高效液相色谱-串联质谱法测定蜂蜜中的甲基乙二醛

目的建立一种蜂蜜中甲基乙二醛的高效液相色谱-串联质谱法的测定方法。方法采用高效液相色谱-串联质谱法测定蜂蜜中的甲基乙二醛,蜂蜜样品直接用水提取,2,3-二氨基萘为衍生化试剂,常温下避光反应8 h以上,以0.1%甲酸水-乙腈为流动相,色谱柱分离,通过质谱电喷雾离子源,正离子模式进行定性和定量分析。结果甲基乙二醛的线性范围为0.05~1.0μg/m L,相关系数0.999以上,线性良好,检出限为0.2 mg/kg,定量限为0.5 mg/kg。回收率92.4%~97.5%之间,相对标准偏差(relative standard deviation,RSD)均小于1.3%。结论该方法的精密度、回收率均满足要求,适用于大批量样品的快速检测。     

Correlations of sensory parameters with physicochemical characteristics of Argentinean honeys by multivariate statistical techniques

Honey acceptability is mainly determined by its colour, crystallisation degree and aroma. In the present work, the sensory characteristics and physicochemical parameters of Argentinean honeys from different ecoregions were analysed. Moisture content, Pfund colour, diastase activity, hydroxymethylfurfural content, electrical conductivity, sugar profile and volatile compounds were analytically determined in honey samples, while sensory characteristics (crystal size, fluency score, sweetness, persistence, granularity, crystallisation, colour intensity and aroma) were evaluated by a trained panel. Significant correlations were found between honey crystallisation degree and hydroxymethylfurfural content and diastase activity (P ≤ 0.05). It could be confirmed that honey crystallisation interferes with the visual perception of colour. Floral, fresh fruit, ripe fruit, balsamic and wood aromas could be successfully linked to honey volatile profile (P ≤ 0.05). These results demonstrate that the parameters that could best guarantee the consumers’ preference can be successfully associated with the chemical composition of honey by multivariate statistical analysis.     

元素分析-同位素质谱法鉴定麦卢卡蜂蜜中碳-4植物糖掺假

目的建立元素分析-同位素质谱法(elementanalyzerstableisotopeproportionalmassspectrometry,EA-IRMS)鉴定麦卢卡蜂蜜中碳-4植物糖掺假的新方法。方法样品经前处理后,利用元素分析-同位素质谱仪测定蜂蜜的碳同位素比值δ~(13)C_H、蜂蜜中总蛋白质的碳同位素比值δ~(13)C_P、蜂蜜中花粉的碳同位素比值δ~(13)C_F。用麦卢卡蜂蜜中δ~(13)C值更为稳定的δ~(13)C_F值为标准,δ~(13)C_H值与其进行比较,参照GB/T 18932.1-2002《蜂蜜中碳-4植物糖含量测定方法稳定碳同位素比率法》计算方式,来建立新的计算麦卢卡蜂蜜中碳-4植物糖含量X(%)的计算方式。结果对纯正麦卢卡蜂蜜提出:0X(%)7,δ~(13)C_Fδ~(13)C_Pδ~(13)C_H。新方法利用测定麦卢卡蜂蜜中δ~(13)C值更为稳定的δ~(13)C_F值,代替了原有的比较不稳定的δ~(13)C_P为标准,解决了原方法对于麦卢卡蜂蜜中碳-4植物糖检测的假阳性问题。结论本方法显示出较好的准确度,大大提高了掺假检测的能力。     

