麦草化机浆X-P_(1Y)和X-P_(1Y)-P_2漂白中木素结构的变化

对麦草化机浆经X-P1Y和X-P1Y-P2 漂白前后浆中的木素结构进行了研究。研究结果表明 ,采用活化剂X和强化剂Y的X-P1Y和X-P1Y-P2 的工艺路线进行麦草化机浆H2 O2 漂白 ,P1YEL、P2 EL的酚基含量比REL的酚基含量略有减少 ;而P1YEL、P2 EL的共轭羰基含量、邻苯二酚及邻醌含量却比REL的下降很多。H2 O2 能够有效地同浆中木素发色基团及助色基团进行有效的反应。这正是麦草化机浆采用经X-P1Y和X-P1Y-P2 漂白工艺路线进行H2 O2 漂白其漂后白度能够大幅度提高的根本原因     

木素结构对麦草化机浆白度及可漂性的影响

研究麦草化机浆过氧化氢漂白前后浆中残余木素的发色、助色基团——酚羟基、醌式结构、羰基的含量变化。结果表明，麦草化机浆中的木素发色、助色基团对过氧化氢有一种较强的抗拒作用，过氧化氢并不能有效地破坏木素中的主要发色、助色基团。采用活化木素及加强过氧化氢漂液的渗透性是提高麦草化机浆可漂性的关键。     

麦草化学机械浆漂白机理的研究

对经碱性H2O2漂白以及NaBH4还原处理后麦草化学机械浆的术质素结构进行了分析研究.结果表明,麦草化学机械浆经碱性H2O2漂白后总羰基含量减少了26.4％,后续NaBH4还原处理后木质素中共轭羰基数量又减少了70.0％.漂白破坏了木质素中的发色基团.     

蓝桉CTMP H2O2漂白难点分析

分析了蓝桉化学热磨机械浆(CTMP)在H2O2置换漂白过程中木素中邻醌和甲氧基等功能性基团的变化,对用H2O2难于将蓝桉CTMP漂白至较高白度的原因进行了初步探索.结果表明,漂后浆木素中仍有相当数量的邻醌存在,无法用H2O2完全有效去除.漂后浆木素中甲氧基含量增加,降低了木素的反应活性,不利于H2O2对木素发色基团的脱除.     

麦草秸秆化学机械浆漂白机理的研究

对经碱性H2O2漂白以及NaBH4还原处理后麦草化学机械浆的木质素结构进行了分析研究。结果表明,麦草化学机械浆经碱性H2O2漂白后总羰基含量减少了26.4%,后续NaBH4还原处理后木质素中共轭羰基数量又减少了70.0%,漂白破坏了木质素中的发色基团。     

麦草Soda-AQ浆的过氧化尿素漂白

对过氧化尿素用于麦草Soda-AQ浆漂白的影响因素和反应动力学进行了研究，并与H2O2漂白进行了比较。结果表明，过氧化尿素可以作为H2O2的替代品用于纸浆漂白，其漂白效果略优于H2O2。麦草过氧过氧化尿素漂白在适宜的工艺条件下白度增值可达20%ISO。     

马尾松SGW浆H2O2漂白效率的探讨

SouthWestPulpAndPaper2003,Vol.32,No.61前言我厂机浆分厂用南方马尾松生产磨石磨木浆,并用H2O2进行漂白。据有关资料显示,马尾松磨木浆比云杉、桦木等的磨木浆难被过氧化氢漂白,但其可漂性比马尾松PGW、CTMP、TMP、RMP等浆好。过氧化氢漂白机械浆和化机浆主要是靠H2O2离解生成的氢过氧离子(HOO-)使浆中的发色基团退色,从而提高浆料的白度。H2O2用量增加,浆的白度增加,但漂白成本也随之增加,所以控制好漂白的工艺条件,使得过氧化氢漂白发挥最佳的漂白效率就显得特别重要。2漂白工艺2.1原料情况由于南方马尾松很容易发生蓝变,尤…     

