初中化学“溶液”的项目式教学*——白砂糖的梦想之路

以“白砂糖的梦想之路”为项目学习主题,呈现了初中化学“溶液”的项目教学案例。基于棒棒糖的制作过程开发了系列学习任务,有助于学生在真实的问题情境中发展核心素养和构建灵活的知识基础。     

糖果——化学甜蜜的一面——2014年美国国家化学周活动介绍

介绍2014年美国国家化学周--"糖果--化学甜蜜的一面",其中以实验活动作为重点,对科学阅读、未来化学家等活动板块作简要介绍。同时,针对各个活动予以简要评析,得出对我国化学教学的几点启示:(1)关注食品科学的发展;(2)注重科学阅读的融入;(3)体现实验设计的多元化;(4)重视非正式学习与正式学习的结合;(5)体现"化学服务于生活"的思想。     

Fast and simple method for the detection and quantification of 15 synthetic dyes in sauce,cotton candy,and pickle by liquid chromatography/tandem mass spectrometry

A simple and sensitive liquid chromatography/tandem mass spectrometry (LC-MS/MS) method for the simultaneous determination of 15 illegal dyes (Sudan I, Sudan II, Sudan III, Sudan IV, Sudan Red G, Sudan Orange G, Sudan Red 7B, Para Red, Dimethyl Yellow, Rahodamine B, Sudan Black B, Sudan Red B, Auramine O, Toluidine Red and Orange II) was developed and validated in sauce, cotton candy, and pickle. The samples were extracted with acetonitrile without the use of solid-phase extraction cartridges. Chromatographic separation was achieved on a Zorbax Eclipse Plus C18 column with a flow rate of 500 µL/min at 45 °C, using a gradient elution with A (10 mM ammonium formate in water with 0.1% formic acid) and B (10 mM ammonium formate in acetonitrile (ACN) with 0.1% formic acid) as the mobile phase. The detection was performed on a AB Sciex 6500 Qtrap mass analyzer under multiple reaction monitoring mode. Limit of detection, quantification, linearity, and precision were determined during the validation process. Recoveries ranged from 82% to 119% for all synthetic dyes, in exception to Orange II in cotton candy and pickle, where signal was suppressed due to high matrix interference and poor ionization. This method offers a simple and rapid approach to detect and quantify prohibited dyes in foodstuff that can be utilized in food contaminant laboratories.     

糖果厂模型的最优化搜索方法

讨论了用两台装置搜索两个坏硬币的糖果厂模型 C2 ,给出了一个测试过程 t,使之理论上的最优过程最多相差一次测试 .     

荧光法测定糖果中的总糖含量

合成了带有荧光基团的分子探针,光谱显示探针对糖类物质具有较强的荧光响应.通过条件优化,选取328 nm作为荧光激发波长,p H 10.0的缓冲溶液为最佳测定介质,当测试溶液中葡萄糖浓度为0.05~1 mmol/L时,显示良好的响应线性.方法对果糖中总糖含量测定的检测限为6.2μmol/L,回收率在76.4%~90.0%,RSD达到3.18%.     

Fabrication and characterization of a cotton candy like surface with superhydrophobicity

Superhydrophobic thin films were prepared on glass by air-brushing the in situ polymerization compositions of D₅/SiO₂. The wettability and morphology were investigated by contact angle measurement and scanning electron microscopy. The most superhydrophobic samples prepared had a static water contact angle of 157° for a 5 μl droplet and a sliding angle of ∼1° for 10 μl droplet. Thermal stability analysis showed that the surface maintained superhydrophobic at temperature up to 450 °C. Air trapping and capillary force on superhydrophobic behavior were evaluated.     

