Acrylamide concentrations in grilled foodstuffs of Turkish kitchen by high performance liquid chromatography-mass spectrometry

For over ten years, there has been a considerable interest in determination of acrylamide in foodstuffs. It was known that both protein-rich and carbohydrates-rich foods cooked at high-temperatures can cause acrylamide formation. However, carbohydrates-rich foods such as potato chips and biscuit samples have been the common studied foods compared with protein-rich foods such as meat samples.In this study, determination of acrylamide in these two group foods was examined using HPLC-MS. For this purpose, firstly, the parameters that are thought to affect the response in the HPLC-MS analysis were optimized. The optimized conditions were found to be 0.3 ml min^{− 1} for flow rate of mobile phase, 40 µl for injection volume, 5 °C for column temperature and 70 V for fragmentor potential. The optimized method was applied for the determination of acrylamide levels in Turkish foodstuffs including grilled meat and chicken samples, potato chips, coffee and biscuit. The obtained concentrations for all studied foods were in the range of 20–250 µg kg^{− 1}. The results showed that acrylamide concentrations highly varied depending on the kind of food samples.     

Modifications of spectrophotometric methods for total phosphorus determination in meat samples

Spectrophotometric determination of total phosphorus in meat samples was modified using the molybdenum blue reaction with the following reducing agents: ascorbic acid (AA), hydrazine sulphate (HS), and mixture of hydroquinone and hydrazine sulphate (HHS). Proposed methods were validated by evaluation of statistical parameters such as: linearity, sensitivity, limits of detection (DL) and quantification (QL), precision, and accuracy, against the standard and malachite green (MG) modified procedures and by applying food certified materials. The values of within-day and between-days precision in meat samples for all tested reducing agents were better than 3.4 % and 4.2 %, respectively. The recoveries for CRMs analyses were between 92 % and 102.3 %. Obtained results suggest usefulness of the hydroquinone and hydrazine sulphate mixture in the determination of phosphorus ions.     

肉类食品中杂环胺检测的样品前处理及分析方法的研究进展

杂环胺是畜禽、鱼肉等食品在高温烹饪过程中生成的一类致癌、致突变化合物,高效、高选择性的样品前处理方法和高灵敏的分析方法是食品中痕量杂环胺分析检测的关键。本文综述了近年来溶剂萃取、固相萃取和固相微萃取等样品前处理方法,以及液相色谱、液相色谱-质谱等分析方法在食品中痕量杂环胺检测中的应用,结合现有研究对其发展趋势进行了展望。共引用文献51篇。     

同位素稀释质谱法测定猪肉中克伦特罗含量的国际比对APMP. QM-S6

建立了同位素稀释质谱法（IDMS）测定猪肉中克伦特罗含量的高准确度方法,并应用于亚太计量规划组织（Asia Pacific Metrology Programme,APMP）开展的国际比对“猪肉中克伦特罗含量测定”（APMP. QM-S6）。本研究考察了影响测定结果的喷雾电压值、流动相、色谱柱、提取条件、净化条件等主要因素并进行了优化,并对测定结果的不确定度进行了评定。结果表明:流动相组成以及pH值会影响克伦特罗的质谱响应以及最优的电喷雾电压值;样品溶剂会影响克伦特罗的色谱保留,甲醇溶剂会引起严重的溶剂效应,甚至导致峰分裂;克伦特罗易在固相萃取柱及亲水性滤膜上吸附,且吸附材料和滤膜上吸附的杂质有可能被洗脱,引起基质效应,干扰测定。提取效率最高的方法是采用0.1%（v/v）甲酸乙腈溶液为提取溶剂,通过匀浆进行提取。方法检出限（以信噪比大于3计）为0.2 μg/kg。比对样品中克伦特罗的含量为5.18 μg/kg±0.50 μg/kg（k=2）,比对结果与参考值等效一致,取得国际互认。该方法准确可靠,可为猪肉中克伦特罗的日常检测提供参考。     

