牛初乳的理化性质缓冲容量,表面张力,粘度等性质研究

本文研究了初乳的缓冲容量、表面张力、粘度、折射率、氧化还原电位、电导率等理化性质，通过和常乳值相对照找出其变化的规律性。牛初乳的粘度、折射率高于常乳，缓冲容量、表面张力和常乳相当，但有不同于常乳的性质，氧化还原电位接近常乳的下限值，电导率介于０．００３６２￣０．００５６０Ｓ之间。     

奶牛初乳的缓冲容量性质

本文研究了初乳缓冲容量在泌乳期的变化规律，由于ＣＣＰ的存在酸化时在ＰＨ５有最大的缓部容返滴时在ＰＨ６．３出现缓冲容量的最大值，无ＣＣＰ乳化在ＰＨ４．２时有最大的缓冲容量，去除ＣＣＰ初乳，各泌乳期的缓冲容量大小依次为３ｈｒ〉２４ｈｒ〉４８ｈｒ。     

初乳中的生物活性物质

牛初乳是指奶牛产犊后几天内所分泌的乳汁,其化学组成与常乳具有很大的区别。从生物进化的角度来看,初乳是机体免疫协调的产物之一,是新生婴幼儿及仔畜最理想的食品,也是优良的纯天然保健食品。新生婴儿、新生仔畜(如猪仔、羔羊、犊牛等)必须摄食母     

奶牛初乳的深加工技术

1.前言奶牛的初乳是母牛产犊后七天内分泌的乳液,色泽呈浅黄色,具有浓厚感、富粘性,其理化特点是脂肪、蛋白(尤其是白蛋白和球蛋白)含量高,因此耐热性能很差,加热至60℃以上即开始凝块。由于乳制品加工原料乳的技术条件要求,不得使用产犊后七日内的初乳来加工乳制品,一般情况下,初乳只能喂养小牛,剩下的就浪费掉了。“乳珍”粉就是从初乳中经过先进的工     

初乳、常乳及其制品中的雌性激素

简要介绍了人和牛初乳、常乳及其制品中天然雌性激素的种类、结构、含量、存在状态,并讨论了常规乳品加工对不同雌性激素的影响.     

奶牛初乳循环压力冻干节能工艺研究

以奶牛初乳为试验材料，对影响循环压力有耗的压力范围，循环时间周期，料层厚度等进行了系统优化研究，给出了优化工艺参数，并提出改进的循环压力冻干方案。     

初乳的流变学特性研究

研究了２０～６０℃区间内ｌｎηｒ和总干物质、ｌｎηｒ和１／Ｔ的关系，得出温度在２０～３５℃时，ｌｎηｒ＝０．１４４Ｃ＋２．８１２×１０３１Ｔ－１０．８５及３５～６０℃时，ｌｎηｒ＝０．１４４Ｃ＋２．０５６×１０３１Ｔ－８．４２的关系式。依据上式能够很好地表征２０～６０℃区间内初乳的流变学特征受温度和总干物质的影响情况。     

奶牛初乳的理化性质Ⅰ热稳定性和其化学组成

本文研究了奶牛初乳的热稳定性并对其加以改进,奶牛初乳的成分分析结果表明:奶牛初乳的蛋白质、脂肪、灰分、密度均高于常乳,并随泌乳期的延长而下降逐渐接近常乳水平,pH和乳糖的变化和它们相反;初乳中Ca、Na、Mg、Cl、Fe、Zn、Cu、的含量均高于常乳几倍甚至几十倍,但K、P的含量较常乳低。奶牛初乳不允许作为原料乳应用,除牛犊食用外大部分被废弃,已有研究表明初乳在常量、微量成分、生物活性物质的含量上均有不同于常乳的性质,如初乳中的免疫球蛋白、乳铁蛋白、溶菌酶、过氧化物酶、α-乳白蛋白,β-乳球蛋白、黄嘌呤氧化酶等生物活性物质含量要高于常乳几十倍～几千倍,其分离纯化后应用于食品添加剂和医药工业潜力很大,故有必要对初乳的理化性质作系统的研究和分析,为初乳的开发和利用提供依据。     

