鸡蛋在贮藏过程中品质变化与力学特性的研究

为建立质构特性无损检测鸡蛋新鲜程度的方法,利用质构仪测量了鸡蛋的质构性质(哈夫单位、蛋壳厚度、蛋壳破裂强度和形变、蛋白高度、卵黄膜强度),同时测量了鸡蛋的pH,分析了鸡蛋在贮藏过程中各个参数随时间的变化规律。分别用Excel、SPSS软件分析各参数与贮藏时间的相关性,哈夫单位、pH与贮藏时间显著相关,其相关系数(R2)分别为0.958、0.953;卵黄膜强度与贮藏时间无显著相关(P0.05)。对相关性较显著的参数进行了建模方式比较,分别建立了哈夫单位与贮藏时间的线性方程,蛋清pH与贮藏时间的二次回归方程。研究可为利用质构性质对鸡蛋新鲜程度的快速判断提供理论依据。     

蛋类与蛋制品的营养价值及其应用

<正>蛋类的基本结构每只鸡蛋的标准重量是50克左右,而鸡蛋的十分之一的重量都是蛋壳,蛋壳大部分是由碳酸钙构成的而剩余的碳酸镁和蛋白质只占少部分。角质膜布满蛋壳的表面,蛋壳下膜蛋壳下膜由两层紧紧相贴的膜组成,外层紧贴石灰质蛋壳,称为外壳膜,内层包裹蛋白称为蛋白膜或内壳膜。两层膜均为有机纤维组成的网状结构。外壳     

蛋壳及蛋壳膜吸附性质的研究进展

目前国内禽蛋行业发展迅速,随之带来了大量的蛋壳资源,这引起很多科学家对蛋壳开发利用的关注,并做了大量的研究。本文主要针对目前国内外对蛋壳及蛋壳膜的吸附性质的研究利用现状做一个概述,以便为蛋壳资源的开发利用以及更深一步的研究提供新的思路。     

鸡蛋壳膜的开发与应用前景

我国禽蛋资源丰富,是世界禽蛋生产和消费大国。随着人们对鸡蛋消费量的增加,大量蛋壳的丢弃不仅对环境造成了严重污染,也是资源上的极度浪费。鸡蛋壳膜富含角蛋白、胶原蛋白、透明质酸、硫酸软骨素及其他活性成分。综述鸡蛋壳膜的开发与应用现状,为其在化妆品、食品、医药、轻工业等领域的应用提供理论依据。     

鸡蛋外部品质与其呼吸强度的相关关系

鸡蛋贮藏保鲜问题一直是蛋品行业研究的重点,已有研究表明鸡蛋品质与其呼吸强度存在密切联系。为了 更进一步明确鸡蛋品质与其呼吸强度之间的关系,本研究选取同一品种但不同外部品质指标的鸡蛋作为实验样品, 利用呼吸测定仪测量鸡蛋的呼吸强度,分析鸡蛋品质与其呼吸强度之间的关联。通过SPSS 19.0软件分别比较分析 鸡蛋质量、蛋形指数、蛋比重、蛋壳质量、蛋壳厚度、蛋壳比例（蛋壳质量与鸡蛋质量百分比）以及蛋壳强度对鸡蛋 呼吸强度的影响。结果表明：鸡蛋质量和蛋形指数与呼吸强度之间显著正相关（P＜0.05）;蛋壳厚度和蛋壳比例与 呼吸强度之间显著负相关（P＜0.05）;而蛋壳强度、蛋壳质量以及蛋比重与呼吸强度间相关性不显著（P＞0.05）; 此外,蛋比重与蛋壳强度、蛋壳厚度以及蛋壳比例均极显著正相关（P＜0.01）;蛋壳厚度与蛋壳强度极显著正相 关（P＜0.01）。总之,在鸡蛋外部品质中,鸡蛋质量、蛋形指数、蛋壳厚度及蛋壳比例对鸡蛋呼吸强度影响最大。     

基于声学特性的鸡蛋蛋壳强度检测的研究

蛋壳强度的研究对减少禽蛋因超载荷压缩而引起的破损有重要意义。自行研制了一套禽蛋蛋壳强度检测装置。首先,采集敲击鸡蛋产生的响应信号,通过快速傅里叶变换(FFT)获取其功率谱,再采用常规准静态压缩方法检测鸡蛋最大承受应力,最后利用主成分回归法建立鸡蛋最大承受应力的预测模型。该方法与常规的静态压缩方法检测得到的结果有一定的相关性,相关系数为0.71。研究结果表明基于声学特性的鸡蛋蛋壳强度检测方法是可行的。     