利用非糖物质快速鉴别单花蜂蜜

本文利用非糖物质快速鉴别四种常见的单花蜂蜜(枸杞蜂蜜、荆条蜂蜜、枣花蜂蜜和洋槐蜂蜜)。利用固相萃取除糖提取蜂蜜非糖物质,并用高效液相色谱(HPLC)结合化学计量学进行蜂蜜花源的判定。发现了四种单花蜂蜜的非糖特征标志物。芦丁、丁香酸甲酯、阿魏酸的含量在四种蜂蜜中差异最大。对羟基苯甲酸和脱落酸在枸杞蜂蜜中平均含量分别为0.59μg/g和0.42μg/g,可作为枸杞蜂蜜的花源标志物;对香豆酸和肉桂酸在荆条蜂蜜中平均含量为0.08μg/g和0.05μg/g,可作为荆条蜂蜜的潜在花源标志物;阿魏酸、异阿魏酸是枣花蜂蜜的特征标志物,平均含量分别为0.40μg/g和0.76μg/g;洋槐蜂蜜的特征标志物是芦丁和丁香酸甲酯,平均含量为0.08μg/g和0.14μg/g。利用高效液相色谱指纹图谱结合化学计量学方法(主成分分析和判别分析),四种单花蜂蜜依据其花源被成功区分。本研究对蜂蜜真实性判定有重要参考价值,为后续蜂蜜真伪鉴别奠定基础。     

海南无刺蜂蜂蜜中多酚类物质成分分析及其抗氧化、抗炎活性评价

以海南无刺蜂蜂蜜及其多酚类提取物为研究对象,分别测定分析无刺蜂蜂蜜的理化成分和多酚物质,研究其抗氧化和抗炎活性。通过液相色谱-串联四极杆飞行时间质谱分析多酚类成分,并采用福林-酚法和硝酸铝比色法测定多酚类提取物总酚酸和总黄酮含量。采用1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基、2,2’-联氮-双-(3-乙基苯并噻唑啉-6-磺酸)二铵盐自由基(2,2’-azinobis-(3-ethylbenzthiazoline-6-sulphonate)radical,ABTS~+·)清除实验和铁离子还原力实验评价多酚类提取物的体外抗氧化活性,并采用细菌脂多糖(lipopolysaccharides,LPS)诱导的RAW 264.7细胞体外炎症模型,探究多酚类提取物的抗炎活性。结果显示,无刺蜂蜂蜜水分质量分数为(26.3±0.1)%,p H 3.7±0.2,蛋白质含量为(628.2±9.0)mg/kg,淀粉酶值为(19.6±0.2)m L/(g·h),总糖质量分数为(46.7±6.0)%,包括果糖(21.0±3.7)%、葡萄糖(24.9±2.2)%、蔗糖(0.8±0.1)%;多酚类提取物的总酚酸和总黄酮含量分别为(96.6±0.4)μg CAE/g和(16.1±0.3)μg QE/g;多酚类提取物的DPPH自由基和ABTS~+·清除能力IC50值分别为(435.1±0.4)、(423.0±0.3)μg/m L,铁离子还原力为(0.6±0.02)μmol Trolox/g;在体外抗炎实验中,多酚类提取物能显著抑制由LPS诱导的RAW 264.7细胞NO的释放,并显著抑制促炎症基因i NOS、IL-1β、IL-6和MCP-1的表达,显著增强抗氧化基因HO-1的表达,并呈剂量相关性。综上所述,海南无刺蜂蜂蜜营养成分丰富,富含酚酸和黄酮类物质,且具有很强的抗氧化和抗炎能力,具有良好的开发利用价值。     

超高效液相色谱-质谱串联法测定蜂蜜中喹诺酮类药物残留

目的建立超高效液相色谱-质谱串联法测定蜂蜜中喹诺酮类药物残留的分析方法。方法分析采用Thermo Fisher Gold Hypersil柱(50 mm×2.1 mm, 1.9μm);流动相A为甲醇,流动相B为0.1%甲酸水溶液,流动相流速:0.2 mL/min,柱温:35℃,梯度洗脱;电喷雾离子源正离子扫描(electron spray ionization, ESI+),选择反应监测模式检测(selected reaction monitoring,SRM)。结果 6种喹诺酮类药物在各自范围内线性关系良好,相关系数r均大于0.998,平均加样回收率在82.47%～105.06%,相对标准偏差(relative standard deviation,RSD)均小于5.62%。12批次样品中有2批次检出诺氟沙星。结论该方法前处理简单、快捷、测定灵敏度高、结果准确,可适用于蜂蜜中喹诺酮类药物残留量的检测,为监督检验提供了更为简单准确的方法。     

