茯苓提取物参与灰树花液态深层发酵及对其活性物质产量的影响

中药茯苓提取物参与灰树花液态深层共发酵,进而探究不同溶剂提取的、不同添加比例的茯苓提取物对灰树花活性物质产量的影响。结果表明,添加5 g/L的茯苓醇提液和7 g/L的茯苓水提液时,均能够提高灰树花的生物量及多糖、总黄酮、蛋白的含量。相比于空白对照组,在最适醇提物和水提物添加量下的菌丝体生物量分别提高了24.28%和29.04%,具有显著促进作用(P<0.05)。5 g/L醇提物添加条件下的胞外多糖、胞内多糖、胞外黄酮、胞内黄酮、胞外蛋白、胞内蛋白组与空白组相比具有显著促进作用(P<0.05),分别提高了17.8%、30.29%、8.32%、10.13%、10.49%和10.24%。7 g/L水提液添加条件下胞内多糖、胞外黄酮、胞内黄酮、胞外蛋白、胞内蛋白与空白组相比具有显著促进作用(P<0.05),分别提高了19.8%、3.16%、9.29%、10.24%和8.78%。表明添加一定量的茯苓提取物能够在一定程度上增加灰树花菌丝体的生长和活性代谢产物的含量,并且对多糖的产量影响尤为明显。     

Supervised pattern recognition to authenticate Italian extra virgin olive oil varieties

This work is the logical consecution of our previous investigation on the classification of “monocultivar” olive oils, in which 153 samples from the five cultivars Carboncella, Frantoio, Leccino, Moraiolo and Pendolino [harvested from 1997 to 1999, in the same geographical area (Sabina, Lazio)] were discriminated according to their variety, using Linear Discriminant Analysis (LDA) and Back-propagation Artificial Neural Network (BP-ANN).This study has been now extended to include 50 new samples from three (Frantoio, Leccino, Moraiolo) of the previously examined cultivars and 373 samples from other nine olive varieties (Minuta, Moraiolo, Nocellara del Belice, Nociara, Ortice, Ortolana, Ottobratica, Peranzana, Racioppella and Sinopolese). These new samples were harvested from 1996 to 2000 in six Italian regions (Calabria, Campania, Lazio, Molise, Puglia and Sicilia).Kennard-Stone algorithm was used to partition the samples into the training and test sets and the value of Fisher F-ratio was computed to identify the most discriminating indices in order to reduce the number of input variables.A first study, restricted to the original five cultivars only, showed that 12 variables are necessary in the best LDA model, which was able to correctly recognize 92.7% of the training samples and to correctly predict 90.6% of the test set. On the other hand, the first seven variables only were necessary to obtain a null prediction error over the test and validation set samples using BP-ANN.In a successive stage, ANNs have been used to extend the study to all the 14 cultivars (576 samples). In this case, the first 16 variables according to the value of Fisher F-ratio were included in the best classification model. This model was able to correctly recognize all the samples in the training set (RMS<0.00001) and to correctly predict all the samples in the test (RMS error=0.0008) and validation (RMS error=0.001) sets.     

等离子体活化冰对东方对虾保鲜及品质的影响

以等离子体活化冰与自来水冰室温下(20℃)贮藏对虾,对比二者pH、TBA、TVB-N、菌落总数、细菌群落、质构和色差等指标的变化。结果表明:试验期间,等离子体活化冰处理对虾的TBA和pH值增长速率减缓,TVBN值的升高速度远小于自来水冰组,且等离子体活化冰处理虾的硬度下降幅度也小于自来水冰处理的;等离子体活化冰能够明显抑制对虾中细菌的生长,贮藏第6天时,自来水冰处理虾中菌落总数比等离子体活化冰处理的高2lg CFU/g;二代高通量测序结果表明,等离子体活化水主要对弧菌具有抑制效果,贮藏6d时对照组弧菌属占比62.52%,而试验组仅为40.45%。     

不同粒度充气硬糖的品质特性分析

充气硬糖是含有高压二氧化碳气泡的硬质糖果,溶解时可以产生令人愉悦的跳感。由于充气硬糖颗粒细小,气压值不易直接测定,同时其形状不规则和大小不一的特点给指标测定带来一定的复杂性,目前还没有相关的标准来评价充气硬糖的品质特性。该文将充气硬糖分为10目＜粒径≤4目、20目＜粒径≤10目、30目＜粒径≤20目和粒径≤30目四个粒度等级,研究不同粒度充气硬糖品质特性的差异。实验通过测定充气硬糖的气泡尺寸分布与气体状态参数分析气泡特性与跳感品质的关系,利用理想气体方程计算得到充气硬糖的平均气压在0.73~0.91 MPa之间,平均气压大小随着颗粒减小而降低。采用X 射线衍射测得充气硬糖属于非晶态物质,差示扫描量热仪测得其玻璃化转变温度（Tg）随着颗粒的减小而降低,这可能是气压与吸湿性的不同导致小颗粒的充气硬糖Tg 比较低。充气硬糖的原始水分活度为0.31±0.01,因此在高于30% RH的环境中会发生吸湿。玻璃化转变温度和吸湿性的结果为充气硬糖保藏条件的设定提供了理论参考。     

不同轮次酱香型白酒中特征微量组分的研究

采用气相色谱技术测定了6个品牌七个轮次(共计42个样品)基酒中乙醛、乙缩醛、正丙醇、乳酸乙酯等14个特征成分的含量,初步探究不同轮次中特征成分的变化情况;运用主成分分析法对数据进行降维处理.结果表明:通过主成分分析法得出,第1、2、3、4主成分的贡献率分别为29.217％、20.770％、18.399％、11.371％...     

