腐植酸钠在复杂体系中抗氧化作用的研究

用偶氮氧化物AAPH热分解生成的自由基引发脂质氧化,通过硫氰酸铁法和硫代巴比妥酸反应物法检测脂质的氧化进程,研究腐植酸钠在用非离子表面活性剂Tween 20稳定的葵花油水包油乳状液模拟非均相食品体系和用大豆磷脂脂质体模拟非均相生物体系中的抗氧化活性。结果表明:在葵花油乳状液中0.20、0.50、1.00 mg/mL腐植酸钠和在大豆磷脂脂质体中0.016、0.040、0.080 mg/mL的腐植酸钠均具有抗氧化活性。     

核电站辅助电锅炉蒸汽钠离子质量分数控制技术探讨

高压喷射电极式电锅炉因其特殊的加热原理,出口蒸汽中会夹带一定量的钠离子,钠离子被带入二回路进而对蒸汽发生器产生损坏风险.通过对钠离子质量分数控制技术的分析,利用加药系统将给水的电导率自动控制在某一水平,同时利用汽水分离器进一步去除蒸汽中的钠离子,从而使电锅炉出口蒸汽的钠离子质量分数有效降低,达到高压喷射电极式电锅炉的蒸汽品质,满足核电站运行要求.     

高效液相色谱-飞行时间质谱测定白酒中甜蜜素

为建立高效液相色谱-四极杆-飞行时间质谱法(HPLC-Q-TOF/MS)测定白酒中甜蜜素的分析方法,试验详细优化了色谱质谱条件以及样品提取和净化条件。在该条件下,以高分辨多反应监测(MRM HR)模式扫描,外标法定量,实现了白酒中甜蜜素的精确定量分析。结果表明:甜蜜素在0~100 ng/mL范围内线性关系良好,相关系数r=0.9996。方法定量限为0.1 mg/kg,在3个添加水平下回收率为92.2%~98.9%,相对标准偏差(RSD)为2.6%~5.8%(n=6)。该方法简单、灵敏、准确性高、稳定性好,适用于白酒中甜蜜素的测定。     

两种天然防腐剂的抑菌作用及其在碳酸饮料中的应用

从乌梅、甘草中提取的天然防腐剂用于碳酸饮料中抑菌防腐，三个月后进行卫生指标检测并与苯甲酸钠防腐效果比较，结果显示均合格并可取代苯甲酸钠。     

Fabrication and Adsorption Behavior for Congo Red of Chitosan and Alginate Sponge

With chitosan and sodium alginate as the main raw material, the sponge adsorbents were satisfactorily prepared by freeze-drying and curing molding by CaCl₂. The structure of sponge was characterized by FTIR and SEM and its physical property was measured.

In addition, the different influences on absorbability of CR and analyzing the dynamics and thermodynamics of the adsorption process have been studied, thus it can provide theoretical foundation for the practical application of azo-dye wastewater treatment. The results are as follows: 0.10 g CTS/SA sponge adsorbent has the best absorbability on CR in the condition of 30°C, pH value is range from 6.00 to 7.00, and adsorption time is 45 min and stirring speed of 200 rpm. The adsorption kinetic followed the pseudo-second-order dynamics and it shows good relevance. The CR adsorption of CTS/SA sponge adsorbent can be described as Freundlich isotherm model (R2 > 0.94) and Langmuir isothermmodel (R2 > 0.99). The maximum adsorption capacity of CTS/SA sponges at 30°C can be obtained from the Langmuir model was 121.95 mg/g.     

NaCl在溶液中与表面活性剂AES的相互作用研究

通过对AES-NaCl复合体系的粘度、表面张力的研究,发现表面活性剂AES影响了氯化钠溶液物理化学性质,XPS表明,AES并没有参与氯化钠的结晶过程,没有改变氯化钠的晶体形态.     

