桑皮纤维的结构和性能研究

利用SEM，WAXD，DSC等方法研究天然桑皮纤维的形态结构、结晶结构和热性能。研究结果表明，桑皮纤维表面分布有0．5～1μm微纤维，纤维截面为三角形和椭圆形。纤维结晶度为30％～50％，分解温度为310℃，玻璃化温度为77．8℃。     

拉曼光谱技术在农畜产品品质安全检测中的进展

本文综述了拉曼光谱技术应用于农畜产品品质安全检测的研究进展,从原理及分类出发,以各个技术方向为框架介绍拉曼光谱技术在农畜产品各个方面的进展,并分析实际问题,提出发展趋势。作为无损检测技术的重要支撑技术,拉曼光谱检测技术已经被开发应用于农畜产品品质安全检测的各个方面。激光拉曼光谱技术的成熟推动了拉曼光谱检测技术蓬勃发展,傅立叶拉曼光谱技术、显微拉曼光谱技术、共振拉曼光谱技术和表面增强拉曼光谱技术在农畜产品品质安全检测方面均具有巨大的潜力。     

洗涤方法对有机磷农药残留的影响

目的 比较不同洗涤方法对果蔬表面有机磷农药去除效果的影响。方法 利用可食用的无毒物质洗米水、面粉水、小苏打和食用碱4种洗涤溶液, 对残留有机磷类农药(以氧化乐果为例)的蔬菜样品(白菜)进行清洗, 经萃取、浓缩后, 用磷钼蓝比色法进行测定。结果 面粉水的清洗效果最好, 通过对面粉水清洗效果进行单因素实验和正交实验, 得出最佳清洗效果条件为面粉水浓度为3.5 g /500 mL、浸泡时间为17 min、浸泡温度为32 ℃, 农药去除率达到83%。氧化乐果在为0.8~32.0 μg/mL范围内线性范围良好, 线性方程为Y =0.011X?0.005, 相关系数为0.9955, 检出限为0.8 μg/mL。结论 用面粉水对果蔬进行清洗, 能够有效减少农药残留, 此法简单、便捷、价廉, 适合在日常生活中使用。     

High throughput detection of antibiotic residues in milk by time-resolved fluorescence immunochromatography based on QR code

ABSTRACT

Herein, we have successfully established a novel, rapid, and simple lateral-flow immunoassay based on time-resolved fluorescence and biotin-streptavidin to detect the residues of various antibiotics in milk. The fluorescence signal and sensitivity of immunochromatography were enhanced through biotinylated antibody coupled with streptavidin europium microspheres. Moreover, due to the use of a QR Code and fluorescent reader, quantitative detection and real-time data uploading can be achieved. Under the optimal conditions, the various antibiotic residues were detected in the milk samples. The results showed that the limits of detection of tylosin, lincomycin and doxycycline were 0.10, 0.06, and 0.27 ng/mL, respectively. The recoveries of the spiked milk samples were 88.9%~127%, with coefficients of variation less than 11%, and the test strip can be stored at room temperature for 12 months. This study shows that the proposed time-resolved fluorescence immunoassay is sensitive, rapid and reliable, and has the potential to be used for detection of veterinary antibiotic residues in food safety fields.     

2018年欧盟食品中农药残留情况分析及启示

欧盟向来十分重视食品安全, 在农药残留监管方面, 建立了健全的农药残留监管体系。 本文从欧盟农药残留法规标准、监管部门及分工和欧盟农药残留控制计划3方面介绍了欧盟农药残留监管体系, 从欧盟协调控制计划和国家控制计划两部分分析了2018年欧盟食品中农药残留情况, 涉及样品来源、产品、农药、食品中草甘膦、进口食品、婴幼儿食品、有机食品和动物源性食品等。本文也指出了农药残留产生的原因和风险评估结果, 提出风险管理建议, 并借鉴其监管思路, 提出对我国农药残留监管的几点建议, 为食品安全监管决策提供参考。     

色氨酸残基在双功能酶CCBE中的作用

应用化学修饰剂NBS对从绿色木霉生产的纤维素酶中分离出的既具有壳聚糖酶活性又具有纤维素酶活性的单一组分(简称双功能酶CCBE)进行了修饰。结果表明,CCBE的壳聚酶活性中心需一分子色氨酸残基,CMCase活性中心需两分子色氨酸残基;底物保护作用及酶解动力学研究表明,CCBE的壳聚酶活性中心及CMCase活性中心的一分子的色氨酸残基位于底物结合部位,而CMCase活性中另一分子色氨酸残基位于催化结构中心。     

酶解法测定罗汉果深加工柱流液中β构型糖含量的研究

本研究是用酶解的方法测定罗汉果深加工柱流液中β构型糖的含量,为进一步研究和利用罗汉果资源,提高其利用率增加经济效益提供理论基础.首先测得罗汉果深加工柱流液中总糖含量为23.50％,游离还原糖含量为12.97％;在β-葡萄糖苷酶最佳酶水解条件pH值为4.5,温度为45℃,加热时间为40min,β-葡萄糖苷酶用量为0.2g下,测得柱流液干燥固体中β构型糖的含量为3.43％.     

Residue depletion of sulfachlorpyrazine in edible tissues of broiler chickens

The residue depletion profile of sulfachlorpyrazine was studied in healthy broilers after oral administration of Sulfatyf®, given at a dose of 50?mg sulfachlorpyrazine (SCP) per kg body weight once daily for 3 consecutive days. Twenty-five medicated broilers were slaughtered on the 5th, 10th, 14th and 16th day of post-medication, and muscle, fat with skin, liver and kidney tissues were sampled and analysed using an high-performance liquid chromatography (HPLC) method with satisfactory recovery (74.5%?±?2.9%) and specificity. The estimated values of LOD and LOQ were 18.40 and 55.70?ng?ml^?1, respectively. On the 5th and 10th day of post-medication, the concentrations of SCP residue in all samples examined were higher than the corresponding MRLs established by the European Union and the highest SCP concentrations were measured in muscle. A maximum withdrawal time of 14 days was calculated to ensure consumer safety.     

快速气相色谱法测定烟草中有机氯农药残留

建立了一种同时测定烟草中17种有机氯农药残留量的毛细管气相色谱分析方法。样品在索格利特萃取器中用正己烷和弗罗里硅土一步提取和净化,采用SE-54弹性毛细管柱,GC-ECD(Ni63)检测,外标法定量。试验表明,样品的加标回收率在75.14%~106.93%,相对标准偏差(RSD)为1,52%~16,99%,并对3个不同产地的烟叶样品进行了实际有机氯农药残留量的测定。      

利用米渣蛋白制备氨基酸饮料

以味精厂下脚料米渣为原料，利用木瓜蛋白酶对米渣水解。通过正交试验和验证试验确定酶解米渣蛋白的最适条件，利用其酶解液可配制成氨基酸蛋白饮料。氨基酸蛋白饮料中含蛋白质182．35mg／dL，8种必需氨基酸占总蛋白质的质量分数为39％。