【作者】 刘冬明；

【导师】 李宗军；

【作者基本信息】 湖南农业大学 ， 食品加工与安全， 2011， 硕士

【摘要】 冷却肉与冷冻肉相比,冷却肉具有汁液流失少、营养价值高的优点。本文第一章对冷却肉与新鲜肉、冷冻肉的区别、优点,电击对猪肉品质的影响,冷却肉的冷却目的、条件和方法等方面进行了概述。本文第二章主要针对冷却肉生产过程中,快速冷却的同时容易引起肌肉冷收缩,导致肌肉内理化反应活动的加快,同时血液中的胺的含量也增加,最终致使屠宰后肌肉中糖酵解的速率加快,严重影响冷却肉的品质这一突出问题提出解决方案并进行优化。本文中采用四点式脚部电麻方式对屠宰前的电麻工艺进行优化,改进后的四点式脚部电麻方式电压为100、电击频率为2000Hz、电击时间为2s,晕死后再放血,可以使猪体均匀放血,胴体不会产生淤血,确保猪肉肉色丰润饱满,同时多点电麻可以激活并维持内源性蛋白酶的活力,促进猪肉鲜味物质的生成。采用新工艺对生猪进行电击致晕后屠宰,脊椎断裂率比采用原电击方式降低了60%,pH值下降速率降低了11%,蒸煮损失率降低了13.8%,且在嫩度、肉色感官上也有明显改善。因此,使用此工艺进行生产可明显提高企业产品的质量,增强产品在市场中的竞争力。在实际生产中,出于对生产安全性的考虑,在商业应用中采用低压电刺激工艺进行屠宰前的电击处理也比高压电刺激更具吸引力。本文第三章主要针对原生产工艺中一段式冷却方式造成干耗较大的问题进行研究,原一段式冷却方式生产过程中,冷却肉的干耗在2%以上,而采用二段式冷却方式可较大幅度的降低干耗,本文确定了二段式冷却方式加工冷却肉时的最佳工艺参数为冷却间温度-19℃、风速1.6m/s、冷却时间为2.5h(150min),在此条件下,冷却肉生产过程中的干耗为1.01%,比原工艺降低了50%以上的耗损。使用优化后的电麻与二段式冷却工艺进行生产,提高了冷却猪肉的品质,降低了冷却过程中的耗损,可为企业带来巨大的经济效益。更多还原

【Abstract】 Chill meat Compared with frozen meat, the advantages of chilled meat has less drop loss and more nutritive value.This paper’s first chapter was an overview of advantages of chilled meat, its difference between both fresh meat and frozen meat, the impact to the texture of pork made by stunning and the purpose, condition and method of chilling-down.During production process of chilled meat, the muscles’contraction in rapid chilling would increase the muscle activity and the content of amine in blood. These led to an accelerated rate of muscles’glycolysis which could badly affect the quality of chilled meat. The second chapter was mainly talking about this serious problem and how to improve it. We improved the electrical stunning technic which used before butchering by four-point hoof electrical stunning. This new technic’s voltage was 100, frequency of stunning 2000Hz, time of stunning 2s. Bloodletting after fainting would make bleeding equably and no congestion in carcasses and ensure meat color rich. Meanwhile the technic activated and kept the activity of endogenous proteases which could promote the generating of flavoring substance in pork. Compared with the old one, butchering after fainting by using new technic, the proportion of spine fracture reduced by 60%, the dropping speed of pH value slowed down by 11%, the loss of cooking lowered by 13.8% and there were significant improvements on the tenderness and color sense of meat. Therefore, by using this new technic could significantly improve the quality and enhance the competitiveness of products. In the actual production, with considering the safety of producing, low-voltage electrical stimulation is more attractive than the high-voltage one when it was applied in business.The third chapter did some research of the greater dry consumption by using one-stage cooling in the original production process. During one-stage cooling, dry consumption of chilled meat was more than 2%. However, it could be reduced markedly by using tow-stage cooling. We found out the optimal process parameters of two-stage cooling were-19℃in cooling room,1.6m/s wind speed,2.5h (150min) cooling time. On these conditions, the dry consumption was 1.01% which was lower than the original process more than 50% loss during the production process of chilled meat. Using the optimized electrical stunning and two-stage cooling in production, the improved quality of chilled meat and the reduced dry consumption during cooling would bring great economic benefits to the industry.更多还原