反射光谱法测定食品中挥发性盐基氮

采用反射光谱法测定鱼，肉食品中挥发性盐基氮，方法精密度（ＲＳＤ）为２．６％（ｎ＝６）线性范围为１～８μｇ／ｍｌ，检出限为０．５μｇ／ｍｌ，用于猪肉和鱼鲜度检验，并有对鲜鱼做了连续监测，结果满意。     

乳化剂OP微分电位溶出法快速测定啤酒中痕量铅的研究

探讨了乳化剂ＯＰ存在下，微分电位溶出法（ＤＰＳＡ）测定啤酒中铅的最佳条件。发现铅在含有０．１８～０．６０ｍｏｌ／ＬＨＣｌ介质中于－０．５２Ｖ（ＶＳ．ＳＣＥ）处有一灵敏的溶出峰。检出线为０．０３３μｇ／２０ｍｌ，加标回收率为９５．８％～１０２％，ＲＳＤ为１．５％～４．０％，方法已用于啤酒中铅的直接测定。     

催化动力学光度法测定痕量铁新体系的研究

基于Ｆｅ３＋对ＫＩＯ４氧化紫脲酸铵（ＭＸ）褪色的催化效应，建立了一个催化动力学光度法测定痕量Ｆｅ３＋的新体系．此方法的线性范围为４．０×１０－６～３．２×１０－４ｇ／Ｌ．检出限为１．０×１０－６ｇ／ＬＦｅ３＋，ＲＳＤ为２．１％．方法用于化学试剂及矿样中Ｆｅ３＋的测定，效果满意．     

饲粮完整蛋白质比例对肉雏鸡整体、组织蛋白质周转代谢的影响

试验用４～１５日龄艾维茵母系公鸡分为３组，饲喂按理想氨基酸模式配制成含不同蛋清蛋白与游离氨基酸比例的饲粮（蛋清蛋白氨基酸占８８．６％、４４．３％、０％），研究饲粮完整蛋白质比例对肉雏鸡整体、组织蛋白质周转代谢的影响。结果表明：饲喂游离氨基酸饲粮的第３组鸡整体、胸肌蛋白质生长率（ＦＧＲ）显著（Ｐ＜０．０５）低于第１、２组；其中，蛋白质合成率（ＦＳＲ）以第２组最高，２、３组极显著高于（Ｐ＜０．０１）第１组；降解率（ＦＤＲ）第１组显著（Ｐ＜０．０５～０．０１）低于第２和第３组。整体和胸肌ＦＧＲ的提高，主要是由于蛋白质降解率的相对降低。肝脏蛋白质ＦＧＲ３组间差异不显著（Ｐ＞０．０５），依次为３组＞１组＞２组。血浆寡肽量与整体和组织蛋白质ＦＳＲ、ＦＤＲ、ＦＧＲ间存在显著（Ｐ＜０．０５）的相关关系。结果表明，饲粮完整蛋白质比例影响肉仔鸡血液循环中的某些寡肽和整体与组织的蛋白质周转代谢。     

镀镍液中微量铁测定的研究

研究了镀镍液中微量铁的测定方法。采用５－溴水扬基荧光酮（５－ＢＳＡＦ）为显色剂。在ｐＨ５．０～６．０介质中，Ｆｅ（Ⅲ）与５－ＢＳＡＦ，ＣＴＭＡＢ形成稳定的三元配合物。其最适测定波长在６０５ｎｍ。摩尔吸光系数ε_（６０５）＝１．４×１０５，有色溶液２ｈ内稳定不变，线性范围为０～７μｇ／２５ｍｌ，线性相关系数γ＝０．９９９７，加入回收率在９７．７％～１０３％之间。高含量的各种镀液成分以及２０余种物质不干扰测定。     

水热处理后荞麦抗性淀粉的特殊效用

碳水化合物食品受到水热处理并经冷却后，其中的一部分直链淀粉对酶的降解作用会产生阻抗．根据新近的人体营养学研究结果，抗性淀粉和食物纤维有相似的功效．在斯洛文尼亚和欧洲其他国家，荞麦这种农作物越来越知名．我们分析了直链淀粉、总淀粉（ＴＳ）、快速消化淀粉（ＲＤＳ）、缓慢消化淀粉（ＳＤＳ）和抗性淀粉（ＲＳ），比较了加热前后的变化．荞麦经蒸煮和冷冻干燥，总淀粉的８０％是可迅速转化的能量物质，６％降解速度减慢，余下的１４％可供结肠厌氧发酵．反复的蒸煮和冷却可以加速抗性淀粉的形成（统计确认偏差为α＝０００１）．淀粉消化率和抗性淀粉含量数据表明，荞麦中的葡萄糖分子释放缓慢，抗性淀粉比例高（与小麦粉面包相比），可用于糖尿病人良好的补充食品     

