菊粉、低聚果糖的研究进展

菊粉又名菊糖,经水解后可生成低聚果糖,菊粉和低聚果糖是一种重要的益生元（即双歧因子）,本文主要论述了菊粉与低聚果糖的制取工艺、物化性质、生理功能及应用。     

乳酸菌代谢低聚果糖/菊粉途径及机理的研究进展

合生元又称合生素,指益生元与益生菌结合使用的生物制剂（微生态制剂）,近年来,越来越多研究表明合生元具有多种益处,益生元和益生菌的选择对其最终效果起着至关重要的作用。低聚果糖和菊粉是合生元中常见的益生元,可被肠道内的乳酸菌选择性吸收,通过促进益生菌增殖的方式来改善机体健康。本文综述了乳酸菌对低聚果糖和菊粉的代谢差异及代谢途径,并从分子水平阐述水解酶、转运系统、调控蛋白的作用机制,以期为探明乳酸菌调控低聚果糖和菊粉的代谢网络提供依据;同时总结了近年来低聚果糖/菊粉合生元的应用,为益生元与益生菌的进一步联用提供参考。     

不同功能性低聚糖的益生元功效比较

随着消费者健康意识的不断增强,功能性食品倍受关注.益生元,作为一种功能性食品配料,成为新一代功能性食品的主要角色,目前已广泛应用于国内外各类食品中.为使食品企业和消费者更清楚地了解益生元,更科学客观地选择益生元,本文在国内外大量文献的基础上,对市场上常见的几种功能性低聚糖(如低聚异麦芽糖IMO、低聚果糖FOS、低聚半乳糖GOS、低聚木糖XOS)的益生元功效进行了比较分析.     

低聚糖类益生元对炼乳品质的影响

目的 为实现炼乳的减糖,研究不同低聚糖类益生元替代蔗糖对炼乳品质的影响。方法 选用低聚果糖、低聚异麦芽糖、低聚木糖、低聚半乳糖四种低聚糖类益生元分别作为蔗糖替代物,研究不同替代比的益生元炼乳体系质构、流变、感官、色泽、晶体大小的变化,得到最佳糖替代益生元及替代比例。结果 综合考虑质构、色泽、晶体大小、喜好度排序感官四种指标表明,低聚果糖炼乳和低聚异麦芽糖炼乳品质较为优良,其中低聚果糖炼乳可接受的替代比为15%以内、低聚异麦芽糖炼乳可接受的替代比为25%以内。进一步通过静态流变学试验表明低聚异麦芽糖是最佳糖替代物质,在炼乳体系中其最佳替代比为15%。结论 糖替代比15%的低聚异麦芽糖炼乳既满足了甜感需求,又实现了减糖的目标,此外益生元的加入赋予了炼乳更多的功能性。该研究可为炼乳产品的减糖开发提供一定的理论依据和技术支持。     

低聚果糖的生理功能及生产、应用

低聚果糖是一典型益生元,本文就其生理功能,Fm和GFn两种类型的低聚果糖的制法和它们在食品工业中的应用做一介绍。     

低聚果糖生物学功效及生产技术的研究新进展

低聚果糖是一种优质的益生元,现已成为了重要的功能性食品基料。目前,低聚果糖的生产主要以天然植物酶解和果糖基转移酶法为主,其具有独特的生物学功效,如调节肠道内菌群平衡,改善脂质代谢,促进矿物质元素吸收以及增强免疫力等益生作用,现已广泛应用于食品、保健品、以及饲料领域,是我国第三代保健食品组方首选的功能因子之一。     

益生元对益生菌生长代谢的研究

益生元是一种理想的人体膳食补充剂,可促进益生菌的生长代谢.本试验从活菌数、产酸能力、胞外多糖产量和双乙酰产量4个方面,研究了多种益生元,如低聚果糖、低聚半乳糖、低聚异麦芽糖、低聚木糖、聚葡萄糖、抗性糊精和菊粉对复合益生菌(干酪乳杆菌、鼠李糖乳杆菌)发酵代谢的影响.结果表明,低聚木糖对活菌数和产酸能力具有明显提升作用;抗...     

添加益生元对酸乳凝胶过程及微观结构的影响

为研究菊粉、低聚果糖和低聚半乳糖3 种益生元对酸乳凝胶过程及微观结构的影响,以未添加益生元的酸乳为对照,利用光学微流变仪、Turbiscan稳定分析仪和扫描电子显微镜分别检测添加益生元酸乳在发酵期间及后熟贮藏期间流变学参数、稳定性和微观结构,并进行对比研究。结果表明：添加菊粉更有助于酸乳形成较为均匀、疏松的微观结构;含低聚果糖的酸乳固液平衡值低于0.5,更有利于增强酸乳的固体性质;添加低聚半乳糖的酸乳微观稳定性较好。因此,3 种益生元对酸乳的凝胶过程及微观结构的影响各不相同,未来还可对3 种益生元进行复配处理,添加到酸乳中进一步探究对其综合品质的影响。     

不同益生元对青春双歧杆菌耐胆盐能力的影响

为了解水苏糖、低聚异麦芽糖、低聚果糖3种益生元对青春双歧杆菌耐胆盐能力的影响情况,该研究在PTYG液体培养基中分别添加不同浓度的3种益生元.并在不同的胆盐浓度梯度下进行青春双歧杆菌耐胆盐能力的研究.结果表明,3种益生元均可提高青春双歧杆菌耐胆盐能力,低聚异麦芽糖的效果最好;在猪胆盐浓度为0.3%的PTYG液体培养基中,水苏糖、低聚异麦芽糖、低聚果糖提高青春双歧杆菌耐胆盐能力的最适添加量分别为1.0%、1.5%、O.2%,其中低聚异麦芽糖的添加量(1.5%)提高青春双歧杆菌耐胆盐能力的效果最好.     

低聚果糖的理化特性、生理功效及其应用

低聚果糖是一种典型的益生元,是一种符合当代健康理念的新型糖源。研究显示,动物或人体摄食低聚果糖,可增殖肠道中的双歧杆菌,改善肠道菌群;润肠通便,缓解便秘症状;降低血液中的脂质和胆固醇的含量,改善脂质代谢;抑制肠道中腐败物质的产生,促进钙镁等矿质元素的吸收;增强机体免疫力,降低患癌风险等。优良的理化特性和生理功效,使低聚果糖在食品、保健品、饲料等行业中得到了广泛应用。在我国,低聚果糖的研发已有20余年的历史,无论是基础研究还是应用研究都取得了较大的进展,但与国际先进水平相比仍有一定差距。本文综述了低聚果糖的理化特性、生理功效及其应用,并对当前国内低聚果糖研究领域存在的不足及今后的发展进行了讨论。     

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.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

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.