三种天然食品防腐剂抗菌活性通过分子结构改造而增强的研究

对天然抗菌化合物肉桂醛、肉桂酸和富马酸进行了分子结构改造和活性预测，合成得到了α，β－二溴代肉桂醛、α，β－二溴代肉桂酸酯和α，β－二溴代富马酸二甲酯三种新化合物。对三种新化合物最低抑菌浓度值进行了理论上的计算，并通过实际测定以及与母系其它化合物抗菌活性进行比较加以验证。结果表明，随着α，β－二溴代和酯化，最低抑菌浓度值降低，抗活性增强。α，β－二溴代肉桂醛、α，β－二溴代肉桂酯甲酯，α，β－二溴     

富马酸酯类防腐剂改性方法研究现状

富马酸酯类具有良好的抗茵活性,广泛用做食品防腐剂.近年来人们通过对富马酸酯类进行结构改造,合成具有防腐及其它综合性能的新型食品添加荆.介绍富马酸单酯、溴代富马酸二甲酯、反丁烯二酸蔗糖甲酯等富马酸酯衍生物的改性方法及改性效果的研究现状.     

α—溴代肉桂醛及烷烯基酸酯类对微生物的呼吸代谢的抑制作用研究

采用氧电极法对细菌、霉菌、酵母菌的呼吸耗氧量进行测定，探讨α－溴代肉桂醛及烷烯基酸酯类的抑菌机理，结果表明α－溴代肉桂醛及烷烯基酸酯类能有效地抑制微生物的呼吸代谢途径。比较了典型抑制剂对防腐剂的叠加率，得出α－溴代肉桂醛，α－溴代肉桂酸甲酯，富马酸甲酯，溴代富马酸二甲酯均主要抑制呼吸代谢途径中的ＴＣＡ循环，其中，溴代富马酸二甲酯对ＥＭＰ途径也有明显的抑制作用。     

α－溴代肉桂醛及烷烯基酸酯类对微生物的呼吸代谢的抑制作用研究

采用氧电极法对细菌、霉菌，酵母菌的呼吸耗氧量进行测定，探讨α－溴代肉桂醛及烷烯基酸酯类的抑菌机理。结果表明α－溴代肉桂醛及烷烯基酸酯类能有效地抑制微生物的呼吸代谢途径。比较了典型抑制剂对防腐剂的叠加率，得出α－溴代肉桂醛，α－溴代肉桂酸甲酯，富马酸甲酯，溴代富马酸二甲酯均主要抑制呼吸代谢途径中的ＴＣＡ循环，其中，溴代富马酸二甲酯对ＥＭＰ途径也有明显的抑制作用。     

2种富马酸糖酯的相转移催化合成及抑菌活性研究

以马来酸酐和甲醇为原料,经酯化及异构化得到富马酸单甲酯,再经酰氯化得到富马酸单甲酯单酰氯.富马酸单甲酯单酰氯与葡萄糖或乳糖反应,在相转移催化剂四丁基溴化铵的作用下,得到具有α、β-不饱和羰基结构的富马酸葡萄糖甲酯及富马酸乳糖甲酯.抑菌活性试验结果表明:富马酸葡萄糖甲酯及富马酸乳糖甲酯对混合菌群的生长具有良好的抑制能力,其中富马酸葡萄糖甲酯的抑菌活性与富马酸单甲酯接近.     

α－溴代肉桂醛及烷烯基酸酯类对鲜草菇呼吸代谢的抑制

采用氧电极法对新鲜草菇的呼吸耗氧量进行测定，探讨α－溴代肉桂醛及烷烯基酸酯类对新鲜草菇呼吸代谢的抑制作用。结果表明α－溴代肉桂醛及烷烯基酸酯类能有效地抑制草菇的呼吸代谢，与典型呼吸抑制剂相比较得出，α－溴代内桂醛、α－溴代肉桂酸甲酯、富马酸甲酯主要是抑制草菇呼吸代谢途径中的ＴＣＡ循环，溴代富马酸二甲酯主要抑制ＥＭＰ途径．抑制不同代谢途径的防腐剂混合使用具有协同效应。     