Effect of d-psicose substitution on gelatin based soft candies: A TD-NMR study

Confectionary gels are considered as composite gel systems composed of high amount of sugar and gelling agent such as gelatin or starch. d -Psicose is classified as a type of rare sugar, which is a C-3 epimer of fructose and has 70% of the sweetness of sucrose with a caloric value of 0.39 kcal/g. Utilization of d -psicose in food products is gaining particular interest due to its low caloric value. In this study, gelatin-based soft candies were formulated, and the effect of d -psicose substitution was explored on the quality of the products. For characterization of the soft candies, moisture content, water activity, color, hardness, and glass transition temperature of samples were investigated. X-ray diffraction analysis was also performed to explain the crystallization tendency of jelly candies. Results showed that, the softest sample with the highest moisture content and the smallest crystallization tendency was the sample that included the highest amount of d -psicose. Time domain (TD) NMR relaxometry experiments were also conducted on gel samples, and three distinct proton populations were observed in the relaxation spectrum for all formulations. Spin–lattice relaxation times obtained through monoexponential fitting (T₁) were also obtained to explain some quality parameters.     

饮料及糖果中亮蓝、苋菜红及柠檬黄的简便定量分析EI北大核心CSCD

采用定性与定量相结合,建立了测定饮料及糖果中共存色素亮蓝(BRIB)、苋菜红(AMA)及柠檬黄(TAR)的简便吸收光谱法。BRIB,AMA及TAR在pH 3.50 Tris-HCl条件下,分别与乙基绿反应生成离子缔合物,产生新的特征吸收光谱。定量测定波长分别为588 nm(BRIB体系)、532 nm(AMA体系)和426 nm(TAR体系),表观摩尔吸光系数(κ)分别为4.24×10^(4)L/(mol·cm)(BRIB体系)、3.35×10^(4)L/(mol·cm)(AMA体系)和2.64×10^(4)L/(mol·cm)(TAR体系),线性范围分别为0.05~18.8 mg/L(BRIB体系)、0.05~13.3 mg/L(AMA体系)和0.05~11.7 mg/L(TAR体系),检出限分别为35μg/L(BRIB体系)、27μg/L(AMA体系)和30μg/L(TAR体系),定量限分别为0.61 mg/kg(BRIB体系)、0.47 mg/kg(AMA体系)和0.52 mg/kg(TAR体系)。该方法用于市售饮料及糖果中共存BRIB,AMA及TAR的测定,加标回收率为97.8%~103%(BRIB体系)、97.9%~102%(AMA体系)和98.1%~103%(TAR体系),相对标准偏差分别为2.0%~2.8%(BRIB体系),1.2%~2.6%(AMA体系)和1.6%~2.6%(TAR体系)。     

“糖果厂”模型的最优化搜索方法

讨论了用两台装置搜索两个不合格品的“糖果厂”模型Ｃ２：ΦΦ｜Φｘ,Φｙ,Φｘｙ,ｙｘ｜ｘΦ,ｙΦ,ｘｙΦ,ｘｙ,给出了一个测试过程ｔ,其与理论上的最优测试过程至多相差一次测试,从而较好地解决了文［１］提出的问题     

NMR relaxometry study of gelatin based low-calorie soft candies

ABSTRACT

Soft candies are popular confectionery products. The most significant concern on the consumption of these products is the high amount of sugar and thus the high calories. The use of low-calorie sweeteners is a desirable trend in confectionery research. In this study, gelatin-based soft candies were formulated by using different sweeteners and their characterisation was performed using high and low field nuclear magnetic resonance (NMR) relaxation experiments. To complement the information obtained by NMR experiments, moisture content, water activity, texture analysis and differential scanning calorimeter experiments were also conducted. T₁ and T₂ relaxation times were measured at both low and high fields and also temperature-dependent measurements were conducted at the high field system. Candies were formulated by substitution of sucrose with maltitol, isomalt and stevia at 30%, 50% and 70% ratios. Significant difference was observed on relaxation times. T₁ values were best described by a mono-exponential model, whereas for T₂ relaxation times a bi-exponential model gave better results at both fields.