毛皮退色新工艺

就毛皮退色工艺在以下几个方面进行了系统的介绍:毛皮退色机理;毛皮退色的基本方法,即碱性氧化退色法和催化接触退色法;毛被退色新材料;毛被退色新工艺,即毛皮漂色工艺,毛皮退色、漂白和增白工艺;工艺条件的合理控制以及退色后处理,脱铁、还原漂白、复鞣。并以水貂皮漂金工艺、有色毛皮退色漂白工艺等为例,进行说明。     

对竹浆在碱处理段添加过氧化物光学性质的研究

竹浆这种非木材纤维，仍是印度造纸工业长纤维浆的主要来源。随着社会、经济和工业环境的发展，国家对纸张质量的要求也增高了。印度造纸工业也期望采用先进的技术改进产品质量和增加产量。然而，人们还是采用ＣＥＨ漂序，以次氯酸盐漂白纸浆，虽然它对纸浆的物理和光学性质，已知有坏的影响。本文论及在ＣＥＨ漂序的碱处理段采用过氧化物有效地改进漂白浆的总体质量。用ＣＥＨ漂序白度达到８０％ＥＬ时，在ＣＥＨ漂序中添加０．３％（对绝干浆）的过氧化氢，减少３０％的次氯酸盐用量。同时，浆的退色值下降２５％，整个物理强度大的改进了１５％．工厂规模的试验也证实了实验室研究获得的结论。     

真空—蒸汽脉动烫漂预处理对百合

将真空—蒸汽脉动烫漂预处理技术应用于百合的烫漂预处理,研究蒸汽烫漂时间、烫漂循环次数和真空度对百合烫漂后干燥特性、水分有效扩散系数、色泽和复水比的影响。结果表明：蒸汽烫漂时间、烫漂循环次数和真空度均对烫漂后百合的干燥特性有显著性影响,当蒸汽烫漂时间30 s,烫漂循环3次,真空度90 kPa时,百合烫漂充分,提高了细胞间的通透性并抑制PPO、POD酶的活性,烫漂后在60 ℃热风下干燥,最短为11.7 h;干燥后的百合片色泽L^*值为83.65、ΔE值为5.18,接近于新鲜百合色泽;复水比最高为1.49 g/g,水分有效扩散系数最大为6.85×10^-10 m²/s;综合评分最高为0.98。     

烫漂方式对苹果脆片褐变和多酚及其抗氧化活性的影响

为阐明烫漂方式对热风干燥苹果片品质特性的影响,采用热水、蒸汽和微波对苹果片进行烫漂处理,测定苹果片在烫漂和干燥过程中的色泽、多酚及其抗氧化活性的变化情况。结果表明,热水烫漂苹果片的干燥时间最短,为270 min;不同烫漂方式对苹果片褐变有显著影响(P<0.05),其中热水烫漂的苹果片色泽变化最小,微波烫漂的苹果片色泽最差;与鲜样相比,烫漂方式对苹果片还原糖含量影响较小;干燥过程中微波烫漂的苹果片中产生的5-羟甲基糠醛含量最高,蒸汽烫漂次之,热水烫漂最低;苹果片经热水烫漂和干燥后维生素C损失率分别为34%和52%,而蒸汽烫漂和微波烫漂的苹果片中维生素C损失率较小;热水烫漂的苹果脆片总酚含量最高,达到11.82 mg GAE/g DW;苹果片经烫漂处理后游离多酚和结合多酚单体无显著性变化(P>0.05),但干燥后,所有样品中结合多酚单体含量均显著提高(P<0.05)而游离多酚单体的含量无显著性变化(P>0.05),表明3种烫漂方式都有利于多酚单体的保留;多酚抗氧化能力实验表明烫漂和干燥后苹果片中结合多酚抗氧化活性有显著性变化(P<0.05),其中热水烫漂的苹果...     

洗水对含木棉纤维牛仔面料性能的影响

采用普洗、氧漂、氯漂、锰漂和酵素漂等方法对含木棉牛仔面料进行处理,探讨不同洗水方法对含木棉牛仔面料的K/S值、透气性、断裂强力和断裂伸长率的影响。结果表明,除锰漂、氧漂外,其它三种洗水方法的褪色效果不明显;经过氧漂、锰漂洗水后的牛仔面料,透气率增加14%以上,酵素漂的透气率下降超过14%,而氯漂和普洗的透气率基本不变;氧漂、氯漂处理面料的经纬向断裂强力增加,而锰漂、酵素漂的减小,普洗经向减小,纬向变化不大。     

文摘精粹

深色羊绒染制品退色方法的探讨与比较/林丽云(福建省纤维检验局)//中国纤检/中国纤维检验局.-2011,(20).-58～62通过保险粉和二氧化硫脲在不同条件下对深色羊毛羊绒染制品进行退色处理,通过直观观察、显微镜观察纤维形态以及白绒对比,分析了退色效果和鳞片损伤程度,并对这2种退色剂进行了综合比较,得出适合深色羊绒染制品的退色工艺条件。     

