液质联用检测水产品中氯霉素、氟苯尼考和甲砜氯霉素的残留量

建立了采用液相色谱-质谱同位素稀释法同时测定水产品中氯霉素、氟苯尼考、甲砜氯霉素三种残留药物的方法.样品采用碱化乙酸乙酯提取,同位素内标法定量.氯霉素、氟苯尼考、甲砜氯霉素三种药物的定量限(LOQ)分别为0.05 ng/mL、0.5 ng/mL、0.7 ng/mL;药物质量浓度分别在0.05～1.2 ng/g、0.5～20.0 ng/g和0.7～28.0 ng/g内,与相应的峰面积比值呈良好的线性关系,并且在鱼肉中氯霉素、氟苯尼考、甲砜氯霉素回收率分别为92.2%～125.5%、78.6%～102.7%和79.4%～121.0%,在虾肉中分别为98.5%～128.4%、73.5%～109.6%和87.7%～122.8%.该法具有简单、快速、简化样品前处理步骤等优点.     

酶联免疫法检测克伦特罗残留量的质量控制

对酶联免疫法检测克伦特罗残留量的质量控制方法进行了探讨.应用酶联免疫法检测克伦特罗残留量可从克伦特罗试剂盒的检测下限、校正曲线的线性检验、精密度验证、以及添加克伦特罗标准品做回收率试验等方面来进行质量控制.结果表明,本方法的样品检测下限(定性检出)为0.03ng/mL,定量检测下限为0.1ng/mL;克伦特罗标准校正曲线Y=-0.1884X 0.4159在0.1～8.1ng/mL范围内具有良好的线性相关关系,相关系数为-0.9913;克伦特罗标准液的浓度分别为0.1、0.3、0.9、2.7、8.1ng/mL时,变异系数分别为3.7%、5.3%、9.7%、9.2%、8.7%,在3.7%～9.7%的范围内;当克伦特罗标准品添加水平分别为0.5、1.0ng/mL时,平均回收率分别为84%、90%,在80%～100%的范围内.上述指标均符合残留分析质量控制的要求.     

LC-MS/MS法快速筛查辣椒制品中8种禁用苏丹染料

建立辣椒制品中8种禁用苏丹染料(苏丹红Ⅰ、苏丹红Ⅱ、苏丹红Ⅲ、苏丹红Ⅳ、苏丹红7B、苏丹红G、苏丹蓝Ⅱ、苏丹黄)的液相色谱-串联质谱法快速筛查方法。辣椒制品经正己烷萃取,氧化铝柱净化,用乙腈和0.1%甲酸水溶液作为流动相,经C18色谱柱梯度洗脱分离,质谱仪定性定量。结果表明:8种苏丹染料在2.5 ng/mL～500.0 ng/mL质量浓度范围内,呈现良好的线性关系,相关系数r2≥0.999 5;检出限为0.62 ng/mL～6.25 ng/mL,测定下限为2.5 ng/mL～25.0 ng/mL;平均回收率在92.4%～98.6%之间,RSD在1.7%～3.8%之间。液相色谱-串联质谱(liquid chromatographtandem mass spectrometry,LC-MS/MS)法适用于快速筛查复杂基质辣椒制品中8种禁用苏丹染料。     

氢化物发生-原子荧光光谱法测定醋酸钙中重金属元素

醋酸钙是一种很好的食品添加剂,在食品领域应用极为广泛,因此应严格控制醋酸钙中重金属元素的含量以符合食品安全的要求.本文采用氧化物发生-原子荧光光谱法测定醋酸钙中的重金属元素的含量,并对影响因素以及共存元素的干扰情况进行了考察.研究结果表明,在线性范围分别为0～100ng/mL,0～1.0ng/mL,0～10ng/mL,0～1.0ng/mL的范围内,As,Hg,Se,Cd四种元素的线性方程分别为:If=50383C+18.43,If=9196.9C+269.06,If=241.68C+23.539,If=1174C+62.594.四种元素方法的检出限分为:0.17ng/mL,0.58ng/L,0.011ng/mL,1.61ng/L,应用本方法测得各元素的回收率为96.07%～104.40%.此方法快速、简便,得到结果令人满意,满足测定要求.     

