8种乳酸菌发酵对凤丹花瓣中酚类物质及其抗氧化活性的影响

为筛选合适凤丹花瓣发酵的乳酸菌菌种,比较了8种乳酸菌(植物乳杆菌、保加利亚乳杆菌、干酪乳杆菌、瑞士乳杆菌、鼠李糖乳杆菌、嗜酸乳杆菌、副干酪乳杆菌和嗜热链球菌)发酵凤丹花瓣后,其酚类物质、色差和抗氧化活性的变化。结果表明,植物乳杆菌发酵后的凤丹花瓣总酚和总黄酮含量分别提高了4.95%和12.51%(P0.05);色差值△E变化显著(P0.01);自由基清除活性最高,DPPH自由基清除率增加了11.14%(P0.01),ABTS自由基清除率增加了6.58%(P0.05),还原力增加了16.19%(P0.05)。经保加利亚乳杆菌发酵后,凤丹花瓣的芦丁和槲皮素分别提高了3.16%和0.81%(P0.05)。     

植物乳杆菌发酵马齿苋陈皮工艺优化及发酵液抗氧化活性分析

研究植物乳杆菌发酵马齿苋陈皮的工艺条件及发酵液的抗氧化活性。以总黄酮含量为指标,通过试验确定发酵工艺;通过测定DPPH自由基清除率、羟基自由基清除率和还原力,评价其抗氧化活性。结果表明发酵最佳工艺为发酵时间32 h,料液比1∶20（g/mL）,菌种接种量3%,发酵温度33℃。在最佳发酵工艺条件下所得发酵液的总黄酮含量为0.69 mg/mL,比发酵前总黄酮含量（0.52 mg/mL）提高了32.69%;发酵液DPPH自由基清除率提高了8.84%,羟基自由基清除率提高了38.14%,还原力提高了26.64%。     

桂圆酵素制备及其抗氧化性研究

桂圆酵素以桂圆水提液为发酵底物,选择益生菌为发酵菌种进行制备。以胞外多糖含量为评价指标,对发酵工艺进行研究,通过单因素试验和正交试验确定最佳发酵工艺条件:发酵底物浓度9%、接种量9%、菌种比例(保加利亚乳杆菌:嗜热链球菌:嗜酸乳杆菌:青春双歧杆菌=1:1:1:2)、发酵时间8 d,在此条件下制备的桂圆酵素原液胞外多糖含量达1.1086 mg/m L。抗氧化性研究结果表明,桂圆酵素原液具有DPPH自由基清除能力、羟基自由基清除能力及超氧阴离子自由基清除能力,具有一定的抗氧化活性。     

黄精发酵液制备工艺优化及其抗氧化活性分析

该试验以酵母菌和乳酸菌为混合菌种,以黄精发酵液对1,1-二苯基-2-三硝基苯肼（DPPH）自由基清除率为评价指标,通过单因素和响应面试验优化黄精发酵液制备工艺条件,比较了黄精发酵液与黄精水提液的抗氧化活性差异,并分析了多糖、多酚和黄酮含量与抗氧化活性的相关性。结果表明,黄精发酵液制备工艺条件为发酵时间24 h,发酵温度41 ℃,混合菌种接种量2.1%,乳酸菌∶酵母菌比例2∶1,料液比1∶46（g∶mL）。在此优化条件下,黄精发酵液的羟基、DPPH、ABTS+自由基清除率分别为47.83%、91.40%和91.44%。黄精发酵液的抗氧化活性高于黄精水提液,且黄精发酵液多糖、多酚和黄酮含量显著高于黄精水提液（P＜0.05）。相关性分析结果表明,ABTS+自由基清除率与多糖和多酚含量显著正相关（P＜0.05）,DPPH自由基清除率与多糖、多酚和黄酮含量显著正相关（P＜0.05）。     

