柠檬烯微生物转化及其相关酶的研究进展

柠檬烯是一种重要的功能性单萜,被广泛应用于医药、化妆品、农业和食品等行业中。但柠檬烯的化学性质不稳定,香气值较低,所以其应用受到一定的局限性。而具有与柠檬烯相同骨架的含氧单萜芳香化合物,如α-松油醇、紫苏醇、香芹醇等,不仅具有独特的芳香气味,是高级香精香料的原料,而且还具有较高的经济价值和药理作用。利用微生物法制备的含氧单萜可以被认为是"天然的"。微生物转化法拥有反应条件温和、高效、环保及立体选择性强等优势,已经成为生产天然香料的重要方法。本文对柠檬烯的微生物转化产物作了简要概述,重点介绍了近年来柠檬烯微生物转化的相关研究,进一步总结了柠檬烯微生物转化涉及到的相关酶,尤其是细胞色素P450酶、羟化酶等。最后概述了微生物转化实现工业化的研究方向。     

生物转化法合成天然香料香精

分析了生物转化法合成天然香料香精的优势与发展前景,概述了生物转化法合成天然香料香精的基本原理,介绍了生物转化法合成天然香兰素和2-苯乙醇的方法,旨在推动对生物转化法合成天然香料香精的研究和开发。     

生物合成天然2-苯乙醇细菌的筛选及合成途径分析

从上海国家森林公园土壤样本中筛选到1?株菌株,经过生理生化鉴定和16S rDNA序列分析,该菌属肠杆菌属并命名为Enterobacter sp. MF024。Enterobacter sp. MF024全基因组测序结果表明该菌株包含从头合成途径和艾氏途径合成2-苯乙醇所有关键酶的编码基因。分别以葡萄糖、L-苯丙氨酸为底物进行生物转化实验,并以苯乙醛、苯丙酮酸等合成途径中间产物为底物进行验证,气相色谱-质谱法、红外光谱分析结果进一步说明Enterobacter sp. MF024具备两种2-苯乙醇合成途径,且该菌利用从头合成途径和艾氏途径产2-苯乙醇产量分别达到0.56、1.15 g/L。该菌株以葡萄糖为碳源生物合成2-苯乙醇极具应用前景。     

发酵类食品中微生物鉴定方法及功能研究进展

发酵类食品是主要通过直接接种微生物而产生特殊风味或者将食物浸入含有微生物的臭卤水中,从而获得特殊食品风味的中国传统食品。其中,采用含有微生物的卤水进行发酵是常见的发酵方式。因此,微生物在该类食品中一直扮演着一种非常重要的角色,具有较高的研究价值。本文阐述了发酵类型的食品所需要的卤水中微生物的鉴定常用方法,以及卤水微生物与风味成分的产生之间的关系,同时论述了卤水中微生物在各种发酵食品制作过程中所起到的功能特性,包括提高豆制品的营养价值、延长保质期、去除有害成分等问题,并提出了较为可行的新型发酵类食品卤水改进方向,为进一步开发理想的食品微生物发酵剂,控制有害物质的残留、拓展相关有益微生物资源的研究提供较为明确的指导方向。     

Aspects of biotechnological production of food flavors

Abstract

Three principle technologies and their potential application for bioflavor production are discussed: (i) plant tissue and cell culture, (ii) use of microorganisms, and (iii) use of enzymes. Plant cell and tissue cultures have been received by scientists with great enthusiasm; however, we have now to realize that much more must be learned about chemical and genetic regulation of plant secondary metabolism before any commercial production becomes a reality. Fermentations and microbial transformations are already used in flavor production and there is no doubt that these technologies will become more significant factors in the production of flavor chemicals in the future. As to enzymes, technical biocatalysts already play a role in stereoselective production of fine chemicals. Regarding natural flavors, we have to intensify our studies on biochemistry and bioregulation of enzymic activities from both plants and microorganisms. If this is done, the use of enzymes for the production of complete natural flavors will be realized in the future.     

电子鼻在烟用香精香料检测中的应用

利用电子鼻对香气香味很接近并且类型未知的烟用香精香料进行检测,对获得的数据进行主成分分析(PCA)和统计质量控制分析(SQC),结果表明:电子鼻能够对人工难以识别的烟用香精香料进行快速、准确的识别,并且以图形的形式得到直观、易懂的分析结果,可作为烟用香精香料的品质控制的一种客观、可靠的重要手段。     

食品中香料香精分析方法研究进展

近年来随着生活水平的提高,消费者在追求食品健康安全的同时更看重口味的变化,促进了食用香精的快速发展。但是香料香精的过量使用和非法添加违禁成分等问题依然突出,对消费者的健康造成潜在危害,因此,对食品中香料香精成分进行高通量、灵敏、快速的分析十分必要。本研究综述了食品中香料香精分析方法的前处理技术,包括蒸馏法、固相萃取法、超临界流体萃取法和顶空法等样品前处理方式,详细介绍了各种方法的原理、优缺点及适用范围。对香料香精的检测方法进行了介绍,包括气相色谱串联质谱法、全二维气相色谱串联质谱法、气相色谱嗅觉测量技术、电子鼻电子舌技术、稳定同位素质谱技术、超临界流体色谱技术等检测方法,并对其未来发展进行了展望,以期为食品中香料香精检测技术的发展提供参考。     

