太阳能封装胶膜EVA变色分析

晶体硅光伏组件在制造、测试及使用过程中,封装材料EVA经常发生变色,影响了组件外观及功率.本文通过各种化学分析,分别研究了EVA的几种变色模式,分析了其变色失效机理,提出了避免EVA变色的方法.     

微波处理对全麦粉及全麦生鲜面中PPO 和微生物的抑制研究

试验选取全麦粉为原料,研究了2种不同方式的微波处理(2 000 W,20~80 s和700 W,50~120s)对面粉中微生物和多酚氧化酶(PPO)活性的抑制效果。并验证了2种处理方式对全麦生鲜面中微生物生长速率和褐变速率的延缓作用。结果表明,随微波处理时间的延长,全麦粉中微生物数量和PPO活性均显著下降(P0.05)。微波处理后的全麦粉所制得的生鲜面褐变速率和贮藏前期的菌落总数明显降低,2 000 W处理40 s组全麦生鲜面比700 W处理90 s组表现出更好的颜色贮藏稳定性。     

Development of a Model System to Mimic Beef Bone Discoloration

ABSTRACT: Some current practices used in the meat industry (blast chilling, enhancement, modified atmosphere packaging [MAP]) appear to result in darkening of the bone in fresh meat. The objective of this study was to develop a model system that could be used to evaluate intervention strategies to prevent this discoloration. Beef rib bones were removed from carcasses, split along the transverse plane from the proximal to the distal end of the rib, and then frozen (−20 °C) or held at 4 °C for 24 h. Half were exposed to a phosphate/salt enhancement solution while half served as the control. Samples were packaged in air or modified atmosphere packaged (MAP: 80% O₂/20% CO₂) and displayed in a retail case (4 °C, 24 h). Visual discoloration occurred during the 1st 10 h of display. More darkening (brown, green/black) was observed in previously frozen samples, whereas samples held at refrigeration temperature were redder. CIE L *, a *, and b * values determined after 24 h indicated that samples held in refrigeration before packaging were lighter and redder. After 24 h at 4 °C, previously frozen samples contained more methemoglobin/g protein in the bone marrow than did bone samples that had never been frozen.     

牛肉肠褪色反应机制及控制

对牛肉肠易氧化褪色的原因进行了研究，认为牛肉自身色素蛋白含量高及产品不饱和脂肪酸含量高，是造成牛肉肠易褪色的主要原因。同时，提出了用切断油脂自动氧化的链锁反应、螯合金属离子、调整ｐＨ值、减少氧化残留量等措施，来延缓产品褪色反应的进行。     

活性染料浸染杨木单板光变色的研究

选用活性艳红KD-8B和活性黄K-RN 2种染料配制的染液在不同工艺条件下对东北人工林大青杨单板进行染色,通过测定染色单板在氙光衰减仪内不同时间点下光照射表面材色的L*、a*、b*值,分析染色工艺对单板表面材色指数的影响。结果表明,染液浓度是影响活性艳红染色单板材色指数的主要影响因素,染色温度是影响活性黄染色单板材色指数的主要影响因素。     

雪莲果低聚果糖粗提液的脱色工艺的研究

采用树脂脱色法对低聚果糖粗提取液进行脱色处理,试验结果表明,201×7(717)强碱性阴离子交换树脂对雪莲果低聚果糖提取液中色素的脱除效果最好.最佳脱色条件:上柱流速2mL/min,吸附温度30℃,低聚果糖浓度1.72%.在最佳条件下进行验证试验,脱色率可达90.8%.     

铝硅复合对Fe32Mn7Cr3Al2Si钢氧化改性层耐蚀性的影响

利用XRD、EPMA、阳极极化和电化学阻抗技术研究了铝硅复合合金化对Fe32Mn7Cr3Al2Si钢高温氧化诱发转变层的组织、成分及电化学腐蚀性能影响.在700和800℃空气中对Fe32Mn7Cr3Al2Si奥氏体钢进行循环氧化表面改性,形成的氧化层由内层Al2O3、中间层Mn2SiO4,外层Mn2O3组成.经800℃...     

Genome-based analysis of Pseudomonas paracarnis RQ057, a strain responsible for blue discoloration spoilage in processed cheese

A strain of Pseudomonas causing blue discoloration was isolated from processed cheese ‘Requeijão em Barra’ and studied by whole-genome sequencing. The strain RQ057 was identified as Pseudomonas paracarnis using the TYGS web server and also by in silico DNA–DNA hybridisation and ANIb calculation. Pyoverdine biosynthetic clusters, integrative and conjugative elements (ICE), prophage regions and genomic islands (GIs) were predicted. Furthermore, we observed that copies of genes related to the tryptophan biosynthetic pathway (trpCBAFD), which are exclusive to strains causing blue discoloration, are contained in the region identified as ICE and which was also identified in GIs. This genomic region also contains genes for transposase, type IV transport system (T4SS) and pili construction. Thereby, we can assume that this region contains potential conjugative-transposon-like mobile genetic elements and it has plasmid-like conjugative properties.