灵芝的抗突变作用

用不同的试验终点对灵芝的抗突变作用进行了检测，结果表明，灵芝水提取液（ＡＥＧＬ）对多种诱变剂所致的突变具有显著的抑制作用。ＡＥＧＬ对环磷酰胺（ＣＰ）诱导的小鼠骨髓嗜多染红细胞（ＰＥＣ）微核效应有显著的抑制作用，并呈剂量反应关系。ＡＥＧＬ剂量为１０ｇ／ｋｇ时对ＣＰ诱导的微核效应抑制率达６６．１２％。ＡＥＧＬ剂量在６．２５～１００ｍｇ／皿范围内，对诱变剂４—硝基喹啉—Ｎ—氧化物（ＮＱＮＯ）和２—氨基芴（２—ＡＦ）诱导的鼠伤寒沙门氏菌组氨酸缺陷型回复突变有显著的抑制作用，并呈剂量反应关系。高剂量组（１００ｍｇ／皿）的回变菌落数接近于自然回变数。１ｍｇ／ｍＬ的ＡＥＧＬ对丝裂霉素Ｃ（ＭＭＣ）诱导的人外周血淋巴细胞（ＨＰＢＬ）姊妹染色单体交换和染色体畸变的抑制率分别为７０．７％和７６．５％。     

pH值对 AKD中性/碱性造纸过程的影响

ＡＫＤ中性／碱性造纸在国内已有近十年的历史 ,但造纸厂家接受它并感兴趣是近几年的事。有许多纸厂或机台成功实现由酸性造纸转换到ＡＫＤ中性造纸 ,并取得了比酸性造纸更高的经济效益。影响ＡＫＤ中性／碱性造纸的因素很多 ,湿部 ｐＨ值就是其中一个重要控制参数。本文就湿部 ｐＨ值的作用和影响作一讨论。１试验原料及方法１．１试验原料漂白麦草浆（ＡＰ +ＡＱ制浆 ,ＣＥＨ三段漂）、阳离子淀粉（广西明阳）、ＡＫＤ施胶剂（苏州天马）、Ｃ -ＰＡＭ助留剂（上海创新）、ＧＣＣ填料（上海大恒）。１．２测定方法及仪器Ｚｅｔａ电位测定在…     

蔗渣硫酸盐浆木聚糖酶漂白及纤维素酶和螯合剂对漂白的影响

木聚糖酶及无纤维素酶纯化组份ＣＦＸ（ＣｅｌｕｌａｓｅＦｒｅＸｙｌａｎａｓｅ）对蔗渣硫酸盐浆漂白实验显示，纸浆可漂性提高与酶剂量的关系，结合后续Ｈ２Ｏ２漂白表现出来；酶剂量选择应根据漂白浆卡伯值和酶系组成结合白度和粘度变化等指标确定；漂白废液碳水化合物分析显示纤维素酶ＦＰＡ活力与葡萄糖和木糖糖基比值之间存在线性关系；适时增加螯合剂处理对木聚糖酶和Ｈ２Ｏ２漂白效力有明显提高。     

大豆蛋白质的功能特性研究

本文研究了温度、ｐＨ、氧化剂等因素对大豆蛋白的氦溶解指数（ＮＳＩ％）、乳化活性（ＥＡ）、粘度（ＶＳ）和凝胶强度（ＧＳ）等功能特性的影响。结果表明，温度升高，ＮＳＩ下降，当温度为８０℃，时凝胶强度最大。Ｎａ２ＳＯ３、ＫＢｒＯ３能有效地降低大豆蛋白溶液的粘度，ｐＨ对大豆蛋白功能特性也有很大的影响。     

共胶粘剂对涂料流变特性的影响

本文对氧化淀粉、羧基丁苯胶乳、羧甲基纤维素（ＣＭＣ）和聚乙烯醇（ＰＶＡ）四种胶粘剂进行交叉混合配制成的涂料进行了流变特性研究。实验表明，在剪切速率为１０￣３Ｓ－１以下时，体系都呈剪切稀化特性，表现粘度与剪切速率的关系可用　　表达。含有ＣＭＣ的混合胶粘剂涂料，表现粘度最大；含有ＰＶＡ的混合胶粘剂涂料，表现枯度次之；含羧基丁苯胶乳比例较大的混合胶粘剂涂料，表现粘度最小。     