Changes in the nitrate and nitrite contents of fresh vegetables during cultivation and post-harvest storage

Nitrate and nitrite levels in both germinating seeds and growing vegetables were determined for the following vegetables: short-petioled cabbage (Brassica chinensis), long-footed cabbage (Brassica chinensis var. communis), field mustard (Brassica campestris), broad-leaf mustard (Brassica juncea var. rugosa) and water convolvulus (I pomoea aquatica Forsk). The seeds contained 16–32 ppm nitrogen in the form of nitrate and 0·3–0·8 ppm nitrogen in the form of nitrite. The nitrate nitrogen concentrations of the growing vegetables varied between 300 and 1200 ppm depending on species and their nitrite nitrogen contents were about 0·3–3 ppm. The nitrogen fertilizer urea seemed to induce remarkable nitrate accumulation in the growing vegetables. The influence of storage at different temperatures on the nitrate and nitrite contents of fresh and homogenized vegetables was studied. During the first few days storage temperatures of −10 or 2°C little change in the nitrate and nitrite concentrations was found. However during the first few days of storage at 26 or 32°C the nitrite concentration increased considerably while the nitrate concentration decreased. Nitrate reductase and nitrite reductase activities in the vegetables were estimated at various stages of growth but no significant changes in activity were observed.In view of the effect of dietary nitrate on salivary nitrite formation and on the endogenous formation of carcinogenic N-nitroso compounds. we suggest that more effort should be put into developing methods of cultivating low-nitrate vegetables.     

改性磁性壳聚糖对胭脂红的吸附性能评价

以纳米Fe₃O₄、壳聚糖为材料,采用反相悬浮交联法,用三乙胺做改性剂制备改性磁性壳聚糖,研究其对胭脂红色素的吸附性能影响,考察时间、pH、温度及胭脂红的初始浓度等四个因素对改性磁性壳聚糖吸附胭脂红溶液吸附效果的影响,并对吸附动力学模型、吸附等温模型、吸附热力学和吸附再生性能进行初步探讨。结果表明,当pH=3,吸附时间为270 min,温度为50℃,初始浓度为100 mg/L时,改性磁性壳聚糖对胭脂红溶液的吸附率达到最高,为96.72%。改性磁性壳聚糖对胭脂红溶液的吸附动力学数据符合准二级动力学模型,吸附等温线数据符合Langmuir模型,热力学数据拟合得出ΔH>0,ΔS>0,ΔG<0,得出此反应是吸热反应。经过三次吸附-解析实验,吸附率和解析率仍在40%以上。     

基于嵌入式系统的塑料挤出装置设计

论述了基于ARM 7 TDMI与嵌入式C-OSII实时操作系统的塑料挤出装置的设计,该装置使用多组PID闭环控制模块,通过分段分级加热,实现物料在料筒中均匀熔融,并且精确控制了塑料挤出的单位重量以及压力.     

基于嵌入式系统的立式中空成型装置设计

论述了基于ARM 7 TDMI与嵌入式C-OSII实时操作系统的新型立式中空成型装置的设计,该装置使用多组PID闭环控制模块,通过嵌入式数控系统控制系统各个单元与24工位的旋转立式中空成型装置准确配合,形成高速旋转的立式中空成型系统,达到12 000个/小时的吹瓶速度。     

Atmospheric plasma deposition of transparent semiconducting ZnO films on plastics in ambient air

Transparent zinc oxide (ZnO) thin films have been successfully synthesized on poly (methyl methacrylate) (PMMA), polycarbonate (PC), and polyethylene terephthalate (PET) substrates by atmospheric plasma deposition in ambient air at room temperature. The structural, optical and electrical properties of the ZnO films as well as their adhesion to the polymer substrates were investigated for various deposition conditions. The film surface exhibited a dome-shaped topography comprised of nanometer-sized grains. The size of both the domes and the grains became larger as the plasma power increased. The visible transmittance increased above 95% with decreasing plasma power. The resistivity exhibited a wide variation in the range of 10²–10⁸ ohm cm. The adhesion energies to PMMA varied from 0.2 to 1.5 J/m² with increasing plasma power. While a finer grain structure achieved with lower plasma power was preferable for higher transmittance, it resulted in lower adhesion to the plastic substrates. The study demonstrated the feasibility of depositing semiconducting transparent ZnO films on polymer substrates at low temperature in ambient air using atmospheric plasma deposition.