α—溴代肉桂醛及烷烯基酸酯类对鲜草菇呼吸代谢的抑制

采用氧电极法对新鲜草菇的呼吸耗氧量进行测定，探讨α－溴代肉桂醛及烷烯基酸酯类对新鲜草菇呼吸代谢的抑制作用。结果表明，α－溴代肉桂醛及烷烯基酸酯类能有效地抑制草菇的呼吸代谢，与典型呼吸抑制剂相比较得出，α－溴代肉桂酸、α－溴代肉桂酸甲酯、富马酸甲酯主要是抑制草菇呼吸代谢途径中的ＴＣＡ循环，溴代富马酸二甲酯主要抑制ＥＭＰ途径。抑制不同代谢途径的防腐剂混合使用具有协同效应。     

肝素和硫酸乙酰肝素的生物合成与结构

1概述肝素和HS是一类由糖醛酸和D-葡糖胺二糖重复单位以1-4键连接形成的线性多糖。二糖单位的N-硫酸基、O-硫酸基、N-乙酰基等多种可变取代形成了多种复杂的序列。肝素和HS是糖胺聚糖(GAG)家族(包括硫酸软骨素、硫酸皮肤素和硫酸角质素)中结构最复杂的一类成员。肝素由结缔组织型肥大细胞表达,以肝素蛋白聚糖的     

愈创木基型多聚体木素模型物合成工艺条件的优化

采用正交试验法研究了β-O-4结构愈创木基型多聚体木素模型物合成工艺条件,优化得出适宜的聚合条件为: 时间4.5h,反应温度55℃,溴代乙酰基愈创木酚在二甲基甲酰胺中的质量浓度22%,K2CO3与溴代乙酰基愈创木酚质量比0.7;适宜的还原条件为: 时间10h,反应温度40℃,未还原聚合物在二甲基亚砜中的质量浓度1.6%,NaBH4与未还原聚合物质量比1.4.聚合过程中反应时间影响最大,其次为反应温度、溴代乙酰基愈创木酚在二甲基甲酰胺中的质量浓度,最后是K2CO3与溴代乙酰基愈创木酚质量比;还原过程中未还原聚合物在二甲基亚砜中的质量浓度影响最大,其次为NaBH4与未还原聚合物质量比、反应时间,最后是温度.另外,采用1H-NMR表征了最优条件下合成所得的木素模型聚合物.     

甲基环戊烯醇酮-β-D-吡喃葡糖苷的合成及其热裂解

以D-葡萄糖为原料,分别合成了2,3,4,6-四-O-乙酰基-α-D-溴代吡喃葡糖苷(2,溴代葡萄糖法)和2,3,4,6-四-O-乙酰基-α-D-葡萄糖基三氯乙酰亚胺酯(4'三氯乙腈法),2和4'再分别与甲基环戊烯醇酮(MCP)进行偶联反应,然后脱乙酰基制备了结构不同的MCP-β-D-葡糖苷[3-甲基-1-氧代环戊-2-烯基-β-D-吡喃葡糖苷(1)和5-甲基-1-氧代环戊-2-烯基-β-D-吡喃葡糖苷(1')];用1H NMR和HRMS技术对中间体和产物的结构进行了表征;并研究了糖苷1和1'的热裂解。结果表明:①两种合成方法所得到的产物都是目标产物,溴代葡萄糖法优于三氯乙腈法;②溴代葡萄糖法的最佳反应条件为甲基环戊烯醇酮与化合物2的摩尔比为1:1.2,温度35℃,反应时间5 h,目标产物的产率82.0%,反应总产率59.6%;③卷烟燃吸过程中,糖苷1和1'热裂解为甲基环戊烯醇酮后,其在主流烟气中的转移率分别为16.13%和16.40%。      

海南库拉索芦荟的O-乙酰基含量的测定

通过分光光度法分别测定海南地区库拉索芦荟的凝胶汁、全叶汁、凝胶冻干粉、全叶冻干粉、凝胶烘干粉以及全叶烘干粉各项制品中O-乙酰基含量,评价海南地区库拉索芦荟各制品中的乙酰化多糖的含量。结果显示海南地区库拉索芦荟凝胶汁、全叶汁、凝胶冻干粉、全叶冻干粉、凝胶烘干粉、全叶烘干粉各制品中的O-乙酰基含量分别为431、528、70 350、62 7102、9 580、29 840 mg/kg,该方法简单方便、稳定。     