里氏木霉液体发酵法生产纤维素酶

通过比较几株霉菌产纤维素酶活力，发现里氏木霉ＲｕｔＣ－３０活力最高；采用Ａｖｉｃｅｌ与麸皮复合碳源，以及使用ＫＨ２ＰＯ４－Ｋ２ＨＰＯ４缓冲系统控制发酵液ｐＨ，２８℃摇瓶发酵６ｄ，最高酶活达到ＣＭＣａｓｅ１００－１２５Ｕ／ｍｌ，ＦＰＡ９－１２Ｕ／ｍｌ。采用２．５升发酵罐培养，通过控制ｐＨ和溶氧，纤维素酶活力为ＣＭＣａｓｅ１３３．４Ｕ／ｍｌ，ＦＰＡ１１．６７Ｕ／ｍｌ。用硫铵盐析法提取制得纤维素酶干粉，其活力为ＣＭＣａｓｅ３０７４．９Ｕ／ｇ，ＦＰＡ１６６．７Ｕ／ｇ。     

烤烟成熟过程中主要内源激素的动态变化研究初报

以８０％的冷甲醇浸提烟叶样品中的生长素（ＩＡＡ）、脱落酸（ＡＢＡ），通过控制ｐＨ值，经过多次液液分配并结合聚乙烯吡咯烷酮（ＰＶＰ）和Ｃ１８筒柱进一步分离纯化，用反相液相色谱检测烟叶成熟过程中内源ＩＡＡ、ＡＢＡ的动态变化。结果表明：下部叶叶色黄绿，黄色明显，主脉１／２～２／３白，支脉１／３白；中部叶叶色黄绿以黄为主至淡黄，主脉近全白，支脉近２／３白等外观特征出现时，叶片进入迅速衰老时期，超过上述时期的叶片应为过熟。     

中国丝网印刷协会（SPAC）加入国际网印与制象协会（SGIA）──中国网印业发展中的大事

中国丝网印刷协会（ＳＰＡＣ）加入国际网印与制象协会（ＳＧＩＡ）中国网印业发展中的大事经国家有关部门批准和国际网印及制象协会（ＳＧＩＡ）理事会通过，中国网印协会（ＳＰＡＣ）从１９９６年起正式加入ＳＧＩＡ，成为该协会的国家会员（ＮＡＭＰ）。这是我国丝网印...     

绿豆乳酸菌饮料稳定性的研究

本文从绿豆淀粉的糖化、饮料的均质和添加稳定剂等三个方面对绿豆乳酸菌饮料的稳定性进行了研究。实验选用的α－淀粉酶的最适ｐＨ值为６．５～７．０，最适底物浓度为３０％，最佳糖化条件为７０℃、１００ｍｉｎ。绿豆乳酸菌饮料的最佳稳定条件是：ＰＧＡ添加量０．２％；ＣＭＣ添加量０．２％；发酵豆乳的终点ｐＨ值为４．１～４．２；豆乳浓度为１∶１０；２０ＭＰａ压力下均质两遍。     

里氏木霉 Rut C-30 液态发酵法生产纤维素酶

探讨了增强里氏木霉ＲｕｔＣ－３０产纤维素酶的方法，添加葡糖糖于培养基中，可促进菌体生长，但不能提高产酶；采用Ａｖｉｃｅｌ与麸皮复合碳源，以及使用ＫＨ２ＰＯ４－Ｋ２ＨＰＯ４缓冲系统控制发酵液ｐＨ，在摇瓶发酵条件下，可获得很高活力的纤维素酶，培养６ｄ，酶活可达到ＣＭＣａｓｅ１６６７～２０８４ｎｍｏｌ·ｓ－１·ｍｌ－１，ＦＰＡ１５０～２００ｎｍｏｌ·ｓ－１·ｍｌ－１．采用２．５Ｌ发酵罐培养，通过控制ｐＨ和溶氧，纤维素酶活力为ＣＭＣａｓｅ２２２３．８ｎｍｏｌ·ｓ－１·ｍｌ－１，ＦＰＡ１９４．５ｎｍｏｌ·ｓ－１·ｍｌ－１．     