亚硫酸钠辅助酶解蛋壳膜制备抗氧化多肽的工艺

禽蛋壳膜蛋白含量丰富,蛋白质约占蛋壳膜干重的90%,然而蛋壳膜在食品工业中通常被作为废弃物丢弃,造成了资源浪费和环境污染,因此高效地利用蛋壳膜资源是极为必要的。本研究使用亚硫酸钠辅助酶解法制备禽蛋壳膜抗氧化肽,研究了酶种类、酶添加量、亚硫酸钠浓度和酶解时间对禽蛋壳膜多肽抗氧化性和水解度的影响。结果表明,亚硫酸钠辅助下碱性蛋白酶酶解禽蛋壳膜,效果优于其他四种酶;亚硫酸钠辅助碱性蛋白酶酶解禽蛋壳膜的最佳条件是:碱性蛋白酶添加量12 U/mg,亚硫酸钠浓度40 mM,时间4 h。在最优工艺条件下,禽蛋壳膜多肽的总抗氧化能力为245.88μg/m L,水解度为8.58%,表明禽蛋壳膜的亚硫酸钠辅助碱性蛋白酶酶解产物具有很好的体外抗氧化活性。SDS-PAGE表明禽蛋壳膜多肽的分子量主要在3.3~14.4 ku之间。     

鸡蛋壳的利用

<正> 蛋品厂的鸡蛋壳是很好的天然资源,过去是废弃物,既污染环境,又浪费资源,一经利用,也可变废为宝.蛋壳膜富含溶菌酶,含量约为旦壳的1～1.5‰,蛋壳一般还粘附2%左右的蛋清,所以蛋壳也是溶菌酶的原料资源.蛋壳膜经化学处理可制成蛋膜素,用于化妆品,作护肤霜,对皮肤有滋润、营养、抗衰作用.蛋壳含丰富的无机盐和粘蛋白,可利用制     

鸡蛋蛋壳超微结构与呼吸强度的相关关系

鸡蛋品质变化原因众多,其中一个主要影响因素是其自身的呼吸作用,而蛋壳超微结构又与呼吸作用息息 相关。为了揭示蛋壳各层超微结构与鸡蛋呼吸强度之间的关系,通过扫描电子显微镜获得蛋壳的超微结构图像, 利用MATLAB软件获取相关参数,并用SPSS 19.0软件得出蛋壳厚度、有效层厚度、乳突层厚度、平均乳突大小以 及孔隙度与鸡蛋呼吸强度的相关关系。结果表明：鸡蛋的呼吸强度与蛋壳厚度（R＝－0.36,P＜0.05）、有效层厚 度（R＝－0.47,P＜0.05）之间存在显著性负相关关系;鸡蛋的呼吸强度与平均乳突大小（R＝0.57,P＜0.01）、 孔隙度（R＝0.66,P＜0.01）之间存在极显著性正相关关系;与乳突层厚度的相关性较低,同时得出呼吸强度大的 鸡蛋蛋壳表面比呼吸强度小的蛋壳表面粗糙。总之,蛋壳厚度、有效层厚度、平均乳突大小以及孔隙度对鸡蛋呼吸 强度影响较大。     

食疗健康广场

红蛋染料染鸡蛋,害处多多？很多地方都有喜事吃红蛋的习俗。然而,从卫生保健的角度来看,用化学染料染鸡蛋是有很多害处的目前市售的红色染料,几乎都是芳香族硝基、氨基化合物或其衍生物,其中含有未、萘、苯胺等有毒有害物质。用此类红色染料来染蛋,会危害人体健康：蛋壳上有缝隙,染料中的有毒物质就会渗入蛋内;双手在剥蛋壳和蛋膜时,也极易污染;即使蛋壳不破,煮蛋时水沸腾了,蛋壳和蛋膜的通透性增加,有毒物质也会渗入蛋内;老将蛋煮熟后出锅染红,由于蛋的温度很高,其壳、膜的通透性与在锅内并无多大的差异,污染同样不可避免…     

禽蛋壳膜回收分选装置参数优化

目的：有效利用废弃蛋壳和蛋壳膜。方法：对废弃蛋壳进行分离和分选,利用Fluent和EDEM耦合仿真研究了分选筒上、下出口直径等结构参数对流场特性、颗粒轨迹的影响,分析了流场特性和壳膜的捕捉率,优化了分选筒的气流出口尺寸。以筒顶角度、吸风机负压、送料口风速和固体负荷率作为试验因素,蛋膜和蛋壳的回收率作为评价指标,进行分选蛋壳膜试验,并进行优化设计。结果：减少分选筒上、下出口直径会增大筒内压降损失和近壁切向速度,当上出口直径为0.4D(D为直筒段直径)、下出口直径为0.5D时,蛋壳和蛋膜的捕捉率最高。筒顶角度为45°,固体负荷率为1 000 g/s,送料口速度为4.64 m/s,吸风机负压为336.61 Pa,此时蛋膜回收率为92.94%,蛋壳回收率为97.90%。结论：上出口负压与进料口风速主要影响分选筒内部流场分布,固体负荷率会使物料之间产生不同的相互作用。在优化后的工艺组合下,该分选设备具有良好的分选效果。     

