微波条件下提取天然色素的研究

以柚皮为原料,在微波条件下,以水作溶剂直接从柚皮中提取天然色素。探讨了微波平均辐射功率、辐射时间、溶剂量和柚皮被破碎的程度对天然色素产率的影响,通过正交实验确定了最佳工艺参数。     

微波强化浸取天然色素机理的探讨

利用扫描电子显微技术和透射电了显微技术，分析了微波强化浸取天然色素和传统加热浸取天然色素过程中的柚皮细胞结构，发现微波强化浸取的机理与传统加热浸取的机理不同，在此研究的基础上提出了细胞壁的“电穿孔”机理。     

高频电磁场下柚皮中天然食用色素的浸取

以柚皮为原料,以水为介质,在微波条件下直接从柚皮中提取天然色素。微波浸取与传统方法相比,具有提取率高、节省时间、能源消耗小、安全无污染等特点。扫描电子显微技术分析证明,微波固液浸取的机理与传统加热浸取的机理是不同的。     

微波强化浸取天然色素数学模型的建立

微波强化浸取所得天然色素的产率不仅与微波的辐射功率、辐射时间有关,还与溶剂量、柚皮的破碎度等因素有关。为了把所有因素都考虑进去,首先采用“黑箱方法”先建立一个与数据拟合较好的数学模型,然后再逐渐逼近实验数据,最后用现代计算机技术按最小二乘法原则处理,确定式中的待定系数值。     

柚皮色素稳定性研究

本文介绍分别用水和乙醇提取柚皮色素，并对柚皮红棕色素稳定性作了研究，结果表明，柚皮水溶性色素易于制取产量大。     

天然色素的提取和精制研究进展

天然色素安全,色泽浅淡,目前天然色素的稳定性得到逐步提高,产品应用更加方便安全,所以食品工业对色素的选择越来越趋向于天然食用色素.本文对天然色素的浸提、微波萃取、超临界流体萃取、超声波提取方法和超滤、吸附树脂及凝胶层析精制技术的研究进展进行了综述,并介绍了天然色素的发展、分类和性质特点.     

柚果皮中生理活性成分研究进展

对柚果皮中黄酮类化合物、类柠檬苦素、天然色素及香精油的化学组成、分布、药理作用及应用等进行综述     

微波辅助提取红枣红色素及其稳定性的研究

研究微波辅助提取、超声波辅助提取以及常规提取对红枣红色素提取率的影响.结果表明,与常规提取法相比,超声波辅助提取法对改善红枣色素提取率的效果不显著,而微波辅助提取法能明显提高红枣色素的提取率.通过正交试验确定微波辅助提取红枣色素的最佳工艺,即料液比为1:30,提取功率为420W,提取时间为20 min.研究温度、光照、酸碱度、食盐对红枣红色素稳定性的影响,结果表明红枣色素是一种稳定性比较好的天然色素.     

天然色素的提取和应用研究

随着科技的发展和生活水平的提高，天然色素以其健康、安全的特点，将越来越受人们的欢迎。本文首先介绍了天然色素的几种提取方法：溶剂提取法、超临界流体萃取法、微波萃取法、酶法以及它们各自的优缺点。然后又对几种具有代表性的色素和他们在某些方面的应用做了简要的介绍。最后对天然色素的前景开发中存在的问题和方向做了简单的总结。     

柚皮提取物有效成分的研究概况

柚子(Citrus grandis)是芸香科柑橘属水果.柚皮占整个柚子的43%～48%,除含有水分、维生素、矿物质这些人体必需的营养素,还含有多种对人体健康有益的非营养性生理活性成分,如黄酮类化合物、类柠檬苦素、香精油、天然色素、膳食纤维等.本文对柚皮中黄酮类化合物、类柠檬苦素、天然色素、香精油、膳食纤维的化学组成与结构、生物活性、提取方法以及在食品、医药等方面的应用进行了综述.     

橄榄高纤维面包的制作工艺研究

为提高油橄榄果渣加工利用率，考察了加水量和油橄榄果渣添加量对面包品质的影响。测定橄榄果渣的基本成分及50%、52%、54%和56%的加水量对面包品质的影响，并在传统面包配方的基础上，分析橄榄果渣以5%、10%、15%和20%的质量比例加入后制得的面包品质。从口感、风味、色泽等方面进行面包感官品质评价，从质构和比容方面进行物性指标分析。结果表明，在本研究条件下制作面包，加水量以52%为宜，橄榄果渣添加量在10%时最为适宜。随着橄榄果渣量的增加，面包比容下降，面包内聚性与橄榄果渣添加量呈负相关关系，而硬度、咀嚼性与橄榄果渣添加量呈现正相关。综合考虑面包的外观、品质、香味及纤维含量，以10%的橄榄果渣添加量最适宜。     

