植物抗冻蛋白分离纯化方法的研究进展

为植物抗冻蛋白是一类具有热滞活性的蛋白质,它能抑制冰晶的生长和重结晶。因其特殊的结构和功能,植物抗冻蛋白对延长冷冻食品的贮藏期和提高产品质量具有积极意义。从复杂提取液中高效分离纯化出抗冻蛋白已成为当前热点和难点问题,作者介绍了近年来植物抗冻蛋白分离纯化方法的基本原理和研究进展,主要有传统层析分离方法、SDS-PAGE电泳、冰特异吸附分离法和浊点萃取法,展望了抗冻蛋白分离纯化方法的未来发展方向。     

抗冻蛋白及其在食品加工中的功能

来源于寒带海洋鱼类的抗冻蛋白具有抑制冰结晶的生长的作用 ,包括抑制重结晶 ,同时还具有影响冰晶组织结构的作用。鱼体内存在着较高浓度的抗冻蛋白 ,大约为30 mg/ ml左右 ,是一些肽类或一些小蛋白分子 ,大部分的氨基酸数不超过 40个。抗冻蛋白的结构蛋白既有糖蛋白也有非糖蛋白 ,其中一些已可以通过化学方式合成。目前 ,抗冻蛋白应用在食品中最成功的实验是将其添加到冷冻乳制品中以减少重结晶现象。但是显而易见 ,成本问题是影响其在食品中应用的最大障碍。也是食品科研工作者所需研究的关键。     

食品新秀抗凝蛋白

从在寒冷海水中生存的鱼体内提取的抗凝蛋白,具有抑制冰的再结晶作用。 控制冰冻食品内冰晶体的增加是一项很难的工作,所以,食品专家对抗冻蛋白的作用很感兴趣。 除了能够降低水结冰的温度,抗冻蛋白还能大大地抑制冷冻食品再结晶作用和抑制在贮藏和融化期间大块冰晶的相应增加。 食品专家研究抗凝蛋白已经近３０年,主要是研究它们的结构、功能和作用机制。最早发现生活在南极和北方的海鱼的血液和组织能够使鱼抗冻,而其它鱼却难以忍受如此的低温。 研究表明,食品中添加了这些物质确实有用。如果它们能合理地应用并在价格上被人接受,…     

抗冻蛋白研究进展及其在新型食品冷冻工艺中的应用

针对抗冻蛋白的研究现状,对抗冻蛋白的特性、抗冻机理及在食品工业中的应用等方面进行综述.阐述抗冻蛋白在食品领域实现商业化应用所存在的问题,提出可能的研究方向,并对抗冻蛋白发展及应用前景进行展望,提出高活性重组抗冻蛋白的研发、化学合成抗冻蛋白类似物和模拟物以及抗冻蛋白的酶促修饰等方法,以期望实现抗冻蛋白在大规模商业化食品生...     

特异性亲和吸附法纯化冬小麦麸皮抗冻蛋白

抗冻蛋白是一种可以非依数性降低体系冰点的蛋白质,在生命体内具有非常重要的生理作用,广泛地应用于食品、医学和生物技术等领域.首先通过热重分析仪法和分配系数法研究证明冬小麦麸皮抗冻蛋白(TaAFP)具有较强的亲水性和亲冰性,进一步使用特异性亲和吸附法对其纯化,产率1.64%,获得电泳纯TaAFP.纯化过程中充分利用其自身较强的亲水和亲冰的特性.该方法具有步骤少、耗时较短等优点,比传统的色谱方法更加快捷高效,但是对纯化过程的控制要求严格.     