QuEChERS结合超高效液相色谱-串联质谱法同时测定畜禽肉中44种食源性兴奋剂和6种孕激素

利用QuEChERS结合超高效液相色谱-串联质谱法建立了畜禽肉中44种兴奋剂和6种孕激素的检测技术。样品粉碎均质后加入内标,依次加入水和含0.5%乙酸的乙腈溶液振荡提取后,加入氯化钠和无水硫酸镁脱水离心,上清液采用PSA、C₁₈、中性氧化铝和无水硫酸镁分散固相萃取材料进行净化,净化液经氮气吹干,复溶后用超高效液相色谱-串联质谱仪测定。被测物采用ACQUITY BEH C₁₈(100 mm×2.1 mm, 1.7 μm)色谱柱,以0.1%甲酸-5 mmol/L乙酸铵水溶液和甲醇为流动相分离,在电喷雾正离子模式下,以多反应监测(MRM)方式采集,采用基质匹配标准曲线内标法定量分析。50个被测物包含6类化合物:β₂-激动剂类(19个)、β-阻断剂类(3个)、蛋白同化激素类(11个)、糖皮质激素类(8个)、利尿剂类(3个)、孕激素(6个)。所有被测物在各自的范围内线性关系良好,相关系数>0.99, β₂-激动剂类和β-阻断剂类的线性范围为0.1~20 μg/L,糖皮质激素类的线性范围为0.5~200 μg/L,蛋白同化激素类、孕激素类、利尿剂类的线性范围为0.2~50 μg/L。方法的定量限范围为0.1~0.4 μg/kg。在低、中、高3个浓度水平下的加标回收率试验中,50种目标化合物在鸡肉、猪肉、牛肉、羊肉中的平均回收率范围为50.3%~119.9%,相对标准偏差(RSD, n=6)范围为0.42%~15.1%。采用该法和国标方法(GB/T 21981-2008)同时对市售的9个肉样品(包括3个牛肉、3个猪肉、2个鸡肉、1个鸭肉)进行了比对检测,对检出的氢化可的松、可的松含量采用t检验进行统计学分析,结果表明,两种方法测得的数据没有显著性差异。采用该法测定了12个来自某养殖场的牛肉样品,结果共检出4种食源性兴奋剂,其中氢化可的松的含量范围为3.3~22.6 μg/kg,检出率为100%;可的松的含量范围为1.5~2.1 μg/kg,检出率为67%;雄烯二酮含量范围为0.7~1.2 μg/kg,检出率为17%;睾酮含量范围为0.6~1.5 μg/kg,检出率为42%。该法操作简单,准确灵敏,重复性好,适用于不同种类畜禽肉中食源性兴奋剂和孕激素的检测。     

Ultrasound-assisted thawing of frozen white yak meat: Effects on thawing rate,meat quality,nutrients, and microstructure

The objective of this study was to assess the effects of ultrasound-assisted thawing (UAT) on the quality of longissimus dorsi muscles from white yak meat (WYM). Ultrasonic power levels of 0, 200, 400, and 600 W (frequency of 20 kHz) were used to assist thawing. The thawing rate, meat quality, nutrient substances, volatile compounds, and microstructure of the WYM were determined. The results showed that ultrasonic thawing treatment reduced thawing times by 30.95–64.28% compared to control. The meat quality results revealed that the thawing loss, cooking loss, L* and b* values, and pH values decreased significantly while the a* value and cutting force increased significantly (P < 0.05) at the lower 400 W power level compared with the control. In addition, the free amino acid (FAA), mineral, and vitamin (especially water-soluble vitamins) contents were significantly (P < 0.05) increased with the ultrasound treatment. UAT significantly (P < 0.05) increased the content of volatile compounds, an effect that was highest in the UAT-400 W group. Partial least squares discrimination analysis (PLS-DA) showed that 2,4-heptadienal was critical in distinguishing the UAT groups from the control. When the ultrasonic power was lower than 400 W, the muscle cell area was significantly (P < 0.05) increased but decreased when higher power was used. Therefore, UAT improves the thawing efficiency and quality of frozen WYM, particularly at a power level of 400 W, and these findings have potential applications in the meat industry.     