二溴对甲基偶氮甲磺光度法测定食品中微量铅

研究了新显色剂二溴对甲基偶氮甲磺（ＤＢＭ－ＭＳＡ）与铅的显色反应。在０．２４ｍｏｌ／Ｌ的磷酸介质中，铅与ＤＢＭ－ＭＳＡ形成稳定的蓝色配合物，其组成比为铅ＤＢＭ－ＭＡＳ＝１２，λｍａｘ＝６４２ｎｍ，ε＝９．５×１０４Ｌ／（ｍｏｌｃｍ）．铅在０～０．６μｇ／ｍＬ范围内符合比耳定律，测定０．４μｇ／ｍＬ时大多数金属离子的允许量在毫克量级。用于食品中微量铅的测定，结果令人满意。     

安琪牌葡萄酒活性干酵母在枸杞酒酿造中的应用

对安琪葡萄酒活性干酵母在枸杞汁中的发酵条件进行了研究，表明５０～１００ｐｐｍ的ＳＯ２使用量，０．２％～０．４％的接种量，发酵的酒质较好，并采用分次加糖，降低渗透压的方法进行发酵，对提高酒质，缩短发酵周期有利。采用安琪牌葡萄酒活性干酵母酿制干型的枸杞酒，具有典型的枸杞果香和发酵产生的酒香，同时对控制发酵过程，稳定酒质有很大的好处。     

化学发光型葡萄糖传感器法测定食品中的葡萄糖

报道报一种基于用溶胶凝胶法固定葡萄糖氧化酶（ＧＯＤ）的化学发光型葡萄糖传感器，此传感器用于流动注射化学发光分析体系，可实现对葡萄糖的在线检测，测定的线性范围为１０￣１０００μｍｏｌ／Ｌ，检出限为０．８μｍｏｌ／Ｌ１０次测定的ＲＳＤ为１．６％，单次测定能在１ｍｉｎ内完成。方法可用于各种食品中葡萄糖含量的测定。     

石墨炉原子吸收光谱测定饲料中的砷

本文研究了用石墨炉原子吸收光谱法测定饲料样品中的砷，采用氧化镁添加干式灰化法消解样品，有效地抑制了砷的挥发；添加硝酸镍，大大提高了石墨炉工作程序中的灰化温度，从而降低干扰，提高灵敏度；同时，使用标准加入法，以消除样品基体中磷的干扰。该方法测定高含磷样品的检出限：ＤＬ＝０．２ｍｇ／ｋｇ；变异系数：ＣＶ＝２．８％（ｎ＝９）；添加到饲料样品中的砷的回收范围：８９－９８％；用本方法测定饲料中砷，所得结果与     

南方山葡萄酒的氧化褐变动力学研究

为深入了解红葡萄酒的氧化机制,利用加速氧化的方法,通过分析2种南方山葡萄酒氧化褐变过程中,褐变程度、红色色调、游离SO2、氧化还原电位以及氧化前、后主要理化指标的变化,研究南方山葡萄酒的氧化褐变动力学、主要影响因素及对葡萄酒品质的影响。试验结果表明:南方山葡萄酒的氧化褐变动力学符合0级动力学模型方程,桂葡1号葡萄酒耐氧化能力高于刺葡萄酒,然而其红色色调的保持力要低于刺葡萄酒。在加速氧化过程中,葡萄酒的游离SO2快速下降,氧化-还原电位加速上升,且二者呈显著的负相关关系。加速氧化30 d后,2种葡萄酒的总酸、挥发酸升高,其pH值和主要的抗氧化物质(原花青素、游离花色苷、总酚)均显著下降。     

Determination of molecular and free sulphur dioxide in foods by headspace gas chromatography

