ACE-inhibitory and antihypertensive properties of a bovine casein hydrolysate

The aim of this study was to investigate the potential angiotensin converting enzyme (ACE)-inhibitory activity and the antihypertensive effect, after a single oral administration, of a pepsin hydrolysed bovine casein (HBC) and a fraction with molecular mass lower than 3000 Da (HBC < 3000). ACE-inhibitory activity was measured by spectrophotometric assay. These products were orally administered by gastric intubation. The systolic (SBP) and the diastolic blood pressure (DBP) were measured in spontaneously hypertensive rats by the tail cuff method before administration and also 2, 4, 6, 8, and 24 h post-administration. HBC showed a potent ACE-inhibitory activity. This activity was 10 times higher in HBC < 3000. HBC and HBC < 3000 decreased the arterial blood pressure of the rats. The decrease in the SBP observed for HBC (400 mg/kg) or HBC < 3000 (200 mg/kg) was less pronounced than that caused by 50 mg/kg of captopril (antihypertensive positive control). However, the maximal decreases in DBP caused by HBC or HBC < 3000 were as high as the maximum decrease observed for captopril. The antihypertensive effect of these products was transient and reverted 24 h after the administration. HBC and HBC < 3000 exert antihypertensive effect caused by small peptides with ACE-inhibitory activity.  

臭氧灭菌机理及消毒副产物溴酸盐控制技术研究进展

臭氧消毒作为氯消毒的替代方法,在饮用水处理中被越来越多地应用.臭氧灭菌作用是通过生物化学氧化反应实现的,灭菌性能试验表明,臭氧几乎对所有细菌、病毒、真菌及原虫、卵囊都具有明显的灭活效果.但是含有溴离子的水臭氧化过程中形成的消毒副产物溴酸盐,被国际癌症研究机构定为2B级潜在致癌物.臭氧氧化过程中溴酸盐的生成有臭氧氧化和臭氧/氢氧自由基氧化两种途径,控制溴酸盐可以从控制其形成和生成后去除两个方面进行.降低pH、添加氨气、氯-氨工艺和优化臭氧化条件是控制溴酸盐形成的方法,溴酸盐生成后则可以利用物理、化学和生物方法去除.因此要实现臭氧、致病菌与溴酸盐三者的平衡需进一步探讨臭氧灭菌机理及溴酸盐控制方法.  

稳定性同位素稀释气相色谱-质谱法测定白酒中DBP、DEHP含量及不确定度评定

采用稳定性同位素稀释气相色谱-质谱法对白酒中DBP、DEHP的含量进行测定,并对整个测试过程的不确定度来源进行系统分析。样品提取、离心后取上层有机相进行测定,利用选择离子监测模式,以氘代同位素标记物作内标,以m/z 149和m/z153为定量离子对,对其定性定量测定,并对测试过程中引入的各个分量进行评定与合成。结果表明,DBP、DEHP在0.2~2.0 mg/L浓度范围内线性关系良好,r≥0.999,定量限为0.05 mg/kg,不同加标水平中的平均回收率为DBP:91.2%~100.4%,RSD为2.24%~2.79%(n=5);DEHP:99.0%~110.6%,RSD为4.98%~5.44%(n=5)。当DBP测定结果为0.572 mg/kg时,扩展不确定度为0.040 mg/kg,DEHP测定结果为0.251 mg/kg时,扩展不确定度为0.025 mg/kg,k=2,p=95%。该方法准确可靠,可用于白酒中DBP、DEHP的含量测定。并且建立的不确定度评定方法可用于气相色谱-质谱法测定白酒中DBP、DEHP浓度的不确定度评估。标准溶液配制和标准曲线拟合、样品前处理以及分析仪器是主要的不确定度来源。  