提高化机浆过氧化氢漂白效率的途径

化机浆由于保留了大部分的木素，在不透明度、松厚度、印刷性能等方面，具有制造高级印刷纸的特性。一般来漂的化机浆白度都较低（＜55％，腮O），如何在较经济条件下使化机浆经过漂白达到高白度，成为人们一直所期望的目标。在总结已有研究的基础上。加上自己的漂白实践，提出了提高化机浆过氧化氢（H刃。）漂白效率进行高白度化机浆漂白的途径，供同行参考。提高化机浆H刀。漂白效率的途径，主要采用合理的组合漂白工艺，高效率地资合金属离子，分离溶出树脂，并活化浆中与H刀。反应的发色基团，使H刃。漂白过程在尽可能少分解的条件下…     

药液回用的桉木化机浆节水漂白性能研究

对漂白滤液回用的桉木化机浆漂白开展了研究。本研究所使用的桉木化机浆漂白性能良好,2%H2O2用量可以将之漂白至白度80%ISO以上。单次回用漂白滤液,浆料的漂白白度增加了0.3%I S O,多次回用对漂白性能没有出现明显负面影响。经过多达7次的漂白滤液回用的漂白,与常规漂白比较,白度仅略有下降。对药液回用的漂白浆料的得率、漂白滤液的残余H2O2含量、COD、电导率等分析结果表明,随着漂白滤液回用次数的增加,漂白残液的残余H2O2略有降低,COD和电导率逐渐增加;随着漂白滤液回用至5次以上,漂白滤液的电导率和C OD达到一稳定值。对浆料的物理指标的分析结果表明:漂白滤液回用对漂白浆的松厚度、抗张、耐破和撕裂强度等物理性能没有明显不良影响。使用漂白滤液回用的漂白技术,每生产1t桉木漂白化机浆可望节约2m3新鲜水,10kg Na2Si O3和0.5kgD TPA。     

麦草乙醇浆臭氧漂白后过氧化氢补充漂白

麦草浆常规漂白工艺污染较大,故采用QZP短序TCF工艺漂白乙醇麦草浆。本文对麦草乙醇浆臭氧漂白后H2O2补充漂白进行了研究。高锰酸钾值18.2,白度26.4%ISO,黏度1135mL.g-1。经臭氧漂白后(臭氧用量为1.2%时),麦草乙醇浆高锰酸钾值4.0,白度增加到60%ISO,黏度为966mL.g-1。研究结果表明,在纸浆浓度12%,柠檬酸三钠用量1.0%情况下,H2O2补充漂白最佳条件为:H2O2用量3.0%,NaOH用量1.8%,漂白温度70℃,漂白时间120min,漂后浆的高锰酸钾值2.0,白度84%ISO,黏度908mL.g-1。     

呋喃氟尿嘧啶衍生物M1、M2的合成

目的探索高效低毒的抗肿瘤药物。方法替加氟(FT-207)为先导化合物,经取代反应、水解反应制得N1-(四氢-2-呋喃基)-N3-乙酸基-5-Fu,在N,N,-二环己基碳酰亚胺(DCC)作用下分别与2-氨基-1,3,4-噻二唑及2-氨基-5-甲基-1,3,4-噻二唑反应,生成目标化合物M1及M2。结果 M1及M2结构经红外光谱、质谱、元素分析和核磁共振氢谱确证。结论合成路线合理,操作简便,值得进一步研究。     

免疫亲和层析净化-高效液相色谱法同时测定牛奶和奶粉中黄曲霉毒素B1、B2、G1、G2、M1、M2

建立牛奶和奶粉中黄曲霉毒素B1、B2、G1、G2、M1、M2的免疫亲和层析净化和柱后衍生高效液相色谱测定方法。样品经溶解、离心、过滤后,通过免疫亲和柱,黄曲霉毒素特异性抗体选择性地与存在的黄曲霉毒素抗原键合,形成抗体-抗原复合体。甲醇-乙腈混合溶液(4:5,v:v)洗脱,带荧光检测器的高效液相色谱仪经柱后衍生测定,外标法定量。标准曲线线性良好,添加回收率在57.0%～88.7%,相对标准偏差在3.37%～16.9%,牛奶中各黄曲霉毒素检出限:B1为2ng/kg,B2为1ng/kg,G1、G2为3ng/kg,M1、M2为5ng/kg;奶粉中B1为20ng/kg,B2为10ng/kg,G1、G2为30ng/kg,M1、M2为50ng/kg,检测低限能够满足各国对牛奶和奶粉中黄曲霉毒素的限量要求。该方法准确、快速、灵敏度高,适用于牛奶和奶粉中黄曲霉毒素的测定。     