A study was made of the equilibria between SO2 in packaged liquid foods and gaseous SO2 in their headspace atmospheres as a basis for a new analytical method for the determination of molecular and free SO,. Using a gas-chromatographic method developed previously to determine SO2 at the 1 × 10⁻³ mg/l level in atmospheres saturated with water vapour, studies with aqueous solutions showed that headspace SO2 was directly proportional to molecular SOz in accordance with Henry's law.
Using the Henry's law constant for the S02/H20 system, determinations of molecular SOz were made on a white and a red wine and a fruit juice, each adjusted to five levels of pH to achieve different concentrations of molecular SO,. The results observed by the headspace method showed good agreement with those determined by a reference analytical method with white wine and fruit juice, but with red wine the reference method gave values which were more than 45% higher. Free SO2 was determined in a range of white wines by the headspace and reference methods, and the results showed high correlations.
The headspace method is rapid, precise and non-destructive. A major advantage is that, during the analysis, it does not change the complicated equilibria between SO, and its ionised species, hence complexes of SO2 and food constituents are not disturbed.     

Determination of sulphite in wine by coulometric titration.

A method for the determination of both free and bound S(IV) in white wine samples by coulometric titration with electrogenerated iodine is described, the S(IV) speciation being performed by extracting SO2 from samples acidified wiith hydrochloric acid. Titrations of samples treated with NaOH led to the total S(IV) concentration, the results being in agreement with the ones obtained by the distillation procedure as well as by using the classical Monier-Williams method. An average recovery of 97% was obtained for samples spiked with S(IV) in the range 0.4-1.2 mM, which demonstrated the validity of the proposed procedure. The repeatability was 1.3% and the limit of detection was estimated as 0.01 mM. Results from direct titrations of wine added to the electrochemical cell are reported, which give indications of the stability of adducts towards the reaction with iodine.     

多依果红心火龙果复合果酒发酵工艺优化及抗氧化活性分析

目的 通过响应面法优化多依果、红心火龙果复合果酒的发酵工艺，并对其抗氧化活性进行分析。方法 在单因素试验的基础上，以酒精度和感官评分“归一化”后的总评“归一值”为响应值进行响应面优化实验，并对发酵工艺优化所得的复合果酒进行1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl, DPPH)和2,2-联氮-二(3-乙基-苯并噻唑-6-磺酸)二铵盐[2''-azinobis-(3-ethylbenzthiazoline-6-sulphonate), ABTS]自由基清除率实验分析。结果 复合果酒发酵最佳工艺参数为：多依果、红心火龙果的质量比1:1、蔗糖添加量17%、二氧化硫添加量69 mg/kg、酵母接种量1.4%和初始pH 3.3，常温发酵7 d。在此最佳酿造工艺条件下，复合果酒为亮红色，酒精度达到11.3% vol，总黄酮含量为9.0 mg/kg，对DPPH和ABTS自由基的清除率最高可达89.75%和81.26%，总体抗氧化能力高于多依果汁而略低于维生素C。结论 多依果红心火龙果复合果酒口感谐调，并且较好地保留了水果的抗氧化活性成分，为多依果产业的发展提供了一定的理论支撑。     

Determination of pesticide residues in wine using gas chromatography with nitrogen-phosphorus and electron capture detection

A multiresidue method employing an extraction step with ethyl acetate followed by clean-up using an Isolute silica column and determination using gas chromatography with nitrogen-phosphorus and electron capture detection was validated for a wide range of pesticide residues in white and red wine. Recoveries between 70 and 110% and relative standard deviations below 20% were obtained for nearly all target analytes using matrix-matched standards. Limits of detection based on three times the signal-to-noise ratio were in the range 0.002-0.01 mg l^-1 for most compounds. The chromatograms were generally free of interference peaks resulting from co-extractives, although a few were noted for red wine with nitrogen-phosphorus detection. Ninety-two wine samples collected in Greece and Yugoslavia during 2 consecutive years were screened for residues of 84 pesticides, 71% of which were registered for use on vines in one or both countries. A total of 20% of the samples were obtained from field trials, and of these, one Greek wine contained iprodione 0.3 mg l^-1 and six Yugoslavian wines, for which vinclozolin had been added to the must as part of a different study, contained residues of this pesticide. No residues were detected in any of the other samples.     

