美国黑琥珀色素稳定性的研究

研究了美国黑李(黑琥珀)色素的稳定性,结果表明:该色素耐热性好;pH值对该色素有明显影响,适宜酸性环境;一般金属离子对该色素影响不大,但Fe3 离子、Al3 离子对黑李色素的影响较大;食盐、淀粉对该色素无不良影响;VC、H2O2则有不良影响,该色素耐还原能力稍强,耐氧化能力稍差;防腐剂苯甲酸钠对该色素影响不明显。     

细叶美女樱红色素的提取及性质研究

研究了细叶美女樱花红色素的提取条件和理化性质.结果表明:pH1.0的体积分数为95%乙醇是细叶美女樱花红色素的最佳提取剂;细叶美女樱花红色素属花青素类色素,易溶于水和酸性乙醇;pH值对色素影响明显,在酸性条件下色泽稳定且具有热稳定性;光照能加快色素降解;金属离子Na 、Ca2 、Al3 、Zn2 对色素色泽无影响,而Cu2 、Fe3 、Pb2 有不良影响;色素的抗氧化较差而抗还原性能较好;蔗糖、葡萄糖和盐等添加剂对色素无影响.     

石斑木果皮红色素稳定性的影响因子

实验研究石斑木果皮红色素的理化性质和光、温度、金属离子、食品添加剂等对色素稳定性的影响．结果表明：该色素在80℃以下较稳定;日光照射,金属离子K^＋、Na^＋、Mg^2＋、Ca^2＋、Cu^2＋、Mn^2＋、Fd^3＋等对色素液的吸光度有明显的不良影响;高浓度VitC和柠檬酸对色素降色明显;蔗糖和苯甲酸钠对色素无较大影响．     

阴香果实色素提取条件及其稳定性研究

该文主要研究了从阴香果实中提取色素的方法和条件.测试了pH值、温度、光照、金属离子等因素对色素稳定性的影响.结果表明,该色素提取的最佳条件是:用无水乙醇作提取剂;阴香果实重(g)与提取剂的用量(ml)比为1:5;提取温度为65~75℃.提取液pH为3～4.实验发现,阴香果实色素既溶于极性溶剂,也溶于非极性溶剂:色素在弱酸弱碱性条件下稳定性良好;对光、热耐性较好:色素对Fe3+,Zn2+十分敏感;食品中添加的防腐剂对色素的稳定性影响不大.     

凤仙花红色素的提取及性质研究

以凤仙花为原料进行红色素的提取和理化性质研究,结果表明,酸性乙醇溶液提取效果最佳;色素的水溶性好;加热后耐光性好;柠檬酸、维生素C、蔗糖、碳酸氢钠、常见金属离子对色素无影响或影响很小;过氧化氢、亚硫酸钠对其影响很大.     

紫粒小麦籽粒色素稳定性的研究

以紫粒小麦麸皮的乙醇浸提色素溶液（pH=2）为材料,进行了紫粒小麦籽粒色素的光谱特性的测定以及pH、温度、自然光、氧化剂（H202）、还原剂（NazS03和维生素C）、防腐剂（苯甲酸钠）和柠檬酸、食盐、蔗糖等食品饮料添加剂以及常见金属离子（VF^2＋、Ca^2＋、Zn^2＋、Mg^2＋、Al^3＋、Cu^2＋、Fe^3＋）等对紫粒小麦籽粒色素稳定性影响的测定．结果表明,在可见光区,紫粒小麦籽粒色素酸性乙醇溶液的最大吸收波长为520nm;紫粒小麦籽粒色素的颜色与pH有关,pH越小颜色越鲜艳,在pH≤3时紫粒小麦籽粒色素呈现稳定的棕红色;蔗糖、食盐、热、还原剂对紫粒小麦籽粒色素的影响很小;常见金属离子除Cu^2＋、Fe^3＋外,其他均对紫粒小麦籽粒色素无影响;紫粒小麦籽粒色素抗光照但不抗氧化。     

