【作者】 赵庆；

【导师】 王清章；

【作者基本信息】 华中农业大学 ， 食品科学与工程， 2011， 硕士

【摘要】 本文综述了国内外鸡蛋的储藏保鲜技术的现状,提出了分别以不同浓度的臭氧、负离子结合保鲜盒包装处理贮藏鸡蛋的技术方案,在30℃、相对湿度80%的条件下,以不同浓度的臭氧、负离子处理鸡蛋贮藏四周的比较试验,首先研究臭氧及负离子对贮藏过程中鸡蛋的感官品质、理化指标、微生物指标(主要是贮藏过程中菌落总数)的变化规律。其次通过对于影响鸡蛋安全的主要的三种细菌(金黄色葡萄球菌、大肠杆菌及沙门氏菌)的具体研究,来探索臭氧、负离子的杀菌效果。第三,研究了对于鸡蛋溶菌酶的作用。最后,研究鸡蛋主要营养指标的变化。主要实验结果如下：1.用臭氧及负离子处理的鸡蛋,在理化指标(失重率,蛋黄指数、哈夫单位,蛋白pH)、感官指标(蛋白、蛋黄、系带)及微生物指标(贮藏过程中的菌落总数)上显示出了良好的效果,而空白对照组情况明显差于处理组。就感官及理化指标而言,负离子的效果好于臭氧；就微生物指标而言,臭氧的效果好于负离子。2.臭氧对于金黄色葡萄球菌、大肠杆菌及沙门氏菌杀菌效果显著。随着臭氧作用时间的延长,杀菌效果呈上升趋势。作用4min后,金黄色葡萄球菌、大肠杆菌及沙门氏菌的杀菌率分别达到：54.17%、85.24%、89.16%。负离子对于金黄色葡萄球菌、大肠杆菌及沙门氏菌有一定的杀菌效果。随着负离子作用时间的延长,杀菌效果呈上升趋势。但总体而言,负离子的杀菌效果明显弱于臭氧。作用7min后,金黄色葡萄球菌、大肠杆菌及沙门氏菌的杀菌率分别达到20.76%、25.24%、58.97%。3.臭氧处理会抑制溶菌酶酶活,臭氧处理10min、20min、30min后,溶菌酶酶活分别下降了24.12%、38.39%、53.70%。臭氧处理导致溶菌酶的二级结构发生变化,体现在α-螺旋的增多,说明,溶菌酶的活性变化与构象变化有着密切的关系。负离子处理也会抑制溶菌酶酶活,负离子处理10min、20min、30min后,溶菌酶酶活分别下降38.39%、50.71%、62.65%。负离子处理导致溶菌酶的二级结构发生变化。溶菌酶变性后,其原有的空间结构发生改变或消失,导致活性中心消失而失去原来的催化活力。由此可见,在臭氧、负离子保鲜鸡蛋的过程中,虽然臭氧、负离子对于鸡蛋的各项感官指标、理化指标及微生物指标起到良好的作用,但臭氧、负离子也是一把“双刃剑”,会对于溶菌酶的活性有所抑制。从而可以推论,臭氧、负离子处理保鲜鸡蛋与蛋清溶菌酶的活性大小没有相关性。这可能是由于蛋清溶菌酶的作用在于杀菌来起到一定的保鲜作用,而臭氧、负离子本身的杀菌作用就强于蛋清溶菌酶的作用,已经可以起到足够的保鲜作用。4.使用臭氧、负离子对鸡蛋进行处理后,在四周的贮藏时间内,臭氧及负离子对于鸡蛋的水分含量、蛋白质含量、脂肪含量以及氨基酸组分的保持均高于空白对照组。其中,臭氧组在水分含量、蛋白质含量、脂肪含量上较空白对照组分别高出0.49%、0.18%、0.10%。从氨基酸组分分析来说,除了脯氨酸外,臭氧组的其他的氨基酸含量均高于空白对照组。负离子组在水分含量、蛋白质含量、脂肪含量上较空白对照组分别高出0.48%、0.28%、0.20%。从氨基酸组分分析来看,贮藏四周后,除了组氨酸外,负离子组的其他的氨基酸含量均高于空白对照组。5.在30-C,相对湿度80%的条件下,臭氧和负离子对于鸡蛋保鲜都起到一定的作用,在与同期的空白对照组比较来看,臭氧和负离子组的鸡蛋保鲜效果良好。综合臭氧、负离子对于鸡蛋保鲜试验中的感官指标、理化指标、微生物指标、酶以及各营养指标的分析来看,负离子处理对于保持鸡蛋的商品特性有较好的作用：在略高于常温的30℃的条件下,4周后,负离子组的鸡蛋未散黄、未出现腐败的气味,这对于位于气候炎热地区或者夏季鸡蛋的贮运保鲜具有一定的借鉴意义。更多还原