橡木桶陈酿对红葡萄酒抗氧化性的影响

采用2,2'-联氮-双-3-乙基苯并噻唑啉-6-磺酸（ABTS）方法动态监测经橡木桶陈酿和未经橡木桶陈酿的红葡萄酒的反应过程,比较在测定其抗氧化活性的反应条件上的差异,从而确定适合检测的最佳反应条件,并分析橡木桶陈酿对红葡萄酒中酚类物质含量和抗氧化活性的影响。结果表明,ABTS方法测定经橡木桶陈酿的红葡萄酒抗氧化活性的最佳反应时间范围是240～280 min,最佳稀释比例范围为1∶100～2∶100,未经橡木桶陈酿的最佳反应时间范围是220～260 min,最佳稀释比例范围是3∶100～4∶100,此条件下各因素与自由基清除率的线性关系R2均＞0.999。试验证明,采用合适的检测方法测定不同陈酿方式酒的抗氧化活性有利于提高检测效率和准确性,经橡木桶陈酿过的红葡萄酒中的酚类物质含量和抗氧化活性更高。     

萃取分光光度法测定白砂糖中微量亚硫酸盐

提出了以甲醛溶液作吸收液,分光光度法测定白砂糖中微量亚硫酸盐的新方法。在酸性及过量的Cl-存在下,亚硫酸盐与碘酸钾和盐酸副玫瑰苯胺反应,生成易被异戊醇萃取的稳定的离子缔合物,在λ=560nm处,分光光度法测定。亚硫酸盐(以二氧化硫计)的线性范围为0～50μg,RSD≤3.4%,检出限为2μg。方法简便灵敏,试剂毒性小。结果与国标法相符。     

离子液体双水相萃取-HPLC分析红酒中的痕量氯酚类物质

建立亲水性离子液体[C_4MIM]BF_4与无机盐(NH_4)_2SO_4形成的离子液体双水相萃取富集红酒样品中6种痕量氯酚类物质的方法。通过考察离子液体和盐的种类、pH值、离子液体和盐质量分数对氯酚萃取率和富集倍数的影响,确定萃取氯酚的最优条件。在最佳萃取条件下,6种氯酚的线性范围为20~200μg/L,相关系数(R~2)达到0.999,6种氯酚的检出限在3.68~12.16μg/L之间。对实际红酒样品进行测定,加标回收率为87.73%~103.44%,相对标准偏差在0.33%~6.35%之间。该法操作简单、迅速、绿色且具有较高的萃取效率。     

Iron decreases the antioxidant capacity of red wine under conditions of in vitro digestion

The hypothesis that iron and phenolics interact in the lumen during digestion and, consequently, decrease the antioxidant capacity of phenolics, was investigated in vitro. Mixtures of red wine, iron, and three dietary factors that may reduce or chelate iron in the lumen, namely ascorbic acid, meat and casein, were subjected to a simulated gastrointestinal digestion. The process involved incubation of samples for 4.5 h at 37 °C, at different pHs, in the presence of peptic enzymes and fractionation of digests through a dialysis membrane. Antioxidant capacity (FRAP assay), iron concentration (ferrozine assay) and total phenolic content (Folin-Ciocalteau assay) were measured in the in vitro digests. Iron decreased the antioxidant capacity and the total phenolic concentration of red wine. Ascorbic acid increased, while meat and casein decreased, the antioxidant capacity of red wine. Based on these results, it was concluded that protein and iron interact with red wine phenolics during the in vitro digestion and decrease their antioxidant capacity, supporting the initial hypothesis.     

Determination of residues of propamocarb in wine by liquid chromatography-electrospray mass spectrometry with direct injection.

A simple, sensitive and reliable liquid chromatography-mass spectrometry method with direct injection of diluted samples is reported for the determination of propamocarb residues in wine. Red and white wines were diluted 40- and 20-fold, respectively, using water. Liquid chromatography was performed with a mobile-phase gradient and detection was by electrospray mass spectrometry in a positive ionization mode. Propamocarb was detected as the protonated molecular species at m/z 189. Using matrix-matched calibrant solutions, a calibrated range equivalent to 0.05-2.0 mg kg(-1) in red and white wines and limits of detection of 0.025 mg kg(-1) for white wine and of 0.05 mg kg(-1) for red wine (0.00125 microg ml(-1) of sample solution injected) were readily achievable. Recovery of propamocarb hydrochloride from wine spiked before dilution was in the range 91-115%. The chromatograms were free of isobaric interferences. In a small wine survey (72 samples), no residues of propamocarb were detected above 0.1 mg kg(-1).