高效毛细管电泳 间接紫外吸收检测法测定食品中的氨基酸

研究了鸟氨酸、脯氨酸和谷氨酰胺的高效毛细管电泳 间接紫外吸收检测的特征。以5　mmol/L 对氨基苯磺酸钠 10 mmol/L KH2PO4(pH 11.5)为运行缓冲液,在分离电压12 kV下,于11 min实现了上述3种氨基酸的基线分离,迁移时间和峰高的相对标准偏差分别小于0.72%和2.0%,检测限分别为6.78,8.71,7.86 mg/L。应用该法测定食品中的氨基酸及各氨基酸在样品中的加标回收率,3种氨基酸的加标回收率为96.8%~104%。     

State-of-the-art advantages and drawbacks on the application of vibrational spectroscopy to monitor alcoholic fermentation (beer and wine)

Wine production is directly linked with the monitoring of the fermentation and critical fermentation parameters such as total sugars and ethanol concentration, and the production of CO₂. Commonly used sensors applied in the wine industry to monitor wine fermentation are those based in single sensors such as temperature probes and manual density measurements (e.g., specific gravity). These sensors are used several times per day and have been the only source of data available from which the stage of the fermentation and the evolution rate could be monitored. Therefore, an ideal method for fermentation process control and monitoring should enable a direct rapid, precise, and accurate determination of several target compounds, with minimal or no sample preparation and reagent consumption. This article reviews the state of the art in the applications of both near and mid infrared spectroscopy to monitor beer and wine fermentation.     

Analysis of aflatoxins in nonalcoholic beer using liquid–liquid extraction and ultraperformance LC‐MS/MS

Aflatoxins AFB1, AFB2, AFG1, and AFG2 are toxic secondary metabolites produced by Aspergillus flavus and Aspergillus parasiticus and posses a potential threat to food safety. In the present work, liquid–liquid extraction and ultraperformance LC‐MS/MS method has been applied for the determination of four naturally occurring aflatoxins AFB1, AFB2, AFG1, and AFG2 in nonalcoholic beer. Aflatoxins extraction from nonalcoholic beer was carried out using liquid–liquid extraction procedure. The effects of solvent‐types were studied to obtain maximum recovery of the target analytes with minimum contamination. Among different solvents, the aflatoxins extraction was best achieved using ethyl acetate. The obtained recoveries were ranged from 85 to 96% with good quality parameters: LOD values between 0.001 and 0.003 ng/mL, linearity of the calibration curve (r² > 0.999), and repeatability (run‐to‐run) and reproducibility (day‐to‐day) precisions with RSDs lower than 5% (n = 5) achieved at 0.50 ng/mL concentration. The optimized liquid–liquid extraction in combination with ultraperformance LC‐MS/MS was applied successfully to the analysis of AFB1, AFB2, AFG1, and AFG2 aflatoxins in 11 nonalcoholic beers and were detected up to 15.31 ng/L in some of the samples.     

替代模板分子印迹聚合物的制备及其用于人尿、牛血清和啤酒中7种双酚类物质的选择性固相萃取

以酚酞(PP)为替代模板,采用本体聚合法制备了选择性识别7种双酚类物质(BPs)的分子印迹聚合物(MIP)。将制备的PP-MIP用作固相萃取(SPE)填料,成功应用于人尿、牛血清和啤酒样品中7种BPs的分离净化。建立了同时测定人尿、牛血清和啤酒样品中的7种BPs的MIP-SPE-HPLC分析方法。3种样品中7种BPs的方法检出限范围均为1.2~2.0 μg/L。结果表明,7种BPs在0.02~2 mg/L范围内线性关系良好,相关系数(r)大于0.9998;空白样品中加标水平为100和500 μg/L的回收率范围为90.1%~107.1%,相对标准偏差(RSD)不高于8.1%。该方法简便、准确、灵敏、可靠,可用于人尿、牛血清和啤酒中7种BPs的快速检测。     

水溶性酵母β-葡聚糖的制备及免疫活性评价

以废啤酒酵母(Saccharomyces cerevisiae)为原料, 通过稀酸与稀碱处理获得碱不溶性酵母β-葡聚糖(SCBG), 进而在低温强碱/脲水溶液中氧化降解得到水溶性酵母β-葡聚糖(SCBGs), 再经层析柱分离得到4个纯化组分(SCBGs-0-1, SCBGs-1-1, SCBGs-1-2和SCBGs-1-3). 利用高效液相色谱、 高效凝胶渗透色谱与十八角激光光散射联用技术、 核磁共振波谱及与刚果红结合实验等对4个纯化组分的单糖组成、 分子量及化学结构进行了分析, 并通过其对巨噬细胞RAW 264.7吞噬能力及NO和TNF-α释放量的影响评价其免疫活性. 研究结果表明, 各纯化组分均由单一的葡萄糖构成, 是一类以β-1,3-D-葡聚糖为主链且在主链C₆位羟基上具有分支的β-1,3/1,6-葡聚糖,其分子量依次为198000, 960000, 270000和18700, 除SCBGs-1-3外, 其余3个组分均具有超螺旋结构, 且4个组分均能显著增强RAW 264.7的免疫活性.     