Zur Untersuchung von Milch und Milchprodukten auf die Aflatoxine B1, B2, G1, G2 und M1

Zusammenfassung Der vom Bundesgesundheitsamt vorgelegte Entwurf zur Bestimmung der Aflatoxine B₁, B₂, G₁ und G₂ wurde auf die zusätzliche Erfassung des Aflatoxins M₁ überpruft. Es wurde Wert darauf gelegt, die ursprüngliche Methode nur wenig zu ändern, um die zahlreichen Vorschläge zur Aflatoxin-Analytik nicht noch weiter zu vermehren. Mit verhältnisäßig geringen Änderungen können alle Aflatoxine, also B₁, B₂, G₁, G₂ and M₁ in flüissiger Milch, Milchpulver, Butter, Käse, Quark, Saline, Joghurt und Fruchtjoghurt quantitativ erfaßt werden.

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Investigations of aflatoxin B₁, B₂, G₁, G₂, and M₁ in milk and milk products

Summary The method proposed by the Federal Department of Health for the determination of aflatoxin B₁, B₂, G₁, and G₂ was tested for additional determination of aflatoxin M₁. With relatively small changes of the original method, all aflatoxins including. B₁, B₂, G₁, G₂, and M₁ can be determined quantitatively in milk, milk powder, butter, cheese, quark, cream, yoghurt and fruit yoghurt.

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37. Mitteilung: Zur Aflatoxinbildung in Milch und Milchprodukten.     

Zur Untersuchung von Milch und Milchprodukten auf die Aflatoxine B1, B2, G1, G2 und M1

Der vom Bundesgesundheitsamt vorgelegte Entwurf zur Bestimmung der Aflatoxine B₁, B₂, G₁ und G₂ wurde auf die zusätzliche Erfassung des Aflatoxins M₁ überpruft. Es wurde Wert darauf gelegt, die ursprüngliche Methode nur wenig zu ändern, um die zahlreichen Vorschläge zur Aflatoxin-Analytik nicht noch weiter zu vermehren. Mit verhältnisäßig geringen Änderungen können alle Aflatoxine, also B₁, B₂, G₁, G₂ and M₁ in flüissiger Milch, Milchpulver, Butter, Käse, Quark, Saline, Joghurt und Fruchtjoghurt quantitativ erfaßt werden.     

Evaluation and Improvement of Extraction Methods for the Analysis of Aflatoxins B1, B2, G1 and G2 from Naturally Contaminated Maize

The extraction procedure for aflatoxin determination in maize is based on a methanol–water (8 + 2 v/v) or an acetone–water (85 + 15 v/v) mixture. Initially, the extraction efficiency of two solvents was evaluated for each aflatoxin. Different results were obtained for highly contaminated maize: significantly higher levels of aflatoxin B₁ were obtained by acetone–water, on the contrary higher levels of aflatoxin G₂ were achieved by methanol–water. Then, acetone–water mixtures in different proportions (7 + 3, 6 + 4 and 5 + 5 v/v) were tested to improve the extraction of aflatoxin G₂. Applying these extraction mixtures, the values both of aflatoxin B₁ and of other aflatoxins were generally higher compared to those obtained by acetone–water 85 + 15; moreover, acetone–water (6 + 4) and (7 + 3) showed the best extraction efficiency for all aflatoxins.     

免疫初乳中IgG1和IgG2的分离纯化

采用硫酸胺盐析,DE－52离子交换色谱,SephacryIS-100凝胶过滤色谱从免疫初乳分离纯化出了IgG1和IgG2,经SDS－PAGE电泳及免疫电泳证实为纯品,并对IgG1和IgG2的抗体凝集价进行了测定。     

Vitamins B1 and B2 contents in cultivated mushrooms

Mushrooms have long been treated as a delicacy. Nowadays however, many researchers consider them to be nutraceutical foods, which has stimulated new and existing Brazilian producers to search for more productive techniques and to introduce other species. The objective of this study was to determine the vitamin B₁ and B₂ contents in mushrooms. The main species of mushroom cultivated in Brazil and analysed in this study are: Agaricus bisporus (white button mushroom and portobello), Lentinula edodes (shiitake) and Pleorotus spp. (shimeji and oyster mushroom). The methodology employed used acid hydrolysis followed by enzymatic hydrolysis and separation of the vitamins by high performance liquid chromatography using a C₁₈ reverse phase column and fluorescence detector. The results obtained for thiamine (vitamin B₁) were from 0.004 to 0.08 mg/100 g and for riboflavin (vitamin B₂), from 0.04 to 0.3 mg/100 g.     