蛋壳膜的分离及应用初探

蛋壳膜中含有与人皮肤弹性有关的角蛋白及构成胶原蛋白的羟脯氨酸。加入蛋壳膜水解液的化妆品,可以使肌肤显得细腻光滑,有弹性。以废弃的鸡蛋壳为原料,利用12m ol/L浓盐酸进行壳膜分离,得到的蛋壳膜在碱溶液中水解为15%的蛋壳膜水解液,将其脱色、脱味后在化妆品的生产上进行应用初探。     

鸡蛋壳、壳下膜分离工艺优化

为了开发利用鸡蛋壳和蛋壳膜,首先必须使二者分离。本文采用机械粉碎、水浮选和稀酸处理相结合的方法进行壳膜分离,筛选了鸡蛋壳、壳下膜分离的条件;通过单因素实验考察盐酸体积、反应时间、盐酸浓度对蛋壳膜脱钙率的影响,并采用响应面分析方法,对稀盐酸除蛋壳膜中残留蛋壳的工艺条件进行优化。结果表明：鸡蛋壳在粉碎机运行5 s/次、粉碎3次的条件下壳膜分离效果最佳,出粉率58.72%,脱膜率87.91%,综合得分72.91;用盐酸去除蛋壳膜中残留蛋壳的最佳工艺条件为粗蛋壳膜1 g时,使用盐酸体积20 mL、反应时间19 min、盐酸浓度0.5 mol/L,此时脱钙率可达89.21%。该工艺为鸡蛋壳的精深加工提供技术支撑。     

超声波法制备蛋壳柠檬酸钙的工艺研究

为充分利用鸡蛋壳丰富的钙资源,通过单因素与三元正交多项式回归设计相结合的研究方法,构建出超声波法高效制备蛋壳柠檬酸钙的三元正交多项式回归模型,并优化出最佳工艺条件为：蛋壳粉颗粒细度180 目、料液比1:60、超声功率700W、超声时间25min、柠檬酸与蛋壳粉的质量比2:1、柠檬酸钙得率可达90.83%。超声波法与传统方法相比,不但提高了蛋壳柠檬酸钙产品得率,而且还克服了柠檬酸钙在制备过程中的凝聚沉淀现象。     

Internal quality of coated eggs with soy protein isolate and montmorillonite: Effects of storage conditions

The development of the bio-nanocomposite coating materials for eggshells has received more attention because of the decline in interior egg quality. This work evaluated the effects of weight loss, Haugh unit, yolk index, air space and albumen pH, eggshell strength, number of microorganisms on eggshells, contact angle and water vapor permeability of uncoated eggs and eggs coated with soy protein isolate/montmorillonite emulsions (5/0, 5/0.20, 5/0.50, 5/0.80; w/w) during 6 weeks at 25°C. A scanning electron microscope was used to visualize morphologies of soy protein isolate and the soy protein isolate/montmorillonite composite coatings, and the scanning probe microscope was determined. Compared with uncoated and soy protein isolate-coated eggs, the interior egg quality was improved by the increase of Haugh unit, yolk index, air space or eggshell strength, and decrease in weight loss, albumen pH, or the number of microorganisms on eggshells. The higher contact angle indicated the hydrophobicity of coatings. The values of water vapor permeability with 0.2% montmorillonite, 0.5% montmorillonite, and 0.8% montmorillonite were reduced by 21.14, 57.78, and 69.13%, respectively, as compared to those of soy protein isolate coatings. The images by a scanning electron microscope indicated that coatings could cover the cracks of eggshells to preserve the interior egg quality. The experimental values of the scanning probe microscope showed that montmorillonite would not penetrate through the eggshell pores, and it was safe to coat with montmorillonite. This study highlights the use of soy protein isolate/montmorillonite coating to maintain the internal quality and enhance the shelf life of eggs stored at 25°C.     

Eggshell factors influencing eggshell penetration and whole egg contamination by different bacteria, including Salmonella enteritidis