Effects of Various Viscosity Enhancers and pH on Separating Haem from Porcine Red Blood Cells

Haem derived from animal blood is a valuable source of organic iron which may be used as a supplement in foods. The purpose of this study was to examine the effects of sodium carboxymethyl cellulose (NaCMC), propylene glycol alginate (PGA) and sodium alginate (SA) as viscosity enhancers on the separation of haem from porcine red blood cells, and on the distribution of iron between the haem and non-haem fractions of the extracts. Iron determinations were carried out spectrophotometrically on the supernatants obtained by centrifuging the cell suspensions and on two successive washings of the cells. In the first washings the total extracted iron content using NaCMC was highest when a high-viscosity grade was used; there were no significant differences (P>0·05) between the results obtained with this material and those obtained using PGA or SA. There were also no significant differences (P>0·05) among the three treatments in terms of non-haem content. The absorbances at 540nm of the first washings were lower when the washing was carried out at pH 1·4 rather than at pH 1·0 or 2·0. There were no significant differences associated with changes in the viscosity enhancer in the absorbances of the second washings, but the absorbances at pH 1·4 were generally higher than those at pH 1·0 or 2·0. Enhancement of the absorbances on the addition of 1,10-o-phenanthroline indicated that the extracted iron was present in the ferrous form.     

Effect of Propylene Glycol Alginate and Xanthan Gum on Stability of O/W Emulsions

The role of xanthan gum and propylene glycol alginate in stabilizing model oil-in-water salad dressing emulsions has been studied using rheological measurements, particle size analysis and surface tension. Increasing xanthan gum concentration within the gum ratio gave higher viscosity due to formation of aggregates with larger sizes. Propylene glycol alginate (PGA) was surface-active leading to reduction in surface tension of air/water surfaces. Reduction in viscosity was seen in the presence of PGA.     

复配稳定剂在搅拌型酸奶加工中的应用研究

研究了海藻酸丙二醇酯(PGA)、果胶和变性淀粉作为复配稳定剂在搅拌型酸奶中的应用.结果表明,海藻酸丙二醇酯、果胶与变性淀粉有较好的协同作用,通过三因素二次正交旋转组合设计实验,建立了粘度与三种稳定剂配比之间的动态模型,得出了三种稳定剂的最佳配比(%)是0.15:0.08:1.20.在冷藏(4℃)贮存25d后,搅拌型酸奶的组织状态细腻、均匀滑爽、无乳清析出、风味和口感良好.     

Rheological Properties of Solutions and Emulsions Stabilized with Xanthan Gum and Propylene Glycol Alginate

The rheological effects of propylene glycol alginate (PGA) added to solutions and model emulsions containing xanthan gum (XG) were studied using controlled stress rheometry with concentrations appropriate for salad dressings. For samples with XG and XG + PGA blends, solutions and emulsions showed a Newtonian plateau at low shear stresses. The Newtonian plateau of a solution accurately predicted (r²= 1.00) the Newtonian plateau for an emulsion of equivalent gum concentration. Addition of PGA to constant levels of XG showed a more than additive increase in the Newtonian plateau viscosity for solutions and emulsions. For XG aqueous solutions, pseudoplasticity decreased upon addition of PGA. Storage and loss moduli increased with addition of PGA to XG for solutions and emulsions, although G’ for solutions of PGA alone were negligible.     

RHEOLOGICAL CHARACTERISTICS OF SELECTED FOOD GUM MIXTURES IN SOLUTION2

The viscosity of pure and mixed dilute solutions of commercial alginate, carrageenan, guar gum, CMC and gelatin solutions at different mixing ratios were measured by a coaxial viscosimeter at different shear rates. The results are presented in the form of measured viscosity divided by the expected viscosity, if no interaction between the gums existed. This technique provides a clear demonstration of the existence of synergism or antagonism between the gums and helps in quantitatively assessing their extent.     

