POLYCYCLIC AROMATIC HYDROCARBONS IN PRODUCTS OF A BEET SUGAR FACTORY IN VOJVODINA: LEVELS AND INTAKES

The levels of 16 EPA polycyclic aromatic hydrocarbons (PAHs) were investigated in samples of sugar beets and their products representative for a beet sugar factory located in the central part of Vojvodina, the main agricultural region in Serbia. The sum of the detected PAHs ranged from 51 pg g ^?1 ww for molasses to 391 pg g ^?1 ww for dried sugar beet pulp. The concentration of benzo(a)pyrene (BaP) for all sample types was about or less than 100 pg g ^?1 ww, which is far less than the existing Serbian and EU tolerances set for some foodstuffs. The Serbian intake of BaP via total sugar consumption that ranged from 70–85 g per capita day ^?1 , was assessed to be from 0.029 to 0.035 ng kg ^?1 b.w. day ^?1 . Furthermore, the toxic equivalency factor (TEF) approach was used to estimate the carcinogenicity of PAH mixture found in analyzed samples.     

铜冶炼分析X射线荧光仪工作标准样的研制

通过对铜冶炼分析的X射线荧光工作标准样品的制备、化学分析法定值、压片法制样、建立标准曲线、用基本参数法和经验系数法进行校正、最后进行精密度和准确度验证的全部过程。分析数据表明,这套用于铜冶炼控制分析的X射线荧光工作标样在制备和应用上都比较满意。     

2011—2012年中国银分析测定的进展

通过查阅2011—2012年国内发表的银分析测定文献,分类综述了这两年度银分析测定的进展概况,主要包括银的分离富集和各种测定方法,并对银分析测定方法的研究发展方向提出建议和展望。引用文献87篇。     

非木材纤维制浆清洁生产技术方案备料与蒸煮工段

我国人多地少,森林资源相对匮乏,林纸一体化不能完全解决原料短缺问题,而同时我国非木材纤维原料很丰富,加强非木材纤维原料制浆造纸意义重大。以苇浆生产线备料和蒸煮工段为例,采用先进和清洁生产的工艺技术和设备,可以最大限度地实现物质和能量的综合循环使用,符合制浆造纸行业清洁生产评价指标体系和循环经济的要求。本文重点介绍了芦苇原料备料和蒸煮工段的清洁生产技术方案。     

烟气脱硝技术应用于制浆造纸行业

近些年随着造纸行业的产能集中,污水治理技术也逐渐成熟,碱回收工段内的电厂、锅炉以及水泥窑等排放的尾气,尤其是涉及燃煤的烟气治理问题逐渐成为新课题,控制氮氧化物更是势在必行。国家环境保护“十二五”规划中将氮氧化物纳入总量控制指标体系,加大对二氧化氮减排力度,改善大气环境质量。目前对氮氧化物的控制尚处于试点和起步阶段,国家政策的重点是固定源如发电厂、工业锅炉、水泥窑等烟气脱硝治理。针对目前应用较广泛的烟气脱硝技术SCR、SNCR和SNCR-SCR联合脱硝法,着重介绍了SCR脱硝技术。     

The Usefulness of Intermediate Products of Plum Processing for Alcoholic Fermentation and Chemical Composition of the Obtained Distillates

In this study, an evaluation of intermediate products of plum processing as potential raw materials for distillates production was performed. Effects of composition of mashes on ethanol yield, chemical composition and taste, and flavor of the obtained spirits were determined. The obtained results showed that spontaneous fermentations of the tested products of plum processing with native microflora of raisins resulted in lower ethanol yields, compared to the ones fermented with wine yeast Saccharomyces bayanus. The supplementation of mashes with 120 g/L of sucrose caused an increase in ethanol contents from 6.2 ± 0.2 ÷ 6.5 ± 0.2% v/v in reference mashes (without sucrose addition, fermented with S. bayanus) to ca. 10.3 ± 0.3% v/v, where its highest yields amounted to 94.7 ± 2.9 ÷ 95.6 ± 2.9% of theoretical capacity, without negative changes in raw material originality of distillates. The concentrations of volatile compounds in the obtained distillates exceeding 2000 mg/L alcohol 100% v/v and low content of methanol and hydrocyanic acid, as well as their good taste and aroma make the examined products of plum processing be very attractive raw materials for the plum distillates production.     

