大曲中产酱香芽孢杆菌的筛选及其代谢产香探析

对茅台酒生产各环节所采集的28个样品进行了初步分析,从高温大曲制作过程的不同环节筛选出芽孢杆菌104株,用麦曲模仿升温发酵筛选产香的菌株,经鉴定分别为枯草芽孢杆菌、解淀粉芽孢杆菌、地衣芽孢杆菌等,其中产酱香优良的菌株25株,分为多种香味,与不产香型的细菌对比,产酱香的25株均能产生二乙酰、乙偶姻、蛋白酶、淀粉酶等,结合茅台的生产流程分析了其产香的可能机制,得到结论：芽孢杆菌在大曲发酵过程中产生蛋白酶和淀粉酶等多种酶类和代谢物质,进而在高温、偏酸环境下通过美拉德反应产生吡嗪等多种茅台酒特征香味物质。     

美拉德反应所引起的食品安全问题的研究进展

美拉德反应赋予了食品独特的风味,至今被用于食品加工工业,但是近二十年的研究发现美拉德反应也会产生许多对人体有害的化学物质。对美拉德反应产物中有毒物质的研究现状进行了综述,以及在参考国外做法的基础上倡议相关部门制定相应的检测和最高含量的限制标准,并对食品工业今后的发展做出了展望。     

美拉德反应机理研究新进展

美拉德反应在食品、生物体系中具有重要的意义。现在一般接受的反应机理是:开环形式的Amadori重排产物经1、2—和2、3—烯醇化,然后进行脱水,但这一假说不能很好地说明模拟体系中美拉德反应产物的形成途径。新近提出的现状Amadori产物直接脱水机理则能对反应过程中杂环和多聚产物的来源作出很好的解释。该机理对美拉德反应的控制,风味化学研究都具有直接的指导意义。     

酒精体系下美拉德反应的研究进展

美拉德反应过程复杂,产物多样,且其反应产物在食品体系中广泛存在,有些产物进入人体后在体内累积并影响健康。目前国内对水相体系中的美拉德反应研究较多,非水相中的研究颇少。然而,我国作为酒类饮料饮用大国,酒精对美拉德反应的影响尚不明确。因而以酒精媒介为切入点,通过研究酒精体系下的美拉德反应从而实现对其有害产物的有效控制,将对提高酒精饮料食品安全发挥重要的作用。从酒精体系对美拉德反应产物的影响和酒精体系中不同的环境因子对美拉德反应的影响两方面的研究进展进行综述。     

美拉德反应与肉的风味

美拉德反应、脂质氧化以及硫胺素的降解是形成肉类香味物质的主要途径，美拉德反应产物除了直接形成风味物质外，还会形成二羰基化合物，与脂质和硫胺素的降解产物反应生成肉香味的化合物。本文还介绍了美拉德反应以及美拉德反应产物在肉制品中的应用。     

贻贝煮汁酶解液美拉德反应条件优化及其产物氨基酸组成分析

为提高对贻贝副产物的利用,以木瓜蛋白酶水解贻贝煮汁得到的酶解液为原料,经联合脱腥后进行美拉德反应,以感官评价及褐变程度为指标,研究影响贻贝煮汁酶解液美拉德反应呈味效果的各因素,并通过单因素试验及响应面试验设计优化工艺条件,以获得氨基酸态氮含量高且色泽风味好的产物。结果表明：响应面优化的美拉德反应最佳工艺条件为还原糖添加量3.3%、氨基酸添加量3.1%、加热时间55 min、初始pH 8.0,经高效液相色谱测定,贻贝煮汁液和美拉德反应产物中均检测出17 种氨基酸,在最优条件下的美拉德反应产物中,总氨基酸及必需氨基酸含量与煮汁液相比,分别增加了315.91%和428.84%。可见,经美拉德反应后的产物在营养和风味上均优于贻贝煮汁液,是研制新型贻贝调味品的理想原料。     