微波加热杀菌对牛乳品质的影响

为了掌握微波加热杀菌对牛乳品质的影响,该文以牛乳层厚度和微波功率为试验因素、以营养成分的损失为指标进行了试验研究。研究的结论是：（1）牛乳的微波加热杀菌比水浴加热杀菌对乳中维生素C的影响要小。（2）牛乳层厚度和微波功率对乳脂肪的影响较为显著,而对乳蛋白质的影响均不显著。（3）牛乳层厚度越小,对乳脂肪的影响越小,随着牛乳层厚度的增加乳脂肪的损失增加,但越来越缓慢;微波功率越大,对乳脂肪的影响越小,基本呈直线下降。     

牛初乳中免疫球蛋白的测定

以单向免疫扩散法测定了牛初乳中的IgG。结果表明,产犊后第1次挤乳,初乳gG平均为67.23mg/mL,之后随泌乳进行迅速下降,24h后降到小于5mg/mL,到第5天已降到常乳水平。     

牛初乳对免疫抑制小鼠免疫功能影响的研究

目的探讨牛初乳对免疫抑制小鼠免疫功能的影响。方法将ICR雌性小鼠随机分为五组:正常对照组,模型对照组和牛初乳低、中、高剂量组。观察不同剂量牛初乳对免疫抑制小鼠脾指数、胸腺指数、细胞免疫、体液免疫、单核-巨噬细胞吞噬功能及脾脏T淋巴细胞亚群的影响。结果三个剂量组的脾指数和胸腺指数显著低于正常对照组(P<0.01)。中、高剂量组脾脏T淋巴细胞增殖能力显著高于模型对照组(P<0.01)。三个剂量组溶血空斑数均显著高于模型对照组但低、高剂量组低于正常对照组(P<0.01)。三个剂量组校正后吞噬系数α明显高于模型对照组及正常对照组(P<0.01)。中剂量组脾脏T淋巴细胞中CD4+百分比显著高于模型对照组及正常对照组(P<0.01)。结论牛初乳能够有效提高免疫抑制小鼠细胞免疫、体液免疫、单核-巨噬细胞吞噬功能和脾脏CD4+百分比。     

介绍一种简单易行的测定表面张力的仪器

本文介绍了一种简单易行的由移液管改制的测定表面张力的仪器及其操作原理和使用方法。     

凹印机印刷过程中的张力计算与张力控制

张力控制是凹印机整机控制的核心.印刷过程中,张力变化范围小,套印精度就容易控制.为了对凹印机张力控制的主要影响因素进行正确分析,在考虑料卷轴芯结构形式和重量分布的情况下,推导出凹印机放卷过程中的新的张力计算公式.在对我国凹印机几种张力控制的类型进行介绍的基础上,对张力传感器检测、浮动辊检测、浮动辊/反馈复合式检测等几种张力控制方式作了介绍.     

蛋白质溶液表面张力及其与功能性质的关系

为了探讨蛋白质溶液表面张力的变化规律，本文利用表面张力计和食品流变学方法系统地研究了蛋白质溶液表面张力随液滴停留时间的变化及其与功能性质的关系。结果表明：高浓度时，液滴停留时间与表面张力的变化遵循下列一次方程In[（θt-θe）/（θw-θe）]=-kt。对同一蛋白质来说，k值随浓度的增加而增大。蛋白质起泡力与k值呈极显著的线性关系，泡沫稳定性与k值呈正相关。蛋白质的乳化性低浓度时与表面张力呈正相关；高浓度时，乳化性与k值呈正相关。     

Bioactive Compounds of Colostrum and Its Application

Colostrum is the initial milk secreted by bovine during parturition and the first few days after birth. Colostrum is a gift of nature used to protect the newborn’s immune system and provides passive immunity against pathogens. The presence of bioactive components such as insulin-like growth factor I and II (IGF-I and IGF-II), lactoferrin, lysozyme, lactoperoxidase, and immunoglobulin make the colostrum active against pathogens such as Escherichia coli, Salmonella typhimurium, Shigella dysenteria, Listeria monocytogens, Streptococcus mutans, Bacillus stearothermophilus, and Bacillus subtilis. It is also active against Herpes simple virus type-I (HSV-I), Human Immuno-deficiency virus-I (HIV-I), and human cytomegalovirus. Lysozyme is an antibacterial and lytic enzyme; whereas lactoperoxidase is a major antibacterial found in colostrum; it is toxic to gram-positive and gram-negative bacteria. Lactoperoxidase inactivates the polio virus, vaccinia, and human immunodeficiency virus type-I in-vitro. Immunoglobulins are considered an important bioactive component in colostrum, and it contains high levels of immunoglobulin G (Ig G). Immunosupplementation with bovine milk antibodies has been shown to provide local protection to the gastrointestinal tract against disease. The restricted technical and hygienic problems, along with the unstable physio-chemical nature of colostrum, has resulted in minimal utilization of colostrum on Industrial scale.     

