The effect of ripening and storage conditions on the distribution of tyramine,putrescine and cadaverine in Edam-cheese

The aim of the work was to describe the development of selected biogenic amines (histamine, tyramine, putrescine and cadaverine) in 4 layers of Dutch-type cheese (Edam-cheese) depending on 3 ripening/storage regimes during a 98-day period. Biogenic amines were analysed by means of ion-exchange chromatography. A further goal was to identify microbial sources of biogenic amines in the material analysed. Phenotype characterization and repetitive sequence-based PCR fingerprinting were used to identify the isolated bacteria. The highest content of tyramine, putrescine and cadaverine was determined in cheeses stored in a ripening cellar at a temperature of 10 °C during the whole observation period. Lower biogenic amines content was determined in samples which were moved into a cold storage device (5 °C) after 38 days of storage in a ripening cellar (10 °C). The lowest concentrations of biogenic amines were detected in cheeses which were moved into a cold storage device (5 °C) after 23 days of storage in a ripening cellar (10 °C). During the 98-day period, histamine was not detected in any of the regimes. Within the cheeses analysed, non-starter lactic acid bacteria Lactobacillus curvatus, Lactobacillus casei/paracasei and Lactobacillus plantarum were detected as the main producers of the biogenic amines tested. In starter bacteria Lactococcus lactis subsp. lactis and Lactococcus lactis subsp. cremoris the decarboxylase activity tested was not detected.     

常温固化大豆蛋白胶黏剂制备非结构集成材研究

研究利用豆粉、环氧类固化剂、水性弹性体乳液制备了一种常温固化大豆蛋白胶黏剂,并用于制备非结构集成材.结果表明,胶黏剂最优配方为18 g豆粉、82 g水、2.52 g环氧固化剂、36 g水性弹性体乳液,胶黏剂固体含量27.8％,适用期可达36 h;集成材优化制备工艺为涂胶量190～210 g/m2、加压时间3 h、加压压...     

撕裂性能增强型阻燃面料的制备与研究

以轶纶95聚酰亚胺双股纱线为原料、2/2和3/3方平组织为织物组织结构,制备防护服外层阻燃面料试样,并对其热防护性能、拉伸断裂强力和撕裂强力进行测试.结果表明,所制备的试样可满足防护服热防护性能的要求.2/2方平组织试样的经纬向拉伸断裂强力分别达1 337.3 N和1 252.8 N,经纬向撕裂强力性能显著提高(分别为146.3 N和133.9 N).3/3方平组织试样经纬向的撕裂强力更好,分别为195.6 N和177.7 N,可很好地满足阻燃防火面料的使用要求.方平组织阻燃面料有望在消防等领域发挥更大的作用.     

基于魔芋葡甘聚糖的微纤丝膜的制备及其抗菌性能研究

以魔芋葡甘聚糖(KGM)为原料,结合聚丙烯酰胺(PAAM),运用微流体纺丝技术制备KGM/PAAM微纤丝膜。研究KGM/PAAM溶胶的流变性。采用傅里叶红外光谱(FT-IR)、热重分析(TGA)、扫描电镜(SEM)、X射线光电子能谱(XRD)方法,表征微纤丝膜。将氧氟沙星颗粒负载于微纤丝膜中做抗菌试验。研究表明:(1)制备KGM/PAAM纺丝溶胶的最佳比例为:KGM∶PAAM(质量比)=1∶1;(2)制得的KGM/PAAM微纤丝膜形成有序的网状结构,纤维直径100μm,膜的热稳定性增强;(3)抗菌试验结果表明KGM/PAAM微纤丝膜具有良好的抑菌特性,对副溶血性弧菌有明显的抑菌效果,对大肠杆菌、金黄色葡萄球菌的抑菌圈直径分别为39.6,31.5 mm。本试验结果为开发新型食品包装材料,提供理论参考。     

基于运行误差估算的电能表准确性预计

极值理论在误差分析中有着重要应用,电能表准确性取决于误差偏大数据的分布,且超过某一阈值的超出量数据近似符合广义帕累托分布.文中根据台区内考核表与分表的量测数据估算分表运行误差,引入超阈值(Peak-Over-Threshold,POT)模型、讨论了阈值选取、广义帕累托分布模型拟合,并给出了广义帕累托分布的参数估计公式,...     

一种关联时滞大系统的状态反馈控制器的设计

基于线性矩阵不等式 (LMIs)方法 ,对具有N×N个任意未知常时滞的线性连续大系统 ,研究了关联矩阵在一般分解条件下的稳定化控制器的设计问题 ,给出了分散无记忆状态反馈控制器存在的充分条件 ,在此基础上 ,提出了具有较小反馈增益的分散状态反馈控制器的设计方法 ,最后用两个示例说明了本文方法具有较少的保守性     

基于PLC、HMI的火焰淬火机床系统的设计

为了提高采煤机链轮、刮板机链轮和大型齿轮等产品的淬火质量和效率,同时也为打破德国＂贝丁豪斯＂公司在国际上对火焰表面加热自动淬火技术的垄断,填补国内火焰自动淬火技术的空白,本文基于西门子可编程控制器（PLC）和人机界面触摸屏（HMI）,配套相关的组态软件,通过传感与通信技术,完成了火焰淬火机床系统自动化控制。HMI对火焰淬火全过程实现智能化可视操作及实时、历史信息监控。通过试验,达到了淬火硬度要求,加热时间较贝丁豪斯公司的产品缩短了近30%,淬火效率和质量有了很大的提高。     

Yellow pigment from gardenia fruit: structural identification and evaluation of cytotoxic activity in HepG2 cells by induction of apoptosis

Food Science and Biotechnology - The preparation process of yellow pigment (YP) from gardenia (Gardenia jasminoides) fruit was investigated, and the main components of YP were characterized by...     

棉针织布涂料染色工艺优化和应用

阐述了涂料染色的机理,介绍了涂料染色的工艺流程和要求,并对染色后织物进行了摩擦牢度和刷洗牢度的测试。探讨并分析了不同涂料、阳离子改性剂种类和用量、分散剂、黏合剂对涂料染色后织物的色深值、摩擦牢度和刷洗牢度的影响,并进行工艺优化,确定了大生产的工艺条件,指出了生产中的注意事项和一些病疵的解决办法。