蛋白酶在宰前嫩化和肉类加工中的应用

肉类是人类生活中不可缺少的食品。在肉的全部质量特征中,外观质量在很大程度上决定消费者是否选购,而消费者通常都把嫩度作为重要的特征。嫩度的变化取决于许多因素,它是可以改变的。一般来说,宰前因素对结缔组织的数量、分布和类型都有作用,从而影响着嫩度。     

An evaluation of simple cleaning methods that may be used in red meat abattoir lairages

Concrete tiles artificially contaminated with field strains of Escherichia coli and Salmonella kedougou, with and without the presence of bovine faecal matter, to simulate visually clean and visually dirty surfaces respectively, were cleaned using a specially designed mechanical rig. Cleaning was carried out using (1) water under mains pressure, (2) water under pressure, (3) water under pressure with a proprietary sanitising agent, (4) steam under pressure and combinations of (5) mains water followed by steam under pressure or (6) water under pressure followed by steam under pressure. Thirty replicates of each of visually clean and visually dirty concrete surfaces were cleaned using each method. Where there was no faecal matter, the use of a proprietary sanitiser at maximum recommended concentration, or the application of steam under pressure gave greater reductions in microbial contamination than the use of mains or a pressure wash. Where the surface was visually contaminated with the faecal material, the use of a pressure wash followed by immediate steam application gave reductions in microbial contamination comparable with the use of a proprietary sanitiser at maximum recommended concentration. The use of steam alone on a visually dirty surface was not an effective means of reducing microbial contamination. A small pilot trial under commercial conditions ranked the efficacy of cleaning treatments as follows: pressure washing followed immediately by steam application was the best method of cleaning a holding pen floor, followed by use of a sanitising agent at the greatest concentration recommended by the manufacturer, and then by pressure washing alone. Pressure washing followed by a delayed steam application appeared to give a poor final result on the surface.     

浅谈低压泡沫清洗消毒技术在肉类工业中的应用

简要介绍了低压泡沫清洗消毒技术的原理及特点,分析了其在肉类加工工业中的使用方法和优势。     

pH值对屠宰肉品质的影响

介绍了pH值的概念、pH值在家畜屠宰过程中的作用、pH值对内制品品质的影响.论述了pH值对内及肉制品产品加工的特性,通过控制加工过程中产品的pH值来保证产品质量.     

屠宰工艺对冷却肉滴水损失的影响

系统地分析了生猪屠宰工艺对冷却肉滴水损失的影响.综述了禁食、致昏、戳刺、放血和胴体冷却与冷冻等工艺对冷却肉滴水损失的影响,探讨了提高冷却肉肌肉保水性的措施.     

织物干洗工艺探讨

探讨了表面活性剂与四氯乙烯干洗剂配合对织物洗涤效果及抗静电性的影响。以涤纶、纯棉、全毛织物为实验主体,模仿沾染天然污垢;对几种表面活性剂进行配比与筛选,通过所测白度及其半衰期和静电压值的比较,得到对不同织物获得所对应的混合干洗剂及抗静电剂的较好配方。实验表明：无论是对涤纶、纯棉还是全毛织物,在洗涤过程中于干洗剂中加入油溶性表面活性剂和少量水制成的混合干洗剂,不仅能有效防止污垢再沉淀,也有助于水溶性污垢的去除。洗涤质量优于不加表面活性剂的洗涤方式,且表面活性剂的加入对织物抗静电性也有一定影响。     

An alternative process for the manufacture of whole milk powder

The traditional process of manufacturing whole milk powder has some negative aspects: high heat treatment of the milk and, owing to fouling during evaporation, loss of product. To reduce these negative aspects an alternative way of producing whole milk powder was investigated in pilot-plant experiments. Milk was first separated into skim milk and cream and then treated further. Skim milk was subjected to a low heat treatment and concentrated by evaporation. The cream was subjected to a high heat treatment and mixed with the concentrated skim milk. The standardized whole milk concentrate was then spray dried. This process of manufacturing whole milk powder compared favourably with the traditional process with respect to product losses, the physical properties of the whole milk powder and the flavour of the reconstituted milk.     

The influence of slaughter method on the residual blood content of meat

The effect of slaughter method on the residual haemoglobin content of the M. longissimus dorsi and the amount of blood lost at exsanguination of sheep was investigated. The influence of stunning method (electrical, 90 V, or captive bolt pistol), pithing and bleeding-out position were examined. Sheep bled lying lost more blood than those bled hanging and electrically-stunned animals lost more blood than those stunned with a captive bolt pistol; pithing had no effect. The residual haemoglobin content of the muscle did not vary significantly between methods and there was no relationship between it and the amount of blood lost at slaughter.     

