小白菜硝酸盐含量与NO3－/NH4+及氮代谢关键酶的相关性

采用液体培养实验研究了不同NO3－与NH4＋浓度比（分别为50∶50、75∶25和100∶0）对10 个品种小白菜（Brassica chinensis L.）的硝酸盐含量、光合系统参数及氮代谢关键酶活性的影响。结果表明,随着硝铵比的增加,小白菜总干质量逐渐增加（除品种天津小白菜和大头清江白菜的总干质量随硝铵比的增加先降低后升高,品种香港春秀甜白菜（236）和正旺达88的总干质量先升高后降低外）,与c（NO3－）∶c（NH4＋）为50∶50比较,增幅分别为12.66%～76.88%（c（NO3－）∶c（NH4＋）为75∶25）和17.98%～95.07%（c（NO3－）∶c（NH4＋）为100∶0）;小白菜叶和根中的硝酸盐含量增加,而叶柄硝酸盐含量则表现出先增加后下降的趋势,小白菜硝酸盐的含量叶柄（3 882.62～5 448.81 mg/kg）＞叶（2 004.86～4 146.50 mg/kg）＞根（505.39～2 188.68 mg/kg）。小白菜叶片中硝酸盐含量与硝酸还原酶活性成显著负相关,而与亚硝酸还原酶和谷氨酰胺合成酶活性成显著正相关。小白菜叶片中硝酸盐的含量随着净光合速率（Pn）和胞间二氧化碳浓度（Ci）的增加而下降,随蒸腾速率（Tr）的增强而增加。     

京郊主要蔬菜产品器官硝酸盐与亚硝酸盐含量分析与评价

对京郊52种蔬菜产品,以及同一种类不同品种、同一品种产品的不同部位的硝酸盐、亚硝酸盐和VC含量等进行测定。结果表明：供试蔬菜产品器官的硝酸盐含量在不同种类、品种及其不同部位间存在明显差异。以蔬菜鲜质量器官中硝酸盐含量均值计算,根菜类(420.66mg/kg)＞叶菜类(281.24mg/kg)＞茎菜类(279.54mg/kg)＞果菜类(176.54mg/kg)＞花菜类(157.93mg/kg);同种蔬菜品种间的硝酸盐含量相差1.13～5.48倍;产品器官不同部位的硝酸盐含量也有较大差异,如结球叶菜硝酸盐含量外叶＞中叶＞内叶,叶柄＞叶片,黄瓜果实顶部、基部＞中部,果肉＞果心,萝卜根皮＞根肉。各供试蔬菜产品器官的亚硝酸盐含量多在1mg/kg以下,个别蔬菜种类如茼蒿可达6.74mg/kg,不同蔬菜种类、品种和部位间亚硝酸盐含量差异不如硝酸盐含量差异明显。果菜类、叶菜类和花菜类蔬菜产品器官的VC含量普遍较高,如辣椒可达146.56mg/100g,但品种间VC含量差异不显著。由此可见,目前京郊蔬菜产品器官中的硝酸盐和亚硝酸盐含量多在安全范围内,但仍建议消费者科学合理进行蔬菜种类搭配以保障人体健康。     

北京市春季蔬菜硝酸盐含量测定及居民暴露量评估

为了解北京市春季蔬菜中硝酸盐污染及居民硝酸盐暴露情况,于2006年3-5月从北京市16个菜市场采集应季蔬菜7大类26个品种341份样品,用国标法(GB/T5009.33—2003)分析蔬菜中的硝酸盐含量。随机抽取北京市15岁以上常住居民152户428人,以记账法对居民日常蔬菜摄入量进行调查,结合蔬菜硝酸盐含量的检测结果,进行居民蔬菜硝酸盐暴露量评估。叶菜类硝酸盐含量最高(3156.94±1425.62mg/kg),茄果类的含量最低(172.36±148.08mg/kg),硝酸盐含量依次为叶菜类>根茎类>葱蒜类>瓜类>豆菜类>花菜类>茄果类,但同一类蔬菜不同品种的硝酸盐的含量差别较大;同一品种的蔬菜中硝酸盐含量差别也很大。居民每日通过蔬菜摄入的硝酸盐量为328.21mg(以中位数计),比WHO/FAO的ADI值(300mg/d)高9.4%。北京市春季蔬菜的硝酸盐污染较严重,居民仅由蔬菜摄入的硝酸盐量已经高于ADI值,因此需要加强监督管理,以保护居民健康。     

