变色纤维的开发和应用

概述了变色纤维的起源、概念、主要类别和变色技术的基本方法，展望了变色纤维的广阔应用前景。     

热敏变色涂料变色原理及发展

主要论述了不同热敏变色涂料的变色原理、研究动态、印花加工方法及影响因素，并提出了热敏变色印花今后的发展。     

变色纤维的开发和应用

概述了变色纤维的起源、概念与主要类别．分别阐述了变色纤维的溶液纺丝法、熔融纺纹法、后整理法以及接枝聚合法等变色生产技术．展望了变色纤维的广阔应用前景。     

鲜切果蔬变色及其控制技术研究进展

影响鲜切果蔬外观品质最主要因素之一是变色。变色不仅影响鲜切果蔬外观品质,而且会影响其营养价值、风味等。本文主要概述了鲜切果蔬主要变色现象,包括褐变、黄化、白变和脱绿等,阐述了几种变色的机制及极易出现这几种变色现象的鲜切果蔬种类,同时还综述了目前控制鲜切果蔬变色的技术,主要包括化学方法(如化学护色剂处理、可食性涂膜、天然植物提取液处理等)、物理方法(如低温贮藏、热处理、气调贮藏、超声波处理等)和综合处理方法,以期为以后相关研究者提供参考借鉴。     

变色材料在智能纺织品中的应用

在智能纺织品中,变色纺织品是应用较广的一个分支。文章从变色材料的分类着手,综述热致变色、湿敏变色、感光变色、电致变色四类材料的变色原理、变色性能、主要制备工艺及在纺织领域的应用,并进行未来的展望,以期为变色材料在智能纺织品中的发展提供一定参考,拓展设计思路。     

微胶囊技术在智能纺织品上的应用

通过微胶囊封装技术对相变和变色材料进行包覆,所制备的相变或变色微胶囊除了具有储热或变色功能外,还具有耐腐蚀、耐高温以及使用寿命长等优点,从而拓展了纯相变或变色材料的使用范围。简述了相变微胶囊和变色微胶囊的主要制备方法、存在问题以及改进措施,介绍了将相变微胶囊和变色微胶囊整理到纺织品上的方法以及整理后纺织品所具有的性能,并展望了相变微胶囊和变色微胶囊的研究方向。     

热敏变色涂料色原理及发展

主要论述了不同热敏变色涂料的变色原理，研究动态，印花加工方法及影响因素，并提出了热敏变色印花今后的发展。     

馒头储存后变色诱因分析

分析了馒头储存后变色的诱因.采用理论和实验相结合的方法,排除了焦糖化反应、添加剂过量和酶促褐变引起馒头变色,结果发现微生物感染馒头表皮是馒头变色的主要原因.     

热敏“动态”变色涂料的应用

传统的纺织品颜色是静态的,为了提高商品的吸引力,目前各厂家正致力于开发变色印花。变色涂料是一种能随外部条件变化而改变颜色的涂料。 变色涂料分为可逆变色涂料和不可逆变色涂料两种。纺织品变色加工所用变色涂料都是可逆的,变色涂料产生变色的方法主要有3种:光敏变色、湿敏     

可逆变色微胶囊在纺织工业中的应用

采用微胶囊技术进行纺织品的可逆变色材料加工,系通过微胶囊技术将显色体与显色剂、溶剂等物质一起包覆于囊心内,而微胶囊的囊壁起到了隔离外界环境的作用,从而提高了变色材料的耐疲劳性和稳定性,进而延长了纺织品的使用寿命。概述了变色微胶囊的制备技术及其在纺织品中的应用,主要有光致变色、热致变色两大类微胶囊,并对变色微胶囊今后的发展进行了展望。     

鱼腥草多糖活性炭脱色工艺研究

研究了鱼腥草多糖活性炭脱色的工艺。以多糖含量和脱色率为指标,在单因素筛选的基础上,采用正交试验法对脱色工艺进行优选。优化的脱色工艺为:在pH 4.0,20℃的条件下,加入0.4%活性炭,搅拌40 min。该脱色工艺适合工业化应用。     

