Hen Egg Yolk Prevents Bacterial Adherence: A Novel Function for a Familiar Food

ABSTRACT: The aim of this study was to evaluate the ability of unfractionated hen egg yolk to prevent the attachment of Salmonella typhimurium to murine intestinal epithelial cells in vitro. Inhibition of adherence was examined microscopically and by an ELISA. Both methods showed that egg yolk from immunized and unimmunized hens significantly reduced bacterial adherence. Optical density (OD) readings ± SD of 0.825 ± 0.016 for untreated bacteria were reduced to 0.335 ± 0.024 and 0.267 ± 0.021 for bacteria pretreated with egg yolk from immunized hens and unimmunized hens, respectively. Microscopic analysis showed that egg yolk from either immunized or unimmunized hens reduced bacterial adherence from 17 ± 2.7 bacteria per epithelial cell to less than 4 bacteria per epithelial cell. These results show that hen egg yolk significantly inhibits adherence of S. typhimurium to intestinal epithelial cells in vitro. Boosting of specific antibody levels does not enhance this antiadhesive effect, suggesting that egg yolk contains novel antiadhesive factors.     

淘汰蛋鸡肉糜功能特性影响因素研究进展

淘汰蛋鸡肉糜加工过程中的漂洗，加热，添加剂应用是影响其功能特性的主要因素。作者介绍了淘汰蛋鸡肉糜的功能特性，并对其主要影响因素－加工工艺和添加剂进行了综述论述。     

Physical evaluation of popped cereal snacks with spent hen meat

Various blends of spent hen meat and grains (potato starch, corn starch, and rice flour) were popped using a popping machine. Lowest bulk density was observed in the snack with 1:2 ratio of meat and potato starch. Except for the popped snack with meat and rice flour, as the starch content increased, bulk density decreased gradually. Popped snacks with grains only were higher in L* value than those with meat and grains. The a* and b* values increased with increasing meat content. All popped snacks were significantly different (P<0.001) in bulk density, color, and breaking force. As the grain content of snacks increased, the size of the air cells also increased. Results of scanning electron microscopic and optical microscopic observations revealed the popping degree of snack with starch and spent hen meat was affected by the presence of meat. The optimum ratios of meat to grain for high expansion ratio were determined to be 1:2 and 1:3 of meat to corn starch and potato starch.     

Mechanical and rheological properties of fresh egg pasta as affected by shell egg production factors

The aim of this work was to study the influence of hen age and housing system on egg performances in fresh pasta production, focusing on mechanical and rheological properties of pasta. Samples of pasta were prepared with eggs laid by Hy‐Line Brown hens (from 27 to 68 weeks old) housed in conventional cage, barn and organic systems. Only hen age significantly affected pasta properties. In particular, as regards raw pasta, the loosest structure was obtained using eggs laid by the youngest hens (27–30 weeks old). On the contrary, in cooked pasta, the weakest structure was observed when eggs were laid by hens aged 53–68 weeks. However, differences, although significant, were small and thus most likely not sensorially perceivable. Significant correlations were found between mechanical and rheological properties of raw fresh egg pasta, meaning that small deformation measurements are as valuable as large deformation tests for the characterisation of this product.     

鸡蛋中磺胺类残留物提取方法

为获得鸡蛋中磺胺类药物残留检测的提取方法,分别在鸡蛋中添加高、中、低浓度的磺胺类药物,根据GB/T 20759-2006《畜禽肉中十六种磺胺类药物残留量的测定：液相色谱-串联质谱法》的方法以及自行设计方法对样品进行前处理,用液相色谱-串联质谱检测。结果表明：添加量在10～200ng/g范围内,鸡蛋中回收率为20.8%～69.29%,回收率未能达到标准;GB/T 20759-2006在提取、浓缩、除脂、标准曲线绘制方面对于禽蛋类食品不适用,需根据禽蛋类的特殊性制定专门的检测标准,而自行设计方法所得回收率为77.92%～95.26%,可以满足检测的要求。     

Effects of L‐carnitine supplementation to diets with different fat sources and energy levels on fatty acid composition of egg yolk of laying hens

BACKGROUND: The present study was carried out to determine the effects of feeding diets with two different levels of metabolisable energy (ME) (11.51 or 10.88 MJ ME kg^?1 diet) and three different sources of fat (palm oil, sunflower oil or fish oil) with or without supplemental L ‐carnitine (0 or 500 mg kg^?1 diet) on the fatty acid (FA) composition of egg yolk and the passage of n3 polyunsaturated FAs to egg yolk in laying hens. RESULTS: The ∑n3, particularly C22:6n‐3, FA contents of egg yolk were significantly reduced by adding of L ‐carnitine (C2) to different fat sources (P < 0.01). The ratio of n6/n3 was reduced from 53.77 to 17.72 in eggs yolks when ME was lowered in the diet with C2‐sunflower oil (SFO) whereas it was enhanced from 2.19 to 9.31 in C2‐E2 (low energy) diet with fish oil (FO) (P < 0.001). The diet with E2 or C2 containing FO resulted in a decrease of the C22:5n‐3, C22:6n‐3 and ∑n3 FA contents of egg yolk (P < 0.001). On the other hand, supplementation of C2 to diets with SFO or palm oil (PO) caused to a decrease in the C22:6n‐3 and ∑n3 FA contents of egg yolk (P < 0.01). A significant increase of the ratio of n6/n3 in egg yolk can be seen by feeding with E2 diet by adding of C2 to all fat sources like in E1 (normal energy) diet (P < 0.001). CONCLUSION: Dietary treatments resulted in major changes in FA composition of egg yolk. The supplemental C2 in diet decreased the C22:5n‐3, C22:6n‐3 and ∑n3FA contents in egg yolk. The use of FO in diets with E2 significantly reduced the passage rate of C22:6n‐3 FA to egg yolk. Copyright © 2008 Society of Chemical Industry     

Comparative study on the characterization of antisera of anti‐aflatoxin B1 from rabbit and laying hen

Polyclonal antisera specific for aflatoxin B₁ (AFB₁) were developed in rabbits and laying hens immunized with AFB₁ conjugated to bovine serum albumin (AFB₁‐BSA). During the immunization schedule, AFB₁‐specific antisera from rabbits started to obviously be secreted after 60 days of the first AFB₁‐BSA injection, reached to a peak at day 120, and started to go down at day 135; while in regard to laying hens, antibodies began to largely be produced at day 90, arrived to a peak at day 135, and began to go down at day 165. The rabbits consistently produced anti‐AFB₁ antisera in 2‐fold higher amounts than the laying hens during the antisera production process. But rabbits' and laying hens' antisera to AFB₁ were found not to be apparently different in cross‐reaction with aflatoxin analogs. Both rabbits' and laying hens' antisera could be used as immunological reagents for detecting AFB₁ in agricultural commodities.