微萃取瓶富集-液相色谱法测定苹果醋中苯甲酰脲农药

采用自制微萃取瓶富集-高效液相色谱法测定苹果醋中苯甲酰脲类农药.异辛烷作萃取剂,反相C18色谱柱,乙腈:甲醇:水=20:65:15流动相,流速1.0mL/min,波长260nm处紫外检测.杀铃脲、氟铃脲和氟苯脲在0.5μg/mL～100μg/mL范围内线性良好,相关系数大于0.9998.平均回收率分别为93.85%、102.69%、73.50%,相对标准偏差小于5.41%,方法检出限分别为5.0ng/mL、6.0ng/mL和5.2ng/mL.     

虾肉中氯霉素的UPLC/MS-MS检测方法研究

建立虾肉中氯霉素残留的超高压液相色谱/质谱/质谱测定方法.用乙酸乙酯提取,蒸干后用蒸馏水溶解残渣,直接过Oasis HLB小柱净化,洗脱液收集吹干后用流动相定容,用UPLC/MS/MS测定.在0.5 ng/mL～10ng/mL浓度范围内,该方法的回收率为71.2%～110%.批内变异系数为6.3%～16.8%.批间变异系数为14.3%～19.7%.该方法测定虾肉中氯霉素的最低检测限为0.1 ng/L.     

基于不同半抗原的呋喃唑酮代谢物免疫检测方法的建立与比较

为实现呋喃唑酮代谢物3-氨基-2-恶唑烷酮（3-amino-2-oxazolidinone,AOZ）的快速定量检测,制备AOZ- 牛血清蛋白单克隆抗体,建立2 种分别基于抗3-（4-羧基苯亚甲基）-氨基-2-恶唑烷酮（CPAOZ）、抗AOZ的单克 隆抗体酶联免疫检测试剂盒。CPAOZ检测试剂盒在1.0～100.0 ng/mL范围具有较好的线性,IC50值为14.6 ng/mL, 检测限为6.56 ng/mL,回收率为97.6%～101.3%;AOZ检测试剂盒在0.5～12.5 ng/mL范围具有良好线性,IC50值为 3.9 ng/mL,检测限为0.45 ng/mL,回收率为94.1%～97.4%。这2 种检测试剂盒对于其他硝基呋喃类抗生素及其代谢 物均不存在交叉反应。从经济、方便、快速、灵敏等因素来考虑,后者更具有发展前景。     

转基因食品中Btcry2Ab/2Ac杀虫蛋白直接竞争ELISA试剂盒的研制

研制了用于检测转基因食品中Btcry2Ab/2Ac杀虫蛋白的直接竞争ELISA试剂盒,研究结果表明:该试剂盒的最低检测限为40ng/mL,线性检测范围为40～2000ng/mL,回收率在98.52%～102.27%之间;板内、板间变异系数分别在1.55%～7.17%和3.78%～7.39%之间;试剂盒在4℃下至少可保存6个月以上。     

LC-MS/MS法分析尿液中丙烯醛、巴豆醛代谢产物——3-HPMA和3-HMPMA

建立了一种同时检测人尿样中丙烯醛和巴豆醛巯基尿酸类代谢物--N-乙酰基-S-(3-羟基丙基)半胱氨酸(3-HPMA)、N-乙酰基-S-(3-羟基丙基-1-甲基)半胱氨酸(3-HMPMA)的液相色谱-三重四级杆串联质谱(HPLC-MS/MS)方法.该方法以3-HPMA-D、3-HMPMA-D,作内标,采用Isolute ENV+固相萃取柱对样品进行净化,Agilent Extend C<,18>柱分离,多离子监测模式检测3-HPMA和3-HMPMA,并采用该方法测定了8名吸烟者和8名非吸烟者尿样中3-HPMA和3-HMPMA的含量.结果表明:①3-HPMA和3-HMPMA的精密度为2.41%～11.22%,回收率为91.11%～114.66%,检测限分别为1.0和1.3 ng/mL;②8名吸烟者尿样中3-HPMA含量为943.05～6303.54ng/mL,3-HMPMA含量为1061.73～6373.74 ng/mL.8名非吸烟者尿样中3-HPMA含量为14.13～640.93 ng/mL,3-HMPMA含量为23.36～119.40 ng/mL.     