美拉德反应与食品工业

综述了美拉德反应的化学反应过程、研究状况以及其在食品加工与贮藏过程中对食品色泽、香味以及营养与卫生的重要影响。     

牡蛎酶解液-葡萄糖美拉德反应前后体系的溶解特性及氨基酸组成分析

以牡蛎酶解液(oyster enzymatic hydrolysate,OEH)与葡萄糖建立美拉德反应体系,采用化学方法和高效液相色谱法测定美拉德反应前后体系的氮溶解指数(nitrogen solublility index,NSI)、三氯乙酸-氮溶解指数(trichloroacetic acid-nitrogen solublility index,TCA-NSI)及氨基酸组成变化,研究美拉德反应体系的溶解特性及以不同形式存在的氨基酸对美拉德反应的贡献及美拉德反应活性。结果表明,美拉德反应产物(Maillard reaction products,MRPs)的溶解特性显著高于OEH,在pH 3. 5～9. 0,NSI值在95. 15%～98. 08%,TCA-NSI值达到94. 73%,有94. 73%的蛋白质以游离氨基酸和小分子肽的形式存在。OEH中的游离氨基酸和肽均参与了美拉德反应,肽的美拉德反应活性要高于游离氨基酸,总氨基酸中参与美拉德反应的主要氨基酸为Arg、Trp、His、Tyr、Gly、Lys、Thr、Ser、Ala 9种,游离氨基酸中的主要氨基酸为Val、Ala、Leu、Gly、His、Arg 6种,肽中的主要氨基酸为Tyr、Arg、Trp、Ser、His、Pro、Lys 7种。     

美拉德反应及其产物在食品改性中的应用研究进展

近年来,随着食品工业的发展,美拉德反应在食品加工中应用广泛。该文阐述美拉德反应的机理、美拉德反应产物（Maillard reaction products,MRPs）的制备方法、美拉德反应及其产物在食品改性中的应用,并对美拉德反应及其产物的研发提出了展望,以期为从事该方面研发工作的科技工作者提供新思路。     

美拉德反应法制备鸡肉味香精

实验是利用鸡骨架酶解液为原料,通过美拉德反应制备鸡肉味香精。探讨了还原糖的添加量,反应温度,反应时间,pH值等因素对鸡肉香精热反应体系的影响,并得到制备鸡肉味香精的各因素最佳水平组合,即当木糖添加量为2.5%,反应pH为8,反应温度为120℃,反应时间为25 min时的美拉德反应产物具有优良的鸡肉香精风味。     

The poetics and politics of curriculum as representation

The notion of knowledge that is expressed in current notions of curriculum is fundamentally realist. Curriculum is not, however, as the realist notion implies, a site of transmission of knowledge conceived as a mere revelation of the 'real'. Curriculum is itself a representation: not only a site in which signs that are produced in other places circulate, but also a place of production of signs in its own right. To conceive of curriculum as representation means to highlight the work of its production. There is a place here for a poetics of curriculum. However, to understand the curriculum as representation means also to emphasise its political effects. Representation is always authorised representation: the text that constitutes curriculum is not simply a text; it is a text of power. To conceive of curriculum as representation implies to see it simultaneously, inseparably, as a poetics and as a politics.     

Biovanillin from agro wastes as an alternative food flavour

This review provides an overview of biovanillin production from agro wastes as an alternative food flavour. Biovanillin is one of the widely used flavour compounds in the foods, beverages and pharmaceutical industries. An alternative production approach for biovanillin as a food flavour is hoped for due to the high and variable cost of natural vanillin as well as the limited availability of vanilla pods in the market. Natural vanillin refers to the main organic compound that is extracted from the vanilla bean, as compared to biovanillin, which is produced biologically by microorganisms from a natural precursor such as ferulic acid. Biovanillin is also reviewed as a potential bioflavour produced by microbial fermentation in an economically feasible way in the near future. In fact, we briefly discuss natural, synthetic and biovanillin and the types of agro wastes that are useful as sources for bioconversion of ferulic acid into biovanillin. The subsequent part of the review emphasizes the current application of vanillin as well as the utilization of biovanillin as an alternative food flavour. The final part summarizes biovanillin production from agro wastes that could be of benefit as a food flavour derived from potential natural precursors.© 2012 Society of Chemical Industry     

Changes in the nutrient quality of meat in an obesity context

Today, being either overweight or obese is becoming the norm both in developing and developed countries. Developing countries often experience a double burden of nutrition-related diseases, as both over and undernutrition are experienced, with overweight presently exceeding underweight in most developing countries. Global diet trends such as moving from a traditional diet to more refined foods and increased sugar and saturated fat intake are identified as contributing to excess energy intake. The nutritional content of meat is non-homogenous and dynamic and meat has changed considerably in fat content, in many countries, during the last decade due to consumer demand. Choosing a particular meat cut of a specific fatness level, prior to cooking and consuming it without added high energy condiments, as well as trimming on the plate, can make a significant contribution to decrease energy intake, from a total diet perspective. Prudent portion size is also of importance. Meat is recognised as an important source of protein, vitamin B(12), Vitamin D and essential Omega 3 fatty acids, as well as bio-available minerals such as iron, zinc and selenium.     

