Effects of double-muscling on carcass quality, beef tenderness and myofibrillar protein degradation in Belgian Blue White bulls

Carcass properties and meat quality characteristics of 32 Belgian Blue White double-muscled bulls (DM) were compared with those of 59 bulls of the same breed with normal conformation (N). DM showed superior carcass quality as revealed in increased dressing percentage, meat production yield, conformation grade, muscle/fat and muscle/bone ratios (all P < 0·001). Longissimus dorsi (LD) shear force values, drip and cooking losses at 8 days post mortem (pm) were significantly higher (P < 0·001) for DM, whereas sarcomere lengths were not different. Calpain 1 and calpastatin levels at 1 h and 24 h pm were tremendously decreased in DM as were also cathepsin B and L levels at 1 and 8 days pm (P < 0·001). As evident from semi-quantitative SDS-PAGE, these differences were accompanied by higher titin and lower 30 kDa levels (P < 0·001) in DM. Troponin-t levels were not different, but very low. Intramuscular collagen content was significantly lower in DM (P < 0·001). This suggests that lower background toughness in DM was compensated for by reduced post-mortem proteolytic tenderization. Discrepancy with literature reports regarding tenderness of DM might be related to the extreme muscularity of the Belgian Blue White breed, compared to other DM breeds. The results also suggest that reduced protein turnover might be involved in the muscle hypertrophy phenomenon within this breed, because of likely reduced levels of calpains and cathepsins in living DM animals.     

Incidence of different pork quality categories in a Portuguese slaughterhouse: A survey

This study was designed to evaluate the incidence of the PSE/DFD status in a Portuguese pig slaughterhouse, covering two seasons of the year (spring and summer) in order to find out if the proportions of those poor meat quality categories were sufficient to concern the meat industry. Meat quality classification was based on the measurements of the pH(60), pH(24), drip losses and colour (L, a, b) in the longissimus dorsi muscle (between the last third and fourth ribs) of 380 pigs randomly chosen from the line. The high global incidence of PSE and likely PSE (30%) as well as DFD (10%) carcasses and the enormous variation of the meat quality between the different days of analysis proves that the pig population presents a great variation of halothane genotype and that handling procedures have to be optimized in order to decrease stress and glycogen store depletion. The percentage of PSE carcasses during the summer season was double that found in the spring, probably due to a higher environmental temperature and relative humidity.     

Physiological aspects of androstenone and skatole formation in the boar-A review with experimental data

The advantages of boars in fattening performance and carcass traits when compared with the other sexes are explained by testicular anabolic hormones. The steroid androstenone with a pronounced urine-like odour is the main objection against boar meat. More recently skatole (faecal odour) has been identified as another contributor to off-odour of pork. Androstenone is synthesized in the testes, secreted into the circulation and accumulated in adipose tissue due to its lipophilic property. Its biosynthesis is linked to the synthesis of anabolic testicular hormones. Therefore no practical method is available to maintain the sex-dependent anabolic potential of boars and to suppress androstenone selectively. Skatole is formed from tryptophan by specialized microbes in the colon when energy in the colon is limited. Gonadal hormones, but also growth hormone and IGF-1, favour its formation. Oestrogens, which are synthesized in high amounts in boar testes, decrease voluntary food intake, thus lowering the intestinal passage rate. Additionally oestrogens probably influence directly intestinal contractions via specific gut receptors. It appears, however, that glucocorticoids are more important. They counteract mitogenic hormones, such as IGF-1, ultimately leading to gut mucosal cell degradation. The resulting cell debris probably is the main source of tryptophan for microbial skatole formation. In contrast to androstenone, skatole formation can be easily suppressed by dietary means.     

助剂与染料在染浴内的相互作用

助剂与染料在染浴内的相互作用Ａ．Ｄａｔｙｎｅｒ１前言助剂，顾名思义是以润湿与匀染、将溶解度低的染料予以分散而协助染色。匀染时，当纺织品加入染浴后，助剂即刻使其润湿并控制吸附染料，与染料之间发生相互作用。本文介绍了两类染色助剂：表面活性剂及分散剂。前者...     

餐饮中采用PLC控制传送带的设计

厨房中的传统采用人工进行饭菜的传送,本设计采用系统控制的方法进行传送,点餐也支付可以通过通用支付方式来进行进行信号的触发,从而将信号传递到自动控制系统,本文主要对得到控制信号的系统进行控制,从而减轻餐厅的点餐压力,更好的实现自动化控制.在分析、处理随机信号逻辑关系的基础上,提出了PLC的编程方法,设计了一套完整的餐台点餐送餐采用传送带控制系统方案.采用本方案实现传送餐控制,能够解决继电器——接触器触点多,故障率高、可靠性差、安装调试周期长、维修工作量大、接线复杂等缺点.使点餐送餐运行更加安全、方便、舒适.     

履带车辆行驶平顺性仿真及试验

基于虚拟样机技术,结合三维造型软件、有限元分析和多体动力学软件,对履带车辆行驶平顺性仿真技术进行了研究.建立履带车辆的刚柔混合虚拟样机模型及随机不平路面模型,生成平顺性仿真模型系统,通过在F等级随机路面行驶仿真,得到车辆行驶时驾驶员座椅位置振动加速度曲线,根据评价标准对车辆进行平顺性评价,并与实车试验测试数据的计算结果进行对比分析.结果表明,仿真模型系统及评价方法合理,可以为提高和改善履带车辆的机动性能提供有效的方法和手段.     

太阳能独立光伏发电系统控制系统的研究与设计

太阳能具有取之不尽、用之不竭和清洁安全等特点,是理想的可再生能源。太阳能光伏发电技术作为太阳能利用的一个重要组成部分,被认为是二十一世纪最具发展潜力的一种发电方式,对于缓解能源危机、减少环境污染以及减小温室效应具有重要的意义。论文分析研究了基于TMS320F2812 DSP的独立光伏发电系统及其控制系统的硬件设计和软件编程思路。