Determination of nitrates,nitrites and oxalates in food products by capillary electrophoresis with pH-dependent electroosmotic flow reversal

This paper describes an innovative and rapid capillary electrophoretic method for the simultaneous analysis of nitrates, nitrites and oxalates, which are anions of food interest. The novelty of our method is based on reversing the electroosmotic flow without using any buffer additive nor performing a capillary coating, but simply employing a buffer at low pH values.     

植酸对白菜乳酸发酵过程中微生物生长代谢及亚硝酸盐积累影响初探

白菜乳酸发酵过程中添加不同浓度的植酸，研究其对发酵过程中细菌总数、pH值、亚硝酸盐含量变化的影响。结果表明，添加植酸对酸及上述三个指标影响明显。     

Effect of tomato paste and nitrite level on processing and quality characteristics of frankfurters

Fourteen treatments of frankfurters (18% fat) were produced with two levels of sodium nitrite, 0 and 150mg/kg (0.015%), and seven levels (0%,2%,6%,8%,12% and 16%) of tomato paste with 12% soluble solids The higher the tomato paste level the higher the preference of consumers for frankfurters based on their colour. Frankfurters with 16% tomato paste had a sour taste while those with 12% tomato paste were the most acceptable. In a 2nd experiment three treatments of frankfurters (18% fat) were produced with 0, 50 and 100mg/kg of sodium nitrite and 12% tomato paste and a fourth (control) with only 150mg/kg sodium nitrite. Treatments with 12% tomato paste had lower (p<0.05) pH values and residual nitrite, and higher (p<0.05) thiobarbituric acid values, lightness and yellowness than control. Frankfurters with reduced levels of sodium nitrite (50 and 100mg/kg) and 12% tomato paste had the highest (p<0.05) redness. Storage time affected (p<0.05) all quality attributes. The nitrites added to frankfurters can be reduced from 150mg/kg to 100mg/kg in combination with 12% tomato paste without any negative effect on the quality of the product.     

高效自养型硝化细菌的分离及硝化条件优化

以焦化废水处理系统中的活性污泥为菌源,分离出具有较高硝化能力的自养型硝化细菌Z2。液体培养基中培养4天,菌株Z2的硝化效果可以达到100%。通过在不同温度、初始pH、摇床转速下研究其对菌株Z2硝化效果影响,得到该菌株的最优硝化条件为温度30℃,pH8.0,摇床转速250r/min。不同接种量的研究表明,增大接种量有利于硝化作用的进行。当底物亚硝酸盐氮浓度从101.51mg/L增加到507.55mg/L时,并未抑制该菌株硝化作用的进行。硝化过程中培养体系的pH逐渐增大,在理论上有利于硝化作用的进行。     

Nanoparticles of organosilane-based nitrite ionic liquid immobilized on silica for the diazotization of aniline derivatives and subsequent synthesis of azo dyes

Imidazolium based nitrite ionic liquid containing trimethoxysilyl group was prepared from the reaction of N-methylimidazole and (3-chloropropyl) trimethoxysilane. This ionic liquid was immobilized on silica covalently to give nanoparticles with the imidazolium nitrite moiety remaining intact. The diazotization reaction was performed as a model reaction to examine the activity of these nanoparticles as a nitrosonium source. Excellent performance was exhibited in the diazotization reaction of various aniline derivatives in the presence of HCl under mild heterogeneous conditions (room temperature and short reaction time). In-situ coupling of diazonium salts to a range of tertiary anilines, phenols and naphthols afforded the requisite azo dyes in good yield, using standard experimental procedures.     

Assessment of estimated daily intake of nitrite by average consumption of processed foods in Korea

This study has been performed to estimate the average daily intake of nitrite used in Korea as a color fixative. The crude estimation of daily intake was calculated based on maximum permitted levels (MPL) and national food disappearance data in 1998. In order to refine estimated daily intake (EDI), daily food consumption nationwide National Health and Nutrition Survey in 1998 and the concentration of nitrite in their permitted foods were applied. The crude EDI of nitrite was 17.85 μg/kg bw/day, representing 25.5% of acceptable daily intake (ADI) assigned by JECFA. The refined average EDI for nitrite was 0.87 μg/kg bw/day, representing 1.25% of ADI. For average consumers of age–sex groups ranged from 0.2 to 4.8 μg/kg bw/day, representing 0.3%–6.9% of the ADI.     

Interactive Effects of Fly Ash and CNI on Corrosion of Reinforced High-Performance Concrete

The interactive effects of fly ash and CNI in corrosion of reinforced concrete were investigated. A 3⁴ full factorial design was developed considering water to cement ratio, fly ash percent, CNI and cracked condition as factors. The response factors were the weight loss calculated from Linear Polarization Resistance measurements and the pit depth of the steel bars embedded in concrete. Small-scale concrete slabs containing steel reinforcement with a cover depth of 20 mm were cast for this purpose. The slabs were subjected to a simulated marine environment with two cycles of wetting and drying per day during one year; after the exposure, the slabs were broken, the bars were cleaned and the pith depth measured by using SEM. Under the studied conditions, it was found that CNI alone does not provide corrosion protection of the steel reinforcement even for uncracked silica fume concrete in a 0.45 w/c ratio; however, the combination of CNI and fly ash can be useful to overcome this problem. The results indicate that low w/c ratio concrete in its crack state creates conditions suitable for the development of pitting corrosion.     

流动化学分析法测定海水中硝酸盐亚硝酸盐

采用萘乙二胺分光光度法测定亚硝酸盐、锌-镉还原法测定硝酸盐与连续流动化学分析法进行同时测定对比,结果采用t检验法的"成对数据的比较"来判定,两种方法针对单个盐度点样品无显著性差异。采用流动化学分析法,进行浓度及盐度适用范围实验;本次方法实验显示硝酸盐氮和亚硝酸盐氮含量的适用范围分别为0.005～1.0 mg N/L和0.004～0.1 mg N/L;盐度适用范围实验显示盐度0～40的水样测定结果一致性良好。     

Beyond celery and starter culture: advances in natural/organic curing processes in the United States

Over the past 10years there has been ongoing development of curing processes with natural ingredients designed to meet consumer demand and regulatory requirements for natural and organic processed meats. Initially, these processes utilized celery concentrates with a high nitrate content combined with a nitrate-reducing starter culture. Subsequent advances included celery concentrates with the nitrate converted to nitrite by suppliers. Further, as questions developed concerning reduced concentration of preservatives and the microbiological safety of these processed meats, additional advances have resulted in a wide variety of ingredients and processes designed to provide supplementary antimicrobial effects for improved product safety.