葡萄酒发酵过程中白藜芦醇含量变化的研究

跟踪2005年河北沙城、昌黎、天津蓟县和宁夏御马葡萄产区的干红葡萄酒生产过程,分别采集以赤霞珠葡萄为原料的不同发酵时期的样品,用高效液相色谱检测白藜芦醇含量,研究葡萄酒发酵过程中白藜芦醇含量的变化规律。结果表明,尽管不同产地在发酵过程中生成的白藜芦醇含量有所不同,但都随着果胶酶添加和酵母发酵的进行,白藜芦总醇含量逐渐上升,至主发酵时白藜芦总醇含量达到最高,进入苹果酸-乳酸发酵后,白藜芦醇含量有所下降并维持一定的水平。     

金属粉末质量控制对金刚石工具性能影响的探讨（下）

文章研究探讨了金刚石工具用Fe、Cu、Ni、Sn、Zn等单质金属粉末及预合金粉末质量对金刚石工具的烧结质量及应用性能的影响。通过对各种金属粉末的氧含量、粒度、松比等性能指标的考量,重点探讨了氧含量对工具质量及性能的影响,对各类金属粉末而言,当其可控的氧含量〈4000×10-6时,工具的性能可保持稳定与正常发挥。     

新工科理念下“纺纱原理”课程教学模式的研究

纺纱原理课程存在教学内容更新滞后、教学手段和方法缺乏灵活性、考核方式不能挖掘和激发学生的能力等问题,所以必须进行纺纱原理课程的教学改革。课程通过网络学习平台,增加线上网络和线下学生自学以弥补课堂学习时间的不足。这既可以提升学生的自学能力、掌握基本的原理知识,又可以追踪与原理有关的纺织科技前沿、紧跟新工科发展的趋势。学生课下自学,课上主导课堂,激发了学生学习的积极性和参与性。采用阶段性和总结性考核相结合的方式,由教师、学生和专家组成的评价组进行综合评分。     

Effect of blanching and drying treatments on quality of bamboo shoot slices

The enzymes activity, texture, pectin, microstructure and colour change in bamboo shoots (Dendrocalamus latiflorus) were examined to evaluate the effect of blanching and drying treatments on quality of bamboo shoot slices (BSS). Peroxidase (POD), phenylalanine ammonia‐lyase and polyphenol oxidase in BSS will become completely inactive at 95 °C for 6‐, 9‐ and 12‐min blanching treatments, respectively. The hardness and protopectin (PP) content decreased after the blanching treatment. Meanwhile, the content of water‐soluble pectin increased initially and then decreased gradually during the blanching. After the blanching treatment, the L* and a* of BSS decreased, while b* increased, ΔE > 2. The hardness of rehydrated BSS decreased by 43.57% after freeze drying (FD), which, however, decreased more after hot air drying (HAD). The pectin of rehydrated BSS was also determined to explain the hardness change in BSS. The BSS acquired similar microstructure of fresh samples after FD, while microstructure of BSS was severely damaged after HAD. The colour of BSS changes significantly after drying treatment. However, FD can maintain better colour of BSS than HAD. The results may provide a reference for industrial production of BSS.     

Preference and juiciness of Iberian dry-cured loin as affected by intramuscular fat content, crossbreeding and rearing system

Preference ranking tests for juiciness and overall liking of dry cured loins from Iberian pigs with different genetic backgrounds (pure Iberian or crossbred Iberian×Duroc pigs), reared under different productive systems (outdoors on acorns and grass or indoors with mixed diets) and with different intramuscular fat (IMF) content, were conducted. IMF showed a positive influence on preference for juiciness and liking in subjects over 25 years of age, while younger consumers showed a similar trend for juiciness but not for preference. Loins from pure Iberian pigs showed significantly better ranking for juiciness and overall liking than those from crossbred pigs, even when the IMF content was similar. Dry cured loins from pigs reared outdoors and fed on acorns and pasture were ranked significantly better than those from animals fed indoors on concentrates, even though the mixed diets used were enriched in monounsaturated fatty acids and vitamin E in order to obtain meat with similar features to that of pigs reared outdoors, and despite very similar IMF contents. In conclusion, dry cured loins with high IMF content, from pure Iberian pigs and reared outdoors on acorns and grass attain the highest consumer preference.     

棉型中空纱强度与PVA含量关系的研究

采用水溶性维纶纱线作纱芯,棉作外包纤维,在传统的环锭纺纱机上纺制棉包芯纱,溶去芯纱,制得棉型中空纱。并对棉型中空纱的强力与PVA含量的关系进行了试验、分析与讨论。其结果对中空纱的纺制有指导意义。     

Comparison of deterioration of rye under two different storage regimes

Deterioration of stored rye samples was studied at different moisture contents and temperatures. Germination, presence of visible and invisible microflora, and free fatty acid values (FAV) were determined for samples at 10.0, 12.5, 15.0 and 17.5% moisture content (wet mass basis) stored at 10, 20, 30 and 40 °C for 16 weeks. Results of deterioration at constant moisture content (case 1) were compared with previously reported results for deterioration under declining moisture content (case 2). Germination rate was almost the same for all the moisture content samples stored at 10 °C for both cases, but a significant decrease was observed at other temperatures with high moisture content. Fatty acid values remained similar in both cases when rye was stored at 10 and 20 °C, whereas at 30 and 40 °C, FAVs of the rye samples in which the moisture content was maintained were high and increased with an increase in temperature and moisture content. Visible mould appeared early in the samples whose moisture content was maintained. Penicillium spp. and Aspergillus glaucus group were the predominant fungal species present in both the cases throughout the study. The rate of deterioration was significantly different between the two cases.     

谈颜色探索BIGC微信公众号的学习资源建设

"颜色探索BIGC"公众号是北京印刷学院新媒体学院数字媒体艺术专业教学团队建设的微信公众平台,是为补充课堂教学的内容而开发的一个公众号。它以艺术设计中的色彩设计为主要内容,既有主题突出的、以介绍传统色彩知识为主的版块,又有碎片化的、定期推送的有关色彩设计的文章,具有原创性和专业性的特点。文章的内容注重与设计热点相结合,并且运用新颖的交互形式、结合大量的图片使信息的传递更加生动、有效,有益地拓展了课堂教学的内容,收到了良好的教学效果。     

酸性媒染低铬染色法对毛织物可萃取铬含量的影响

采用汽巴-嘉基低铬染色法和拜耳铬系数染色法对毛织物染色后,按Oeko-Tex标准100规定的条件,使用等离子发射光谱法测定该毛织物上的可萃取铬含量,分析了铬含量与染色法的关系.结果表明:酸性媒介黑PV和酸性媒介黑T的用量为3%～8%(owf)时,使用汽巴-嘉基低铬染色法,可萃取铬含量基本小于Oeko-Tex标准100中重金属铬的限量指标2mg/kg(2ppm);其他5只染料用量在1.5%(owf)以下时,使用2种酸性媒染低铬染色法,其毛织物上的可萃取铬含量均达标.     

微波法硫酸酯化枸杞多糖的研究

采用微波辅助的方法对枸杞多糖的硫酸酯化进行研究,改进了枸杞多糖硫酸酯硫酸根含量的测定方法。通过对反应溶剂的种类、多糖残基与酯化试剂的摩尔比、反应温度和时间等因素的正交实验,确定了较佳的硫酸酯化反应条件;在对枸杞多糖硫酸酯硫酸根含量测定方法的研究中,以醋酸钡替代氯化钡,其标准曲线回归性比氯化钡的好,且精密度较高、稳定性较好、安全可靠,是多糖硫酸根含量测定的较理想的方法。