RP-HPLC法测定石斛鲜汁中纳他霉素残留量研究

为研究纳他霉素在石斛汁中的降解规律,试验建立一种快速、准确检测石斛汁中纳他霉素含量的方法。石斛汁中纳他霉素采用甲醇超声萃取10 min进行高效液相检测,使用SGE protecol C_(18)(5μm, 4.6 mm×250 mm)色谱柱,流动相为V_甲醇︰V_0.5%乙酸水溶液=57:43,检测波长为305 nm。纳他霉素在1.0～20.0μg/m L范围内线性关系良好,定量检出限为0.5 mg/L (S/N=10)。基质对纳他霉素降解影响较大,石斛汁冷藏1周,在纳他霉素初始添加量为24及48 mg/L的石斛汁样品中,纳他霉素含量分别降低62.99%及56.67%;在贮藏1及2周后,其残留量符合国标GB 2760—2014规定的最大残留量(10 mg/kg)要求。此次研究为纳他霉素在石斛鲜汁中的安全使用提供了技术支持。     

纳他霉素与其它保鲜剂在酱卤制品中的应用

用纳他霉素0.3g/kg,分别与脱氢乙酸0.5g/kg,乳酸链球菌素0.5g/kg,脱乙酰甲壳素(壳聚糖)5g/kg用量搭配混合使用,利用它们的不同抑菌效果,比较和评价纳他霉素和其它三种保鲜剂的作用,结果表明:单独使用纳他霉素对酱卤制品抑菌效果,不如纳他霉素分别与脱氢乙酸、乳酸链球菌素、脱乙酰甲壳素(壳聚糖)协同使用时好。     

高效液相色谱法同时测定糕点中富马酸二甲酯与纳他霉素

建立高效液相色谱法同时测定糕点中富马酸二甲酯与纳他霉素的检测方法。样品经10 mL甲醇溶解、超声提取后,采用Phenomenex Gemini C18色谱柱(150 mm×4.6 mm, 5μm)分离,以甲醇与20 mmol/L乙酸铵溶液(50∶50, V/V)为流动相,两者分离效果较好。富马酸二甲酯与纳他霉素在0.5～20.0 μg/mL质量浓度范围内线性关系良好(R2=0.999 9),检出限(LOD)(S/N=3)分别为0.04 mg/kg与0.20 mg/kg。加标回收率分别为94.430%～99.616%和95.860%～101.968%,精密度试验结果变异系数(CV)分别为1.09%～2.02%和1.54%～2.66%。该方法与国标方法测定样品中富马酸二甲酯与纳他霉素含量的相对标准偏差(RSD)分别为0.789%和0.918%,符合方法学要求,表明该方法准确可靠、精密度良好,可用于实际样品中富马酸二甲酯与纳他霉素的同时测定。     

高效液相色谱法同时测定果蔬汁饮料中20种禁限用食品添加剂

研究了同时测定果蔬汁饮料中20种禁限用食品添加剂的高效液相色谱方法:采用甲醇-水提取样品中的添加剂,在ZORBAX SB-C18色谱柱上分离,以甲醇-乙酸铵为流动相进行梯度洗脱,采用二极管阵列检测器多波长分析,外标法定量.结果表明,20种添加剂在0.5~50.0μg/m L质量浓度范围内线性关系良好,相关系数大于0.999 0,方法检出限范围0.5~12.5 mg/kg,定量限范围2.5~40.0 mg/kg,平均加标回收率范围80.1%~100.9%,相对标准偏差1.5%~4.9%.对10种市售果蔬汁饮料中添加剂含量测检结果表明,该方法操作简单、检测添加剂种类多、分离效果好、回收率和精密度均满足要求,适用于果蔬汁饮料中多种添加剂的同时检测.     