抗冻蛋白及其应用前景

综述了抗冻蛋白(Antifreeze Protein,AFP)的分类,包含鱼类抗冻蛋白、植物抗冻蛋白、昆虫抗冻蛋白、真菌及细菌抗冻蛋白;并就其特性及提取方面进行了介绍。本文还介绍了近年来抗冻蛋白在食品行业、医学、农业等方面的应用进展:在食品行业作为食品添加剂,显著改善食品品质;在医学方面,作为冷冻保护剂成功实现了动物的卵母细胞、精子、胚胎、组织等的低温保存;在农业方面,利用基因工程的方法,得到具有抗冻蛋白基因的转基因植物,能显著提高其抗冻性。     

植物源抗冻蛋白作用机制及其在食品中的应用

抗冻蛋白是一类具有热滞活性的蛋白质,它能够与冰晶吸附结合,降低溶液冰点,阻止冰晶生长,而且可以抑制冰晶再结晶现象。因其特殊的结构和功能,抗冻蛋白对延长冷冻食品的贮藏期和提高冷冻产品质量具有积极意义。本文简述了植物源抗冻蛋白的研究概况,综述植物源抗冻蛋白在食品加工方面的作用机理和分离纯化方法及在未来食品领域的应用,以期为植物源抗冻蛋白在食品冻藏中的应用提供理论参考。     

抗冻蛋白及其在食品中的应用

阐述了抗冻蛋白的发现、分子结构、分类及其功能特性和抗冻机制，并讨论了抗冻蛋白在食品技术中的应用。     

抗冻蛋白的研究进展及其在食品工业中的应用

抗冻蛋白是一类具有热滞效应、冰晶形态效应和重结晶抑制效应的蛋白质,因其特殊的结构和功能,抗冻蛋白引起了研究人员的极大兴趣．探讨了近年来抗冻蛋白的研究进展,介绍了目前已知的抗冻蛋白的来源、特性、测定方法、基因结构及在食品工业中的应用．抗冻蛋白对冷冻食品有显著的品质改良功能,是未来冷冻食品工业中极具潜力的抗冻添加剂．     

抗冻蛋白及其在食品工业中的应用

抗冻蛋白是具有热滞性 ,能改变冰晶的形态和抑制冰重结晶的一类蛋白质 ,本文简要介绍了各种抗冻蛋白的结构、功能、特征。对其在冷冻食品工业的原料生产、加工、和储藏运输中的应用及存在的问题进行了系统的综述     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.     

低温带皮菜籽粕微粉的不同粒级部分的功能特性

为研究低温带皮菜籽粕微粉的不同粒级部分的功能特性,以经低温脱脂的带皮菜籽粕为原料,经微粉碎后筛分成212~425μm、150~212μm和106~150μm的3个不同粒级的微粉样品,检测这些样品的吸水性、吸油性、乳化性和乳化稳定性、蛋白质体外消化率。结果表明:1 3个不同粒级的微粉样品之间的粗纤维含量存在显著差异,表明三者的结构组成成分有一定差异。23个微粉样品的乳化活性和乳化稳定性随粒度级别的减小而显著增加(P0.01)。33个微粉样品的蛋白质体外消化率随粒度级别的减小而显著增加(P0.01)。4不同粒级带皮菜籽粕微粉样品的吸水性与吸油性受其结构组成物质不同和粒度的双重影响,与粒度的相关性不明显。     

Microbiology of food taints

Fresh and processed foods are often spoilt by the presence of undesirable flavours and odours caused by microbial action. The aim of this paper is to review the current knowledge of microbiologically induced taints that occur in a wide range of foodstuffs, including meats, poultry, fish, crustaceans, milk, dairy products, fruits, vegetables, cereals and cereal products. Examples have been chosen where the compounds responsible for the taint have been identified and sufficient data obtained to demonstrate the involvement of microorganisms. However, in some cases the full identity of the causative organism may not have been elucidated. The types of microorganisms covered by this review include bacteria, fungi, yeasts, actinomycetes and cyanobacteria. Although cyanobacteria do not in general infect foods, their presence in aqueous systems and water supplies can lead to off-flavours in aquatic organisms and processed foodstuffs. Several examples of each of these processes are discussed. Wherever possible, the likely biosynthetic pathway used by the microorganism to produce the offending compound in a foodstuff is indicated.