Steam Treatment of Minimally Processed Carrot Sticks to Control Surface Discoloration

The effects of steam treatment and storage at 2° on surface discoloration and phenolic changes in modified atmosphere packaged carrot sticks was studied. Steam treatment retarded surface discoloration, soluble phenolic and isocoumarin production and lignin formation. Heat inactivation of phenylalanine ammonia-lyase (PAL), peroxidase (POD), and syringaldazine oxidase (SOX) also occurred. Surface discoloration on nonheated samples was accompanied by elevated levels of soluble phenolics, lignin and elevated PAL, POD, and SOX activities over time. Control of surface discoloration by steam appeared to be related to retardation of phenylpropanoid metabolism.     

Endogenous Polyphenoloxidase Activity Associated with the "Black Ring" Defect in Canned Beet (Beta vulgaris L.) Root Slices

Discoloration of canned beet root slices resulted after 5–10 min exposure of beet roots to live steam, and subsequent incubation of slices in air at least 20 min. The “black ring” of discoloration moved radially toward the center of the slice as time of steam-peeling was increased. Dipping slices (prepared after steam-peeling) in solutions of inhibitors of PPO before incubation in air inhibited or prevented discoloration. Based on these data, thermal stability of PPO and POX, heat penetration profiles, and location of the discoloration zone, a model to explain discoloration was developed.     

Some Chemical Factors Affecting the Quality of Processed Yam

Three species of yams (1) white (2) water, and (3) yellow were studied. Each was divided into three sections: head (stem end), middle and tail-and examined for quality characteristics which are important in the utilization of yam for convenience foods. The characteristics studied were susceptibility to discoloration and chemical composition including nutrients such as ascorbic acid, nitrogen constituents, total lipid and polyphenols. The polyphenol content was positively correlated with discoloration and was affected by storage time as well as by the section of yam utilized. The concentration of polyphenols was highest in the head region, which exhibited the greatest discoloration. The middle section was most suitable in preparating light-colored yam products since it was lowest in phenols and exhibited the least discoloration.     

Post-harvest kernel discoloration and fungi activity in long-grain hybrid,pureline and medium-grain rice cultivars as influenced by storage environment and antifungal treatment

Milled rice grade is diminished as the quantity of discolored kernels increases. This study evaluated the magnitude of kernel discoloration and relationship to fungal growth for long-grain hybrid (XL 753), long-grain pureline (Roy J.) and medium-grain (Titan) rice, exposed to storage moisture contents (MCs) of 16 and 21%, wet basis, temperatures of 20, 30, 40 °C, and durations up to 16 weeks. Impact of postharvest treatments with the antifungal agents, natamycin and sodium chloride, on rice discoloration and fungal growth was compared with untreated (control) samples. Subsamples were taken every four weeks to determine total fungal counts, discoloration, and water activity. Rice stored at 40 °C had six-to eleven-times more discoloration than at 20 °C. Increased storage duration significantly increased discoloration. Discoloration was not different between MC levels. Discoloration was significantly lower by sodium chloride treatment, while natamycin was not effective compared to control. Rice samples treated with sodium chloride also had significantly less water activity (mean a_w = 0.73) compared to samples treated with natamycin (mean = 0.84) and control samples (mean = 0.83). Hybrid rice had significantly less discoloration compared to pureline and medium-grain. Fungal counts were similar across all cultivars. Increasing temperature and duration decreased fungal count. An inverse relation between fungi and discoloration suggests microbe activities did not explain discoloration. The findings provide important information to growers and processors on conditions necessary to maintain rice quality.     