Stability and rheological behaviour of salad dressing obtained with whey and different combinations of stabilizers

In this work the stability and the rheological behaviour of salad dressing containing 'Minas Frescal' whey cheese was studied. The salad dressing was stabilised by xanthan gum (XG), propylene glycol alginate (PGA) and carboxymethylcellulose (CMC). All samples were stable for a period of 4 months. The rheological model of Ostwald-de-Waelle (Power-Law) was used in order to fit the data and to obtain the rheological parameters of flow behaviour index ( n ), consistency coefficient and apparent viscosity (η_ap). All formulations showed a pseudoplastic behaviour and the PGA contributed to increase the values of flow behaviour index. Consistency coefficient was similarly affected by XG and PGA fractions. Apparent viscosity was highly influenced by the hydrocolloid CMC, with higher values of apparent viscosity in the proportion of 0.25/0.25/0.5% (PGA/XG/CMC). Hydrocolloid association (ternary mixtures) was statistically significant, resulting in an increase of K and η_ap parameters. The results show that salad dressing with whey as aqueous phase and stabilised by a ternary combination of XG, PGA and CMC can be a technological alternative to the food industry.     

Mouthfeel and flavour of fermented whey with added hydrocolloids

High-methoxy pectin (HMP), propylene glycol alginate (PGA), carboxymethyl cellulose (CMC) and xanthan gum (XG) were added separately to whey fermented by a yoghurt starter culture at concentrations that yielded a viscosity similar to that of commercial fermented milk beverages. Mouthfeel and flavour of the samples were assessed by a highly trained panel, and volatile analysis was performed by proton-transfer reaction mass spectrometry to determine the effect of hydrocolloids on the partition of flavour compounds in the headspace. CMC and HMP produced significantly higher thickness than PGA and XG; PGA caused a ‘gritty’ mouthfeel. The yoghurt aroma of the samples containing CMC and PGA was perceived as less intense compared with the control, consistent with a reduced concentration of key volatile compounds in the headspace of these samples.     

不同条件对胖大海胶表观黏度的影响

以胖大海胶研究对象,研究pH、钙离子浓度、不同阳离子、蔗糖及其他胶体对胖大海胶黏度的影响。结果表明:pH偏高或偏低、阳离子存在均使胶体溶液表观黏度下降;随着蔗糖浓度增加,溶液表观黏度逐渐增大;胖大海胶与瓜尔豆胶复合后胶体溶液黏度大于原胶体的黏度,而与黄原胶、海藻酸钠、琼脂复合则小于原胶体黏度。     

明胶与海藻酸钠的相互作用及其应用

研究了不同浓度明胶、海藻酸钠混合溶胶粘度变化 ,以及不同 pH值和不同离子浓度对体系粘度变化的影响 ,结果表明 ,明胶与海藻酸钠主要的交互作用力为二成分间静电引力。在此基础上 ,对仿生鱼翅的生产工艺和配方进行了初步研究。综合粗蛋白含量、硬度、拉伸强度和透明度等结果得出 :8%明胶、2 %海藻酸钠在纺丝原液 pH为 6 0时 ,制备的仿生鱼翅效果最佳。     

Application of decolourised hsian‐tsao leaf gum to low‐fat salad dressing model emulsions: a rheological study

The effects of mixed gums, including decolourised hsian‐tsao leaf gum (dHG) mixed with propylene glycol alginate (PGA) or xanthan gum (XG), and egg yolk concentration on the rheological properties of low‐fat salad dressing model emulsions were studied. All model emulsions showed pseudoplastic flow behaviour. Model emulsions with PGA addition showed the lowest pseudoplasticity, followed by those with dHG and then XG addition. Increasing the PGA level in the dHG/PGA system reduced the pseudoplasticity. Increasing the XG level in the dHG/XG system did not change the pseudoplasticity significantly but imparted a significant increase in viscosity. Dynamic viscoelasticity measurements indicated that model emulsions with dHG or XG addition could be classified as elastic gels. However, model emulsions with PGA addition essentially belonged to the class of either dilute or concentrated solutions rheologically, depending on the egg yolk concentration. The rheological characteristics of individual gums were found to be confounded in generating the rheological characteristics of model emulsions containing them. Copyright © 2004 Society of Chemical Industry