Grain boundary segregation and its influences on ionic conduction properties of scandia doped zirconia electrolytes

Solid oxide fuel cell is a promising energy conversion system which converts chemical energy into electrical energy directly. Electrolyte is the key component and determines the working temperature. In this paper,ceria and scandia co-doped zirconia electrolytes sintered from 1300 to 1550 ℃ were chosen as research objects. Scanning electron microscopy, X-ray diffraction and transmission electron microscopy were performed to characterize the ceramic samples. The effects of grain size and grain boundary element segregation on the electrical conductivity were focused. Electrochemical impedance spectroscopy was used to calculate the bulk, grain boundary and specific grain boundary conductivity. Results show that the bulk and grain boundary ionic conductivity increases with the increasing grain size.However, the specific grain boundary conductivity decreases with the increasing grain size. This is explained by the fact that Sc~(3+) is segregated at the grain boundary, which leads to higher oxygen vacancy concentration when sintered at lower temperature.     

鸡脂肪热氧化与风味的关系

以鸡脂肪为原料,测定脂肪在烹调温度下氧化过程中的羰基值,过氧化值,酸值随加热时间的变化,并以这些测定值为监控指标对不同时间的氧化产物作感官评价。研究结果表明,鸡脂肪氧化能产生较好风味感,并且风味感产生的最佳时间为10 h,此时羰基值为22.5 meq/kg。     

白胡椒和肉桂对冰鲜鸡的保鲜效果研究

以冰鲜鸡的菌落总数、挥发性盐基氮、pH、感官质量作为保鲜效果评价指标,研究了不同浓度的白胡椒和肉桂醇溶提取液处理冰鲜鸡在0～4℃贮藏的保鲜效果。结果表明,白胡椒和肉桂的醇溶提取液在冰鲜鸡中有显著的保鲜作用,其中1.0%白胡椒和1.0%肉桂保鲜效果较好,可明显降低样品菌落总数和挥发性盐基氮(TVB-N)并有效控制pH值上升,样品在10天仍有较好的感官指标,可延长保质期7天。     

百里香酚和肉桂醛联用对沙门氏菌的协同抑菌效应及其应用

研究了百里香酚和肉桂醛联用对沙门氏菌的抑菌效果,并将两者作为复配抗菌剂应用于盐焗鸡中以探究其保鲜效果。采用微量稀释法确定了百里香酚和肉桂醛对沙门氏菌的最小抑菌浓度及联合抑菌效果,结果显示百里香酚和肉桂醛的最小抑菌浓度均为0.25 mg/mL、最小杀菌浓度均为0.5 mg/mL;此外,两者联用时的分级抑菌浓度指数为0.75,表明百里香酚和肉桂醛具有较好的协同抑菌效应;该结论同样被时间-杀菌曲线、扫描电子显微镜、PI染色实验的结果所证实,百里香酚和肉桂醛联用可以显著地破坏沙门氏菌细胞膜的完整性,改变细菌形态,从而导致胞内物质泄漏、最终菌体裂解死亡,表明其具有一定的防腐保鲜应用潜力。因此,该研究以盐焗鸡作为食品模型从微生物和脂质氧化两方面探究了百里香酚和肉桂醛的防腐保鲜效果,结果显示百里香酚和肉桂醛联用可以显著地抑制盐焗鸡中细菌的增殖和脂质的氧化,表明百里香酚和肉桂醛联用可以作为一种天然复配抗菌剂应用于盐焗鸡等熟肉制品的保鲜中。     

即食枸杞盐煽香乳鸽加工工艺研究

在乳鸽中添加枸杞等辅料,能改善盐煽乳鸽的风味。在盐煽过程中,盐煽温度、盐煽时间、乳鸽重量、枸杞加入量、食品添加剂加入量、粗盐加入量均能影响乳鸽的口味。通过试验,枸杞盐煽乳鸽的最佳工艺为：盐煽时间90min,温度300％,乳鸽含量450g,构杞15g,鸽精1g,精盐用量500g。     

冷冻鸡肉块保水、保鲜的研究

本文研究了添加保水剂和改变加工条件,对鸡肉块解冻后失水率的影响.单因素实验结果表明,较好的浸泡温度为20℃,较好的浸泡时间是30min,聚丙烯酸钠添加量为0.0012%,其作用效果随浸泡时间的延长而提高,焦磷酸钠添加量为0.08%,当它与卡拉胶混合时,需在室温下搅拌3min.而正交试验显示最佳混合液组成是焦磷酸钠为0.08%,聚丙烯酸钠0.0012%,浸泡时间为30 min.     