Trans-shell infection routes and whole egg contamination of 7 selected bacterial strains; Staphylococcus warneri, Acinetobacter baumannii, Alcaligenes sp., Serratia marcescens, Carnobacterium sp., Pseudomonas sp. and Salmonella enteritidis, recovered from egg contents, were studied. The first objective was to correlate bacterial eggshell penetration with various eggshell characteristics and bacterial strains. An agar approach was used to assess the eggshell penetration. The second objective was to assess the contamination of whole eggs with the bacterial strains; whole intact eggs were used in this case. The intact shells of agar-filled and whole eggs were inoculated with 10(3) -10(4) cfu of the selected strains. During 3 weeks storage at 20 degrees C and 60% relative humidity, the bacterial eggshell penetration was regularly monitored. The whole egg contamination was only analyzed after 3 weeks. The eggshell characteristics such as area eggshell, shell thickness and number of pores did not influence the bacterial eggshell penetration. For each individual bacterial strain the mean cuticle deposition was lower for penetrated compared to non-penetrated eggshells. For the individual strain Carnobacterium sp. and for the global results of all strains this difference was statistical significantly. The whole egg contamination was not influenced by neither the area of the eggshell nor the porosity of the eggshell. The results of the agar approach indicate that the Gram-negative, motile and non-clustering bacteria penetrated the eggshell most frequently; Pseudomonas sp. (60%) and Alcaligenes sp. (58%) were primary invaders followed by S. enteritidis (43%). All selected strains were able to penetrate; penetration was observed most frequently after ca. 4-5 days. Particularly S. enteritidis was a primary invader of whole eggs: the membranes and/or the content of 32% of the whole eggs was contaminated. The remaining bacterial eggshell contamination with the selected strain was determined after 3 weeks storage. Penetrated eggshells and contaminated whole eggs showed a significantly higher bacterial contamination on the eggshell compared to non-penetrated eggshells and non-contaminated whole eggs respectively (global results of all strains). The influence of hen age on bacterial eggshell penetration and egg content contamination was not significant. While the agar approach is suitable to study the influence of the eggshell characteristics on the bacterial eggshell penetration, the intact egg approach gives an estimation of the penetration of the shell followed by the probability of survival and migration in whole eggs.     

禽蛋表面细菌污染及影响因素的调查分析

目的检测养殖场的禽蛋受细菌污染的情况,调查分析禽蛋表面细菌污染的主要影响因素。方法根据GB 4789.2-2010食品安全国家标准食品微生物学检验菌落总数测定对饲养场的蛋壳表面、饲料、垫草中的细菌菌落总数进行测定,采用沉降法测定饲养场空气中的细菌数,并进行统计分析。结果饲养场鸡蛋和鸭蛋表面的细菌菌落总数分别达到4~6和6~7个数量级,且饲养场的空气、饲料以及垫草中的细菌数越多,从蛋壳表面检测出来的细菌数也越多。结论养殖场的禽蛋均受到不同程度的细菌污染,且饲养场的空气、饲料、垫草是造成禽蛋表面细菌污染的主要原因,禽蛋生产过程中卫生管理非常重要。     

EFFECT OF RAPID COOLING OF SHELL EGGS ON MICROCRACK DEVELOPMENT, PENETRATION OF SALMONELLA ENTERITIDIS, AND EGGSHELL STRENGTH

Eggs were subjected to cryogenic cooling treatments using liquid CO₂ or liquid N_2. In order to minimize the thermal stress in eggshells due to rapid cooling, a two-stage air-cooling method was also evaluated in this study. Eggs were cooled from an initial temperature of 25C to approximately 7C. It was found that cooling produced microcracks on eggshells. However, rapid cooling did not increase the penetration of Salmonella enterica serovar Enteritidis (Salmonella enteritidis) into egg contents. When egg contents alone were sampled for Salmonella enteritidis, extending the immersion time from 24 to 48 h significantly (P < 0.01) increased the penetration of Salmonella enteritidis from 5.0 to 25.0%. When egg contents together with eggshells were sampled, Salmonella enteritidis was detected in 100% of the egg samples at the above two time intervals. There were no significant differences (P > 0.05) in the eggshell strength between control (no cooling) and cooling treatments, indicating that cooling did not weaken eggshell strength.     

Influence of eggshell condensation on eggshell penetration and whole egg contamination with Salmonella enterica serovar enteritidis

Shells of agar-filled and whole eggs were inoculated with 10(3) to 10(4) CFU of Salmonella enterica serovar Enteritidis per eggshell. The agar-filled eggs were used to study bacterial eggshell penetration, and the whole egg results were used to characterize contamination of the egg contents. In each group, half of the eggs were stored for 21 days at 20 degrees C and 60% relative humidity (RH), and the other half was stored for 24 h at 6 degrees C and then for 20 days at 20 degrees C. The latter conditions resulted in condensation on the eggshell for 30 min from the moment the eggs were placed in the 20 degrees C chamber. Taking into account the ages at which hens were studied (39, 53, and 67 weeks), an average of 62% of the eggshells with condensate were penetrated compared with 43% for the control group; this difference was significant (P < 0.01). No significant difference in whole egg contamination was found; 18% of the control eggs were contaminated compared with 22% of the condensate eggs. Whole egg contamination was significantly higher for eggs from the hens at an older age (67 weeks). This difference probably was not due to a higher penetration potential because differences were not observed for the corresponding agar-filled eggs. Condensation on the eggshell seemed to encourage bacterial penetration of the eggshell but had a smaller impact on whole egg contamination.