树枝状结晶氯化钠的研究

实验主要是在氯化钠重结晶过程中加入某种添加剂，以改变氯化钠的晶形，变成树枝状。我们通过改变添加剂种类、添加剂质量、蒸发温度水平、饱和溶液温度水平四个条件来进行实验，重点讨论了使氯化钠结晶呈树枝状的添加剂种类及质量范围。通过实验得到使氯化钠结晶呈树枝状的添加剂种类及质量范围。通过实验得到使氯化钠结晶呈树枝状的添加剂有葡萄糖和163BR两种，且得到了一定的蒸发温度条件下这两种添加剂的质量范围，讨论了所形成的树枝状盐的部分性质，如吸湿情况、小晶体比率等。     

Effects of sodium caseinate‐ and milk protein concentrate‐based edible coatings on the postharvest quality of Bing cherries

Bing cherries were coated with sodium caseinate‐ or milk protein concentrate‐based edible coatings. Besides the proteins (100 g kg^?1), the coating formulations also included glycerol (about 300 g kg^?1 protein) and either beeswax or a stearic–palmitic acid blend at a concentration of 0, 100 or 300 g lipid phase kg^?1 of protein. All coatings, especially those containing 300 g kg^?1 stearic–palmitic acid blend, successfully reduced water loss of the fruits. The edible coatings had a beneficial effect on the sensory quality of the cherries, and there were significant (p < 0.05) effects of the coating treatments on soluble solids, titratable acidity and pH. Copyright © 2004 Society of Chemical Industry     

碳酸氢钾和氯化钠对烟草转化株烟碱转化的诱导作用

以白肋烟TN90高转化株为材料研究了无机盐处理烟株早期叶片对烟碱转化的诱导作用及机理。结果表明,1.2%的碳酸氢钾水溶液和1.2%的氯化钠水溶液均具有显著的诱导转化株早期叶片烟碱转化作用,碳酸钠效果较差。比较碳酸氢钾处理、氯化钠处理分别对常规TN90品种烟株转化株的早期鉴定结果和自然晾制后烟叶的烟碱转化率发现,采用2种无机盐鉴别出的转化株均包括了所有在自然晾制后产生的转化株,且还可鉴别出一些在正常晾制条件下不能有效鉴别的低转化株;早期测定的烟碱转化率一般高于烟叶自然晾制后的烟碱转化率,有利于提高鉴定的准确性和有效性。碳酸氢钾可显著促进叶片内源乙烯的释放,在处理溶液中添加10-4mol/LAVG抑制乙烯的合成可逆转碳酸氢钾对烟碱转化的诱导。     

Investigation on Sodium Benzoate Release from Poly(Butylene Adipate‐Co‐Terephthalate)/Organoclay/Sodium Benzoate Based Nanocomposite Film and Their Antimicrobial Activity

Polymeric nanocomposites embedded with nontoxic antimicrobial agents have recently gained potential industrial significance, mainly for their applicability to preserve food quality and ensure safety. In this study, a poly(butylene adipate‐co‐terephthalate) (PBAT)/organoclay (CMMT) based nanocomposite film doped with sodium benzoate (SB) as antimicrobial agent was prepared by a solution mixing process. A homogenous dispersion of organoclay (cetyltrimethylammonium‐modified montmorillonite [CMMT]) in PBAT matrix was observed by X‐ray diffraction and transmission electron microscopy. PBAT/CMMT nanocomposite film showed higher barrier properties against water and methanol vapor compared to the PBAT film. The release of SB from PBAT and its nanocomposite film was measured and the relevant data were fitted to the Weibull model. The higher values of Weibull's shape factor and scale parameter as corroborated by experimental findings indicated faster rate of SB release from PBAT/CMMT/SB nanocomposite film, when compared to the pristine PBAT film. Bacterial inhibition studies were accomplished against 2 food pathogenic bacteria, Bacillus subtilis and Staphylococcus aureus, by determining the zone of inhibition and corresponding growth profiles. Both bacterial inhibition studies and growth profiles established that PBAT/CMMT/SB demonstrated better antimicrobial activity than PBAT/SB film. Therefore, PBAT/CMMT/SB nanocomposite film can be used for food packaging application as it showed good barrier properties and antimicrobial activity against food pathogenic bacteria.