双刺参胶囊中紫丁香苷及人参皂苷Rg1、Re、Rb1的含量测定

建立双刺参胶囊中紫丁香苷及人参皂苷Rg₁、Re、Rb₁的高效液相色谱法(HPLC)含量测定方法。分别采用依利特APS和Nano-Micro UniSil 5-120 C₁₈色谱柱,以乙腈-水为流动相,梯度洗脱,流速1.0 mL/min,进样量10 μL,人参皂苷Rg₁、人参皂苷Re及人参皂苷Rb₁在柱温35 ℃、波长203 nm下,紫丁香苷在柱温30 ℃、波长265 nm下进行检测。结果表明:人参皂苷Rg₁、人参皂苷Re、人参皂苷Rb₁及紫丁香苷分别在15.30~306.00 μg/mL(R2=0.9999)、16.95~339.00 μg/mL(R2=1.0000)、18.45~369.00 μg/mL(R2=1.0000)和4.60~46.00 μg/mL(R2=0.9999)范围内呈现良好的线性关系,其检出限分别为0.77、0.89、0.93、0.12 μg/mL;其定量限分别为2.21、2.71、2.74、0.38 μg/mL。其精密度实验的RSD值分别为1.30%、1.21%、1.99%、0.79%;其重复性实验的RSD值分别为2.49%、2.35%、2.55%、0.80%;其平均加样回收率分别为100.13%、100.50%、102.33%、101.55%,其RSD值分别为0.67%、0.99%、0.29%、0.68%。实验结果表明供试品溶液在48 h内稳定,该方法专属性高、重复性好,可用于双刺参胶囊中紫丁香苷及人参皂苷Rg₁、人参皂苷Re、人参皂苷Rb₁的含量测定。本实验为双刺参胶囊的质量标准制定提供了基础数据。     

磷脂酶A1(Lecitase Ultra)大孔树脂固定化研究

选用9种树脂对磷脂酶A1(Lecitase Ultra)进行固定化,比较得出最适合的固定化载体为D101型号的大孔树脂.对其固定化条件进行优化,得到了固定化最优的条件为:酶液和树脂液料比1∶1(mL/g),磷酸盐缓冲液pH为6.5,室温下固定化时间60 min.在此条件下的得到的固定化酶的酶活力为750.0 U/g.通过扫描电子显微镜观测了固定化前后,树脂表面特征的变化.     

Production of enniatins A,A1, B,B1, B4, J1 by Fusarium tricinctum in solid corn culture: Structural analysis and effects on mitochondrial respiration

Enniatins (ENs) are secondary fungal metabolites with hexadepsipeptidic chemical structure and they possess a number of potent biological activities that can contaminate several kind of food and foodstuffs increasing the exposure risk for consumers. ENs are produced by several Fusariun strains including Fusarium subglutinans, Fusarium proliferatum and Fusarium tricinctum. Production of a mixture of ENs was performed by culturing F. tricinctum ITEM 9496 on white corn as substrate. The solid culture components were dried and subsequently extracted with water/methanol (50/50 v/v, 0.5% NaCl), homogenised, filtered, extracted by ethyl acetate and analysed by liquid chromatography with diode array detection (LC-DAD). The crude extract was first separated by low pressure liquid chromatography (LPLC) and then further purified by liquid chromatography (LC), resulting in six compounds with a purity higher than 95% as calculated by ¹H NMR, and with a yield of 30–300 mg per compound. The chemical structures of the ENs were determined by liquid chromatography coupled to mass spectrometry (LC–MS) and nuclear magnetic resonance (NMR). The biological activity of the resulting ENs was determined using a mitochondrial respiration test. We discovered that all the ENs studied induced an increase in the mitochondrial respiration resulting in uncoupling of the oxidative phosphorylation. This effect was most likely due to flux of K⁺ ions into the mitochondrial matrix. The order of potency of the ENs derivatives was: A₁ > B₁ > B > A > B₄ > J₁. These results suggest a correlation between the chemical structures and bioactivity and confirm the severe risks for human associated with consumption of enniatins.