Degradation kinetics of anthocyanins in acerola pulp: Comparison between ohmic and conventional heat treatment

Degradation kinetics of monomeric anthocyanins in acerola pulp during thermal treatment by ohmic and conventional heating was evaluated at different temperatures (75–90 °C). Anthocyanin degradation fitted a first-order reaction model and the rate constants ranged from 5.9 to 19.7 × 10⁻³ min⁻¹. There were no significant differences between the rate constants of the ohmic and the conventional heating processes at all evaluated temperatures. D-Values ranged from 116.7 to 374.5 for ohmic heating and from 134.9 to 390.4 for conventional heating. Values of the free energy of inactivation were within the range of 100.19 and 101.35 kJ mol⁻¹. The enthalpy of activation presented values between 71.79 and 71.94 kJ mol⁻¹ and the entropy of activation ranged from −80.15 to −82.63 J mol⁻¹ K⁻¹. Both heating technologies showed activation energy of 74.8 kJ mol⁻¹ and close values for all thermodynamic parameters, indicating similar mechanisms of degradation.     

Synthesis,characterisation and analytical application of Fe3O4@SiO2@polyaminoquinoline magnetic nanocomposite for the extraction and pre-concentration of Cd(II) and Pb(II) in food samples

This work describes a novel Fe₃O₄@SiO₂@polyaminoquinoline magnetic nanocomposite and its application in the pre-concentration of Cd(II) and Pb(II) ions. The parameters affecting the pre-concentration procedure were optimised by a Box–Behnken design through response surface methodology. Three variables (extraction time, magnetic sorbent amount and pH) were selected as the main factors affecting the sorption step, while four variables (type, volume and concentration of the eluent, and elution time) were selected as main factors in the optimisation study of the elution step. Following the sorption and elution of analytes, the ions were quantified by flame atomic absorption spectrometry (FASS). The limits of detection were 0.1 and 0.7 ng ml^?1 for Cd(II) and Pb(II) ions, respectively. All the relative standard deviations were less than 7.6%. The sorption capacities of this new sorbent were 57 mg g^?1 for Cd(II) and 73 mg g^?1 for Pb(II). Ultimately, this nanocomposite was successfully applied to the rapid extraction of trace quantities of these heavy metal ions from seafood and agricultural samples and satisfactory results were obtained.     

Dithizone-modified graphene oxide nano-sheet as a sorbent for pre-concentration and determination of cadmium and lead ions in food

Graphene oxide nano-sheet was modified with dithizone as a novel sorbent for selective pre-concentration and determination of Cd(II) and Pb(II) in food. The sorbent was characterised by various analytical methods and the effective parameters for Cd(II) and Pb(II) adsorption were optimised during this work. The high adsorption capacity and selectivity of this sorbent makes the method capable of fast determinations of the Cd(II) and Pb(II) content in complicated matrices even at μg l^?1 levels using commonly available instrumentation. The precision of this method was < 1.9% from 10 duplicate determinations and its accuracy verified using standard reference materials. Finally, this method was applied to the determination of Cd(II) and Pb(II) ions in common food samples and satisfactory results were obtained.     

河内白曲生产中提高酸性蛋白酶活力的方法

结合生产实际对影响河内白曲酸性蛋白酶活力的因素进行分析和工艺改进。结果表明,以麸皮为主要原料,加入5%的豆粕,入房水分为52%~56%,培养温度32℃~37℃,控制好起温并及时排潮,可明显提高白曲的酸性蛋白酶活力。