虾类抑制黑变保鲜技术研究进展

虾类中因富含大量人体必需氨基酸、微量营养素而备受关注。本文介绍了虾类的基本信息及其在储藏加工过程中主要存在的黑变问题和机制,以及各种虾保鲜、抑制黑变的方法。首先介绍了化学方法,包括现阶段正在使用或已被研究的化学合成试剂及天然试剂的作用机制及相关研究。主要的化学合成试剂有乙二胺四乙酸、4-己基间苯二酚、亚硫酸盐、焦亚硫酸钠、氯化钠等。天然试剂主要包括抗坏血酸、植酸、阿魏酸、曲酸、麦角硫因、儿茶酚、葡萄籽、竹叶抗氧化物、茶黄素、壳聚糖、紫菜多糖、鳄梨等;物理方法包括调控温度、气调保鲜、辐射、可食用性涂抹材料、冰保鲜冰、压力调控、臭氧等;其他新兴方法包括乳酸菌法、饥饿法、酸性电解冰法等。还介绍了近几年应用于虾保鲜的综合应用方法,如冷藏和气调保鲜技术相结合,用壳聚糖包裹再添加石榴皮提取物,用橙子油和明胶复配,焦亚硫酸钠和绿茶与迷迭香提取物的同时使用,壳聚糖与虾蛋白脂浓缩物等;最后提出对于新型廉价的保鲜方式的开发,各种天然抑制剂的研究,以及将2种或2种以上试剂进行搭配使用以取得更好的协同效果的研究将成为今后虾保鲜抑制黑变的热点。     

蔗秆表皮层的SEM-EDAX研究

用SEM-EDAX法研究蔗秆表皮层的超微结构及元素组成。结果表明，在实验条件下，蔗秆表皮层的外表面由C、O、Mg、Al、Si、Cl6种元素组成，Si的含量为30．464％；颗粒状物的Si含量为53．833％。蔗秆表皮层径切面中含C、O、Mg、Al、Si、K、Ca7种元素，自外向里各种元素的含量呈规律性变化。表皮层是Si等矿质元素高度密集、超微结构非常复杂的多层结构；表皮层中的Si绝大部分在碱法制浆的低温蒸煮阶段就被溶解转移到黑液中，残留物几乎为纯C组成。蔗秆表皮层的超微结构、Si等元素的存在状态及脱除机理有待进一步研究。     

甘薯淀粉对山药凝胶肠理化特性的影响

为研究甘薯淀粉对山药凝胶肠理化特性的影响,对不同甘薯淀粉添加量下山药凝胶肠的质构特性、色度、热特性、水分状态、微观结构以及结晶特性进行了测试。结果表明：甘薯淀粉的添加显著增强了山药凝胶肠的硬度、胶着性、咀嚼性、内聚性和回复性,但黏性、弹性和白度下降;当甘薯淀粉添加量达到20%时,凝胶肠硬度达到7 060.65 g,胶着性为5 263.38 g,咀嚼性为4 623.80 g,内聚性为0.75,回复性为0.42,接近市售火腿肠的质地。甘薯淀粉的添加降低了山药凝胶肠的含水量和水分子的自由度,导致淀粉分子运动受限从而使相对结晶度和回生焓降低,凝胶肠质地更为致密。     

Influence of colour intensity on the perception of colour and sweetness in various fruit-flavoured yoghurts

A study was made of the influence of colour concentration on the perception of flavour, sweetness and colour intensity, and also of opinions about colour suitability, in yoghurts with strawberry, lemon, fruit of the forest and orange flavours. The results indicated that, even with the same content of each fruit flavour and sugar, the greater the concentration of colourant, the greater was the intensity of taste perceived by the assessors in yoghurts with strawberry, orange and fruit of the forest flavours. With regard to perception of sweetness, only in the yoghurts with fruit of the forest flavour was it found that the greater the concentration of colourant, the greater was the sensation of sweetness.In the range of colourant concentrations studied for the four flavours, it was found that the colour considered most suitable corresponded to the yoghurts with intermediate colourant concentrations and that, for the four flavours studied, the greater the concentration of colourant, the greater was the sensation of intensity of colour.     

Modellversuche zur Abschätzung der Raumluftbelastung durch Holzschutzmittel

The wood preservative concentrations in the air of living rooms or model rooms differ greatly, as can be seen from the data published. It is extremely difficult, or even impossible, to determine the influence of exterior parameters, such as temperature, moisture in the air, wood species etc, on these values. This, however, would be desirable for the development of new preservatives. A method is, therefore, proposed by which the potential air concentration in rooms can be assessed on the basis of experimentally determined rates of evaporation. In addition, data on the dimension of the wood surface, the size of the room, the exchange of air per hour, and the actual saturated vapour pressure of the wood preservative are required. A few simplified hypotheses have to be made. A simple device for measuring the rates of evaporation is described.     

