品种和储存时间对鸡蛋蛋黄氧化指标和常规蛋品质的影响

Effects of Variety and Storage Time on Oxidation Index of Egg Yolk and Conventional Egg Quality

试验旨在探讨两个品种鸡蛋在不同储存时间蛋黄蛋白质和脂质氧化指标、营养成分和常规蛋品质、微生物污染情况的变化趋势。将490个褐壳蛋和360个绿壳蛋编号后置于室温下储存,从采集当天开始,每隔7 d测定50个鸡蛋的蛋黄共轭二烯、丙二醛和表面巯基的含量,同时测定常规品质;在采集当天和储存70 d后测定30个鸡蛋蛋黄氨基酸、脂肪酸和胆固醇含量;在采集当天、储存21 d、储存70 d后检测10个鸡蛋的微生物指标。结果显示:两种鸡蛋蛋黄中的初级氧化产物共轭二烯在前28 d逐渐升高(P<0.05),28 d后显著下降,致使次级氧化产物丙二醛的量显著上升(P<0.05),蛋白质表面巯基含量逐渐降低(P<0.05),上述3个指标在品种间差异显著(P<0.05);绿壳蛋蛋黄中的氨基酸、必需氨基酸、饱和脂肪酸和不饱和脂肪酸总量显著高于褐壳蛋(P<0.05),两种鸡蛋的哈氏单位、蛋黄系数等常规品质指标在储存期间变化显著(P<0.05);整个试验期间均未在鸡蛋表面和内容物中检出沙门菌等致病菌,蛋壳表面菌落总数随着保存时间的延长逐渐增加。综上所述,品种和储存时间对鸡蛋蛋黄氧化指标、营养成分、安全性和常规蛋品质均存在显著影响,绿壳蛋营养价值高于褐壳蛋,储存期间的氧化进程也快于褐壳蛋,故存储期与褐壳蛋有差异。

The purpose of the experiment was to explore the changes of yolk protein and lipid oxidation indexes,nutritional components,conventional egg quality and microbial contamination of two varieties of eggs at different storage times.Four hundred and ninety brown-shell eggs and three hundred and sixty green-shell eggs were numbered and stored at room temperature.From the day of collection,the yolks of 50 eggs were collected every 7 days to determine the content of conjugated diene,malondialdehyde and surface sulfhydryl group,and the conventional quality was measured at the same time;The content of amino acids,fatty acids and cholesterol in yolk of 30 eggs were measured on the day of collection and 70 days after storage.The microbial indexes of10 eggs were detected on the day of collection,21 days of storage and 70 days of storage.The results showed that the conjugated diene,the primary oxidation product in yolk of the two varieties of eggs,gradually increased in the first 28 days(P<0.05),decreased significantly after 28 days,resulting in a significant increase in the content of malondialdehyde(P<0.05),and there was a gradual decrease in the content of sulfhydryl groups on the protein surface(P<0.05).The three indexes above were significantly different between varieties(P<0.05).The total content of amino acids,essential amino acids,saturated fatty acids and unsaturated fatty acids in the yolk of green-shell eggs were significantly higher than that in brown-shell eggs(P<0.05).The conventional quality indexes of the two varieties of eggs,such as Haugh unit and yolk coefficient,changed significantly during storage(P<0.05).During the whole experiment,Salmonella and other pathogenic bacteria were not detected on the surface and contents of eggs,and the total number of colonies on the surface of eggshells gradually increased with the extension of storage time.In conclusion,varieties and storage time had significant impact on oxidation index of egg yolk,nutrition,safety and conventional egg quality,and the nutritional value of green-shell eggs was higher than that of brown-shell eggs,and the oxidation process during storage was also faster than that of brown-shell eggs,so the storage period should be different from that of brown-shell eggs.