Residues after fumigation with methyl bromide: bromide ion and methyl bromide in middlings and final cereal foodstuffs

Methyl bromide and bromide ion concentrations were estimated in pasta manufactured before and after fumigation with methyl bromide. The first trial estimated the bromide ion concentrations in fumigated and unfumigated flours and in pastas obtained from these. The concentration of bromide ions in fumigated flours was not significantly different from unfumigated flours. Only some pastas, manufactured from fumigated flours, showed a higher bromide ion concentration than those manufactured from unfumigated flours. The second trial evaluated the bromide ion concentrations of rices, white flours, flours, pastas made only from flours, pastas with eggs and pastas with eggs and spinach, before and after exposure to methyl bromide in their retail packagings. The bromide ion concentrations in fumigated pastas with eggs, pastas with eggs and spinach and rice were higher than in those unfumigated. In the pastas with eggs the bromide ion concentration after fumigation increased ten times (from about 4 to 40 mg/kg). Results showed that the bromide ion and methyl bromide levels estimated in all the foodstuffs examined were lower than the maximum limits fixed by several different national regulations.     

离子液体型表面活性剂的合成及性能研究

以咪唑、溴代戊烷为原料合成N-戊基咪唑,再用N-戊基咪唑与溴代辛烷、溴代癸烷、溴代十二烷、溴代十四烷,利用超声波辅助合成一系列N,N’-二烷基咪唑溴化铵.采用‘H-NMR对N-戊基咪唑以及N,N’-二烷基咪唑溴化铵进行了结构表征.测定了N,N’-二烷基咪唑溴化铵的电导率和表面张力.结果表明:N,N’-二烷基咪唑溴化铵有较高的电导率并且随着浓度的增大而线性增大;N,N’-二烷基咪唑溴化铵可以降低水溶液的表面张力,且随着浓度的增大表面张力降低,随着烷基链的增长临界胶束浓度减小.     

樱桃中溴形态分析方法及其在熏蒸过程追溯中的应用

建立樱桃中溴形态的分析方法,对比未熏蒸与熏蒸后樱桃中溴甲烷残留量和无机溴含量,研究溴甲烷熏蒸与溴残留的关系。采用水超声提取,以36 mmol/L硝酸＋67 mmol/L氨水作为流动相,经阴离子色谱柱分离,高效液相色谱-电感耦合等离子体质谱法分析樱桃中的溴形态,并使用电感耦合等离子体质谱法确证樱桃中总溴含量,顶空进样-气相色谱法检测樱桃中溴甲烷残留量。研究表明,溴形态分析方法中溴酸根的回收率在89.7%～101.4%之间,相对标准偏差为2.1%～3.5%,溴离子回收率为85.5%～107.3%,相对标准偏差为4.4%～7.0%,定量限为0.10 mg/kg。溴甲烷熏蒸后樱桃中只含有溴离子,其含量与总溴含量相符。熏蒸后樱桃中的溴甲烷残留量随时间递减,溴离子含量明显高于未熏蒸,且不受时间与保存条件的影响产生显著变化。本方法可对樱桃的溴甲烷熏蒸过程进行追溯,为水果的进出口风险监控和质量控制提供依据。     

乙酰溴法测定棉籽壳中木质素的含量

摘 要 本文采用乙酰溴法测定棉籽壳木质素的含量,对木质素的乙酰化反应进行了优化试验。结果表明：木质素乙酰化的最佳反应条件为乙酰溴体积分数30%、反应温度80℃、反应时间60min、高氯酸浓度0.69mol/L;乙酰溴法测得的棉籽壳木质素含量为19.59%。相较Klason法,该测量方法简单迅速,重演性和精密度好。     

Contents of plasticizers in cap-sealing for bottled food and their migration into food

Plasticizers in cap-sealing for bottled foods were analyzed. Twenty-three domestic samples and 80 imported samples, a total of 103 samples, were tested. Among them, 93 contained chloride, and 62 contained di(2-ethylhexyl) phthalate (DEHP), diisodecyl phthalate, O-acetyl tributyl citrate, diacetyllauroyl glycerol, di(2-ethylhexyl) adipate, diisononyl phthalate or dicyclohexyl phthalate. Twelve samples with DEHP-containing caps were further tested for plasticizer levels in the foods. Higher DEHP was detected in oily and fluid food specimens. However, the intake of plasticizers calculated based on usual food consumption did not exceed the tolerable daily intake level in any of the cases. A food sample containing the highest level of DEHP was stored under various conditions, and DEHP that migrated from the cap-sealing into the food was determined. Shaking the bottles increased migration of DEHP into foods.     