食品用萜类化合物的生物合成研究进展

萜类化合物在食品中有重要的应用,可用作香精香料、甜味剂、营养强化剂等,作为一类天然添加剂而受到人们的青睐。生物 合成法作为萜类化合物合成中最具发展潜力的方法而备受关注。 该文从萜类化合物在食品中的应用,萜类化合物生物合成途径,微 生物合成萜类化合物的研究进展三方面进行介绍,旨在为生物合成食品用萜类化合物的研究提供参考。     

天然香精香料与生物技术

天然香精香料是高价值的精细化工产品和食品添加剂,但原料来源有限且提取成本高。利用生物技术生产这类产品具有广阔的前景。简述了发酵工程、酶工程、细胞工程和基因工程在香精香料中的应用,并探讨了生物技术在香精香料中的应用前景。     

乳酸菌生物转化药食同源植物活性成分研究进展

随着人们对营养与健康意识的不断提高,植物基食品尤其是药食同源类植物近年来受到极大关注,其主要活性物质包括皂苷、黄酮、多糖及挥发油等,而作为传统及现代食品发酵工业中常用发酵剂菌种的乳酸菌,属于人体肠道内固有有益微生物,具有良好的生物转化及促进人体健康的作用.因此,利用具有高安全性的乳酸菌发酵转化药食同源植物以产生更多活性...     

Liposomal nanocapsules in food science and agriculture

Liposomes, spherical bilayer vesicles from dispersion of polar lipids in aqueous solvents, have been widely studied for their ability to act as drug delivery vehicles by shielding reactive or sensitive compounds prior to release. Liposome entrapment has been shown to stabilize encapsulated, bioactive materials against a range of environmental and chemical changes, including enzymatic and chemical modification, as well as buffering against extreme pH, temperature, and ionic strength changes. Liposomes have been especially useful to researchers in studies of various physiological processes as models of biological membranes in both eukaryotes and prokaryotes. Industrial applications include encapsulation of pharmaceuticals and therapeutics, cosmetics, anti-cancer and gene therapy drugs. In the food industry, liposomes have been used to deliver food flavors and nutrients and more recently have been investigated for their ability to incorporate food antimicrobials that could aid in the protection of food products against growth of spoilage and pathogenic microorganisms. In this review we briefly introduce key physicochemical properties of liposomes and review competing methods for liposome production. A survey of non-agricultural and food applications of liposomes are given. Finally, a detailed up-to-date summary of the emerging usage of liposomes in the food industry as delivery vehicles of nutrients, nutraceuticals, food additives, and food antimicrobials is provided.     

我国西部野生食品资源开发前景广阔

<正> 中国西部7省,包括四川、云南、贵州、陕西、甘肃、青海、宁夏,地跨亚热带、温带两个气候带,地貌多样,生态复杂,野生资源得天独厚,特别是天然的食品资源,不仅品种丰富,而且绝无污染之嫌。在目前崇尚“天然的返朴归真”的世界食品业中,这些野生资源就更为珍贵了。     

新剂型香精及其包埋技术的应用

新剂型香精区别于传统液体香精的地方在于采用了包埋技术,将各种保护性壁材以不同方式和过程包覆香精,从而保护香精,赋予香精更优越的性能。文中介绍了五种新剂型香精:分子胶囊香精、纳米胶囊香精、微胶囊香精、颗粒香精、爆珠香精,并阐述了其制备方法及优缺点。     

发酵乳风味物质乙醛、双乙酰的合成途径及其调控机制

乳酸菌在发酵过程中能够产生醇、醛、酮等多种风味物质,这些风味物质和乳酸菌在糖酵解过程中产生的乳酸、生醋酸、丙酸等有机酸相互作用,形成具有独特风味的发酵乳。在酸奶的风味物质中,乙醛、双乙酰是其主要成分。目前,关于酸奶风味物质研究的焦点主要集中在通过改变乙醛、双乙酰的代谢途径提高乙醛、双乙酰的产量上。这篇综述主要描述了乳酸菌在酸奶发酵过程中生产的风味物质、以及乙醛、双乙酰的合成途径和国内外学者在乙醛、双乙酰产量调控方面取得的研究成果。     