深圳市市售蔬菜中硝酸盐含量调查

随机抽取深圳市市售的7类蔬菜86批次样品,进行硝酸盐含量检测并分析。结果表明,在不同类型的蔬菜中硝酸盐的含量差异较大,总体而言,叶菜类蔬菜的硝酸盐含量最高,其余依次为根菜类、鳞茎类、瓜类、豆类、茄果类与食用菌类。在所调查的86批次样品中,硝酸盐含量低于432 mg/kg的蔬菜所占比为65.1%,高于1 440 mg/kg的蔬菜所占比为16.3%。     

紫外分光光度法测定蔬菜中硝酸盐的不确定度评定

根据JJF-2005《化学分析测量不确定度评定》和JJF 1059.1-2012《测量不确定度评定与表示》,建立数学模型对紫外分光光度法测定白菜、芦笋和番茄中硝酸盐含量的不确定度分量进行评定和合成。结果表明:当白菜中硝酸盐含量为854.67 mg/kg时,其扩展不确定度为30.77 mg/kg(k=2);当芦笋中硝酸盐含量为136.90 mg/kg时,其扩展不确定度为12.65 mg/kg(k=2);当番茄中硝酸盐含量为103.54 mg/kg时,其扩展不确定度为12.30 mg/kg(k=2)。该评定方法对提高紫外分光光度法测定蔬菜中硝酸盐含量的准确度具有指导意义。     

腌渍咸菜中硝酸盐含量测定的方法探讨

腌渍咸菜中硝酸盐含量测定的方法探讨刘钧杜井雷张淑伟乔敏马振苓（山东省济宁市卫生防疫站）硝酸盐广泛存在于自然界中，特别是随着硝酸盐化肥的大量使用，可增加植物中硝酸的蓄积，并且有许多蔬菜能从土壤中浓集更多的硝酸盐，如萝卜、莴苣等。硝酸盐在细菌的硝基还...     

厦门市售蔬菜重金属、硝酸盐和亚硝酸盐污染研究及评价

为了解厦门市蔬菜中有害重金属、硝酸盐和亚硝酸盐的污染情况,于2004年8月至2005年12月从厦门市各超市、农贸市场、蔬菜批发市场和蔬菜产地上采集46个品种532份蔬菜样品,用国标法(GB/T5009.11-17-1996、GB/T5009.33-2003)分别分析蔬菜中的重金属、硝酸盐和亚硝酸盐的含量。结果表明,检测样品中Pb、Cd、As、Hg、硝酸盐和亚硝酸盐的平均值分别为0.0099、0.083、0.056、0.003、1090.3、0.59mg/kg;根据国家标准1-2,仅部分品种如菠菜、甘蓝、花菜、萝卜的铅超标,有潜在污染风险;大部分蔬菜中砷、汞、镉三种重金属的含量都较低,潜在的污染风险不大。硝酸盐污染程度严重的占36.5%;中、重度污染的占20.2%;轻度的占43.3%,硝酸盐含量依次为嫩茎叶菜类>根茎类>花菜类>瓜菜类>鲜豆菜>茄果类>水生蔬菜类,各样品间含量差别较大;而蔬菜中亚硝酸盐含量相对较低。     

离子色谱法测定蔬菜中的硝酸盐、亚硝酸盐、磷酸盐及总磷、总氮

以白菜为例建立超声辅助提取(UAE)离子色谱法(IC)测定蔬菜中硝酸盐、亚硝酸盐、磷酸盐、总氮、总磷含量的方法,并对白菜各部位的硝酸盐、亚硝酸盐及磷酸盐含量的分布进行研究。结果表明：当进样量为20μL,使用Na2CO3-NaHCO3 为淋洗液,NO2 － 、NO3 － 、PO43－、总氮(TN)、总磷(TP)的最小检出限分别为0.015、0.014、0.030、0.014、0.061mg/L,相关系数为0.9990～0.9999,RSD 为0.22%～0.94%,回收率为80.0%～110.0%。该法简便快速、精密度和准确度高,15min 就可完成白菜中硝酸盐与亚硝盐、磷酸盐含量的分析。     

市场上发酵菜中亚硝酸盐含量的调查研究

蔬菜发酵主要是多种微生物并存的一种发酵过程,形成亚硝酸盐不可避免。本实验通过对市场上发酵菜中亚硝酸盐含量的调查分析,结果表明：市场上发酵菜中亚硝酸盐的含量依次为辣椒类（30.44mg/kg）〉萝卜类（27.45mg/kg）〉白菜类（26.92mg/kg）〉黄瓜类（14.65mg/kg）。发酵菜均不同程度地含亚硝酸盐,以辣椒类最多,其次是萝卜类和白菜类,含量最少的是黄瓜类。所检测的20个样品中有5个样品的亚硝酸盐超标,超标率为25%。各类发酵菜中亚硝酸盐的含量与pH、肠道菌数量有关,pH值较低的发酵菜中肠道菌数量少,亚硝酸盐含量也低;相反,pH值较高的发酵菜中肠道菌数量多,亚硝酸盐含量也较高。一定含量范围内的食盐对亚硝酸盐含量影响不大。     

复合果蔬取代部分硝酸盐对降低发酵香肠中亚硝胺的作用

分析复合果蔬替代硝酸盐对发酵香肠中N-亚硝胺生成的影响,探究发酵香肠生产过程中复合果蔬取代部分硝酸盐的可能性。制备4 组中式发酵香肠：阴性对照组（negative control group,NCG,空白组）、阳性对照组（positive control group,PCG）、芹菜樱桃组（celery and cherry group,CCG）、卷心菜番茄组（cabbage and tomato group,CTG）,考察在发酵及成熟过程中亚硝酸盐、亚硝胺及生物胺含量的变化。结果表明：发酵过程中,果蔬发酵香肠（CCG和CTG）与PCG亚硝酸盐含量同样呈现先增加后降低趋势,但CTG峰值（65.52?mg/kg）显著低于PCG（105.31?mg/kg）。4?组发酵香肠均能检出N-二乙基亚硝胺（N-nitrosodiethylamine,NDEA）,而果蔬发酵香肠（CCG和CTG）在发酵后期NDEA含量（1.23 μg/kg未检出）显著低于PCG（3.72 μg/kg）。干燥成熟阶段,果蔬发酵香肠（CTG和CCG）亚硝酸盐残留量（36.45?mg/kg和47.97?mg/kg）显著高于NCG（24.49?mg/kg）和PCG（31.40 mg/kg）,但在干燥3 d后下降至国家标准限量（30 mg/kg）以下。成品中总生物胺含量排序为NCG＞PCG＞CCG＞CTG,CTG中未检出组胺和酪胺。各组样品中N-二甲基亚硝胺（N-nitrosodimethylamine,NDMA）（PCG除外）和NDEA含量均随干燥进程而逐渐增加,但是果蔬发酵香肠（CCG和CTG）在干燥结束时NDMA（0.16?μg/kg和0.11?μg/kg）和NDEA含量（4.33?μg/kg和4.13?μg/kg）低于NCG（1.73?μg/kg和9.50?μg/kg）,与PCG（0?μg/kg和4.74?μg/kg）相当。实验表明复合果蔬浆替代部分硝酸盐,可降低中式发酵香肠的N-亚硝胺和生物胺含量。     

冷藏对蔬菜中亚硝酸盐及硝酸盐含量的影响

目的 探索冰箱冷藏(4℃)条件下蔬菜中硝酸盐和亚硝酸盐含量随时间的变化,对冷藏食品的安全性进行评价.方法 分别采用重氮偶合分光光度法和麝香草酚分光光度法对生菜、菠菜、油麦菜及苦苣4种常用蔬菜在冷藏条件下其亚硝酸盐及硝酸盐的含量变化进行测定.结果 1～4d内,生菜、苦苣中的亚硝酸盐含量随着时间的延长逐渐增加;菠菜、油麦菜中亚硝酸盐含量分别在第2天和第3天达到最大,之后逐渐降低,而菠菜中亚硝酸盐含量在第4天又出现上升趋势.4种蔬菜中亚硝酸盐含量4d中最大值仅为0.419 4 mg/kg(生菜),均＜4 mg/kg的限量值.苦苣和油麦菜中硝酸盐含量在1～4d内逐渐上升.菠菜中硝酸盐含量第2天达到418.48 mg/kg,之后又降低至20.83 mg/kg.生菜中硝酸盐含量在第3天达到最大值317.26 mg/kg,之后逐渐下降,但均在安全范围内(432 mg/kg).结论 在4℃下冷藏4d后,4种常见蔬菜均可安全食用.可见,冷藏能有效减缓亚硝酸盐和硝酸盐含量的升高.     

Nitrate and nitrite in vegetables on the Danish market: content and intake

The contents of nitrate and nitrite in lettuce, leek, potato, beetroot, Chinese cabbage and white cabbage on the Danish market were determined for 3 years in the period 1993-1997 as part of the Danish food monitoring programme. These vegetables are supposed to provide the major contribution to the intake of nitrate from the diet. Results for nitrate and nitrite in fresh and frozen spinach are also shown. The highest content of nitrate was found in lettuce followed by beetroot, Chinese cabbage, fresh spinach, leek, frozen spinach, white cabbage and potatoes. For all the products a great variation in the content of nitrate was found. For lettuce a characteristic variation throughout the year is clearly seen with the highest content in the winter period the lowest content in the summer period. Generally, the content of nitrite was low but in spinach high contents were found, probably due to improper storage conditions during transportation. The intake of nitrate and nitrite from these vegetables is calculated on the basis of two different consumption surveys. For both surveys the average intake of nitrate from the vegetables included in the monitoring programme is estimated to be approximately 40mg day^-1, whereas for nitrite the average intake is approximately 0.09mg day^-1. The total intake of nitrate and nitrite is estimated to be respectively 61mg day^-1 and 0.5mg day^-1.     

大白菜贮藏过程中硝酸盐和亚硝酸盐含量变化分析

在不同贮藏温度（0、10、20 ℃）、贮藏方式（未包装、0.04 mm PE保鲜袋包装）条件下贮藏大白菜（Brassica rapa pekinensis）16 d后,采用高效液相色谱法测定大白菜中硝酸盐和亚硝酸盐含量的变化。结果表明,在不同贮藏温度和贮藏方式条件下,硝酸盐和亚硝酸盐的含量随着贮藏时间的延长均呈现先增加、后降
低、再上升的趋势,其中硝酸盐的含量在整个贮藏期间,均在低于432 mg/kg的安全食用范围内;亚硝酸盐含量在20 ℃贮藏条件下贮藏7 d即超过了4 mg/kg的安全摄入量,而其他贮藏条件均在安全食用范围内。大白菜中硝酸盐与亚硝酸盐的含量在贮藏过程中随贮藏温度的降低而显著减少,到贮藏末期（16 d时）20 ℃和10 ℃贮藏大白菜中硝酸盐含量分别是0 ℃贮藏的1.2 倍和1.1 倍,亚硝酸盐含量分别是0 ℃贮藏的1.4 倍和1.2 倍。PE保鲜袋包装有助于减少大白菜在中、低温（10、0 ℃）贮藏中硝酸盐与亚硝酸盐的含量,但在高温（20 ℃）贮藏中其含量增加。因此,建议贮藏大白菜时最好采用PE保鲜袋包装和0～10 ℃的贮藏温度,以保证其硝酸盐和亚硝酸盐含量不超标。     

Nitrate and nitrite quantification from cured meat and vegetables and their estimated dietary intake in Australians

High dietary nitrate and nitrite intake may increase the risk of gastro-intestinal cancers due to the in vivo formation of carcinogenic chemicals known as N-nitroso compounds. Water and leafy vegetables are natural sources of dietary nitrate, whereas cured meats are the major sources of dietary nitrite. This paper describes a simple and fast analytical method for determining nitrate and nitrite contents in vegetables and meat, using reversed-phase HPLC-UV. The linearity R² value was >0.998 for the anions. The limits of quantification for nitrite and nitrate were 5.0 and 2.5 mg/kg, respectively. This method is applicable for both leafy vegetable and meat samples. A range of vegetables was tested, which contained <23 mg/kg nitrite, but as much as 5000 mg/kg of nitrate. In cured and fresh meat samples, nitrate content ranged from 3.7 to 139.5 mg/kg, and nitrite content ranged from 3.7 to 86.7 mg/kg. These were below the regulatory limits set by food standards Australia and New Zealand (FSANZ). Based on the average consumption of these vegetables and cured meat in Australia, the estimated dietary intake for nitrate and nitrite for Australians were 267 and 5.3 mg/adult/day, respectively.     

Survey of nitrate and nitrite contents of vegetables grown in Korea.

A scientific basis for the evaluation of the risk to public health arising from excessive dietary intake of nitrate in Korea is provided. The nitrate () and nitrite () contents of various vegetables (Chinese cabbage, radish, lettuce, spinach, soybean sprouts, onion, pumpkin, green onion, cucumber, potato, carrot, garlic, green pepper, cabbage and Allium tuberosum Roth known as Crown daisy) are reported. Six hundred samples of 15 vegetables cultivated during different seasons were analysed for nitrate and nitrite by ion chromatography and ultraviolet spectrophotometry, respectively. No significant variance in nitrate levels was found for most vegetables cultivated during the summer and winter harvests. The mean nitrates level was higher in A. tuberosum Roth (5150 mg kg(-1)) and spinach (4259 mg kg(-1)), intermediate in radish (1878 mg kg(-1)) and Chinese cabbage (1740 mg kg(-1)), and lower in onion (23 mg kg(-1)), soybean sprouts (56 mg kg(-1)) and green pepper (76 mg kg(-1)) compared with those in other vegetables. The average nitrite contents in various vegetables were about 0.6 mg kg(-1), and the values were not significantly different among most vegetables. It was observed that nitrate contents in vegetables varied depending on the type of vegetables and were similar to those in vegetables grown in other countries. From the results of our studies and other information from foreign sources, it can be concluded that it is not necessary to establish limits of nitrates contents of vegetables cultivated in Korea due to the co-presence of beneficial elements such as ascorbic acid and alpha-tocopherol which are known to inhibit the formation of nitrosamine.     

食品原料安全与初加工食品质量安全控制——以新鲜蔬菜的质量控制为例

新鲜蔬菜富含多种维生素与纤维素等对人体健康有益的成分,是健康膳食的主要成分之一。人们对蔬菜的需求和消费量在近10 年中持续增高。新鲜蔬菜以其易腐烂的生物特性,及作为原产品或者初加工产品的鲜食特性,在消费中存在着化学、物理和微生物安全风险,是产生食源性疾病的主要源头之一。由于新鲜蔬菜的质量安全风险存在于供应链的各个环节,因此控制蔬菜的安全质量措施要贯穿整个供应链。基于食品供应链的食品安全管理体系（Food Safety Management System,FSMS）的实施非常重要。在蔬菜供应链的各阶段安全控制中,各种安全管理控制体系需要应用于相应的不同阶段。     

Nitrate and nitrite in vegetables from areas affected by war-time operations in Croatia

To evaluate nitrate and nitrite contents in cabbage and potatoes, the most consumed vegetables in Croatia, and to examine if war-time operations in Croatia affected nitrate and nitrite levels in vegetables, potatoes and cabbage cultivated in the war region (East Slavonia) and out of war regions were analyzed. Data showed that nitrate contents were higher in the samples from the war region (32% and 24% in potatoes and cabbage, respectively) but differences were not statistically significant. The nitrate levels found in potato samples (196 mg NaNO₃/kg fresh weight (FW) and cabbage samples (911 mg NaNO₃/kg FW) were comparable with levels reported for other countries. The nitrite contents in potatoes (321 μg NaNO₂/kg FW) and cabbage (173 μg NaNO₂/kg FW) were lower than the contents reported for most other countries. Further examinations of nitrate and nitrite concentrations in vegetables in Croatia as well as examinations of the influence of war-time operations on accumulation of these toxic contaminants are necessary.