SELECTED ALTERNATIVES TO METHYL BROMIDE IN THE POSTHARVEST AND QUARANTINE TREATMENT OF ALMONDS AND WALNUTS: AN ECONOMIC PERSPECTIVE

Methyl bromide is a highly effective fumigant used in the postharvest and quarantine treatment of tree nuts. There will be a complete phase out in the United States of America (U.S.) of methyl bromide by 2005 according to The Montreal Protocol of 1991 with the exception of preshipment and quarantine uses as stated in the 1998 Clean Air Act. This study analyzed alternative treatment scenarios. The alternatives considered were phosphine, irradiation, and controlled atmosphere storage. Costs for each scenario were developed. Cost increases with irradiation ranged from two to fourteen times the benchmark costs for methyl bromide. Controlled atmosphere storage for both commodities had cost increases ranging from 174% to 256% over methyl bromide costs. Phosphine was used only to treat almonds. Phosphine application costs were 108% and 117% above the benchmark costs for methyl bromide.     

Material labeling of soft plastic toys and plasticizers in polyvinyl chloride products

We investigated the labeling and content of plasticizers of soft plastic toys. First, we investigated material labeling in 96 products purchased in fiscal years 2000 and 2001. Among these products, 43% of those purchased in fiscal 2000 and 68% of those purchased in fiscal 2001 were labeled. We then investigated the kinds and amounts of plasticizers in 73 soft polyvinyl chloride (PVC) toys. Three kinds of phthalates and six other kinds of plasticizers were detected in the soft PVC toys. Diisononyl phthalate, di(2-ethylhexyl) phthalate, diisononyl adipate, and O-acetyl tributyl citrate were detected at high frequency, and in large amounts. The average total content of all plasticizers was 280 mg/g for the products purchased in fiscal 2000 and 227 mg/g for those in fiscal 2001. In fiscal 2001, antioxidants, 4-nonylphenol, and bisphenol A were investigated in addition to plasticizers.     

应用共振散射光谱法研究香柠檬烯的潜在毒性

本文引用DNA嵌入剂理论,通过共振光散射光谱研究了香柠檬烯这种食品调味料分子在大肠杆菌细胞内和体外与DNA分子的相互作用,推算出香柠檬烯分子与DNA分子的结合饱和值,并与溴化乙锭、阿霉素、米托蒽醌、异补骨脂素的结合饱和值进行比较。结果表明：香柠檬烯分子可部分进入大肠杆菌细胞内,其进入细胞和与DNA结合能力比溴化乙锭的弱;在中性环境中,香柠檬烯与DNA的结合饱和值为0.18,溴化乙锭、阿霉素、米托蒽醌、异补骨脂素与DNA的结合饱和值分别为14.70、10.58、3.31、0.34,由此可以推测出：香柠檬烯的毒性远小于溴化乙锭、阿霉素、米托蒽醌的毒性,略小于异补骨脂素的毒性。这为人们快速检测香柠檬烯等类似结构的食品调味剂分子的潜在毒性提供了技术支持和参考。     

0.2%新洁尔灭和5%甲酚皂消毒液灭菌效果研究

目的 验证0.2%新洁尔灭和5%甲酚皂消毒液的消毒效果以及有效期。方法 首先进行薄膜过滤法方法学验证,确定薄膜过滤法可行后,再进行0.2%新洁尔灭和5%甲酚皂消毒液的消毒效果有效性验证,最后进行3次消毒液的有效期验证,确定消毒液的存放有效期。结果 0.2%新洁尔和5%甲酚皂消毒液配制后5天内的杀菌性能是有效的。结论 0.2%新洁尔灭和5%甲酚皂消毒液存放5天内均可用于物品表面的消毒杀菌。