碱法提取大枣渣多糖及活性炭脱色的工艺研究

以多糖含量、多糖得率和脱色率为指标 ,采用正交试验法对碱提大枣渣多糖和脱色工艺进行优选。碱提最佳工艺为 :加入 2 0倍枣渣体积的 0 5mol/LNa2 CO3溶液 ,于 80℃温浸 3h。脱色最佳工艺为 :在 40℃下 ,调节 pH =3 5 ,加入 2 %活性炭 ,搅拌 2 0min。     

Novel bentonite clay-based Fe-nanocomposite as a heterogeneous catalyst for photo-Fenton discoloration and mineralization of Orange II

A novel bentonite clay-based Fe-nanocomposite (Fe-B) was successfully developed as a heterogeneous catalyst for photo-Fenton discoloration and mineralization of an azo-dye Orange II. X-ray diffraction (XRD) analysis clearly reveals that the Fe-B nanocomposite catalyst mainly consists of Fe2O3 (hematite) and SiO2 (quartz) crystallites, and the Fe concentration of the Fe-B catalyst determined by X-reflective fluorescence (XRF) is 31.8 wt %. The catalytic activity of the Fe-B was evaluated in the discoloration and mineralization of Orange II in the presence of H2O2 and UVC light (254 nm). It was found that the optimal Fe-B catalyst dosage is around 1.0 g/L, and the efficiency of discoloration and mineralization of Orange II increases as initial Orange II concentration decreases or reaction temperature increases. In addition, at optimal conditions (10 mM H2O2, 1.0 g of Fe-B/L, 1 x 8W UVC, and pH = 3.0), complete discoloration and mineralization of 0.2 mM Orange II can be achieved in less than 60 and 120 min, respectively. The result strongly indicates that the Fe-B nanocomposite catalyst exhibits a high catalytic activity not only in the photo-Fenton discoloration of Orange II but also in the mineralization of Orange II. The reaction kinetics analysis illustrates that the photo-Fenton discoloration of Orange II in the first 15 min obeys the pseudo-first-order kinetics. The reaction activation energy calculated was 9.94 kJ/mol, indicating that the photo-Fenton discoloration of Orange II is not very sensitive to reaction temperature.     

Prevention of brown discoloration in European oakwood occurring during kiln drying by a vacuum process: Colorimetric comparative study with a traditional process

The efficiency of two kiln drying processes on brown discoloration developments ofQuercus robus (L) andQuercus petraea (Lieb) was studied. A traditional atmospheric pressure system, was compared with other using vacuum and super heated steam. 103 green boards from three different trees were used. After each cycle (6), we analysed and compared the color of the boards using a spectrocolorimeter fitted with the CIELAB analysis. With the traditional system (in moist condition) we obtained 100% brown discoloration, in contrast to vacuum and super heating which did not develop brown discoloration. The brown discoloration is characterised by a decrease in lightness (-6 to-8 units) and color angle (-1 to-2 units) compared to non discolored wood. The discoloration is probably independent of wood origin and can be prevented by quick kiln drying without oxygen.     

山药中多酚氧化酶的活性测定及其护色研究

研究了山药中多酚氧化酶(PPO)的最适pH值、最适温度,设计了不同护色方案,以确立山药的最佳护色条件。采用分光光度法研究pH值、温度对酶活性的影响;比较不同护色液对酶活力的影响;将山药经不同护色条件护色后,低温烘干,粉碎过筛得山药粉,用分光光度法测定其甲醇-水溶液(1∶1)的吸光度。结果表明,以邻苯二酚为底物,山药PPO的最适pH值为5.6,最适温度为35℃,山药的最佳护色条件为:以0.25%的Na2SO3为抗氧化剂,并配以0.25%的柠檬酸和1.5%的NaCl为护色液。     

Color and Bind Strength of Restructured Pork Chops: Effect of Calcium Carbonate and Sodium Alginate Concentration

The effects of calcium carbonate concentration (0.00-0.26%) and sodium alginate concentration (0.0-1.4%) on the amount of discoloration and the raw- and cooked bind-strength of restructured pork chops were investigated. Alginate slightly increased and calcium carbonate decreased the amount of discoloration in the restructured chops. The beneficial effect calcium carbonate had on discoloration did not appear to be due to increased pH. Restructured chops prepared with alginate were more discolored (P<0.05) than restructured chops prepared with salt and phosphate. The optimum concentration of calcium carbonate and alginate required for minimum discoloration and maximum raw-and cooked bind-strength was 0.13% and 0.7%, respectively.