver disease in diverse animals after dietary exposure to this hepatotoxin. The extent of indospicine-contaminated Australian camel meat was previously unknown, and this study ascertains the prevalence of such residue in Australian camel meat. In this study, indospicine levels in ex situ (95 samples collected from an abattoir in Queensland) and in situ (197 samples collected from camels after field culling in central Australia) camel meat samples were quantitated using a validated ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The quantitation results showed 46.7% of the in situ- and 20.0% of the ex situ-collected camel meat samples were contaminated by indospicine (more than the limit of detection (LOD) of 0.05 mg kg^–1 fresh weight). The overall indospicine concentration was higher (p < 0.05) in the in situ-collected samples. Indospicine levels detected in the present study are considered to be low; however, a degree of caution must still be exercised, since the tolerable daily intake for indospicine is currently not available for risk estimation.     

Effect of dietary supplementation of Spirulina (Arthrospira platensis) and Thyme (Thymus vulgaris) on rabbit meat appearance,oxidative stability and fatty acid profile during retail display

The objective of this study was to evaluate the effect of Spirulina and Thyme supplementation on rabbit meat during retail display. At weaning 294 rabbits were allocated to 7 different treatments (42 rabbits/treatment). Rabbits of the control group (C) received a diet without any supplementation throughout the experiment (5–11 weeks of age). The other groups were fed diets containing 5% Spirulina (S), 3% Thyme (T) or both supplements (ST) for the whole trial (5–11 weeks; treatments S, T and ST), or for a part of the growing period (8–11 weeks; treatments C–S, C–T and C–ST). Colour parameters, pH, water holding capacity and drip loss were determined on fresh and stored Longissimus dorsi muscle of 5 rabbits/treatment. Spirulina- and Thyme-supplemented diets had a significant effect on redness and yellowness of Longissimus dorsi. Drip loss was significantly reduced in C–T and T groups that also showed the highest content of α-tocopherol and n − 3 fatty acids content and the lower lipid oxidation.     

Zinc oxide nanoparticles loaded active packaging,a challenge study against Salmonella typhimurium and Staphylococcus aureus in ready-to-eat poultry meat

Zinc oxide nanoparticles were prepared using hydrothermal synthesis approach. Formation of zinc oxide nanoparticles were confirmed by using UV–Vis spectrophotometer, Fourier transform infrared spectrometer and X-ray diffractometer. The particles size (≤100 nm) and structure of nanoparticles were studied under scanning and transmission electron microscope. The nanoparticles were used against two prominent foodborne pathogens, Salmonella typhimurium and Staphylococcus aureus and were found highly effective against both of them. The antibacterial activity of the nanoparticles was determined in solid and liquid media using nutrient agar and broth. Zinc oxide nanoparticles loaded active film of calcium alginate was prepared for active packaging against the same foodborne pathogens (S. typhimurium and S. aureus). Presence and distribution of nanoparticles in active film were confirmed with Fourier transform infrared spectrometer, X-ray diffractometer and scanning electron microscopy. Zinc oxide nanoparticles loaded active films showed antibacterial activity against the target bacteria in Petri dish. The film was also used as an active packaging (a challenge study) in ready-to-eat poultry meat against the same pathogens, and reduced the number of inoculated target bacteria from log seven to zero within 10 days of its incubation at 8 ± 1 °C.     

Effect of muscle and intensity of finishing diet on meat quality of foals slaughtered at 15 months

The effect of muscle and intensity of finishing diet on meat quality of foals slaughtered at 15 months was study. For this work, a total of twenty one foals and six muscles: longissimus dorsi (LD), semimembranosus (SM), semitendinosus (ST), biceps femoris (BF), triceps brachii (TB) and Psoas major & minor (PM) from two different intensities of finishing diet (1.5 vs. 3 kg/day) were analysed.     

Effect of heat treatment on foaming properties of ostrich (Struthio camelus) egg white proteins

The effect of heat-treatment on foaming properties of ostrich albumen was investigated. At pH 7.5, coagulation of ovotransferrin (OT) resulted in minimum foaming capacity (FC) and maximum foam density (FD). While both exposure of sulfhydryl groups of ovalbumin (OV) and OT-OV interactions improved FC at lower pH, neither of them had beneficial effect on FC at pH 9. At pH 9, FC and FD were mildly affected by heat-treatment because of less aggregation of OT, then FC decreased due to covalent aggregates composed of ovomucin and OV, but at higher temperatures, higher level of OV unfolding resulted in enhanced FC.