Comparative study on physicochemical and functional properties of egg powders from Japanese quail and white Leghorn chicken

Physicochemical and functional properties of freeze-dried egg powders (egg white, egg yolk, and whole egg) from Japanese quail and white Leghorn chicken were studied comparatively. All egg powders had protein content in the range of 91.13–97.03 g/100 g powder. The quail egg powder had higher mineral and essential amino acid contents, but lower fat content as compared to chicken egg powders (P < 0.05). Moreover, egg white powder from both quail and chicken presented higher total amino acids content than corresponding whole egg and egg yolk powders, respectively. Fourier transform infrared spectroscopic study revealed that β-sheet is the major secondary structure of all egg powders. Based on differential scanning calorimetry analysis, quail egg powders showed slightly lower denaturation temperatures than corresponding chicken egg powders (P < 0.05). Sodium dodecyl sulfate–polyacrylamide gel electrophoresis study showed the slight difference in protein patterns of corresponding quail and chicken egg powders. The quail egg powders presented higher protein solubility than corresponding chicken egg powders at all pH tested. Furthermore, quail egg powders exhibited higher emulsion activity index and emulsion stability index with higher foam expansion and stability than the corresponding chicken egg powders. Therefore, Japanese quail egg powders could be used as an alternative to white Leghorn chicken egg in the preparation of foods and diets that require high protein content with positive health benefits.     

以云烟87为主的烟末乙醇抽提物风味成分的气相色谱-质谱法分离鉴定

利用不同浓度乙醇浸提一种以云烟87为主的烟末,制备出5种烟末抽提物,经同时蒸馏萃取,结合气相色谱-质谱法(GC-MS)分析,比较了5种烟末抽提物的风味物质。结果表明:对烟草风味有重要贡献的物质(3-甲基丁醛、4-氧化二氢-α-紫罗兰酮、金合欢醇及棕榈油酸等)在烟末的乙醇抽提物中均被检出,而在烟草水提物中未被检出。说明乙醇能促使重要的风味物质溶出,而60%乙醇浸提烟末,得到的酮类、醛类、酯类和醇类含量丰富,是理想的烟草香料的来源。     

一种低温无硼无铅生料乳浊釉的研究

研究了一种无硼无铅生料乳浊釉,并讨论了影响乳浊度的一些因素     

4-羟基吡啶盐酸盐的表征

在合成4-羟基-3-硝基吡啶(HNP)的过程中发现市场上供应的一种4-羟基吡啶(C)仅含78%4-羟基吡啶(HP),含氯量14.4%。在遇到浓硫酸时放出氯化氢气体,怀疑(C)是HP的盐酸盐。为了证实,制备了HP的两种盐酸盐HP.HCl(A)和(HP)2.HCl.H2O(B),分析了它们的组成,用X-射线粉末衍射谱,熔点和水溶液的pH值作为参数进行表征。据此,证实了(C)就是(B)。在此基础上修改了HNP的合成工艺得到了高于文献报道的纯度和收率。     

粉末涂料粉碎分级系统研究

粉末涂料粉碎分级系统是粉末涂料制备过程的重要环节。针对粉末涂料的特点和对粒径的需求,在研究ACM冲击式粉碎机和SCX超细分级机基础上,探索了2条不同工艺流程的粉碎分级系统,分析了影响该工艺及系统的粉碎分级性能的因素。实验表明,进行2次分级的粉末涂料粉碎分级系统,能分别控制粒径的上限和下限,使得粒径分布窄,合格产品的质量分数为96%,平均粒径为40μm。     

Effect of electrolyte characteristics on electrowinning of copper powder

This paper is concerned with studying the effect of electrolyte characteristics on the production process of electrolytic copper powder from partially depleted Cu containing synthetic electrolytes by electrowinning technique. The main electrolyte characteristics are temperature, circulation rate, Cu and H₂SO₄ concentrations, residence time in the cell, and utilization of organic bath additives. The process is positively affected by increasing the values of all of the studied parameters except for the addition of organic bath additives, which causes a negative effect. However addition of organic bath additives remarkably increases the degree of refinement of the produced powders. In most cases pure and fine copper powders were obtained with a dendritic shape, as indicated by scanning electron microscope (SEM) analysis.     

三鹿降血脂奶粉调节血脂作用的研究

观察了三鹿降血脂奶粉调节血脂的作用。用Wistar品系雄性大鼠60只随机分为6组,全部饲以高脂饲料,在此基础上分别饲以蒸馏水、普通奶粉及3个不同剂量的降血脂奶粉。实验期45d,实验前后测量体重,并采用酶法测定血清总胆固醇(TC)、总甘油三酯(TG)及高密度脂蛋白胆固醇(HDL-C)。结果表明,实验前后的各组大鼠体重均明显增加,但各实验组间无显著性差异(P>0.05)。处理组大鼠血清TG水平显著低于对照组(P<0.05或P<0.01);高剂量降血脂奶粉组大鼠血清HDL-C水平显著高于对照组(P<0.05);各组大鼠血清TC水平则未见有显著性差异。结论,三鹿降血脂奶粉对实验大鼠体重无影响,但可以显著降低TG并可显著升高HDL-C水平。     

挤压对蛋黄粉性质的影响

采用双螺杆挤压膨化机对蛋黄粉进行加工,研究挤压工艺对蛋黄粉挤压产品色泽、可溶性蛋白质和氨基酸的影响。结果显示,提高进料水分,降低机筒温度,有利于降低挤压蛋黄粉的色差值,并能减少可溶性蛋白质和氨基酸的损失;螺杆转速提高,挤压蛋黄粉的色差值呈总体降低趋势,而可溶性蛋白和氨基酸的含量呈先提高后降低的趋势。     

新型大豆食品——大豆酸凝乳粉的研究

以大豆为原料,用嗜热链球菌和保加利亚乳杆菌比例1:1之混合菌种为发酵剂,并添加适量添加剂A和B,经喷雾干燥制得的大豆酸凝乳具有与酸牛乳相似的外观和口感,产品得率达92%。本实验确定了制作大豆酸凝乳粉的最佳工艺条件,并经正交实验确定了由大豆酸凝乳粉制备酸凝乳的最佳发酵条件。     

榛子粉的主要成分和功能特性研究

从作用温度、酸度、Ca2+浓度等方面,测定了榛子粉的主要成分含量、榛子蛋白质等电点。就浓度、pH值、温度、离子强度等影响因素,测定了榛子粉的乳化性、乳化稳定性、吸油性、起泡能力、泡沫稳定性、蛋白质溶解性。结果表明,榛子粉乳化性和乳化稳定性随其浓度增加而增大;NaCl浓度在0～0.4 mol/L,榛子粉的乳化性和乳化稳定性随离子浓度的增大而增大;榛子粉的吸油性随浓度的增大而增强,随温度的增高而增强;榛子粉的起泡能力及泡沫稳定性均随着浓度的增大而增强,起泡能力随离子强度、pH值的增大而增强,泡沫稳定性随离子强度的增大而减弱,在pH值为5时表现出最强的稳定性;榛子粉蛋白质在水中溶解度为159.20g/mL。