液相色谱-串联质谱法测定祛痘化妆品中5种硝基咪唑类化合物

采用液相色谱-串联质谱(LC-MS/MS)法建立了测定祛痘化妆品中5种硝基咪唑类化合物(甲硝唑(MNZ)、洛硝哒唑(RNZ)、二甲硝咪唑(DMZ)、羟基甲硝唑(MNZOH)和1-甲基-5-硝基-2-羟甲基咪唑(HMMNI))的方法。样品经乙酸乙酯提取,采用Hypersil GOLD C_(18)色谱柱(2.1 mm×100 mm,3μm)分离,依次用丙酮、甲醇和V(氨水):V(乙腈)=5:95的混合溶液淋洗,采用LC-MS/MS在多反应监测(MRM)正离子模式下检测,基质外标法定量。结果表明:MNZ,RNZ和DMZ在0~50μg/L内呈良好线性关系,MNZOH和HMMNI在0~100μg/L内呈良好线性关系;5种硝基咪唑药物线性相关系数R~20.99;在试样中进行3个水平的加标回收实验,平均回收率为84.3%~115.0%,相对标准偏差(RSD)为1.66%~10.30%(n=6),适用于祛痘化妆品中硝基咪唑类化合物的检测和确证需要。     

液相色谱法测定饮料中合成着色剂的不确定度评定

目的：评估液相色谱测定法[1]对饮料中合成着色剂检测结果的影响。方法：根据测定方法建立数学模型,然后对不确定度的分量逐一进行计算,最终合成不确定度报告。结果：当k=2（95%置信概率）时：柠檬黄的含量为（12.1±0.6）μg/kg,苋菜红的含量为（9.96±0.48）μg/kg,靛蓝的含量为（10.0±0.5）μg/kg,胭脂红的含量为（9.98±0.46）μg/kg,日落黄的含量为（9.98±0.48）μg/kg,诱惑红的含量为（10.0±0.5）μg/kg,亮蓝的含量为（10.0±0.5）μg/kg,赤藓红的含量为（10.0±0.7）μg/kg。结论：评估对液相色谱法测定饮料中合成着色剂过程的质量控制及检测结果可信度的保证有实际意义。     

HPLC-MS/MS法同时测定美白化妆品中4-甲氧基水杨酸钾和苯乙基间苯二酚的含量

建立了HPLC-MS/MS法测定美白类化妆品中4-甲氧基水杨酸钾(4-MSK)和苯乙基间苯二酚(377)含量的方法.样品经过质量分数40％乙腈水溶液超声提取后,以甲醇/水(体积分数80％)为流动相洗脱,采用电喷雾负离子模式监测.结果表明,4-MSK和苯377在5～500 ng/mL浓度范围内与其响应值均呈良好线性关系,...     

卡拉胶/刺槐豆胶对猪肉糜品质的影响研究

亲水性胶体是用于改善肉制品品质的常用添加剂之一。本文通过在猪肉糜中添加卡拉胶和刺槐豆胶,研究两种胶体及其复配对猪肉糜色差、质构、水分活度的影响。研究结果表明,适宜比例的卡拉胶与刺槐豆胶的复配胶对猪肉糜品质的改善起到了一定的作用。卡拉胶/刺槐豆胶添加量为0.16%/0.24%时,猪肉糜品质较佳,硬度达到521.20±15.40,咀嚼性达到27.00±10.40,失水率降低至0.040±0.002。     

Comparison of fabric properties knitted by pin spacer compact and conventional compact yarns

This study examined the influence of pin spacer apparatus attachment on compact yarn quality parameters and physical properties of knitted fabrics manufactured using those 100% cotton compact yarns. Two groups of compact yarns were spun on regular compact yarn spinning frame with and without addition of pin spacer apparatus which is placed at the end of the drawing unit of regular compact yarn spinning frame. Totally eight yarns were spun at four different yarn number levels (Ne 24/1, Ne 30/1, Ne 36/1 and Ne 40/1) and two different spinning conditions (with and without pin spacer apparatus). Spun yarn types were then knitted on the industrial sized plain knitting machine. Knitted fabrics were used in the greige and dyed form to evaluate their bursting strength (kPa), dimensional change, abrasion related mass loss (%), pilling resistance, air permeability (mm/s) and colour difference. Test results were then statistically evaluated and influence of pin spacer attachment on yarn quality parameters and fabric properties was determined. In the frame of this experimental work, attachment of pin spacer apparatus improved compact yarn characteristics especially at yarn evenness, imperfection and hairiness values. In case of knitted fabric properties, it was found that pin spacer apparatus attached compact yarn utilization significantly improved air permeability properties of knitted fabrics.     

