新型微生物源天然食品防腐剂及其抑菌性能

天然食品防腐剂按其来源不同可分为植物源天然防腐剂、动物源天然防腐剂以及微生物源天然防腐剂等类型。天然微生物源食品防腐剂由于其本身的优越性,越来越受到人们的青睐。主要对5种新型微生物源天然食品防腐剂(即乳球菌肽、溶菌酶、聚赖氨酸、苯乳酸及曲酸)的理化特性、抑菌机制和抑菌特性等进行了概括和论述,旨在为我国新型、安全、高效微生物源天然食品防腐剂的研究和开发提供参考。     

Potential influence of water level changes on energy flows in a lake food web

Large seasonal water-level fluctuations may influence isotopic signatures of primary producers and the types and amounts of these potential food sources accessible to aquatic fauna of Poyang Lake,the largest freshwater lake in China.In this study,the isotopic signatures of primary producers and consumers were determined,stable carbon and nitrogen isotope analysis and mixing models were combined to investigate the influence of water levels on the diet and isotopic composition of Poyang Lake fish and inverteb...     

食品双螺杆挤出机温控系统的模糊免疫PID控制

食品双螺杆挤出机机筒温度对挤压产品产量和质量影响很大,实现对机筒温度的有效控制是一项重要工作.建立控制对象的数学模型,借鉴生物体免疫机理,设计出模糊免疫PID控制器,并进行了仿真研究.结果表明,该温控系统鲁棒性强,响应速度快,动态误差小,性能优于单一的PID控制,能满足食品加工工艺的要求.     

二次微分电位溶出法测定食品中镉、锌含量

建立了二次微分电位溶出法测定食品中镉、锌含量的方法.优化了试验条件如pH值、电沉积电位、平衡电位等,线性范围:镉0～16 ng,锌0～800 ng;检出限分别为0.24 ng/mL、0.71 ng/mL,RSD<2.5%(n=7).该法测定食品样品结果与石墨炉原子吸收法一致.     

面向农产品安全的关键质量链分析

针对农产品质量安全控制问题,在传统过程能力分析的基础上,将农产品食品链视为一个过程网络,应用PERT/CPM的基本思想,提出了基于质量损失的关键质量链分析评价方法。最后以菠菜产品的种植加工进行了实例分析。     

Feeding ecology of the common sun skink,Eutropis multifasciata (Reptilia: Squamata: Scincidae), in the plains of central Vietnam

We studied the feeding ecology of Eutropis multifasciata in the tropical plains of central Vietnam to understand better the foraging mode, spatiotemporal and sexual variation in dietary composition, and rarefaction curves of prey-taxon richness for males and females. Stomach contents (n = 161) were collected from October 2013 to May 2014 using a nonlethal stomach-flushing technique. A total of 680 food items (624 animal items and 56 plant items) was found in 161 stomachs of skinks, representing 19 unique animal categories. We found that the diet of E. multifasciata is composed mainly of small, sedentary and clumped prey and that this skink specialises on spiders, insect larvae, snails, grasshoppers and crickets (with a combined importance index of 60%). Dietary composition, prey size and total prey volume in E. multifasciata changed between dry and rainy seasons and among regions. The total volume of food items consumed by males was larger than that of females, and the diversity and evenness index of prey categories were larger in males than in females. However, using rarefaction curves revealed that females have the higher prey-taxon richness after points between 130 and 140 prey items for frequency, and between 160 and 170 prey items for number of items, and the differences were not statistically significant. The foraging behaviour of E. multifasciata best fits a ‘widely foraging’ model.     

Mating behaviour and maternal care in the tropical savanna funnel-web spider Aglaoctenus lagotis Holmberg (Araneae: Lycosidae)

Despite their abundance and diversity, Neotropical spiders have been the subject of relatively few studies of behavioural ecology. The sexual behaviour and maternal care of the spider Aglaoctenus lagotis (Lycosidae) is described here. We performed experimental manipulations to test the hypothesis that males are attracted by female cues in the web. Two predictions were tested: (a) webs used by a virgin female will attract more males than webs used by an inseminated female; (b) the main cue in the web is chemical, so webs recently used by virgin females will attract more males than those that are not recently used. Additionally, we tested the hypothesis that maternal care increases offspring survivorship. Results showed that males are attracted by recently used webs (z = 0.0015; p = 0.037; z-test) and webs of virgin females (z = 0.041; p = 0.036, z-test). Male sexual behaviour presented three different categories: court, pre-mate and mate. After the mating, the females built a cocoon that was transported adhered to the spinnerets and held by the last pair of legs. After the hatching of the eggs, the young migrated to the dorsal region of the mother's body for 5 days. During maternal care the mother eliminates a yellowish drop from its oral cavity, which is collected by the young. During the development of the young until adulthood, the offspring that have their mother present in the first stages of life have greater survival compared with those without maternal care. Our results make it possible to perform comparative analyses between a South American Lycosidae species and other species distributed worldwide.     

Species of the genera Bakera and Mangganeura (Homoptera: Auchenorrhyncha: Typhlocybinae) occurring on mango and other crop plants in the Oriental region

The genera Bakera (Bakera), Bakera (Guinobata) and Mangganeura (Homoptera: Auchenorrhyncha: Typhlocybinae) are re-described and compared. Sandalla is considered a synonym of Bakera (Guinobata) (syn. nov.).

Bakera (Bakera) nigrobilineata (Melichar) (=vittata Mahmood) is redescribed and illustrated from mango in the Philippines, on which it is frequently abundant, and found in association with Bakera (Bakera) luzonica sp. nov. which is described. Bakera (Bakera) abaca sp. nov. is described from the Philippines having been collected on abaca (Manila hemp). Bakera (Guinobata) nigroscuta Mahmood is redescribed from the Philippines and its association with coconut confirmed. Mangganeura reticulata Ghauri, described from Malaysia on mango, has been found in Thailand and the hitherto unknown female is described.     

媒体负面报道对公司股价影响的研究:来自白酒塑化剂事件的证据

金融学理论认为,资本价格会因意外重要事件的冲击而发生变化.过去许多文献讨论过股票价格与媒体报道这一外部冲击之间是否存在显著关系,但是,这些研究所得结论并不尽一致.基于此,本文以白酒塑化剂事件为例,分析塑化剂曝光新闻数量对白酒公司股价的影响.研究表明,塑化剂曝光在较长时间内影响了白酒板块的股价,但是曝光事件对各个公司股价影响的程度不一.此外,研究还发现,中央反腐抑制了白酒板块的股价.     

基于SD-SEM模型的消费者食品安全风险感知的信息搜寻行为

本文利用系统动力学模型和结构方程模型来研究消费者食品安全风险感知和消费者信息搜寻行为之间的关系,在总结消费者食品安全风险感知和消费者食品安全信息搜寻行为研究文献的基础上,利用结构方程确定消费者食品安全风险感知的影响因素及其之间的路径系数,进而建立系统动力学模型模拟信息搜寻行为对消费者食品安全风险感知的影响,以提出降低消费者食品安全风险感知的建议.