高效液相色谱法测定凉皮中的脱氢乙酸

目的建立凉皮中脱氢乙酸含量的高效液相色谱测定方法。方法样品用水提取,经过0.45μm微孔过滤膜过滤后进样分析。色谱柱:CNW#174;Athena C18-WP色谱柱(250 mm×4.6 mm,5μm);流动相:10 mmol/L乙酸铵水溶液(90%),甲醇(10%);洗脱方式:等度;检测器波长:230 nm;流速:1.0 m L/min;柱温:室温;进样量:3.0μL;采用色谱峰保留时间定性,外标法峰面积定量。结果脱氢乙酸平均回收率98.9%~100%,相对标准偏差0.730%~1.810%,在1.0~50.0μg/m L范围内线性良好,相关系数0.9994,定量限10.0 mg/kg。结论该方法具有样品预处理简单,分析速度快,灵敏度高的特点。针对厦门市流通领域中的样品实际检测,发现流动摊贩所售凉皮制品中脱氢乙酸含量多数超过1000 mg/kg的限量规定。     

紫外可见分光光度法测定橄榄油中的叶绿素铜

建立了紫外可见分光光度法测定橄榄油中的叶绿素铜含量的检测方法,样品特征波长为653nm,优化了波长校正方法,校正曲线y=0.032x+0.024,R~2=0.9969,对同一橄榄油添加回收率为81%~97%,精密度0.20%~2.22%。空白值的标准偏差S=0.0066,检出限LOD=3S/K=0.62mg/kg,定量限LOQ=10S/K=2.06mg/kg,K=0.032为线性方程斜率。选择三个671nm吸光度差异较大的三个样品(其中一个最小、一个居中、一个最大),分别在检出限、定量限、两倍定量限做添加回收,检出限加标回收率为48%~90%,定量限加标回收率为77%~93%,两倍定量限加标回收率为89%~96%。     

加压毛细管电色谱法分析调味果蔬汁饮品中5种有机酸

建立一种可以同时测定调味果蔬汁饮品中草酸、柠檬酸、酒石酸、苹果酸、乙酸的加压毛细管电色谱法。样品加入10%乙醇提取并超声30 min,检测的流动相为80%乙腈-水(含0.05 mol/L KH2PO4,pH 2.5),施加+5 kV电压进行分离,二极管阵列检测器的检测波长为210 nm,并以外标法峰面积定量。结果表明,5种目标物在1.0μg/mL～50.0μg/mL浓度范围内线性良好,检出限范围为0.20 mg/kg～0.30 mg/kg,定量限范围为0.60 mg/kg～1.0 mg/kg,加标回收率达到90.5%～95.7%。该方法具有操作简单、专属性强、灵敏度高等优点,可满足调味果蔬汁饮品中多种有机酸的检测要求。     

高效液相色谱法测定果酱中的纳他霉素

目的建立高效液相色谱法测定果酱中纳他霉素残留的检测方法.方法果酱样品经甲醇-水-冰乙酸(体积比为208010)溶剂提取.采用Hypersil ODS2 C18(200mm×4.0mm i.d.,5.0μm)色谱柱_,甲醇-0.75%磷酸水溶液(体积比为7525)为流动相,流速1.00mL/min,检测波长304nm.结果果酱中纳他霉素含量在0.5-100mg/kg范围时与峰面积呈良好的线性关系(r=0.9999),加标回收率93.14%～8.24%(n=6),相对标准偏差(RSD)0.72%～1.49%;在番茄酱和草莓酱样品中,其检出限分别为0.06mg/Kg和0.05mg/Kg(信噪比为3).结论该方法简便、准确,可作为果酱中纳他霉素含量的测定方法.     