氢化物发生-原子荧光光谱法测定大米中微量硒

研究了氢化物-原子荧光光谱法对大米中微量硒的测定,方法灵敏度高、准确度好.在最佳条件下,荧光强度与硒浓度在0.213～100ng/mL范围内呈线性关系,检出限达0.213ng/mL,相对标准偏差为2.2%以下,回收率为99.13%～105.20%.     

CHEMICAL AND ANTIOXIDANT PROPERTIES OF CULTIVATED AND WILD FRAGARIA AND RUBUS BERRIES

ABSTRACT

Content of individual sugars, organic acids, total phenolics (TPH), some important phenolic compounds (kaempferol, myricetin, quercetin, and ellagic acid) and total antioxidant capacity (TAC) in the fruits of strawberry, raspberry and blackberry were studied. A comparison was made between cultivars and wild relatives of each species (Fragaria vesca L., Rubus idaeus L. and Rubus fruticosus L.). The main sugars found were fructose and glucose both in the fruits of wild species and the studied cultivars. Citric acid was determined to be the major organic acid in most of tested berries with the exception of blackberry cultivars, where malic acid was dominant. The content of individual phenolic compounds varied among the wild species, as well as among the studied cultivars. Ellagic acid content was higher in F. vesca, R. idaeus and R. fruticosus (122.5 µg/g FW, 12.71 µg/g FW and 61.7 µg/g FW, respectively) than that obtained in analyzed cultivars. Overall, TPH expressed higher values in the wild strawberry and blackberry species in comparison to the studied cultivars, and consequently, the highest levels of TAC were recorded in F. vesca (5.78 mg asc/g FW), followed by R. fruticosus (4.95 mg asc/g FW).

PRACTICAL APPLICATIONS

In recent years, both wild and cultivated berries have become very attractive for consumers because of potentially beneficial phytochemicals contained in these fruits. Fruit nutritional quality can be described by standard quality parameters (sugars and organic acids), and the analysis of antioxidant capacity influenced by specific related compounds. The importance of flavonoids and other phenolics have been suggested to play a preventive role in the development of cancer and heart disease. A significant positive correlation observed in this study between total phenolics and total antioxidant capacity indicate the need for the use of wild species in the breeding programs of small fruits, especially strawberry and blackberry, in order to increase their nutritive value and the health benefits.     

姜与人体营养健康

对姜的营养、保健功能及其在日常生活中的应用进行了介绍，更利于推动我国调味品业的进一步研究与开发。     

Tencel机织物的染整加工及所用染化料

Ｔｅｎｃｅｌ纤维易于原纤化和很高的横向膨润性对染整加工设备选型、工序安排、染化料选用提出了很高的要求，关键的助剂是润滑剂、纤维素酶、柔软剂、树脂整理剂、防原纤化助剂，于是详细讨论了Ｔｅｎｃｅｌ机织物的前处理、初级原纤化、酶处理、染色、二次原纤化和柔性、树脂整理及染化料的应用。     

新合纤及其制造加工技术

说明了日本新合纤(新聚酯)的发展阶段,介绍了国外(日本西欧和美国)新合纤的市场情况,指出了日本在新合纤领域目前处于世界最先进水平。概括了新合纤制造加工技术及1990～1992年间日本各合成纤维厂商推出的新合纤产品。最后指出了新合纤存在的某些缺点。     

BARLEY AND MALT TANNINOGENS AND BEER QUALITY

Anthocyanogen and catechin contents (tanninogen values) were determined for ten two-row and thirteen six-row barleys and for their corresponding malts. Four barley-malts were then selected for brewing, one with high, one with low, and two with intermediate tanninogen contents. The brews were made using bottom-fermenting (lager) as well as top-fermenting (ale) yeasts, both at 50–55° F. and at 68° F. The quality of the beers, as expressed by standard analyses and flavour evaluation, is discussed in the light of the tanninogen contents of the barleys and the different brewing parameters (yeast type and fermentation temperature).     