陶瓷色釉料在日用陶瓷生产应用中引起的缺陷研究

日用陶瓷在陶瓷行业中具有不可替代的地位。在日用陶瓷生产中,陶瓷色釉料又使日用陶瓷具有了与众不同的装饰效果,但是日用陶瓷在装饰过程中经常会出现一些缺陷,极大地降低了日用陶瓷的优质品率。本文重点阐述了日用陶瓷生产中陶瓷装饰所引起的主要缺陷,为有效地预防日用陶瓷装饰缺陷提供了很好的理论依据和实际操作的参考价值。     

Effect of vitamin E supplementation and diet on fatty acid composition and on meat colour and lipid oxidation of lamb leg steaks displayed in modified atmosphere packs

Groups of 8 lambs were allocated to one of five concentrate diets supplemented with all-rac-α-tocopheryl acetate containing 30 (C30), 60 (C60), 120 (C120), 250 (C250) and 500 (C500) mg/kg dry matter. Two other groups were fed grass silage and 400 g/day concentrate with 60 (S60) or 500 (S500) mg α-tocopheryl acetate/kg dry matter. Within diet, vitamin E level did not affect growth performance or carcass characteristics. Basal diet did not affect final live weight, conformation and fatness scores. M. semimembranosus from S lambs contained more α-tocopherol than that of C lambs on the same intake and by day 6 in MAP (75%O2/25%CO2) chroma and a* were below acceptable levels in C30 lambs. TBARS were higher in C30 and C60 muscle than in other treatments (P < 0.001) after 3 and 6 days display. Muscle fatty acid composition varied with basal diet but lipid oxidation depended more on vitamin E concentration with an initial concentration of 1.9 μg/g muscle preventing significant lipid oxidation.     

Physico-chemical, textural and structural characteristics of sous-vide cooked pork cheeks as affected by vacuum, cooking temperature, and cooking time

This paper describes the influence of different factors on sous-vide cooked pork. Pork cheeks were cooked at different combinations of temperature (60 °C or 80 °C), time (5 or 12 h) and vacuum (vacuum or air packaged). Weight losses were lower and moisture content higher in samples cooked for a shorter time (P = 0.054) and at a lower temperature (P < 0.001). Samples cooked at 60 °C showed more lightness (L*) and redness (a*) (P < 0.001). Lipid oxidation showed an interaction between cooking time and temperature (P = 0.007), with higher TBARs values for samples cooked for 12 h at 60 °C and lower for those cooked for 12 h at 80 °C. Samples cooked at 80 °C for 12 h showed lower (P < 0.05) values for most textural parameters than all the other types of samples. Vacuum packaging showed no influence on any of the studied variables. For the treatments evaluated, cooking temperature × time combination seems to be more important than vacuum packaging in the textural and colour parameters of pork cheeks.     

Physical changes and physiological characteristics of red and green peel during nectarine (cv. Hu018) maturation

BACKGROUND: The aim of this study was to determine physical changes in nectarine and distinctive physiological characteristics related to red and green peel under stresses occurring during fruit maturation, information on which is currently not available. RESULTS: Fruit firmness increased from 4 to 6 weeks after blooming (WAB) then decreased from 6 WAB until ripening. Anthocyanins in red and green peel during nectarine maturation were identified by high‐performance liquid chromatography as cyanidin 3‐glucoside together and, at a much lower level, cyanidin 3‐rutinoside. Cyanidins in red and green peel decreased from 4 to 8 WAB then increased from 8 to 12 WAB. Anthocyanin contents were positively correlated with PAL, POD, A*, MDA and O$_{2}^{\bullet-}$ values and inversely correlated with L* and B* values. Red and green peel during maturation could be separated by hierarchical cluster analysis of the tested data. CONCLUSION: This study has provided an overview of red and green peel characteristics during nectarine (cv. Hu018) maturation. Values of A*, anthocyanins, O$_{2}^{\bullet-}$ , MDA, PAL, PPO and POD in red peel were higher than those in green peel, while values of L*, B* and chroma in red peel were lower than those in green peel throughout fruit maturation. Copyright © 2011 Society of Chemical Industry     

宰后成熟过程中猪肉色泽变化研究

研究了正常未注水猪肉和注水猪肉在室温(25℃)和冷藏(4℃)条件下色泽(L*、a*、b*、ΔE*)的变化,在宰后成熟过程中(0,12,24,36,48,60,72 h)进行测定。结果表明:在试验时间范围内,正常肉和注水肉在室温和冷藏下L*值均下降(p<0.01);未注水肉红度值(a*)变化不明显,注水肉显著升高(p<0.05);未注水肉黄度值(b*)先上升后下降(p<0.01),而注水肉黄度值(b*)上升(p<0.01);ΔE*值无论注水与否室温下差异显著,冷藏不显著。