【Abstract】 This paper reviewed the technological development of the egg storage, and summarized the research results in experiments on the application of ozone and negative ions to preservation of eggs. In the 4 weeks research, the effects of using ozone or negative ions for eggs storage in 30℃, RH 80% were compared. Firstly, study the changes in internal quality, physical-chemical properties and total bacteria of eggs during storage after dealt with ozone and negative ions. Secondly, test the efficacy of ozone and negative ions in disinfection of three kinds of bacteria (Escherichia coli, Staphylococcus aureus and Salmonella), which are playing an important role in the safety of eggs. Thirdly, study the effects of lysozyme after dealing with ozone and negative ions. Finally, study the changes in the nutrition of eggs during storage. The main results were as follows:1. Eggs dealt with ozone and negative ions have shown good effects in internal quality, physical-chemical properties (including weight losing, yolk index, Haugh unit and albumen pH value) and total bacteria of eggs during storage, however, the CK showed bad effects in those index. By considering the index of internal quality and physical-chemical properties, the negative ions groups were better than ozone groups, while the ozone groups had better effects in index of total bacteria than the negative ions groups.2. Ozone had significant impact in reduing bacteria including Escherichia coli, Staphylococcus aureus and Salmonella, bactericidal effect was rising along with time expanding. The antibacterial rate of Escherichia coli, Staphylococcus aureus and Salmonella after 4min was 54.17%、85.24%、89.16% respectively. The negative ions had the same trend like ozone, but underperformed than zone:the antibacterial rate of Escherichia coli, Staphylococcus aureus and Salmonella after 7min was 20.76%、25.24%、58.97% respectively.3. Both ozone and negative ions were capable to restrain the activity of egg white lysozyme. The activity of egg white lysozyme had decreased by 24.12%、38.39%、53.70% after dealt with ozone for 10min、20min、30min; the activity of egg white lysozyme had decreased by 38.39%、50.71%、62.65% after dealt with negative ions for 10min、20min、 30min. The contents of the secondary structures of egg white lysozyme had changed after in treated with ozone and negative ions. Theα-helix increased after dealt with ozone while thea-helix was decreased after dealt with negative ions. The space structure modified after denaturation. Although ozone and negative ions showed good effects in keeping eggs fresh, they were also a double-edged sword to restrain the activity of egg white lysozyme. Therefore, ozone and negative ions have no effects with the activity of egg white lysozyme, for ozone and negative ions have enough ability to disinfect than lysozyme.4. Eggs dealt with ozone and negative ions have shown good effects in nutrition including moisture, protein, fat and amino acid of eggs during storage. The contents of moisture, protein and fat of ozone groups were higher than CK by 0.49%、0.18%、0.10%. The contents of amino acid exceeded than CK except proline. However, the contents of moisture, protein and fat of negative ions were higher than CK by 0.48%、0.28%、0.20%. The content of amino acid exceeded than CK except histidine.5. Ozone and negative ions have shown good effects in keeping fresh of eggs at 30℃, RH 80%. Analysis by synthesis all the index, negative ions groups have good effects on egg fresh keeping. These results provide valuable reference for egg fresh-keeping in warm areas and seasons.更多还原