盛装散装白酒的塑料桶中邻苯二甲酸二丁酯的测定

据调查,农村市场广泛使用塑料桶盛装散装白酒。以正己烷作为提取溶剂,采用超声波辅助提取盛装散装白酒的塑料桶中邻苯二甲酸二丁酯(DBP),高效液相(HPLC)测定其含量。以提取时间、料液比、提取温度进行单因素实验,采用响应曲面Box-Behnken设计分析方法对其最佳提取条件进行优化。结果表明,邻苯二甲酸二丁酯最佳的提取条件为:提取时间为52min、料液比为1∶40、提取温度为49℃,在此条件下,DBP提取量为32.21mg/kg,与理论预测值基本吻合。在0.5～50.0mg/L范围内邻苯二甲酸二丁酯具有良好的线性关系(R2=0.9998),最低检出限0.017mg/L;标准品精密度实验的相对标准偏差为0.40%,邻苯二甲酸二丁酯的回收率为99.68%及相对标准偏差为0.85%,结果表明,该提取方法准确可靠,为食品的安全性和增塑剂的风险性评估提供了基础数据。  

Diet and plasma evaluation of the main isomers of conjugated linoleic acid and trans-fatty acids in a population sample from Mediterranean north-east Spain

The aim of the present study was to describe the dietary pattern of a representative sample of 516 adult participants (203 men and 313 women) from Catalonia, a Spanish Mediterranean region, to assess their current dietary and plasma levels of trans C18:1, the major trans-fatty acid (TFA), and cis-9, trans-11 CLA, and trans-10, cis-12 CLA, the two major conjugated linoleic acid (CLA) isomers, and to evaluate their correlation with several cardiovascular disease risk factors. The population was a random sample derived from the Catalan Nutrition Survey. Plasma levels of the CLA isomers were determined in a subsample of 100 volunteers. The Catalan diet seemed to maintain some traits of the ‘traditional’ Mediterranean diet, although other components were lost. The dietary intakes of saturated fatty acids (SFA), TFA, cis-9, trans-11 CLA, and trans-10, cis-12 CLA were 12.3%, 0.84% (2.0 g/d), 0.030% (71.5 mg/d), and 0.0015% (3.4 mg/d) of the energy intake, respectively. Trans C18:1 accounted for 0.19% of the total plasma fatty acids, while the sum of cis-9, trans-11and trans-10, cis-12 CLA isomers represented about 0.09% of the plasma fatty acids. Trans C18:1 isomers correlated significantly with the intake of French fries and pastries, while cis-9, trans-11 CLA significantly correlated with the intake of dairy products and ruminant meat. None of the cardiovascular disease risk factors were found to be associated with the plasma levels of TFA or CLA. The results of this study suggest that monounsaturated fatty acids (MUFA) are the main dietary fat source in the Catalan population, due to their regular olive oil consumption. Moreover, plasma levels of the main TFA and CLA suggest that the Catalan diet is not at present strongly influenced by the occidental dietary patterns. However, a reduction of the intake of SFA in the Catalan population should be recommended.  

Highlighting the base zone effect on the compression and recovery properties of the rugs with innovating Double-Base Persian rug

This paper investigates the compression and recovery properties of the rugs by highlighting the base zone effect. To fulfill this purpose, a new type of rug named Double-Base Persian Rug was prepared. In the new rug, the warping was done such that we have two sets of warp sheets (back base and front base warp yarns). So that, a gap between these two bases were created that could be filled with various types of fillers. A total of seven rug samples; a conventional Persian rug as the base of comparison and six new types of rug samples were produced. Then, the compression and recovery properties of the rug samples were investigated by static loading test. Generally, the results indicated that the rug base structure and the inherent characteristics of the materials used in the rug base as a filler positive affect the rug compression and recovery properties.  