HPLC法测定食品中的防腐剂和合成着色剂

试验旨在建立HPLC法鉴别并测定饮料类食品中的4种防腐剂和7中合成着色剂。方法采用Waters xbridge shield rp18色谱柱(4.6 mm×250 mm,5μm)进行分离,梯度洗脱,DAD检测器检测,外标法定量分析,紫外光谱图定性分析。结果表明,各物质浓度在1~25 mg/L时线性良好,标准曲线相关系数均大于0.999;检测限:苯甲酸0.16 mg/kg、山梨酸0.12 mg/kg、苋菜红0.08 mg/kg、脱氢乙酸0.13 mg/kg、胭脂红0.09 mg/kg、日落黄0.07 mg/kg、诱惑红0.41 mg/kg、碱性橙21 0.41 mg/kg、碱性橙22 0.30 mg/kg、酸性红0.32 mg/kg、纳他霉素0.35 mg/kg;样品在低、中、高三点加标回收率均在90%~110%之间;精密度和重复性的相对标准偏差RSD(n=6)均在5.0%以内。该方法具有操作简单、准确度高、灵敏度高等优点。     

变波长高效液相色谱法同时测定酱腌菜中的安赛蜜和脱氢乙酸

建立了一种同时测定酱腌菜中安赛蜜和脱氢乙酸的变波长高效液相色谱检测方法。样品中安赛蜜和脱氢乙酸用水提取,硫酸锌和氢氧化钠沉淀蛋白,经C18色谱柱(250×4.6mm,5μm)分离,程序化变波长检测,外标法定量。在设定的条件下,安赛蜜、脱氢乙酸分别在0.4～80mg/L、1～200mg/L浓度范围内呈现良好的线性关系(R2> 0.9995),定量限分别为2.0mg/kg、5.0mg/kg。在低、中、高3个添加水平下,安赛蜜、脱氢乙酸的平均回收率分别在96.0%～102.3%之间和97.8%～101.7%之间,相对标准偏差分别在0.5%～2.2%之间和0.6%～1.8%之间。实验结果表明该方法简单快捷、结果准确、重现性良好,适用于酱腌菜中安赛蜜和脱氢乙酸含量的测定。     

Probiotics and prebiotics--perspectives and challenges

Owing to their health benefits, probiotics and prebiotics are nowadays widely used in yogurts and fermented milks, which are leader products of functional foods worldwide. The world market for functional foods has grown rapidly in the last three decades, with an estimated size in 2003 of ca US$ 33 billion, while the European market estimation exceeded US$ 2 billion in the same year. However, the production of probiotics and prebiotics at industrial scale faces several challenges, including the search for economical and abundant raw materials for prebiotic production, the low-cost production of probiotics and the improvement of probiotic viability after storage or during the manufacturing process of the functional food. In this review, functional foods based on probiotics and prebiotics are introduced as a key biotechnological field with tremendous potential for innovation. A concise state of the art addressing the fundamentals and challenges for the development of new probiotic- and prebiotic-based foods is presented, the niches for future research being clearly identified and discussed.     

常用消毒灭菌法及其机理与应用

介绍了采用消毒灭菌方法,有加热消毒法,紫外线辐射法和化学药剂消毒法。常用化学药剂有醛类、含氯消毒剂、醇类消毒剂以及高锰酸钾、生石灰等,阐释了消毒与灭菌两个概念的区别。     

益生素、益生菌与结肠癌

介绍了益生素和益生菌及其作用机理。在动物模型中，有大量的数据证实益生素和益生菌能够预防癌症．而在人体内还没有直接实验证据。它们抑制癌症的确切机理目前尚不清楚，其抑制机理可能是：肠道菌群代谢活动的改变，肠道理化环境的改变，潜在的致癌物质的黏附和降解，肠道菌群的改变、抗癌或抗诱变物质的形成、提高宿主的免疫应答、影响宿主的生理活动以及发酵不能被消化的食物并形成有益代谢产物。     