Capsicum--production, technology, chemistry, and quality. Part III. Chemistry of the color, aroma, and pungency stimuli

The spice capsicum, the fruits of the genus Capsicum (Family Solanaceae), is a very popular food additive in many parts of the world, valued for the important sensory attributes of color, pungency, and aroma. A large number of varieties are widely cultivated and traded. The characteristic carotenoids of the bright red paprika and cayenne-type chillies, the high character impact aroma stimuli, the methoxy pyrazine of green bell capsicum, the esters of ripe tabasco and the highly potent pungency stimuli, and the capsaicinoids of African and other Asian varieties of chillies, have been of great interest to chemists and biochemists. Research workers in other disciplines such as genetics and breeding, agriculture, and technology have been interested in this spice to develop new varieties with combinations of different optimal levels of the stimuli for the sensory attributes and to maximize production of storable products for specific end uses. Physiologists have been intensely studying the action of the highly potent pungency stimuli and social psychologists the curious aspect of growing acceptance and preference for the initially unacceptable pungency sensation. In the sequential review of all these aspects of the fruit spice Capsicum, the earlier two parts covered history, botany, cultivation and primary processing, and processed products, standards, world production, and trade. In Part III, the chemistry, the compositional variations, synthesis and biosynthesis of the functional components, the carotenoids, the volatiles, and the capsaicinoids are comprehensively reviewed.     

纸张三维结构的CLSM表征及纸张特性研究

为采用纤维复配的方法提高蔗渣浆纸张的物理性能,探究了棉浆、马尾松浆、竹浆、桉木浆以及蔗渣浆自身特性和纸张结构。首先检测不同浆种纤维的自身特性,然后提出了一种基于激光扫描共聚焦显微镜(CLSM)的纸张三维结构表征方法,计算纸张的孔隙率用于表征纤维间的相对结合面积,两者结合分析了棉浆、马尾松浆、竹浆、桉木浆与蔗渣浆配抄纸张物理性能的贡献因素。结果表明,CLSM所得到的纸张孔隙率计算值与实验检测值的相对误差小于8%;配抄后纸张物理性能的实验值均大于计算值,具有协同作用,配抄纤维对蔗渣浆纸张物理性能提升的贡献度从大到小依次为:纤维结合能力、纤维自身强度、纤维长度,其中配抄50%马尾松浆的蔗渣浆纸张物理性能提高最大,纸张的抗张指数、耐破指数、撕裂指数分别提高56. 8%、99. 3%、108. 1%。     

Effect of urea during in vitro maturation on nuclear maturation and embryo development of bovine cumulus-oocyte-complexes

High concentrations of urea in reproductive tract fluids are detrimental to bovine reproduction. Therefore, in experiment 1, the effect of 6 mM urea on nuclear maturation of cumulus-oocyte-complexes (COC) collected from abattoir ovaries was studied. After 4, 8, 12, 16, 20, and 24 h of in vitro maturation, the nuclear stages of samples of the COC were determined. During the first 8 h of maturation, germinal vesicle breakdown and chromosome condensation, resulting in the metaphase I stage, occurred at higher rates in the presence of urea. Segregation of the chromatids and extrusion of the polar body seemed to be impaired in the presence of urea, resulting in a higher percentage of oocytes arrested in metaphase I or telophase, and a lower percentage of oocytes in metaphase II after 24 h of maturation. Overall, nuclear progression of COC matured in the presence of urea differed from COC matured in control medium. In experiment 2, COC were matured for 24 h either in the presence or absence of 6 mM urea followed by in vitro fertilization and culture. After fertilization, a sample of the COC was fixed and stained to determine the fertilization rate. The cleavage rate was determined 3 d after start of maturation, and the stage of embryonic development was recorded 7 and 9 d after start of maturation. Based on cultured oocytes, urea in the maturation medium decreased the subsequent percentage of fertilization, cleavage, and development on d 7 and 9 (43.2, 56.1, 14.8, and 18.2%, respectively for urea vs. 64.1, 68.8, 22.4, and 23.9%, respectively for the control group). Embryonic development as a percentage of cleaved oocytes was not significantly affected by urea. Therefore, negative effects of urea were evident primarily during oocyte maturation and fertilization.     

中国古代首服中的蝉及其符号意义北大核心CSCD

历代首服中装饰物多样,其中蝉纹饰物造型精巧别致,具有独特的符号价值和文化内涵。文章采用文献研究法对蝉符号的历史渊源和寓意进行深层解读和剖析,总结其表现特征;从墓葬出土及绘画中的蝉纹金珰及附蝉首服对蝉的情感表达、含义象征进行归纳、整理。研究表明:蝉是古代中国首服的重要纹饰,并在作为首服纹饰的过程中完成了文化符号、思想符号及民族符号的构建。蝉饰不仅设计巧妙而且品种丰富,无论在佩戴身份还是种类用途都分化明细。其传播原因受官宦权位、雅士情感、黄老学说等因素的影响,体现出纹饰的发展演变与社会文化息息相关。