畜禽肉及饲料中氟苯尼考残留免疫分析方法研究

针对动物源性食品及饲料中氟苯尼考的残留问题,通过抗原制备、动物免疫和细胞融合筛选,成功得到可高特异性识别氟苯尼考的单克隆抗体,并建立了氟苯尼考的间接竞争酶联免疫分析（icELISA）方法。经单因素实验优化策略,确定最佳反应条件为：包被抗原质量浓度0.05 μg/mL,抗体质量浓度为0.1 μg/mL,最佳药物、抗体和二抗稀释液均为磷酸缓冲液（PBST）,抗体稀释液吐温－20含量0.05%,竞争反应时间30 min,二抗质量浓度为0.167 μg/mL,二抗反应时间30 min。在该条件下,建立了氟苯尼考的icELISA 检测方法,其IC50为9.48 ng/mL,线性检测范围为1.75 ~ 51.36 ng/mL,检出限（LOD）达0.64 ng/mL,且与氯霉素等结构及功能类似物均无明显交叉反应,特异性良好。实际样品的加标回收率为88.1% ~ 107%,相对标准偏差（RSD）< 15%。将所建立的方法用于畜禽肉及饲料样品的检测,结果与HPLC－MS/MS判定结果一致,说明该方法适用于畜禽产品及饲料中氟苯尼考的残留检测。     

Aronia melanocarpa (Michx.) Elliot,Chaenomeles superba Lindl. and Cornus mas L. Leaf Extracts as Natural Preservatives for Pork Meat Products

The aim of this study was to investigate the possibility of using Aronia melanocarpa, Chaenomeles superba, and Cornus mas leaf extracts as natural preservatives for pork meat products. Pork sausages were stored in modified atmosphere packaging (MAP) (80% N₂ and 20% CO₂) at 4 °C for 29 days. The total psychrotrophic counts (TPC) were determined during the storage period, along with the numbers of Enterobacteriaceae and lactic acid bacteria (LAB). The extracts improved the microbial quality of the meat products but to a lesser extent than sodium nitrate (III). They reduced the amounts of Enterobacteriaceae and LAB. The A. melanocarpa leaf extract showed the strongest preservative effect. The bacterial biodiversity of the meat products was investigated based on high-throughput sequencing of the 16S rRNA gene. Two predominant bacteria phyla were identified, Proteobacteria and Firmucutes, mostly consisting of genera Photobacterium, Brochothrix, and Carnobacterium. The extracts also influenced microbial community in sausages decreasing or increasing bacterial relative abundance. The extracts significantly inhibited lipid oxidation and improved the water-holding capacity of the meat, with C. superba extract showing the strongest influence. In addition, A. melanocarpa and C. superba improved the redness (a*) of the sausages. The results of this study show that A. melanocarpa, C. superba, and C. mas leaf extracts can extend the shelf life of meat products stored in MAP at 4 °C.     

Development of an analytical method for the determination of the residues of four pyrethroids in meat by GC–ECD and confirmation by GC–MS

The development of an analytical method for the determination of four selected pyrethroid insecticides at residue level in beef meat is presented. Acetone and petroleum ether at 40-60 degrees C were chosen as extraction solvents. A two-step clean-up was performed using an Extrelut NT3-C(18) system followed by a Florisil column, with disposable, ready-to-use cartridges. Instrumental analysis was carried out on a gas chromatograph equipped with an electron capture detector (GC-ECD), using matrix-matched and internal standard calibration techniques. Confirmatory analysis by GC-MS was performed. Recoveries at the EU Maximum Residue Limit (MRL), 0.5 x MRL and 1.5 x MRL levels and the repeatabilities were widely satisfactory. The main advantage of the method was the reduction of analysis time as compared with previously published works. The applicability of the method to different matrices and pesticide classes will be investigated.     

Polarographic study on the presence of antibiotics in food

EU and Italian laws dealing for the presence of antibiotics or, more in general, drags in food established limits for different kinds of food. Suitable rules exist about the medical treatment of cattle in relation to the production of milk and meat. The adoption of a procedure to check the respect of the law limits is necessary. In this paper, the presence of different classes of antibiotics in milk and in homogenised meat is investigated. Generally, HPLC methods are applied for this purpose. In this paper, the application of polarographic analysis is studied and the results are compared with the chromatographic ones. The comparison is relative to all the phases of analysis including the sample preparation. The results show the advantage of the proposed procedure.