分散微固相萃取-超高效液相色谱-高分辨质谱法测定葡萄酒和啤酒中多菌灵和噻菌灵

基于强阳离子交换填料（PCX）,采用分散微固相萃取前处理技术,结合超高效液相色谱-四级杆-静电场轨道阱高分辨质谱联用技术,建立了一种快速测定葡萄酒和啤酒中多菌灵和噻菌灵的方法。通过对分散微固相萃取技术中PCX用量、洗脱溶剂中氨水的体积分数、乙腈的体积分数和洗脱体积的优化,实现了样品中多菌灵和噻菌灵的有效净化。经BEH C₁₈（50 mm×2.1 mm,1.7 μm）色谱柱分离后,通过静电场轨道阱质谱靶向单一离子监测（targeted single ion monitoring,tSIM）结合数据依赖的二级质谱扫描（data dependent tandem mass spectrometry,ddMS²）采集模式进行定性定量分析。待测物多菌灵和噻菌灵在一定浓度范围内均呈良好线性关系,相关系数R²≥0.9999。在葡萄酒和啤酒基质中,多菌灵和噻菌灵的检出限分别为0.02和0.01 μg/L,定量限分别为0.06和0.03 μg/L。在0.1、1.0、100 μg/L 3个添加水平下,多菌灵和噻菌灵的加标回收率分别为95.6%~110.2%和87.5%~102.8%,日内精密度（RSD_r）分别为1.8%~5.2%和1.3%~4.8%,日间精密度（RSD_R）分别为4.3%~8.7%和4.8%~9.4%。该方法快速、简便、灵敏,适用于葡萄酒和啤酒中多菌灵和噻菌灵的残留检测。     

A Simple Method for Evaluating the Bioactive Phenolic Compounds’ Presence in Brazilian Craft Beers

There are a significant number of analytical methodologies employing different techniques to determine phenolic compounds in beverages. However, these methods employ long sample preparation processes and great time consumption. The aim of this paper was the development of a simple method for evaluating the phenolic compounds’ presence in Brazilian craft beers without a previous extraction step. Catechin, caffeic acid, epicatechin, p-coumaric acid, hydrated rutin, trans-ferulic acid, quercetin, kaempferol, and formononetin were analyzed in fifteen different craft beers. The method showed good linearity (R² ≥ 0.9966). The limit of detection ranged from 0.08 to 0.83 mg L⁻¹, and limits of quantification were between 0.27 and 2.78 mg L⁻¹. The method showed a satisfactory precision (RSD ≤ 16.2%). A good accuracy was obtained by the proposed method for all phenolic compounds in craft beer (68.6% ˂ accuracy ˂ 112%). Catechin showed higher concentrations (up to 124.8 mg L⁻¹) in the samples, followed by epicatechin (up to 51.1 mg L⁻¹) and caffeic acid (up to 8.13 mg L⁻¹). Rutin and formononetin were observed in all analyzed samples (0.52 mg L⁻¹ to 2.40 mg L⁻¹), and kaempferol was less present in the samples. The presence of plant origin products was determinant for the occurrence of the highest concentrations of phenolic compounds in Brazilian craft beers.     

固相萃取-高效液相色谱法测定啤酒中的黄腐酚

采用Waters Sep-Pak C18固相萃取小柱对啤酒样品进行分离纯化,建立了啤酒中黄腐酚的固相萃取-高效液相色谱检测方法。选用色谱柱Zorbax Eclipse XDB-C18柱(250 mm×4.6 mm,5 μm),以甲醇和0.1%甲酸水溶液为流动相进行梯度洗脱,柱温25 ℃,流速0.4 mL/min,检测波长370 nm。在此条件下,黄腐酚分离良好且无杂质峰干扰,在0.5～500 μg/L的范围内线性关系良好(r21),在高、中、低浓度下的加标回收率为91.21%～95.58%,相对标准偏差小于2%。方法的检出限为0.24 μg/L,定量限为0.80 μg/L。该方法简便快速、结果准确、重现性好,是检测啤酒中黄腐酚含量的有效方法。     

GC-MS法检测生物检材中的白酒和啤酒

用GC-MS法分析白酒和啤酒中的成分,统计出白酒、啤酒的各自特征成分并加以比较。对添加不同量白酒、啤酒及白酒与啤酒混合物的胃内容物进行检验,对饮用不同量白酒、啤酒及白酒与啤酒混合物的人员分别采集血样进行检验,统计并总结出胃内容物及血液中白酒、啤酒的区分检验方法。当生物检材中乙醇含量大于0．3mg／mL时,利用该方法可以区分检材中的白酒和啤酒。     

固相萃取-气质联用法测定啤酒中9种有机磷农药残留

建立啤酒中9种有机磷农药的固相萃取-气质联用分析方法.采用C18固相萃取小柱对啤酒中的有机磷农药进行提取、净化,用乙酸乙酯洗脱后供气相色谱-质谱分析,用基质匹配标准校正方法补偿基质效应.当添加浓度为50 μg/kg和100μg/kg时,平均回收率为80.3%～95.0%;测量结果的相对标准偏差为1.97%～8.28%(n=6);方法的检出限为1.20～15.3μg/kg.该方法可用于啤酒中痕量有机磷农药残留的测定.