Decontamination of knives used in the meat industry: effect of different water temperature and treatment time combinations on the reduction of bacterial numbers on knife surfaces

Previous regulations in Australia and internationally required that knives used during the slaughter and dressing of carcasses be sanitized by brief submersion in water at 82 degrees C. Many current international regulations allow science-based equivalent alternative procedures to be used. However, limited time-temperature data are available on the response of bacteria to hot-water treatment on knives. The present study was undertaken to determine the effect of combinations of time and temperature ranging from 1 to 60 s and 60 to 82 degrees C on the disinfection of knives artificially contaminated with Escherichia coli and Listeria monocytogenes. In addition, the effect of a prerinse at 40 degrees C on the disinfection of artificially contaminated knives treated under the same controlled conditions as above was established. The experiments, which were carried out with knives in a meat matrix at each of 42 time and temperature combinations, with and without the prerinse, were performed in a laboratory water bath. Bacterial reductions were established by plate counts from the knife blade before and after immersion. Mean log reductions were subjected to statistical analysis, and basic models were generated from the results. The results demonstrated that dipping knives in water for shorter times at higher temperatures, for example, 82 degrees C for 1 s, or longer times at lower temperatures can produce equivalent inactivation of bacteria. Prerinsing knives at 40 degrees C increases the performance of the subsequent dipping step. Models produced from the data in this study can be used to predict suitable combinations of time and temperature to achieve a desired bacterial reduction.     

特种纸的泡沫整理工艺探讨

泡沫整理是近来才开发的一种整理加工新技术,它借助于泡沫的作用把各种整理剂均匀地涂敷在纸页的表面。典型的泡沫整理溶液含水量仅5%～10%,而空气含量为90%～95%,因此,大大地减少了纸页上所需溶液的含水量,缩短了干燥时间,节省了能源消耗。目前,该项整理技术已成功地应用于纸页的防火阻燃、拒水、增白、染色及香纸加工等。     

留兰香茎叶粉对肉兔生长性能和屠宰性状的影响

在肉兔饲料里用5%、10%和15%留兰香茎叶粉替代相应苜蓿草粉探讨留兰香茎叶粉对肉兔生长性能和屠宰性状的影响。结果表明:与对照组相比,5%留兰香茎叶粉组和10%留兰香茎叶粉组平均日采食量、平均日增重有改善向好的趋势(P>0.05),15%留兰香茎叶粉组平均日增重显著降低(P<0.05),3个组全净膛重、半净膛重、全净膛率和半净膛率均有提高的趋势(P>0.05)。添加10%留兰香茎叶粉替代苜宿草粉效果较好。     

Natural hormone patterns of meat from steers and bulls depending on slaughter age

 Natural patterns of steroid hormones (androgens, progestogens and corticoids), their precursors and metabolites were analysed in 48 beef samples with gas chromatography-mass spectrometry (GC-MS). Muscle tissue samples were taken from steers (n=23) and bulls (n=25) of the breed German Simmental, which were slaughtered at different ages (151–705 days of age). Concentrations of testosterone, dehydroepiandrosterone (DHEA), progesterone, cortisol and cortisone in beef from steers were not dependent on age, whereas pregnenolone, androstenedione and epitestosterone increased significantly with increasing slaughter age (r=0.48, P<0.05;r=0.60, P<0.01 and r=0.62, P<0.001, respectively). The concentrations of the metabolite androsterone tended to increase as well. The differences were not significant, however, due to the high level of variability. In beef from bulls cortisone concentrations were inversely correlated with increasing slaughter age (r=–0.47, P<0.05). The decrease from day 175 to day 260 was significant. Testosterone was positively correlated with increasing age (r=0.46, P<0.05). The tissue concentrations at the different slaughter ages did not differ significantly, however. The Δ5-precursors pregnenolone and DHEA tended to show a minimum at the age of 370 days, followed by a significant increase. No age dependence of the progesterone, androstenedione, androsterone, epitestosterone and cortisol concentrations could be detected. Analysis of steroid hormone concentrations may form part of a reliable method for estimating the age of slaughtered cattle. In this study, the age of samples was estimated to within ± an average of 10 weeks. Received: 29 December 1997 / Revised version: 1 March 1998     

生猪宰前皮温、宰后肉温及pH值对肉品质量影响

生猪屠宰后,肉尸(胴体)会产生系列新陈代谢变化.这一过程和结果直接关系到肉品卫生安全质量.宰前皮肤温度与宰后肌肉温度及pH值变化,是影响猪肉品质的三个主要因素.宰前充分休息与饮水,宰后严格冷却工艺和屠宰修正工艺是提高肉品品质的重要措施.     