AREA- AND PERIMETER-DEPENDENT PROPERTIES AND FAILURE OF MATURE-GREEN AND RED-RIPE TOMATO PERICARP TISSUE

The influence of tomato fruit ripeness on area- and perimeter-dependent properties and dominant failure mechanisms of pericarp tissue were investigated. Tissue discs from mature-green and red-ripe fruit were punctured with a flat-ended cylindrical probe and compressed with a flat plate at a constant rate of deformation. Approximately linear force-deformation curves were obtained to tissue failure by both puncture and flat plate compression, interrupted by a region of pseudoplastic deformation at a relatively low initial bioyield force. Based on estimated area- and perimeter-dependent coefficients and firmness (force/deformation) values, initial bioyielding of tissue appeared to be associated with an abrupt increase in cell-to-cell compaction. Puncture of mature-green tissue led to premature failure induced by shearing or rupture of tissue at the probe perimeter. The contribution to puncture of perimeter-dependent or shear-associated forces and a putative "zone of influence" increased markedly with ripening, while the contribution of area-dependent or compression associated forces generally decreased. A concomitant decrease in failure force and firmness with ripening reflected a general loss of both tissue compression and shear strengths. These results suggested that the dominant mode of tissue failure changed with ripening, from cell relaxation and rupture to cell debonding. The data obtained in this study emphasize the need to exercise caution in the interpretation of force-deformation parameters derived from puncture tests alone.     

INSTRUMENTAL AND SENSORY TEXTURE ASSESSMENT AND FRACTURE MECHANISMS OF CHEDDAR AND CHESHIRE CHEESES

Textural attributes of Cheddar and Cheshire cheeses, falling within narrow compositional ranges, were assessed by sensory panels, and from force-compression curves generated by compression between two plates, and, for Cheddar cheese only, by penetrometry. Individual sensory measurements did not relate well to any instrumental one, and were better at discriminating between cheeses. Samples of each cheese variety were fractured in different ways and the fracture surfaces were examined in a scanning electron microscope. Fracture surfaces were formed by cutting directly through the matrix, tearing of the matrix along planes high in fat or cracking at grain boundaries. It is suggested that consideration of fracture mechanism may aid the selection and development of useful instrumental methods for texture assessment of cheese.     

CHEMICAL, NUTRITIVE AND SENSORY CHARACTERISTICS OF TOMATOES BEFORE AND AFTER CONVENTIONAL AND MICROWAVE BLANCHING AND DURING FROZEN STORAGE

The objective of this study was to evaluate the effects of microwave blanching on chemical, physical and sensory characteristics of tomatoes prior to and after frozen storage. Tomatoes were blanched (4 min) using four treatments: conventional boiling water (BW), steam (ST), microwaved in a glass container (MW), and microwaved in boilable bags (MWB). The lowest moisture content occurred in MW‐blanched tomatoes before (92%) and after (86%) frozen storage. These tomatoes had the highest reduced ascorbic acid (RAA) content and the highest RAA retention (> 23 mg/100 g, >91%) after blanching and after frozen storage. After blanching, MWB‐blanched tomatoes were the lightest, while after frozen storage, ST‐blanched tomatoes were the lightest. BW‐blanched tomatoes had generally higher flavor, texture and appearance scores. This study demonstrated that though visual color and sensory attributes were highest for BW‐blanched tomatoes, MW‐blanched tomatoes retained more nutritive value in the finished product.