European citizen and consumer attitudes and preferences regarding beef and pork

This paper presents the combined mid-term findings of the consumer research components of two EU Sixth Framework Programme integrated projects concerning meat, ProSafeBeef and Q-PorkChains. The consumer pillar of ProSafeBeef carried out eight focus group discussions in May 2008, in France, Germany, Spain and the UK. Q-PorkChains conducted a large-scale, web-based, consumer survey in January 2008 in Belgium, Denmark, Germany, Greece and Poland. The first project provides a set of qualitative data from a small cohort of focus groups and the second a set of quantitative data from a larger consumer sample. This paper draws together the main findings of both projects and provides a comprehensive overview of European citizens’ and consumers’ attitudes towards and preferences regarding beef and pork. In general, consumers consider meat to be a healthy and important component of the diet. Consumers support the development of technologies that can improve the health attributes of meat products and guarantee eating quality, but they have a negative view of what they see to be excessive manipulation and lack of naturalness in the production and processing of beef products. In the Q-PorkChains study consumer and citizen segments are identified and profiled. Consumer segments were built upon the frequency and variety of pork consumption. The citizen segments were built upon their attitudes towards pig production systems. Overall, the relationship between individuals’ views as citizens and their behaviour as consumers was found to be quite weak and did not appear to greatly or systematically influence meat-buying habits. Future studies in both projects will concentrate on consumers’ acceptance of innovative meat product concepts and products, with the aim of boosting consumer trust and invigorating the European beef and pork industries.     

节能节水型印染助剂和设备的现状

从节能、节水、缩短工艺流程和环保的角度出发，介绍了国内外研制开发的一系列新型节能、节水型印染助剂和染整设备。     

原花色素及其开发应用

对原花色素的结构、化学特性、制备、分析方法、应用前景作一综述,并重点讨论其生理功能,为在功能性食品、药物、化妆品等领域的深入研究和开发提供参考。     

天然香精香料与生物技术

天然香精香料是高价值的精细化工产品和食品添加剂,但原料来源有限且提取成本高。利用生物技术生产这类产品具有广阔的前景。简述了发酵工程、酶工程、细胞工程和基因工程在香精香料中的应用,并探讨了生物技术在香精香料中的应用前景。     

毛霉型低盐速成豆豉工业化生产工艺与设备

本文介绍了毛霉型低盐速成豆豉的工业化生产工艺及生产线的关键设备。     

组学技术与果蔬采后质量和安全控制

果蔬可以提供营养, 有利于人类健康, 而果蔬的后熟及其与环境的相互作用会影响果蔬采后的质量和安全。对果蔬生物学过程的了解和掌握是减少果蔬采后损失和保障果蔬采后质量和安全的关键。在过去的10多年, 基于组学技术的系统生物学在了解果蔬后熟及其与环境相互作用的分子机制方面得到了越来越多的应用。本文对此做了细致的总结, 指出了存在的不足, 并提出了未来的发展方向。     

Heritability and correlations for body condition score and dairy form within and across lactation and age

The objectives of the current study were to investigate the relationship between body condition score (BCS) and dairy form and changes in genetic parameters for BCS and dairy form within and across lactations and age. Body condition score and dairy form were obtained from the Holstein Association USA, Inc. Records were edited to include those cows classified between 24 and 60 mo of age and between 0 and 335 d in milk (DIM). A minimum of 20 daughters per sire and 15 cows per herd-classification visit were required. The dataset consisted of 135,178 records from 119,215 cows. Repeatability, multiple trait, and random regression models were used to analyze the data. All models included fixed effects for herd-classification visit, age within lactations 1, 2, and 3 or higher, and 5th-order polynomials for DIM. Random effects included sire and permanent environment for all models. Random regression models included age at classification nested within sire or DIM and lactation number nested within sire. Genetic variance for both BCS and dairy form was lowest in early lactation and highest in midlactation. Genetic correlations within and across lactations were high. The genetic correlation between DIM 0 in lactation 1 and DIM 305 in lactation 3 was estimated to be 0.77 for BCS and 0.60 for dairy form. The genetic correlation estimate between 30 mo of age at classification and 50 mo of age at classification was 0.94 for both dairy form and BCS. The repeatability models appeared to generate accurate evaluations for BCS or dairy form at all ages and stages of lactation.