蛋黄磷脂的提纯

利用蛋白质不溶或微溶于某些溶剂的特点,用混合溶剂萃取粗蛋黄磷脂制备精蛋黄磷脂的工艺,该工艺易于实现工业化生产,磷脂纯度可达98%以上。     

Combined exposure to cyanobacterial biomass, lead and the Newcastle virus enhances avian toxicity

Under environmental conditions, wild birds can be exposed to multiple stressors including natural toxins, anthropogenic pollutants and infectious agents at the same time.This experimental study was successful in testing the hypothesis that adverse effects of cyanotoxins, heavy metals and a non-pathogenic immunological challenge combine to enhance avian toxicity. Mortality occurred in combined exposures to naturally occurring cyanobacterial biomass and lead shots, lead shots and Newcastle vaccination as well as in single lead shot exposure. Mostly acute effects around day 10 were observed. On day 30 of exposure, there were no differences in the liver accumulation of lead in single and combined exposure groups. Interestingly, liver microcystin levels were elevated in birds co-exposed to cyanobacterial biomass together with lead or lead and the Newcastle virus. Significant differences in body weights between all Pb-exposed and Pb-non-exposed birds were found on days 10 and 20. Single exposure to cyanobacterial biomass resulted in hepatic vacuolar dystrophy, whereas co-exposure with lead led to more severe granular dystrophy. Haematological changes were associated with lead exposure, in particular. Biochemical analysis revealed a decrease in glucose and an increase in lactate dehydrogenase in single and combined cyanobacterial and lead exposures, which also showed a decreased antibody response to vaccination.The combined exposure of experimental birds to sub-lethal doses of individual stressors is ecologically realistic. It brings together new pieces of knowledge on avian health. In light of this study, investigators of wild bird die-offs should be circumspect when evaluating findings of low concentrations of contaminants that would not result in mortality on a separate basis. As such it has implications for wildlife biologists, veterinarians and conservationists of avian biodiversity.     

咸蛋清蛋白质的絮凝与脱盐研究

咸蛋清中含有大量的优质蛋白质,由于含盐量较高,难以利用。利用适量水稀释咸蛋清,再以壳聚糖溶液絮凝咸蛋清溶液中的蛋白质,然后分离含盐水溶液,从而脱除咸蛋清中的盐。研究了咸蛋清溶液的浓度、pH、温度和壳聚糖溶液浓度等因素对絮凝效果的影响。通过正交试验发现,壳聚糖的加入量是影响咸蛋清蛋白质的絮凝与脱盐的主要因素,其次是咸蛋清溶液pH,然后是咸蛋清溶液浓度、温度;咸蛋清蛋白质的絮凝与脱盐的最佳条件为:10g咸蛋清,加水量10g,壳聚糖溶液(1.00g/100mL)用量1.25mL,咸蛋清溶液pH=6、温度20℃,粗蛋白质回收率为86.21%。     

酶法改性提高全蛋粉起泡性能的研究

为提高全蛋粉的起泡性能,利用中性蛋白酶酶解全蛋液,采用响应面法建立了酶解改性提高全蛋粉起泡性能的二次回归模型,并验证了该模型的有效性,探讨了酶解温度、酶解时间、酶添加量三因素对全蛋粉起泡力(FA)和泡沫稳定性(FS)的影响,同时分析比较了改性前后全蛋粉的微观结构和分子量变化。结果表明最适改性条件为:酶解温度42℃,酶解时间90min,酶添加量1120u/g;与未改性全蛋粉相比,酶解改性后的全蛋粉FA从62.96%提高到77.36%,FS从20.67%提高到37.54%。     

市售鲜鸡蛋中沙门氏菌的分离鉴定及毒力岛基因检测

目的:监测市售鲜鸡蛋中沙门氏菌的污染情况,检测分离菌株的致病性及其毒力岛基因携带情况,了解沙门氏菌分离株毒力岛基因的携带与其致病力的相关性。方法:从陕西省不同地市的超市中随机购买鲜鸡蛋,无菌取其蛋壳膜分离沙门氏菌,聚合酶链式反应方法扩增沙门氏菌菌属特异性invA基因鉴定分离株;对分离菌株进行无特定病原体(SPF)雏鸡的致病性试验,依据GenBank发表的基因序列,设计引物聚合酶链式反应检测沙门氏菌毒力岛(SPI)核心蛋白基因。结果:从陕西省55家超市1100枚鲜蛋中分离鉴定出30株沙门氏菌,分离率达2.73%;动物致病性实验表明,30株沙门氏菌中13株有致病力,其中强致病力菌株有7株,占23.3%;分离菌株的毒力岛基因携带率分别为:SPI-1 60%、SPI-2 73.3%、SPI-3 100%、SPI-4 90%、SPI-5 76.7%,毒力岛基因SPI-1+SPI-2的携带与细菌致病性有关。结论:市售鲜鸡蛋中沙门氏菌携带率为2.73%,分离菌株对动物具有一定的致病力,毒力岛基因SPI-1+SPI-2的携带与沙门氏菌的致病性呈正相关。     