四氯化碳玻璃试管法测定面粉含砂量探讨

小麦粉含砂量测定是时小麦加工成面粉工艺流程环节的评判,也是反映面粉质量的一项重要指标.笔者通过多年实践,采用一种简单装置来代替现用的球型漏斗装置,该装置既保证粉与泥砂的分离效果.又做到省时、省力、省费用.     

浅谈企业局域网信息安全

企业局域网是一个采用Internet技术建立的机构内联网络。它以TCP/IP协议作为基础,以Web为核心应用,构成统一和便利的信息交换平台。针对企业局域网络中存在的各种不安全因素,管理的不完善、人为的蓄意破坏以及技术上的漏洞等问题,设计一套符合企业局域网实际的安全方案,并阐述了方案的具体内容和作用。     

Human Milk Composition and Preservation: Evaluation of High-pressure Processing as a Nonthermal Pasteurization Technology

Human milk is seen not only as a food, but as a functional and dynamic biologic system. It provides nutrients, bioactive components, and immune factors, promoting adequate and healthy growth of newborn infants. When mothers cannot supply their children, donated breast milk is the nutrition recommended by the World Health Organization, as it is a better alternative than infant formula. However, because of the manner in which donor milk is handled in human milk banks (HMB) many of the properties ascribed to mother's own milk are diminished or destroyed. The major process responsible for these losses is Holder pasteurization. High-pressure processing (HPP) is a novel nonthermal pasteurization technology that is being increasingly applied in food industries worldwide, primarily as an alternative to thermal treatment. This is due to its capacity to inactivate microorganisms while preserving both nutritional and bioactive components of foods. This review describes human milk composition and preservation, and critically discusses HMB importance and practices, highlighting HPP as a potential nonthermal pasteurization technology for human milk preservation. HPP technology is described and the few currently existing studies of its effects in human milk are presented.     

Taxonomic free sorting

Free sorting is a quick and reliable means to assess similarities among a set of stimuli by a panel of subjects. In this procedure, subjects form as many groups of stimuli as they consider necessary, with the understanding that each group is formed with stimuli that are perceived as similar. However, no information is available about the structure of the groups formed by each subject. In practice, these groups are considered as equally distant from each other. This is a questionable assumption as it may not reflect the perception of the subjects towards the stimuli. Taxonomic free sorting is designed to cope with this problem. Once the subjects have achieved the free sorting of the stimuli, they are instructed to organize, step by step, the stimuli into a hierarchical structure thus giving more insight into the similarities among products. Statistical treatments of the data thus obtained are discussed and the procedure of evaluation is illustrated on the basis of a case study.     

PLC在人造板调供胶控制中的应用

介绍了PLC控制的调供胶系统。该系统以CPU226为控制主机、以触摸屏为人机界面、以变频器为主要操作对象,具有操作简单、可靠性高等特点。在程序中使用了PID调节功能。详细介绍了系统配置、主要问题的解决和编程思路。     

Extraction and quantification of main pigments in pesto sauces

Pesto is a widely diffused Italian pasta sauce, whose main ingredient is basil. Since its appearance is a key factor for marketing, the determination of its pigment content is of fundamental interest. To this aim, a method for the determination of pesto pigments by C18-HPLC is proposed. Only β-carotene was determined directly by Vis-spectrophotometry, as a consequence of sample purification over a silica cartridge. The proposed method is reliable allowing, for the first time, an easy determination of chlorophylls, pheophytins, lutein and β-carotene in a complex matrix such as pesto. The results show great differences in pigment composition among the samples, with pheophytins as the main components. Only non-thermally processed product show appreciable chlorophyll content as a consequence of the different production technique. Principal Component Analysis performed on the pigment contents showed great variability among the different samples.     

纽甜(Neotame)--一种新型强力甜味剂

纽甜是一种新型的强力甜味剂,它是阿斯巴甜的衍生物,甜味比蔗糖甜7000~13000倍,比阿斯巴甜甜30~60倍。其能量值几乎为0且甜味纯正,清新且没有不愉快的风味。纽甜不仅可以广泛用于食品和饮料中,而且可以单独食用或与其它强力甜味剂或多糖混合使用。它在干燥或中性的条件下都十分稳定,尤其在含水的食品体系中要相对稳定。