为确定真空熟制咸鸭蛋蛋黄黑圈现象发生的原因，对真空熟制咸鸭蛋黑圈蛋的黑圈部位和未变色部位以及非黑圈蛋黄的相应部位进行理化分析，在初步确定与黑圈形成有关的物质后进一步研究这些物质的变化。结果表明：黑圈蛋中黑圈部位蛋白质含量降低，分子质量为36 ku处的蛋白质电泳条带变浅，蛋黄颗粒的微观结构混乱无章，蛋白质的变化使黑圈部位pH值由6.20变为7.90，从而导致色素的颜色由黄色变为黄绿色；硫含量在非黑圈蛋蛋黄中分布均匀，而在黑圈蛋中，黑圈部位硫含量为5.17 mg/100 g，高于未变色部位的2.31 mg/100 g；S2-与蛋黄成分的呈色反应表明，其只与含金属离子的卵黄高磷蛋白有呈色反应，可以使正常蛋黄颜色变黑，黑圈蛋黄颜色加深，促进黑圈的形成；Fe、Zn、Cu在黑圈蛋中含量均有一定程度的增加，且均与S2-有呈色反应，但只有Fe与S2-的呈色符合黑圈的特征色，进一步研究发现Fe含量与蛋黄黑圈程度呈正相关；综上，黑圈的形成是在蛋白质、Fe、S2-以及色素的共同作用下导致的。

In order to determine the cause of the “black circle” phenomenon in the yolk of vacuum cooked salted duck eggs, the physico-chemical analyses were carried out on the black circle parts of the eggs with black circles and the corresponding parts of the non-black circle in the yolk of vacuum-cooked salted duck eggs in. The changes in the substances related to the formation of black circle were further studied after a preliminary determination. The results showed that the protein content of the black circle in the eggs with black circles decreased, the protein electrophoresis band at the molecular mass of 36 kDa became lighter, the microstructure of the egg yolk particles was in a mess, and the change of protein altered the pH value of the black circle region from 6.20 to 7.90, causing the change of the pigment color from yellow to yellow-green; The sulfur content is evenly distributed in the yolk of the non-black circled egg, while the sulfur content of the black circle part in the black circled egg was 5.17 mg/100 g, which is higher than that of the non-colored part (2.31 mg/100 g); The color reaction of S2- with egg yolk components indicated that it only led to a color reaction with metal ion-containing phosvitin, which can make the color of normal egg yolk turn black, darkening the egg yolk color, and promoting the formation of dark circles; The contents of Fe, Zn, and Cu in the black circled egg all increased to a certain extent, and all exhibited a color reaction with S2-, although only the color resulting from the reaction between Fe and S2- was in accordance with the characteristic color of the black circle. Further studies revealed the positive correlation between the Fe content and the degree of yolk black circle. In summary, the formation of black circle was caused by the combined action of protein, Fe, S2- and pigment.

公益性行业（农业）科研专项项目（201303084）