社交媒体中转基因食品的媒介框架研究——基于美国YouTube视频网站的案例分析

社交媒体在科学传播中扮演的角色日益重要,在促进争议科学题材的传播中发挥的作用尤为显著。本文以世界上最大的社交视频网站You Tube中的转基因食品短片为案例,从传播主体、媒介框架和传播技巧三方面来分析社交媒体的框架建构过程。研究发现,在You Tube网站上美国的各种社会组织抢占了绝对的话语主导权,媒体也有积极参与,而政府和科研机构基本处于失语状态。在媒介框架上,最多的一类是关于食品安全、经济和科技的话题,且大部分都具有负面属性。在塑造技巧上,最受欢迎的短片大部分具有刺激性标题、诉诸于情感和特定价值、制造矛盾吸引受众三个显著特点。     

基于高频探测信号的金属探测器的研究

运用于食品领域,是金属探测器的一种新用途。与其他领域相比,在食品工业所使用的金属探测器需要有较高的灵敏度。文中从提高探测信号频率的角度,探讨了频率变化对于金属探测器探测灵敏度的影响,论证了采用高频探测信号是提高金属探测器性能的有效途径。     

保健食品中人参皂甙的测定方法

人参系五加科植物人参PanaxginsengCAMeyer的根。含有多种人参皂甙(panaxsaponin),系三萜皂甙。多数为达玛烷型皂甙,如人参皂甙Ra1、Ra2、Rb1、Rb2、Rb3、Rc、Rd等;少数为齐墩果酸型(C型)皂甙,如人参皂甙Ro。由于甙元不同,达玛烷型皂甙又分为20S-原人参二醇类皂甙(A型)和20S-原人参三醇类皂甙(B型)。其中A型和B型皂甙酸水解后,分别得到人参二醇(panaxadial)和人参三醇(panaxatriol)。本文报导用大孔树脂吸附样品中人参皂甙,先用水洗去糖分,再应用稀乙醇洗下人参皂甙,再用香草醛与人参皂甙反应显色而进行比色。     

美国食品所标示的有关膳食脂肪与冠心病关系的健康声明及对中国出口食品的指导意义

介绍了ＦＤＡ关于食品健康声明的定义,膳食脂肪与冠心病关系,可以标示健康声明的食品要求以及ＦＤＡ在最终通过健康声明之前须考虑的安全性问题,为国内的食品界提供一些参考信息。     

番茄黄瓜菜汁豆腐加工工艺

以番茄汁、黄瓜汁和大豆为原料研制了色泽美观的天然、营养豆腐,丰富了豆腐的品种,有良好的发展前景。     

Physical polymer surface modification methods and applications in food packaging polymers.

Continued innovations in the polymer industry have made polymer surface modification methods a subject of intense research. The importance and necessity of surface modification of plastics are explained, and the advantages of physical surface treatments over the less-sophisticated chemical methods are outlined. Currently available physical surface modification methods for food packaging polymers are reviewed from the food packaging perspective. These physical surface modification methods include flame, corona discharge, UV, gamma-ray, electron beam, ion beam, plasma, and laser treatments. The principle of operation of each method is briefly described, and the advantages and disadvantages of each technique are cited. The extent to which each of these methods can produce the specific modifications desired is discussed. Furthermore, the effects of each treatment on barrier, mechanical, and adhesion properties of food packaging polymers are also examined. Finally, an overview of economic aspects of sophisticated surface modification techniques, including ion beam, plasma, and laser treatments, is presented.     

Class IIa bacteriocins from lactic acid bacteria: antibacterial activity and food preservation

In the last decade, a variety of ribosomally synthesized antimicrobial peptides, or bacteriocins, produced by lactic acid bacteria have been identified and characterized. As a result of these studies, insight has been gained into various fundamental aspects of biology and biochemistry such as bacteriocin processing and secretion, mechanisms of cell immunity, and structure-function relationships. In parallel, there has been a growing awareness that bacteriocins may be developed into useful antimicrobial food additives. Class IIa bacteriocins can be considered as the major subgroup of bacteriocins from lactic acid bacteria, not only because of their large number, but also because of their significant biological activities and potential applications. The present review provides an overview of the knowledge available for class IIa bacteriocins and discusses common features and recent findings concerning these substances. The activity and potential food applications of class IIa bacteriocins are a major focus of this review.     

Prevention of Clostridium botulinum Type A, Proteolytic B and E Toxin Formation in Refrigerated Pea Soup by Lactobacillus plantarum ATCC 8014

The ability of Lactobacillus plantarum ATCC 8014 to inhibit Clostridium botulinum toxin production in pea soup was investigated. Soup containing C. botulinum spores (10³/g) with and without L. plantarum (10⁶/g) were evaluated. Soup containing only type A spores was toxic on days 1 and 2 when incubated at 35°C and 25°C, respectively. Soup containing only proteolytic type B spores was toxic on days 2 and 5 at 35°C and 25°C, respectively. Soup containing only type E spores was toxic at 25°C, 15°C, and 5°C in 7, 7, and 63 days respectively. No toxin was found in soup containing C. botulinum spores plus L. plantarum at any temperature studied.     

生物膜的形成与控制

生物膜对食品工厂的危害极大,可使微生物残存增加,加工车间设备无法适当清洗、清毒;产品受到污染,甚至危害产品的安全。食品加工厂欲控制生物膜的形成,应从设计、生产环节着手,设计出良好的生产环境,注意清洗频率,使用正确的清洗、消毒方法,严格控制生物膜的形成,才能保障产品的卫生安全。     

基于移动平台的食品分拣机械手设计

提出了一种基于移动平台的食品分拣机械手,给出其设计指标、机械以及控制系统结构,对其工作空间进行了仿真计算,并对该机械手的末端定位精度进行了实验研究,结果表明基于移动平台的食品分拣机械手设计合理,可以有效地完成精确操作。