Comparison of the Antimicrobial and Sanitizer Resistance of Salmonella Isolates from Chicken Slaughter Processes in Korea

Salmonella is a foodborne pathogen worldwide. Outbreaks of Salmonella are commonly associated with consumption of contaminated foods such as poultry products. Therefore, the objective of this study was to determine the occurrence, biofilm formation, antibiotic resistance, and sanitizer resistance of Salmonella enterica isolated from chicken carcasses. A total of 318 samples were collected from 15 chicken slaughterhouses in 8 provinces of Korea. They were then examined for Salmonella contamination. S. enterica isolates were tested for their susceptibilities to 15 antimicrobials by broth microdilution method. Their biofilm formation ability and resistance to sanitizers were also evaluated. Eighty‐two isolates of S. enterica were obtained from the 318 samples. There were 14 serotypes and 2 untypable isolates. Fifty‐seven (69.5%) isolates were resistant to at least one antibiotic while 30 (36.6%) isolates were resistant to 5 or more antibiotics. Two S. Senftenberg and 3 S. Montevideo isolates exhibited considerable biofilm formation ability (A₆₀₀>0.2) following incubation in Luria‐Bertani (LB) broth for 48 h. Biofilm cell survival and recovery growth assay after sanitization showed that most isolates were highly susceptible to 2.5% lactic acid and 0.1% cetylpyridinium chloride. Therefore, lactic acid and cetylpyridinium chloride might be alternatively or additionally used in addition to chlorine‐based sanitizers that are frequently used to reduce Salmonella contamination of chicken carcasses. Our results provide basic information on the distribution of Salmonella serotypes in chicken slaughterhouses. This study also highlights the necessity to improve farming practices and use antimicrobial agents cautiously. This study also suggests that sanitization during the slaughtering process might be necessary to reduce Salmonella contamination of chicken carcasses.     

Physicochemical Characterization of a Heat Treated Calcium Alginate Dry Film Prepared with Chicken Stock

Solid sodium alginate was dissolved into chicken stock in order to give a final alginate concentration of 0.9 percent (w/v). Calcium ions present in chicken stock were enough to induce ionic gelation. After drying, Fourier transform infrared spectroscopy, thickness and mechanical properties of films obtained were determined. Calcium alginate‐chicken stock films were heated at 130 °C for different times between 0 and 15 min. Mechanical and optical studies, differential scanning calorimetry, visual aspect and scanning electron microscopy were carried out to describe physicochemical properties of heat treated films. Heating developed a maroon ochre color and increased the brittleness (crispness) of the films related to the intensity of the treatment. Differential scanning thermometry and study on appearance of the films suggested that Maillard reactions may be responsible for the observed changes. Maillard reactions mainly occurred between reducing sugar monomers and free amino groups of gelatin peptides present in the chicken stock, and between alginate and gelatin peptides to a lesser extent. In addition, the plasticizing effect of fat added with chicken stock was also studied. These studies suggest a potential use of heat treated chicken stock films as a substitute of roasted chicken skin.     

烘烤条件对鸡肉糜脯品质影响的研究

以鸡肉为原料,研究鸡肉糜脯工艺中的烘烤环节对终产品色泽、硬度和感官等品质的影响。通过正交实验,确定了鸡肉糜脯烘烤的最佳工艺条件是烘制温度为60℃,烘制结束水分为42%,烤制温度为120℃,烤制结束水分含量为25%。通过极差分析可知:最终水分含量对色泽、硬度和感官结果的影响都是最大的。     

五种单体酶配伍对肉仔鸡生长性能及非淀粉多糖消化率的影响

研究在小麦基础日粮中添加五种单体酶制剂(木聚糖酶、β-葡聚糖酶、纤维素酶、植酸酶和甘露聚糖酶)对1～21日龄肉仔鸡生长性能和非淀粉多糖(NSP)消化率的影响。试验将624只1日龄肉仔鸡按均匀设计方法随机分成13组,其中第13组为对照组,各处理组日粮为上述五种单体酶制剂的不同配伍添加在基础日粮中组成。结果表明,五种单体酶制剂的不同配伍能不同程度提高肉仔鸡生长性能和NSP的消化率。其最佳的配伍水平为:木聚糖酶450 u·kg-1、β-葡聚糖酶47 u·kg-1、纤维素酶333 u·kg-1、植酸酶135u·kg-1、甘露聚糖酶153 u·kg-1。