钽丝超声波清洗工艺改进

针对钽丝清洗工艺清洗洁净度不理想,没有烘干系统易造成二次污染和钽丝划伤等问题,对清洗时超声波强度、超声波频率、清洗液选择、清洗温度和清洗速度进行研究。将原有清洗工艺中的1组超声波+自来水漂洗、自来水垂直喷淋、夹具擦拭,改为2组超声波+纯水漂洗、自来水环式喷淋、冷热风干燥,并采用水溶性生物降解清洗剂替代普通的高效除油剂。采用ZCM-700透反射显微镜及ZRJ-2000显微图像测量工艺改进后生产的钽丝残留物数量。改进后的超声波清洗工艺钽丝洗后残留物数量为5～10个/L,较之前工艺的25～30个/L有较大幅度的降低。采用水溶性生物降解超声波清洗技术,符合安全、环保、健康和节能的要求,是今后发展的趋势。     

茶皂素对肉仔鸡生长性能、屠宰性能和肉质的影响

在肉鸡日粮中添加茶皂素,研究其对肉鸡生长性能、屠宰性能和肉质的影响.对照组饲喂基础日粮,试验1、2、3和4组在基础日粮的基础上分别添加200、300、400和500 mg/kg的茶皂素,试验期为56天.结果表明:与对照组相比,4组平均日增重提高8.74%(P＜0.05)、料重比降低15.52%(P＜0.01)、屠宰率提高2.33%(P＜0.05);2、3组料重比降低了5.60%、10.34%(P＜0.05);1、2组腹脂率降低了6.92%、9.69%(P＜0.05),3、4组腹脂率降低15.92%、15.57%(P＜0.01);2组滴水损失降低5.42%(P＜0.05),而3、4组滴水损失降低11.19%、14.24%(P＜0.01).     

肉类食品保鲜包装材料与技术的研究进展

随着肉类加工产业的进一步发展以及人们对食品质量和安全的高度重视,现代食品包装材料和包装技术的重要性日益突出。肉类食品包装材料和技术的开发与创新是提高现代肉品质量和安全的前提。文章综述了不同种类的新型肉品包装材料(复合包装、活性包装、可食性膜、纳米复合包装)和包装技术(真空包装、气调包装、智能包装)在肉及肉类食品保鲜领域的应用,指出肉类食品包装材料和保鲜技术存在的优点和不足,并对其发展趋势进行了展望。     

Effect of slaughter weight and breed on instrumental and sensory meat quality of suckling kids

The effects of breed and slaughter weight on chemical composition, fatty acid groups, texture, and sensory characteristics of meat of 141 suckling male kids from 5 Spanish breeds were studied. There was a decrease in texture and lightness and hue angle with the increase of the slaughter weight. Fatty acid composition was correlated with the intramuscular fat content. All the breeds except MO had values of n-6/n-3 ratio below 4, which is the healthy limit recommended, and a low atherogenic index as well as a low intramuscular fat content. A multivariate analysis discriminated light kid, which had the most tender and juicy meat, from heavy kid which had more intense kid and milk odours. Blanca Andaluza and Pirenaica had most tender and juicy meat. The effect of slaughter weight on meat traits should be considered separately for each breed to find the most appropriate meat according to consumers preferences.     

Indicator organisms in meat and poultry slaughter operations: their potential use in process control and the role of emerging technologies

Measuring commonly occurring, nonpathogenic organisms on poultry products may be used for designing statistical process control systems that could result in reductions of pathogen levels. The extent of pathogen level reduction that could be obtained from actions resulting from monitoring these measurements over time depends upon the degree of understanding cause-effect relationships between processing variables, selected output variables, and pathogens. For such measurements to be effective for controlling or improving processing to some capability level within the statistical process control context, sufficiently frequent measurements would be needed to help identify processing deficiencies. Ultimately the correct balance of sampling and resources is determined by those characteristics of deficient processing that are important to identify. We recommend strategies that emphasize flexibility, depending upon sampling objectives. Coupling the measurement of levels of indicator organisms with practical emerging technologies and suitable on-site platforms that decrease the time between sample collections and interpreting results would enhance monitoring process control.