Determination of 2,6-diisopropylnaphthalene (DIPN) and n-dibutylphthalate (DBP) in food and paper packaging materials from US marketplaces

A gas chromatography-ion-trap tandem mass spectrometry procedure was developed for the determination of 2,6-diisopropylnaphthalene (DIPN) and n-dibutylphthalate (DBP) in domestic and imported paper packages and food sold in US marketplaces. The procedure involved ultrasonic extraction with dichloromethane, followed by analysis with the gas chromatography-ion-trap tandem mass spectrometry. Calibration curves for DIPN and DBP were achieved with concentrations ranging from 0.01 to 10 µg ml⁻¹ and the corresponding r ² values were 0.9976 and 0.9956, respectively. In most of the fortified samples the recoveries were higher than 80% with a relative standard deviation (RSD) <10%. Using this procedure, it was found that less than 20% of the tested domestic packages and more than 60% of the tested imported food packages contained both DIPN and DBP. The concentrations of DIPN and DBP ranged from 0.09 to 20 mg kg⁻¹ and 0.14 to 55 mg kg⁻¹, respectively, with most of the DINP and DBP levels lower than 20 mg kg⁻¹. DIPN was not detected (<0.01 mg kg⁻¹) in 41 food samples and DBP was only detected in two domestic and four imported food samples with concentrations ranging from <0.01 to 0.81 mg kg⁻¹.  

Contamination of wines and spirits by phthalates: types of contaminants present,contamination sources and means of prevention

This research determines the concentrations of various phthalates in French wines and grape spirits marketed in Europe or intended for export. Dibutyl phthalate (DBP), diethylhexyl phthalate (DEHP) and butyl benzyl phthalate (BBP) were the most frequently detected compounds in the wines analysed. While only 15% of the samples examined contained quantifiable concentrations (> 0.010 mg kg^–1) of DEHP and BBP, 59% of the wines contained significant quantities of DBP, with a median value as high as 0.0587 mg kg^–1. Only 17% of the samples did not contain any detectable quantity of at least one of the phthalates and 19% contained only non-quantifiable traces. In the spirits analysed, DBP (median = 0.105 mg kg^–1) and DEHP (median = 0.353 mg kg^–1) were the substances measured at the highest concentrations, as well as the most frequently detected (90% of samples). BBP was present in 40% of the samples at an average concentration of 0.026 mg kg^–1. Di-isobutyl phthalate (DiBP), which is not permitted in contact with food, was found in 25% of the spirits tested. According to the specific migration limits (SML) for materials in contact with food, slightly more than 11% of the wines analysed were non-compliant, as they exceeded the SML for DBP (0.3 mg kg^–1); just under 4% were close to the SML for DEHP. Concerning spirits, 19% of the samples analysed were considered non-compliant to the SML for DBP and nearly 7% were close to the SML for DEHP. The aged grape spirits analysed were often excessively contaminated with DiBP, which is not permitted to be used in contact with food (> 0.01 mg kg^–1). A study of various materials frequently present in wineries revealed that a relatively large number of polymers sometimes contained high concentrations of phthalates. However, the epoxy resin coatings used on vats represented the major source of contamination.  

甲醛替代产品DBP-1用于啤酒非生物稳定性的研究

在啤酒生产中使用甲醛替代产品DBP—1代替甲醛，研究其对啤酒的非生物稳定性的影响。试验过程中分别对最终麦汁、发酵情况、滤酒情况、成品感官和理化指标、保质期预到等方面进行了分析。试验结果表明在糖化过程中添加DBP—1，可生产出非生物稳定性和口感稳定性较好的啤酒。因此，在啤酒生产中可使用甲醛替代产品DBP--1。  

分子蒸馏脱除核桃油中塑化剂工艺优化

为探索利用分子蒸馏脱除核桃油中塑化剂的合理工艺，采用单因素实验考察了蒸馏温度、进料速度和刮膜转速对核桃油中塑化剂DEHP和DBP脱除的影响，在此基础上以DEHP和DBP的含量为指标，运用响应面法对分子蒸馏脱除核桃油中塑化剂的工艺条件进行优化。结果表明：分子蒸馏脱除核桃油中塑化剂的最佳工艺条件为蒸馏温度150?℃、进料速度250 mL/h、刮膜转速260 r/min，在此条件下核桃油中DEHP含量为0.56 mg/kg，DBP含量为0.05 mg/kg,符合我国对食品中DEHP、DBP的限量要求（DEHP≤1.5 mg/kg， DBP≤0.3 mg/kg）。