腌制方法对鸭蛋黄成分变化及品质影响

研究了鸭蛋在草木灰包裹法和盐水浸泡法腌制过程中,水分含量、盐分含量、R值与Q值,蛋黄总脂肪、可溶性蛋白质和巯基含量的变化以及成熟(7周)后两者蛋黄的感官品质。7周内,随腌制时间的延长,浸泡法鸭蛋黄水分含量明显低于包裹法鸭蛋黄,盐分含量却高于包裹法;蛋清R值高于蛋黄,灰蛋的R值、Q值都低于盐水蛋。第7周,灰蛋和盐水蛋的Q值上升为0.88和0.90;脂肪占湿重的含量上升至48.45%和50.67%,而腌制期总脂肪量是没有变化的;可溶性蛋白质含量增加至6.75%和6.08%;表面巯基和游离巯基下降至0.31、0.28mmol/g蛋黄和1.68、1.34mmol/g蛋黄。灰蛋蛋黄在形态、滋味和气味方面明显优于盐水蛋,感官评分分别为88.9和78.65。     

2012年一季度禽蛋市场形势分析与展望

我国是世界上禽蛋生产与消费的第一大国。近年来我国禽蛋产量逐年增加,禽蛋市场的变化对居民食物消费生活产生一定影响。本文对近期我国禽蛋市场生产、市场、贸易现状进行分析,对未来我国禽蛋市场的价格走势进行了展望。     

Possibilities of enhancing the colour of egg yolk

BACKGROUND: This study attempts to compare two possibilities of enhancing the colour of egg yolk. One of them is based on the ecological rearing of laying hens on natural green grass whereas the other uses a feeding dose supplemented with natural pigments in laying hens reared in individual cages. Is it possible to distinguish these two technologies using yolk colour determination in the CIELAB system? RESULTS: Yolk colour parameters such as L*, a*, and b* in the group of grazed hens are significantly different (α = 0.001) from those observed in hens reared in cages. The yolk colour shows a darker, redder and more yellow colour. The greatest difference was seen in the red colour parameter, a*, that increased more than twice. Visually, this means a shift towards a more orange colour. Compared to grazing in the meadow (ΔE* = 13.257), the addition of artificial pigments in the feed resulted in a more significant increase in the parameter ΔE* (CIE total colour difference), with the greatest value of ΔE* being observed with the use of both pigments (ΔE* = 24.265). CONCLUSION: Grazing increases the parameter a* whereas the values of the parameter C*_ab remain relatively low. The parameter ΔE* is significantly lower in the case of grazing as compared to the supplementation of the feed with pigments. However, colourity parameters cannot be used as a specific standard to identify a particular grazing technology as their values vary during the laying period. Copyright © 2011 Society of Chemical Industry     

蛋清起泡性研究进展

起泡性是蛋清主要功能特性之一,是评价蛋清产品质量的指标之一。本文综述了蛋清起泡性的评价方法、影响蛋清起泡性的因素及提高蛋清起泡性的方法,影响蛋清起泡性的因素主要包括蛋清中蛋白质的组成和结构、环境因素和生产加工工艺,用于提高蛋清起泡性的方法包括物理改性法、化学改性法和酶解改性法三方面。针对不同的影响因素,不同的改善方法都能在一定程度上提高蛋清的起泡性。     

皮蛋蛋白质凝胶形成及其调控的研究进展

凝胶特性是禽蛋蛋白质的重要功能特性。皮蛋作为深受大众喜爱的传统蛋制品,其蛋白质的优良凝胶特性是其被消费者接受的重要指标之一。本文首先简单介绍了禽蛋蛋白、蛋黄凝胶形成的方式及其影响因素,在此基础上,重点综述了料液碱度、温度、时间、金属离子、茶叶等因素对皮蛋蛋白质凝胶的形成及其特性的影响,旨在为进一步研究皮蛋凝胶形成的机制并为指导皮蛋实际生产提供理论指导。