Bioactive Compounds of Colostrum and Its Application

Colostrum is the initial milk secreted by bovine during parturition and the first few days after birth. Colostrum is a gift of nature used to protect the newborn's immune system and provides passive immunity against pathogens. The presence of bioactive components such as insulin-like growth factor I and II (IGF-I and IGF-II), lactoferrin, lysozyme, lactoperoxidase, and immunoglobulin make the colostrum active against pathogens such as Escherichia coli, Salmonella typhimurium, Shigella dysenteria, Listeria monocytogens, Streptococcus mutans, Bacillus stearothermophilus, and Bacillus subtilis. It is also active against Herpes simple virus type-I (HSV-I), Human Immuno-deficiency virus-I (HIV-I), and human cytomegalovirus. Lysozyme is an antibacterial and lytic enzyme; whereas lactoperoxidase is a major antibacterial found in colostrum; it is toxic to gram-positive and gram-negative bacteria. Lactoperoxidase inactivates the polio virus, vaccinia, and human immunodeficiency virus type-I in-vitro. Immunoglobulins are considered an important bioactive component in colostrum, and it contains high levels of immunoglobulin G (Ig G). Immunosupplementation with bovine milk antibodies has been shown to provide local protection to the gastrointestinal tract against disease. The restricted technical and hygienic problems, along with the unstable physio-chemical nature of colostrum, has resulted in minimal utilization of colostrum on Industrial scale.     

Surface tension and foam stability of commercial calcium and sodium caseinates

The static and dynamic surface tension of sodium and calcium caseinates was compared with their foam behavior. The surface tension behavior of sodium and calcium caseinates was similar but the foaming properties differed. Caseinates presented moderate surface activity lowering the surface tension of water to 40 mN/m. The surface pressure vs. composition data were analyzed using a new surface equation of state and obtained 0.1% (w/v) critical concentration and the molecular surface area; in the case of calcium caseinate was larger compared to sodium caseinate. Caseinates were evaluated at the critical concentration by means of dynamic surface tension to compare their behavior; calcium caseinate took longer time to reach equilibrium conditions. Their foam behavior was transient type with maximum foamability around the critical concentration; sodium caseinate presented better foaming properties than calcium caseinate.     

响应面法优化牛初乳免疫球蛋白热保护剂的配方

为筛选一种最佳的牛初乳免疫球蛋白（Immunoglobulin G,IgG）热保护剂,以牛初乳为原料对其IgG进行提取,在单因素实验基础上,以IgG活性保留率作为响应值,选取甘氨酸、麦芽糖醇和菊粉三种物质作为响应因子,采用Box-Behnken响应面法对IgG热保护剂配方进行优化,并通过傅里叶变换红外光谱和内源性荧光光谱表征不同方式处理的牛初乳IgG结构。结果表明,IgG热保护剂的最佳配方:甘氨酸0.48%,菊粉14.98%,麦芽糖醇12.50%,在75 ℃,5 min条件下热处理的IgG活性保留率为36.59%,各因素添加量对IgG活性保留率的影响主次顺序均为:麦芽糖醇>甘氨酸>菊粉。傅里叶变换红外光谱和内源性荧光光谱分析结果表示:与未添加复合热保护剂的牛初乳IgG相比,添加复合热保护剂后的牛初乳IgG,β-折叠含量显著下降（P<0.05）,无规则卷曲含量显著下降（P<0.05）,二级构象呈现较为有序的状态;荧光强度降低,IgG分子堆积更加紧密,结果表明添加复合热保护剂后的牛初乳IgG结构稳定性有所提高。本研究探索出一种新型牛初乳IgG的复合热保护剂配方,为牛初乳功能性食品的进一步开发和利用提供了参考。