龙眼壳黄色素的提取及其稳定性研究

以龙眼壳为原料提取黄色素,并对该色素的稳定性进行研究.实验结果表明,该色素最佳提取工艺为:提取剂为乙酸乙酯,浸提料液比为1∶30,温度为40℃,时间为3 h.稳定性研究表明,该色素对光、热和还原剂的稳定性良好.食品添加剂和金属离子对色素的影响较小,其中柠檬酸,山梨酸钾对色素有增色效应,因此其用量不宜过多;Fe3+、Zn2+、Al3+对色素影响较大.该色素耐酸、不耐碱,在pH值接近10时,色素明显变色且有少量的沉淀物.     

黄色七彩菊花色素的提取及其稳定性研究

以黄色七彩菊花作材料,对其花色素提取条件及理化性质进行研究。以蒸馏水作为提取剂,在单因素实验基础上,通过正交实验优化了色素提取温度、料液比、提取时间,优化提取条件为：温度80℃,料液比1：11．1（g／mL）,提取时间30min。理化性质表明：不同温度、pH值对色素颜色有较大影响,色素的光稳定性及抗氧化性能力较差,色素具有一定的热稳定性和抗还原性能力;Na^＋、K^＋、Ca^2＋、Al^3＋四种离子对色素稳定性影响较小,Cu^2＋、Fe^3＋对色素影响较大。     

胡萝卜色素稳定性研究

本文初步探讨了pH值、紫外光、温度、氧化剂、还原剂和金属离子等对胡萝卜色素稳定性的影响,结果表明:该色素在碱性条件下(pH值11时)稳定性较好;对紫外光敏感;有较好的耐热性;耐氧化性和耐还原性较差;除Fe2 、Cu2 、Zn2 和pb2 四种金属离子外,大多数金属离子对色素的稳定性影响均极其微弱.     

饮料中柠檬黄色素稳定性的研究

采用分光光度法研究了柠檬黄合成色素的pH、光照及热稳定性,并就饮料中常见的几种金属离子和两种食用酸对其稳定性的影响进行了研究。结果表明:柠檬黄色素在pH=2~9范围内,室温避光放置稳定性较好;在pH=4.46时,耐温性较好;阳光直射和自然光照射对柠檬黄色素有一定破坏作用;暗处放置有利于色素的保存;柠檬黄色素与金属离子K 、Na 、A l3 共存,稳定性较好;与Ca2 、Zn2 、Mg2 共存,稳定性次之;少量Fe3 的加入,会使柠檬黄色素溶液增色;Cu2 的加入会使柠檬黄色素溶液变色;在柠檬酸和酒石酸两种食用酸中性质较稳定。     

卡思卡特城堡

It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,     

不同的吃喝玩乐

一、吃和喝吃苹果 eat an apple, 吃药 take medicine,吃糖 have some sweets,吃饭 have one's meals,吃馆子 dine out,吃惊 be surprised/     

漏洞百出的教育

Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help?     

Western and Eastern culture differences in commercial field

The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity.     

只要努力,不要后悔

There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love.     

浅谈移民问题

Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject.     

风的曲线

Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose.     

团图为数的图中的闭团贯数

Given a graph G,a subgraph C is called a clique of G if C is a complete subgraph of G maximal under inclusion and |C|≥2. A clique-transversal set S of G is a set of vertices of G such that S meets all cliques of G. The clique-transversal number, denoted as TC (G), is the minimum cardinality of a clique-transversal set in G. The clique-graph of G, denoted as K (G), is the graph obtained by taking the cliques of G as vertices, and two vertices are adjacent if and only if the corresponding cliques in G have nonempty intersection. Let F be a class of graphs G such that F={G|K(G) is a tree}. In this paper the graphs in F having independent clique-transversal sets are shown and thus TC (G)/|G|≤1/2 for all G ∈ F.     

Sister Carrie, an Adherent of Desires

Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities.