马拉硫磷、杀螟松、甲基嘧啶硫磷与溴氰菊酯在储粮中残留消解与分布的研究

在实验室30℃温度下,马拉硫磷、杀螟松与甲基嘧啶硫磷在稻谷内半衰期(t 1/2)相应为1,2.3,3.7个月的仓库条件下,在小麦内马拉硫磷t 1/2为5.4个月,溴氰菊酯15.6个月。采用砻糠载体法施药,在粮食内残留消解动态呈二次方程反应。喷雾法则消解动态呈一级动力学反应。药剂在稻谷加工产品大米和米饭内残留消解率显著低于小麦粉和馒头。     

进口粮谷中农药残留状况普查与分析

目的根据各进口国粮谷样品农药残留检出情况,确立进口粮谷中重点监测的农药残留品种和评估潜在的农药残留风险。方法采用修改的GB/T 19649-2006和GB/T 20770-2008方法,对粮谷主要进口口岸青岛、深圳和秦皇岛在2010~2014年期间进口的62例大豆、62例大麦和28例大米样品进行了690种农药残留检测,共获得104880个检测数据。结果来自6个进口国的62例大豆样品均未检出农药残留。来自3个进口国的62例大麦样品中,有8例样品检出5种农药,检出率12.9%;其中检出1种农药的样品占4.8%,检出2种农药的样品占6.5%,检出3种农药的样品占1.6%;检出的农药残留水平在10~1000μg/kg范围的占检出总数的85.7%,大于1000μg/kg占检出总数的14.3%。来自6个进口国的28例大米样品中,有5例样品检出5种农药,检出率17.9%;其中检出1种农药的样品占14.3%,检出2种农药的样品占3.6%;检出的农药残留水平低于10μg/kg占检出总数的50.0%,大于10μg/kg占检出总数的50.0%。大麦和大米样品中检出的农药品种为低毒农药的均占80%,检出的农药为中毒农药的均占20%。按照中国最大残留限量(MRL)标准衡量,只有1例大麦样品检出的溴氰菊酯超出标准要求;按照欧盟MRL标准衡量,4例大麦样品检出的杀螟硫磷超出标准要求;按照日本MRL标准衡量,没有样品检出超标农药。结论我国进口粮谷的农药残留检出率低于10%。农药残留水平处于安全水平。但同时也应当加强溴氰菊酯、杀螟硫磷、甲基嘧啶磷、毒死蜱、甲基毒死蜱、丙环唑、嘧菌酯、增效醚的检测,特别是溴氰菊酯和杀螟硫磷农药残留的监控,以保障消费者的食品安全。     

气相色谱-质谱联用结合QuEChERS法快速筛查大米中多种农药残留

采用QuEChERS方法结合气相色谱-质谱联用建立大米中是否存在敌敌畏、草灭达、氧化乐果、五氯硝基苯、敌稗、甲基毒死蜱、杀螟硫磷、甲基吡啶磷、马拉硫磷、毒死蜱、稻丰散、腐霉利、丁草胺、稻瘟灵、三唑磷、联苯菊酯和溴氰菊酯17 种农药的快速筛查方法。样品采用体积分数1%冰乙酸-乙腈提取、无水硫酸镁与氯化钠盐析,经N-丙基乙二胺和十八烷基键合硅胶净化,气相色谱-质谱检测,NAGINATA™软件分析。结果表明：17 种农药在大米中检出限为0.002～0.050 mg/kg。在0.05、0.10 mg/kg和0.20 mg/kg添加水平的平均回收率为80%～110%,相对标准偏差为1.7%～12.3%。该方法耗时短,操作便捷、快速且可靠,适合大米中多种农药残留的快速筛查。采用本方法对25 份大米样品进行测定,检测出毒死蜱、三唑磷和稻瘟灵3 种农药残留,残留量均显著低于GB 2763-2014《食品中农药最大残留限量》规定的限量标准。     

不同药剂对书虱的毒力及其复配与联用增效作用

为书虱的抗性治理提供科学指导,本研究采用培养皿药膜法测定了4种储粮保护剂对5种书虱的触杀毒力,并采用广口瓶密闭熏蒸法测定了8种植物精油对嗜卷书虱的熏蒸活性。同时,评估了药剂复配及其与辣根素精油联用对嗜卷书虱的协同毒力。结果表明,书虱对马拉硫磷、甲基嘧啶磷、高效氯氰菊酯和溴氰菊酯均表现出较高敏感性,LD50在0.041～0.977 μg/cm2之间,可作为敏感基线使用;辣根素精油对书虱的熏蒸活性最高。马拉硫磷和溴氰菊酯复配配比为4:5时,增效作用最佳;而甲基嘧啶磷和高效氯氰菊酯配比在2:1时,增效作用最佳。此外,辣根素与甲基嘧啶磷或高效氯氰菊酯联用均具有增效作用。本研究不仅为书虱抗药性监测提供了药剂敏感基线,而且为书虱化学防治的减药增效和抗性治理提供了新的思路。     

英德横石水镇贫困村蔬菜中农药残留及重金属污染分析

本文研究分析了英德横石水镇溪北村蔬菜中的农药残留和重金属污染。选取24个蔬菜样品,采用气相色谱-双火焰光度检测器(GC-FPD)测定蔬菜中的甲胺磷、甲拌磷、特丁硫磷、甲基对硫磷、杀螟硫磷、甲基异柳磷、丙溴磷、伏杀硫磷、敌敌畏、乙酰甲胺磷、治螟磷、氧乐果、乐果、毒死蜱、马拉硫磷、对硫磷、水胺硫磷、杀扑磷、三唑磷和亚胺硫磷等20种有机磷农药残留;采用气相色谱-电子捕获检测器(GC-ECD)测定蔬菜中的α-六六六、β-六六六、γ-六六六、δ-六六六、百菌清、三唑酮、甲氰菊酯、哒螨啉、氯氰菊酯、氰戊菊酯、溴氰菊酯和氟虫腈等12种农药残留;采用原子吸收-石墨炉法测定铅含量;原子荧光分光光度法测定砷和汞含量,结果表明蔬菜样品中均未检出上述32种农药及3种重金属。研究结果可为英德横石水镇溪北村蔬菜质量定位提供理论依据。     

茶叶中10种农药残留的液相色谱-串联质谱法和气相色谱-串联质谱法测定

建立了茶叶中啶虫脒、乐果、吡虫啉、灭多威、甲基嘧啶磷、腐霉利共6种农药残留的液相色谱-串联质谱(LC-MS/MS)测定方法和溴氰菊酯、乐果、高效氯氟氰菊酯、p,p'-滴滴伊、甲基嘧啶磷、腐霉利、哒螨灵共7种农药残留的气相色谱-串联质谱(GC-MS/MS)测定方法。其中,乐果、甲基嘧啶磷和腐霉利三种农药均能通过两种方法测定。LC-MS/MS法测定的6种农药,在5~200 μg/L范围内线性关系良好(R2>0.995),在10、50、100 μg/kg加标水平下的回收率为70.0%~105.0%,相对标准偏差为0.3%~18.7%。GC-MS/MS法测定的7种农药,在10~500 μg/L范围内线性关系良好(R2>0.996),在10、50、300 μg/kg加标水平下的回收率为82.0%~110.0%,相对标准偏差为1.8%~12.0%。该方法完善了茶叶中10种农药残留检测方法针对实际样品的检测,灵敏度满足国外限量标准要求,适合出口茶叶中农药残留的测定。     

几种药剂对烟草甲生物活性的测定

为了开发有效的贮烟防护剂,试验了7种药剂对烟草甲幼虫和4种药剂对烟草甲成虫的触杀毒力。结果表明,7种药剂中97.1%氟氯氰菊酯对烟草甲幼虫的致死中量最低,对烟草甲幼虫的触杀毒力最强,其次是98.5%溴氰菊酯,27%高效氯氰菊酯,90%甲基嘧啶磷,65.9%氰戊菊酯;供试药剂中对烟草甲幼虫触杀毒力最弱的是66.67%的甲氨基阿维菌素苯甲酸盐。而对烟草甲成虫触杀毒力最强的是90%甲基嘧啶磷。     

烟草中含硫有机磷杀虫剂残留量的测定

采用德国官方食品中农药残留量通用方法测定了239个国产烟叶、49个进口烟叶、12个进口卷烟样品中二嗪磷、甲基对硫磷、毒死蜱、马拉硫磷、杀螟硫磷、乙基对硫磷和倍硫磷的残留量。结果表明,国产烟叶样品中杀螟硫磷、马拉硫磷、乙基对硫磷和倍硫磷的检出率为0.8%~2.9%,未检出二嗪磷、甲基对硫磷和毒死蜱;进口烟叶和卷烟样品中未检出这7种含硫有机磷杀虫剂。     

毛细管柱气相色谱法测定粮食和蔬菜中5种有机磷农药的含量

目的:建立有机磷农药的快速测定分析方法。方法:采用毛细管柱气相色谱法,用氮磷检测器同时测定了敌敌畏、甲基对硫磷、甲基嘧啶磷和对硫磷等5种有机磷类农药的含量。结果:5种农药的线性范围均为0.1～10μg/ml,方法回收率为89.37%～94.28%,最小检出量均为2μg/kg。结论:本法操作简单、快速,重现性好,适合于粮食和蔬菜中有机磷农药残留的快速分析测定。     

8种农药残留在小麦模拟储藏过程中的降解动力学研究

本文研究了8种农药残留（乐果、氰烯菊酯、氟环唑、戊唑醇、咪鲜胺、甲基毒死蜱、甲基嘧啶磷、毒死蜱）在小麦模拟储藏过程中的降解动力学。通过QuEChERS（Quick, Easy, Cheap, Effective, Rugged, Safe）前处理结合超高效液相色谱与三重四级杆质谱串联（UPLC-MS/MS）技术,对不同储藏时间的小麦中农药残留进行检测,结果表明：除氰烯菌酯外,其余7种农药降解均符合一级动力学模型,它们的残留降解速率随温度升高而加快,但受湿度影响不大;在10℃下,7种农药的降解动力学常数k的范围为0.0007~0.0042 d-1,半衰期t1/2为165~990.2 d;在35℃下,k的范围为0.0034 d-1~0.0408 d-1,t1/2为17~203.9 d ;在10℃和35℃下k值最大的分别为甲基嘧啶磷和乐果,k最小的分别为咪鲜胺和氟环唑。咪鲜胺具有最大的降解活化能Ea（87.29 kJ/mol),其k值受温度影响最大,而甲基嘧啶磷的Ea值最小（8.29 kJ/mol),其k值受温度影响也较小。而氰烯菌酯则非常稳定,即使在35℃下近6个月储藏过程中残留量几乎没有变化。     

湖北麻城地区传统老米酒的香气成分的固相微萃取-气质联用分析及比较

为掌握麻城木子店镇及附近乡镇地方特色老米酒的香气成分及特征,通过顶空固相微萃取和GC-MS联用技术分析了当地11个不同企业样品的挥发性成分。结果表明,麻城老米酒挥发性成分以醇和酯类为主,仅含少量挥发酸、酮、醛和酚类成分,其中醇类共7种,以2-甲基丁醇、3-甲基丁醇和2-苯乙醇为主,检出频率高,含量高。酯类共有18种,以2-甲基丙酸2-甲基丁酯、辛酸乙酯、乳酸乙酯、丁二酸二乙酯和十六酸乙酯的检出频率较高。有机酸类有5种,以乙酸和丙酸检出频率较高,但含量较低。另外,还检出了1种酮类、1种酚类和2种醛类物质。说明不同厂家的老米酒香气成分差异较大。     

稻谷不同部位多元素分布规律研究

以收集自三省的66份稻谷为研究对象,通过加工研磨获得糙米和精米,通过ICP-MS获得并筛选出包含铅、镉和砷在内的17种无机元素,结合出糙率和整精米率数据,并研究其在稻谷不同部位（颖壳、米糠层和精米）中的分布规律,并探讨形成原因。通过实验发现,58.3%~73.2%的铅分布在颖壳层,米糠层和精米中铅含量总量相近,分别在15.9%~22.8%和9.8%~18.9%范围内;对于镉元素,44.3%~54.5%分布在精米,而在米糠层含量范围是22.8%~44.1%。对于砷元素,在精米中的残留率为18.6%~22.8%。对于其他的无机元素,大部分在精米加工过程留存率不高于30%。     

Lethality and quality evaluation of in-packaged ready-to-eat cooked Jasmine rice subjected to industrial continuous microwave pasteurization

The use of the pasteurization unit as a measure of the lethal effect of heating processes and overall quality of ready-to-eat Jasmine rice was determined in order to compare the conventional and microwave technology. Cooked Jasmine rice was packed in a polypropylene plastic cup and sealed with a lidding film, then subjected to a continuous microwave system (eight 800 W; 2450 MHz) and conventional steamer. The pasteurization unit, log reduction, microorganism count, color, instrumental textural property, and sensory attributes were investigated over a 30-day storage at 8°C. The pasteurization process time was reduced from 420 s under the conventional process to 216 s under the microwave process for a 5-log reduction of L. monocytogenes. The microwave heating showed greater effectiveness for shelf life, extending the product from 7 days (conventional) to 30 days. Cooked rice after heating by microwave was whiter and showed lower hardness than the conventional heated sample. Throughout storage, sensory attributes of the pasteurized product heated by microwave were acceptable by panelists. The addition of 15% trehalose or 1% soybean oil into the rice before cooking decreased the hardness of the cooked rice during storage. This study successfully demonstrated that the continuous microwave pasteurization process, compared to the conventional process, required less process time for ready-to-eat cooked Jasmine rice and extended the shelf life while providing better product quality.     

The performance of organic and inorganic coated retort pouch materials on the shelf life of ready-to-eat rice products

The performance of organic and inorganic coated retort pouch materials on the shelf life of ready-to-eat (RTE) rice products was investigated. Two different retort pouch structures were used: the organic material coated retort pouch (ORG), organic material coated polyethylene terephthalate (PET)/biaxially oriented nylon (BON)/cast polypropylene (CPP); the inorganic material coated retort pouch (IND), aluminum oxide coated PET/BON/CPP. Two specific cooked rice products, plain and chicken-flavored cooked rice, were utilized for the comparison. For quantitative analysis, moisture content and lightness of the rice products were measured. The moisture content of both the plain and chicken-flavored rice packed in either pouch decreased slightly during the 12 week storage time after retort processing. However, there were no significant differences in quantitative analysis between the ORG and IND for both the plain and chicken-flavored cooked rice. A simple paired comparison test was used to evaluate the sensory characteristics of rice products. Overall, there were no significant sensory differences between the ORG and IND for both the plain and the chicken-flavored cooked rice. These results demonstrated that the newly developed ORG can be used as a retort pouch material for RTE rice products.     

稻谷整粒与粉碎水分测试方法的对比分析

通过连续测试在一定含水量区间内的稻谷籽粒含水量,对比分析国家标准稻谷粉碎测试与国外稻谷整粒测试所得的含水量。结果表明,稻谷经粉碎后测试含水量与整粒测试含水量在整个水分测试区间存在较大差异,整粒测试所得含水量大于粉碎测试所得含水量,并且随着稻谷籽粒含水量的降低2种测试方法间含水量差异性逐渐减小,直至稻谷含水量达到11%左右时2种测试方法间无差异。因此总体来说整粒测试方法所得稻谷含水量测定结果更准确可靠。     

Partial extraction method for the rapid analysis of total lipids and γ-oryzanol contents in rice bran

Total lipids and γ-oryzanol in rice bran were determined by a partial extraction method. The results agreed well with the conventional total extraction methods. The proposed method uses fewer hazardous organic solvents, takes a shorter extraction time and requires no special extraction apparatus. Total lipids and γ-oryzanol in nine rice bran varieties were analysed by the developed technique. Daw Dum 5647 had the highest total lipids and γ-oryzanol while the lowest content was found in KD XBT 313-19-1-1 and SP XBT 43-7, respectively. The adsorption coefficient (K_d) of the lipids and γ-oryzanol, between hexane and bran, at 30 °C are between 1.16 and 2.00 and 2.02 and 2.65, respectively (depending on the moisture content of the bran). From the K_d values, it was estimated that about 92–95% of the lipids and 95–96% of the γ-oryzanol were extracted into hexane at a 10:1 (v/w) ratio of hexane to bran. The effect of solvents on the extraction of γ-oryzanol from rice bran was also studied. It was found that isopropanol was the most suitable solvent for extraction and determination of γ-oryzanol in rice bran. It showed better agreement with the total extraction method.     

基于熵权-逼近理想解排序法结合体外模拟消化评价功能性水稻品质

目的 探究不同品种功能性水稻的品质差异性指标,并进行综合品质评价。方法 以来源于咸宁市农业科学院的7种功能性水稻为研究对象,对其7项基本营养成分、9种矿物质元素含量、3类淀粉含量和1种血糖预测指数共计20项营养品质指标进行对比分析,在利用正交偏最小二乘法-判别分析(orthogonal partial least-squaresdiscriminationanalysis,OPLS-DA)筛选重要差异性指标的基础上,建立熵权-逼近理想解排序法(technique for order preference by similarity to ideal solution, TOPSIS)模型对7种功能性水稻的综合品质进行评价。结果 不同品种功能性水稻的基本营养成分在较小范围内波动,但钾元素含量和淀粉含量的变化范围较大,其中水稻GN 7、GN 5、GN 6在钾元素含量方面表现较好,水稻GN 4、GN 1、GN 3抗性淀粉含量最高,预估血糖生成指数(estimated glycemic index, eGI)值更低,抗消化能力优于其他品种。OPLS-DA分析筛选出锌、钠、钾、抗性淀粉、钙、镁、...     

乌鲁木齐市售大米几项品质指标的初步分析

目的了解乌鲁木齐市售大米的品质状况,为市民购买大米提供参考依据。方法在市场调研基础上,选取乌鲁木齐市市售的不同产地、等级的15种代表性大米,通过原子吸收分光光度法(atomic absorption spectrometry,AAS)和近红外光谱法(near-infrared spectroscopy),检测大米的微量元素、蛋白质、脂肪、糖类等营养成分含量,对乌鲁木齐市场销售大米的品质进行初步研究;结果乌鲁木齐市场销售大米产地以东北和新疆为主;市场销售的东北一级大米价格比二级大米贵1.16元/kg,但其微量元素总含量差异不大,其他指标无显著差异;泰国香米微量元素含量、蛋白质、含糖量均高于新疆地产大米,但泰国香米的价格大约是新疆大米的4倍。因此,从性价比上考虑应该首选新疆地产大米。结论总体来看,新疆地产大米品质略低于东北产大米,但其具备价格优势。     

气相色谱-三重四极杆质谱法测定稻米中27种持久性有机污染物

目的 建立气相色谱-三重四极杆质谱法测定稻米样品中多氯联苯、有机氯农药和多溴联苯醚等27种持久性有机污染物的分析方法.方法 糙米粉样品经水化后,采用乙酸乙酯进行2次直接提取,采用5 g酸性硅胶(44％,m∶m)固相净化柱进行净化后采用气相色谱-三重四极杆质谱在动态多反应离子监测模式进行分析,内标法定量.结果 27种持久...     

糯米的不同干燥方式对米酒酿造的影响

该实验探究了烘干、阴干两种不同的干燥方法对糯米的基本理化特性、糊化特性和发酵特性的影响。结果表明,与阴干糯米相比,烘干糯米含水量低1.1%、出饭率高5.9%、粗淀粉含量高1.55%、直链淀粉含量高0.14%。两种糯米淀粉糊化曲线显示,烘干糯米体系整体黏度低于阴干糯米,具有较高的衰减值和回生值,糊化温度略微下降。对比两种糯米31℃发酵48 h后酿造的米酒,烘干糯米米酒比阴干糯米米酒总糖含量高59.3%、总酸含量高16.5%,酒精度低2.1%vol。结果表明烘干糯米对比与阴干糯米具有更优良的发酵性能。