【作者】 黄壮霞；

【导师】 张慜；

【作者基本信息】 江南大学 ， 食品工程， 2004， 硕士

【摘要】 随着生活质量的不断提高，人们食用牛肉需求量越来越大，牛肉是国际市场上品质最优的主要鲜肉产品。研究MAP保鲜技术在生鲜牛肉上的应用，具有很重要的现实意义。国内关于气调保鲜的研究多集中在生鲜猪肉或猪肉类制品，本文采用牛肉为原料，主要对延长生鲜牛肉的低温货架期进行了重点研究，对生鲜牛肉MAP保鲜低温贮藏的手段和条件进行了一些探索。本文采用气调包装以及结合真空预处理、低温贮藏、添加保鲜剂等方法延长生鲜牛肉的保鲜期。保鲜效果的考察指标主要有：色差值、pH值、菌落总数、H2S 试验和感官评定，单指标分别进行比较，综合评价保鲜的效果。本文首先研究了单纯气调包装技术（MAP）应用于鲜牛肉保鲜，气调包装技术是目前肉类保鲜技术中比较先进的手段，填充的气体成份有：O2、CO2、N2，其中O2、CO2对保鲜效果起直接作用，N2只是起填充气体的作用，试验中选择同样的气体比例，通过不同温度下（常温、4℃、0℃）贮藏，比较鲜牛肉的保鲜效果，最后确定贮藏温度以0—4℃为佳。接着研究分析了气调包装时充入的气体比例对牛肉保鲜效果的差异，最后确定充入的气体比例为40％O2，25％CO2，35% N2时气调包装保鲜效果较好，0—4℃条件下至少贮藏7天。其次，本文进行了气调包装同时添加保鲜剂联合保鲜生鲜牛肉的试验，试验结果表明联合添加保鲜剂对延长鲜牛肉的保鲜期是有效的，文中选择了乳酸、山梨酸钾、抗坏血酸这三种常用食品添加剂作为保鲜剂，通过不同的添加剂量的比较、不同添加组合的比较，最后发现，同时添加0.1g/dL乳酸、2.0g/dL山梨酸钾和3.0g/dL抗坏血酸时，保鲜效果较好，能有效抑制鲜牛肉的菌落总数，使鲜牛肉的保质期延长3天左右。再次，本文还进行了气调包装联合真空预处理手段对鲜牛肉保鲜效果的研究，在气调包装前先经过真空预处理的牛肉，保鲜期大大延长，0-4℃条件下贮藏14天，仍能保持一级鲜肉的感官质量。通过优化试验，发现气体比例、预处理的终温和压力对保鲜效果均有影响，在40％O2，25％CO2，35% N2，终温为4℃ 预冷压力为1200Pa时气调包装保鲜效果最好，0—4℃条件下至少贮藏14天。本试验为今后进一步研究打下了基础，为小包装生鲜牛肉的保鲜提供了技术支持。更多还原

【Abstract】 The demand of beef is increasing with the increase in living standards of Chinese people. It is one of the main fresh meat products in the international market. There is a high demand of good quality beef. Therefore, the study of modified atmospheric packaging (MAP) in the preservation of fresh beef is of practical value and great significance. Unlike other domestic researches involving the technology of MAP, most of which mainly discuss on its appliance in fresh pork or other related products, this study is focused on methods and conditions to preserve fresh beef at low temperature in modified atmosphere with the aim of extending the shelf life. It was studied to apply MAP combined with vacuum and/or preserving agents pretreatment, storage at low temperature in the extension of the shelf life of fresh beef. The parameters about the effect of preservation include color difference value, pH value, total microorganism count, cooking loss, H2S experiment and organoleptic evaluation. The overall evaluation of the effect of preservation was obtained after single factor test was compared.First, application of MAP to preserve fresh beef was studied in this paper. At present MAP was an advanced technology to preserve fresh meat. The atmosphere contained O2, CO2 and N2. The O2 and CO2 had preservative effect and the N2 is only served as a kind of containing atmosphere. The suitable storage temperature of 0—4℃ was obtained based on the experiment of storing the fresh beef at different temperature (ambient temperature, 4℃ and 0℃) in the same atmosphere. To optimize the gas concentrations, this paper studied the effect of different proportion of atmosphere on the preserve of fresh beef. Thus, the oxygen concentration, that is 40％ and the carbon dioxide concentration, that is, 25％ were selected to be most appropriate to preserve fresh meat for 7 days at 0—4℃. Second, the methods of MAP combined with lactic acid, potassium sorbate and ascorbic acid as preserving agents to preserve fresh beef was studied. The result showed it was effective to extend the storage of fresh beef. The test about the additional dosage and proportion of the various preserving agents mentioned above showed the decontaminating of fresh beef with 0.1g/dL lactic acid, 2.0g/dL potassium sorbate, 3.0g/dL ascorbic acid for ten minutes simultaneously prior to packaging in modified atmosphere could significantly reduce total microorganism count of fresh beef and preserved the fresh beef for 10 days. In this study, a better preservative effect was obtained with vacuum pretreatment prior to packaging fresh beef in modified atmosphere. The test showed all of these factors, such as the proportion of atmosphere, final temperature and pressure of vacuum pretreatment, had an impact on the preservative effect. By optimization experiment, the pretreatment with 4℃ as the final temperature and 1200Pa as the pressure of vacuum pretreatment prior to packaging in 40％O2，25％CO2，35% N2 atmosphere had the best effect on preserving fresh beef with a result of 14 days storage at 0—4℃ and the fresh beef still remained the sensory quality as first grade fresh meat. <WP=7>Further research is needed to provide a technology for the storage of fresh beef according to these results.更多还原