Biogenic amines in dairy products

Biogenic amines (BA) are organic, basic, nitrogenous compounds with biological activity, mainly formed by the decarboxylation of amino acids. BA are present in a wide range of foods, including dairy products, and can accumulate in high concentrations. In some cheeses more than 1000 mg of BA have been detected per kilogram of cheese. The consumption of food containing large amounts of these amines can have toxicological consequences. Although there is no specific legislation regarding the BA content in dairy products, it is generally assumed that they should not be allowed to accumulate. Greater knowledge of the factors involved in the synthesis and accumulation of BA should lead to a reduction in their incidence in foods. This article focuses on the factors that affect BA production, in particular environmental conditions, the microorganisms that produce them, the genetic organization and regulation of the biosynthetic pathways involved, and the available methods for detecting the presence of BA or BA-producing microorganisms in dairy products.     

d‐Mannose: Properties,Production, and Applications: An Overview

d ‐Mannose is a C‐2 epimer of d ‐glucose, which is a natural monosaccharide. It can be obtained from both plants and microorganisms. Chemical synthesis and biotransformation of d ‐mannose from d ‐fructose or d ‐glucose by using d ‐mannose isomerases, d ‐lyxose isomerases, and cellobiose 2‐epimerase were intensively studied. d ‐Mannose is an important component of polysaccharides and glycoproteins. It has been widely used in the food, pharmaceutical, and poultry industries, acting as the source of dietary supplements, starting material for the synthesis of drugs and blocking colonization in animal feeds. d ‐Mannose is a glyconutrient with high research value in basic science because of its structure and function. This article presents a review of current studies on sources, characteristics, production, and application of d ‐mannose.     

EVALUATION OF BIOGENIC AMINES FORMATION BY PROTEOLYTIC ENTEROCOCCI STRAINS ISOLATED FROM RAW DROMEDARY MILKS FROM SOUTHERN ALGERIA

Twenty-three strains of lactic acid enterococci isolated from dromedary raw milks in Southern Algeria were investigated for their proteolytic activity and ability to produce biogenic amines by decarboxylating amino acids: histidine, tyrosine and ornithine. All strains tested displayed proteolytic activities, but none of them were able to produce detectable biogenic amines in the usual adequate laboratory media, namely, Joosten and Northolt medium and Leuschner medium. Polymerase chain reaction experiments indicate a positive correlation between the absence of the hdc and odc genes and the lack of histamine and putrescine production for all tested strains. By contrast, all strains appeared to possess tdc gene, but no correlation was found with a negative expression of tyrosine decarboxylase.

PRACTICAL APPLICATIONS

In foods, biogenic amines are mainly generated by decarboxylation of the corresponding amino acids through substrate-specific enzymes of the microorganisms present in this environment, particularly histidine, tyrosine, lysine, ornithine and arginine, and the capability of enterococci and some other lactic acid bacteria to produce biogenic amines has been described. For this purpose, several qualitative and quantitative methods to determine biogenic amines production by these microorganisms have been developed. There is great interest to identify and to characterize the bacteria strains intended for an industrial use and to verify if they are potentially able to produce biogenic amines in order to prevent it's synthesis and limit the poisoning risk.     

巧克力市场与萃取新技术

我国的巧克力市场正处于一个十分重要和关键的时刻,过去几年间,不断的有新公司雄心勃勃地进军这个市场,然而过不了多久又悄然退出,原因何在呢? 另一方面,市场上出现了一项新式的榨制技术,可用于提取芳香物质,香精和香油,而不会改变产品的天然性质,其原理何在呢?在这篇文章里,我们将就这两方面作出简单的探讨。     

食品中香精香料检测前处理技术研究进展

综述食品中香精香料检测的前处理技术,包括蒸馏法、液相萃取法、固相萃取法和顶空法等样品前处理方式,详细介绍各种方法的原理、优点及适用范围,为食品香精香料检测技术的发展提供参考。     

从头合成赤松素大肠杆菌工程菌的构建

赤松素是高价值芪类保健营养品白藜芦醇的类似物,具有预防心血管疾病、抗癌和治疗关节炎等与其相对应的多种生物活性。本研究采用基因工程手段创制出一种从头生物合成赤松素的方法,以缓解目前赤松素供求不足的问题。把带有苯丙氨酸解氨酶(PAL),肉桂酸辅酶A连接酶(4CL)和赤松素合酶(STS)编码基因的组成型表达载体转化高产L-苯丙氨酸大肠杆菌ATCC31884,并通过PCR鉴定后,获得重组工程菌株。工程菌进行摇瓶培养,对培养液进行高效液相色谱检测,确定工程菌具有生物合成赤松素的能力。随后通过对工程菌在不同培养时间产物生成量的比较,结果表明,赤松素在发酵12 h后增长缓慢,24 h培养液中的赤松素含量最高,为0.32 mg/L,而其中间体肉桂酸的积累最高达到52.92 mg/L。这表明,大肠杆菌工程菌能在不添加任何前体物的情况下,利用自身代谢从头合成赤松素,但中间体肉桂酸的转化能力不足,有待下一步实验进行改善。