Trans fatty acids in commercial cookies and biscuits: An update of Portuguese market

Cookies and biscuits are a recognized source of trans fatty acids (TFA). Aware of its consumption worldwide, an update on TFA content was taken in 2012, in a total of 50 samples commercialized in Portugal. Despite the absence of specific Portuguese legislation, TFA amounts in cookies and biscuits are generally low, with TFA amounts lower than 0.1 g per 100 g, and an average of 0.6% in the extracted fat in 49 of the 50 samples analyzed. Unfortunately, one sample presented 27% of TFA in the lipids, highlighting that the problem is still present. Also, a high prevalence of saturated fatty acids was observed, as high as 92.4% in the fat (53.0% on average). This fact is also a major health concern, particularly when the reformulation of these products in the last years (2006–2012) was effective regarding TFA reduction but seemed to have occurred at expenses of increasing SFA, thus reducing the potential beneficial effect achievable by replacing with cis-unsaturated fats, as generally recommended.     

在线会议管理系统中Cookies安全应用的研究

本文首先介绍了在线会议管理系统的体系架构,然后详细分析了该系统中存在的Cookie及其安全问题,并提出了具体的解决方案。     

Use of BPX‐70 60‐m GC columns for screening the fatty acid composition of industrial cookies

The fatty acid (FA) composition of food is requested for labelling purposes and food composition tables. Suitable analytical methods for labelling purposes must be able to efficiently identify and accurately quantify FA as swiftly and cheaply as possible. This study evaluated a middle‐length highly polar column, the BPX‐70 60‐m column, to balance analysis efficiency and duration. The use of a 60‐m column led to the loss of data on minor FA but a gain in analysis time. The column was evaluated by analysing the FA composition of ten cookies made with different kinds of fats, including milk fat, and pure and/or partially hydrogenated vegetable oils. The FA elution order in this GC phase has been poorly documented in the literature compared to equivalent highly polar CPSil‐88 and SP‐2460 GC phases. Co‐elutions and overlaps on the BPX‐70 column were studied and commented upon. Overall, the BPX‐70 60‐m column could be used for rapid screening of the FA composition of simple foods. Analysis of the FA composition of a complex matrix, such as a dairy product, and specific analysis of trans‐FA required a longer highly polar column, possibly after fractionation by silver‐ion liquid chromatography. Compared to other GC phases, the BPX‐70 enabled effective isolation of 18:3 isomers although these isomers co‐eluted with 20:1 isomers on other highly polar GC phases. However, some CLA isomers co‐eluted with other FA on this column, and a specific analysis of these special FA would require another phase and/or different chromatographic conditions.     

防止网上重复投票方法研究

本文对常见的网上投票系统的结构做了简要的分析,并对安全性的问题进行了探讨,列出常见的安全措施,指出了其缺点,最后提出了一种新的解决方法.该方法克服了一些常见方法的缺点,更好地解决网上重复投票,在实际应用中取得了很好的效果.     

Effectiveness of sweet ovine whey powder in increasing the shelf life of Amaretti cookies

The effect of sweet ovine whey powder on physical-chemical and textural changes during storage of Amaretti cookies is reported. The aim of the study was to study the impact of the ovine whey powder on the shelf life of cookies. Two batches of Amaretti cookies were prepared, with and without whey powder. Freshly baked Amaretti cookies were individually packaged with a high water vapour barrier film and stored for 120 days under controlled temperature/humidity conditions. Physico-chemical, textural and sensory changes were inspected at regular intervals during storage.The water-binding properties of ovine whey powder, as revealed by sorption isotherms and magnetic resonance imaging, resulted in delayed firming and increased shelf life of cookies with whey powder with respect to control cookies and did not influence the sensory properties. MRI allows visualizing differences in internal structure and proton distribution of the two batches of Amaretti cookies, pointing out the more homogeneous internal structure of the cookies where whey powder is added.     

Chemical composition, functional properties and baking potential of African breadfruit kernel and wheat flour blends

The chemical composition and functional properties of African breadfruit kernel flour (ABKF), wheat flour (WF) and their blends were determined. Cookies prepared from the blends were evaluated for their protein contents, physical and sensory characteristics. The flour blends had higher protein, fat and ash contents than WF. The level of these nutrients improved with increased amounts of ABKF in the blends. Foaming, water and oil absorption capacities of the flour blends increased, while the foam stability decreased with increased level of ABKF. The protein contents of the composite flour cookies were higher than that of the all WF cookie. There were no significant differences (P > 0.05) in the flavour of the composite flour cookies and that of all WF cookies. However, sensory scores differed significantly (P < 0.05) amongst them for colour, texture and overall acceptability.     

Texture evolution of “Amaretti” cookies during storage

The results of a study on texture evolution during 35 days of storage of amaretti, a typical Italian cookie, packaged in two different ways are reported. Amaretti cookies were wrapped in polyvinylchloride (PVC) film or aluminium foil (ALL), to simulate two different permeability conditions and stored at controlled temperature and humidity. Evolution of texture (such as hardness) and a_w were tested instrumentally by a texture analyser and a hygrometer, respectively. Texture was assessed by a cut and puncturing test. Indices for hardening were the area under the curve (N mm) and gradient (N/mm) for the puncturing test and maximum force (N) for the cut test. Both textural tests showed significantly higher hardening of PVC cookies, compared to the ALL cookies. The latter retained good sensorial properties at the end of the storage period, although their internal structure changed from soft and moist to mealy, while the PVC cookies were no longer edible only 10 days after baking. a_w values decreased and increased in PVC and ALL lots, respectively. The results suggest that hardening may be explained by water loss in PVC and moisture redistribution in ALL.     

基于Struts构架的Web认证

提出了利用Struts构架,设计和实现可重用的Web服务器认证算法,指出了纯Cookies认证算法的不足,论述了SSL安全协议和其在Web上的应用。利用J2EE的servlet重定向机制,实现HTTP和HTTPS无缝的混合使用。使用JSP的用户定制标签和servlet功能,设计了安全、可重用、易扩展的算法。并在Struts和Tomcat Web服务器环境下实现了算法。     

基于Kerberos的Web单点登录研究

该文针对W eb环境中应用Kerberos认证协议存在的两个问题,提出了自己的解决方案。采用基于随机数的质询/响应方式取代基于时间的A uthenticator来解决重放攻击问题,采用Secure Cookies、H ttpSession等来解决W eb环境下服务器间和服务器内的安全会话问题。在此基础上设计并实现了面向W eb应用环境的单点登录系统Ti-SSO。     

企业信息门户单点登录系统的实现

介绍了一个企业信息门户中单点登录系统的实现。系统实现了基于Cookies的单点登录系统,解决了SSO中Cookies不能跨域共享的问题,采用Cookie和Cookie Server来共同保存用户身份信息,具有较好的安全性。同时采用Web服务来实现统一的身份认证,实现了基于LDAP的用户身份信息的保存,最后提出了企业信息门户中一种基于用户、用户组、应用以及角色相结合的权限管理方法。