液相色谱-串联质谱法同时测定蜂蜜中的林可霉素、甲硝唑和氯霉素

目的建立液相色谱-串联质谱法同时检测蜂蜜中林可霉素、甲硝唑和氯霉素含量的分析方法。方法蜂蜜样品加水溶解后,过聚合物基质反相固相萃取柱净化,经5%甲醇水溶液淋洗小柱,再用70%甲醇水溶液洗脱目标化合物。采用0.1%甲酸水溶液和乙腈作为液相色谱流动相进行梯度洗脱。经多反应监测模式,在正离子电离模式下测定甲硝唑和林可霉素,在负离子电离模式下测定氯霉素。同位素稀释内标法定量。结果本方法在10 min内通过质谱正负离子电离模式切换对林可霉素、甲硝唑和氯霉素进行同时测定。3个目标化合物在0.25、5和25μg/kg添加水平的回收率为91.0%～107.1%,相对标准偏差小于11.9%(n=6),林可霉素、甲硝唑和氯霉素的方法定量限分别为0.20、0.14和0.20μg/kg。结论本方法易于操作,灵敏度和重现性良好,适用于监督抽检和风险监测等大批量检测工作。     

Geographical discrimination of honeys through antioxidant capacity,mineral content and colour

The assessment of geographical origin of honey is economically important for producers and consumers as every region may present particular quality characteristics. In this study, honeys from the seven different regions of Buenos Aires province (Argentina) were characterised by their antioxidant capacity (DPPH, FRAP), total phenolic content (TPC), mineral composition, colour and ash. Honeys showed significant differences among their antioxidant capacity (DPPH), ash, colour and mineral content (P ≤ 0.05). Besides, a good antioxidant activity and low amounts of Cu and Zn (<1.0–1.5 and 0.7–1.8 mg kg^?1, respectively) were found in the samples. Significant Pearson's correlations (P ≤ 0.05) among the different parameters were found. Moreover, the linear discriminant analysis allowed the classification of honeys in their original groups with a prediction success of 98%. The present results suggest that honeys could be correctly classified by their geographical origin through their TPC, colour, ash and mineral concentrations.     

Optimisation of process parameters to develop nutritionally rich spray‐dried honey powder with vitamin C content and antioxidant properties

The aim of present research was to optimise the conditions to develop nutritionally rich honey powder using honey, whey protein concentrate (WPC), aonla (Emblica officinalis. Gaertn) and basil (Ocimum sanctum) extract with the help of co‐current spray drier. Response surface methodology was applied to study the effects of inlet temperature (160–180 °C), whey protein concentrate (25–35%), feed flow rate (0.08–0.13 mL s^?1), aonla extract (6–8%) and basil extract (6–8%) on product responses, viz. bulk density, hygroscopicity, antioxidant activity (AOA), total phenolic content (TPC) and vitamin C. Statistical analysis revealed that independent variables significantly affected all the responses. The results demonstrated that increasing inlet temperature lowered the bulk density, hygroscopicity, AOA, TPC and vitamin C, whereas addition of aonla extract and basil extract increased the AOA (82.73%), TPC (63.27%) and total vitamin C content (94.89%) as these functional compounds were encapsulated by WPC. Similarly, with increase in feed flow rate and WPC, there was increase and decrease in the bulk density and hygroscopicity, respectively. The recommended optimum spray‐drying conditions were inlet air temperature (170 °C), feed rate (0.11 mL s^?1), whey protein concentrate (35%), aonla (8%) and basil extract (6%).