深色羊绒染制品退色方法的探讨与比较

本文通过保险粉和二氧化硫脲在不同条件下对深色羊毛羊绒染织品进行退色处理,通过直观观察、显微镜观察纤维形态以及白绒对比分析了退色效果和鳞片损伤程度,并对这两种退色剂进行了综合比较,得出适合深色羊绒染制品的退色工艺条件。     

漂洗方式对鲢鱼品质及氯霉素残留的影响

分别研究水漂、盐漂和碱漂3种漂洗工艺对鲢鱼肉中品质指标及氯霉素残留的影响。结果表明:经漂洗,鲢鱼肉的蛋白质、脂肪和灰分含量均降低,水分含量升高,其中盐漂1∶5的蛋白质和灰分损失最少;盐漂L*值显著高于水漂与碱漂,a*值和b*值变化不显著(P0.05);碱漂对pH值影响最大,水漂最小;漂洗后TBARS值显著降低;盐漂1∶5可达到最佳保水性;水漂和盐漂可显著降低鲢鱼肉中氯霉素残留,但碱漂欠佳。因此,盐漂1∶5是最佳漂洗工艺,它不仅可以保持良好的品质,而且有效降低鱼肉中的氯霉素残留。     

荷兰豆嫩荚干制品的生产工艺优选

通过单因素实验法和正交实验法确定合适的烫漂温度、烫漂时间、烫漂液和浸护液配方;通过比较产品色泽和复水比选择理想的干制工艺。研究表明,烫漂液中添加3%的食盐、200mg/L的柠檬酸和400mg/L的D-异抗坏血酸钠;烫漂温度95℃、烫漂时间为4min;浸护液采用10%糊精、10%蔗糖、5%食盐的配方;用真空干燥法得到的荷兰豆嫩荚的干制品色泽及综合品质最好。     

胡萝卜、油菜的通电加热烫漂研究

研究了通电加热烫漂对胡萝卜、油菜中维生素含量的影响,并与普通电炉加热进行了比较;研究了胡萝卜、油菜通电加热烫漂的最佳工艺条件。实验证明,随着烫漂时间的延长,胡萝卜中的β-胡萝卜素含量明显降低,油菜中VC的含量也明显降低;通电加热烫漂后的维生素含量明显高于电炉加热;而胡萝卜通电加热的最佳烫漂工艺为,烫漂时间3 min,颗粒尺寸10 mm,料液比(g:mL)1∶4,电压220 V;油菜通电加热烫漂的适宜工艺条件为料液比(g:mL)1∶4,烫漂时间0.5 min,电压220 V。     

Pink discoloration in canned pears II.—Measurement of potential and developed colour in pear samples

Procedures are described for the comparative assessment of the leucocyanidin content of pears, which is the principal factor determining their susceptibility to discoloration on processing, and for measuring the shade and depth of discoloration in the processed material. Application of these procedures to pears of different varieties, storage treatment, and processing treatments lead to useful conclusions relevant to the discoloration problem, and establish relations between the three parameters under certain defined processing conditions. The results emphasise the difficulties associated with the assessment of the susceptibility of large consignments of pears to discoloration under normal canning operations.     

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.     

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。     

苹果渣脱色工艺研究

对苹果渣脱色工艺进行了初步研究,以过100目筛苹果渣为原料,用有机溶剂浸泡,提取其中色素得到脱色后的果渣。通过正交实验确定苹果渣脱色的最佳工艺条件:料液比1∶20,浸提时间40min,以乙醇为浸提剂,浸提级数2级,可以获得最佳脱色效果。     

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.     

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.     

Extractive components responsible for the discoloration of Ilomba wood (Pycnanthus angolensis Exell)

The wood of Ilomba (Pycnanthus angolensis Exell) may seriously discolor in the log after felling and also in lumber during drying. The discoloration is associated with the occurrence of bacterial metabolites. The components responsible for the discoloration were extracted completely from the wood before discoloration with hot methanol and separating into petroleum ether, diethyl ether, ethyl acetate and water soluble and insoluble fractions. Bioassays using nutrient liquids inoculated with Pseudomonas fragi revealed that the diethyl ether soluble fraction discolored most. Chemical characterization of the individual components indicated that three different types of components could be involved which are the (?)-epicatechin and (+)-catechin, the intensely red compound and the water soluble component of the methanol extracts. Their contributions to the discoloration are discussed on the basis of their colorimetric characteristics and amounts present in the wood.     

Pink discoloration in canned pears III.—Inhibition by chemical additives

Despite the identification of the pigment responsible for discoloration in canned pears as a tin–cyanidin complex, addition of stannous ions to susceptible pear purée prior to processing partly or completely inhibits the discoloration. This effect cannot be obtained with canned pear halves, but other reducing agents, such as sulphur dioxide, are effective inhibitors of the discoloration. By such treatment canned pears of acceptable quality can be produced from varieties which are normally avoided for processing because of their susceptibility to discoloration. A mechanism whereby reducing agents prevent the formation of pink pigments is described, and an explanation is given of the differences in the effect of stannous ions on pear halves and pear purées.     

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.