不同发酵菌种对大果山楂酵素品质的影响

以大果山楂为主要原料制备山楂酵素,通过使用不同的发酵菌种,即自然发酵、单菌种(酵母菌)、双菌种(酵母菌+醋酸菌)、三菌种(酵母菌+醋酸菌+乳酸菌),对发酵过程中的总酸度、总酚含量、超氧化物歧化酶(SOD)活力、酒精度、2, 2-联苯基-1-苦基阱基(2, 2-Diphenyl-1-picryldrazyl, DPPH)自由基清除率及感官评分进行测定分析,从而研究发酵菌种对大果山楂酵素品质的影响。结果表明:三菌种发酵的酸度较高,形成的总酚含量、SOD酶活力、DPPH自由基清除率较高,酒精度较低,综合感官评价得分较高,说明三菌种复合发酵制备的大果山楂酵素的品质最佳,其次为双菌种发酵,而单菌种发酵的酒精度较高,感官评分低于自然发酵,山楂酵素品质较差。     

益生菌发酵乳模拟胃肠液环境下抗氧化活性

为间接评价益生菌发酵乳在人体内的抗氧化活性,分别采用嗜热链球菌（Streptococcus thermophilus）、德氏乳杆菌保加利亚亚种（Lactobacillus delbrueckii subsp. bulgaricus）、动物双歧杆菌（Bifidobacterium）BB12及嗜酸乳杆菌（Lactobacillus acidophilus）制备SL、SL+BB12、SL+LA三种发酵乳,并对其冷藏过程中模拟胃肠液环境下对ABTS、DPPH自由基的清除能力进行了测定。结果表明,三种发酵乳随冷藏时间的延长其抗氧化活性都逐渐降低,添加菌种BB12和LA的发酵乳抗氧化活性下降的幅度小于SL发酵乳,在相同的冷藏时间下模拟胃肠液环境后抗氧化活性都较原发酵乳降低,但添加益生菌BB12和LA发酵乳在模拟胃肠液环境下抗氧化活性高于SL发酵乳,其中BB12高于LA。SL、SL+BB、SL+LA发酵乳冷藏7 d时对ABTS自由基最大清除率分别为46.21%、58.54%、51.99%,对DPPH自由基最大清除率分别为42.17%、53.34%、49.48%。     

松杉灵芝发酵物对乙醇诱导小鼠胃溃疡的保护作用研究

采用松杉灵芝发酵物处理酒精性胃溃疡模型的小鼠。观察各组小鼠胃组织病理学改变,测定血清中髓过氧化物酶(MPO)、超氧化物歧化酶(SOD)、丙二醛(MDA)、炎症因子白介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)含量及胃组织中Jn K蛋白、Er K蛋白、P38蛋白、NF-кBp65蛋白表达。松杉灵芝发酵物可有效减轻小鼠胃溃疡病理学变化,能显著提高小鼠血清中SOD水平、降低MPO、MDA及炎症因子IL-6、TNF-α水平;降低Jn K蛋白、Er K蛋白、p38蛋白、NF-кBp65蛋白表达水平。说明松杉灵芝发酵物对乙醇诱导的急性胃溃疡有保护作用。     

不同菌种发酵对铁皮石斛多糖及其生物活性的影响

为筛选出可增强铁皮石斛活性的菌种,以铁皮石斛粗多糖水提液为原料,采用6种常用菌种进行纯种发酵。测定发酵前后多糖含量、还原糖含量、多糖分子量、还原糖分子量4个指标并追踪发酵过程中发酵液的体外抗氧化活性和体外降血糖活性。结果显示:发酵可以提高铁皮石斛的抗氧化活性和体外降血糖活性,还原糖含量降低,除曲霉外,其余菌种发酵后多糖含量和多糖分子量均有所下降。面包酵母发酵后,发酵液抗氧化活性最强,对DPPH、OH、ABTS自由基的清除率依次为29.5%、38.2%和31.2%,相比未发酵空白分别提高了56.9%、60.5%和63.4%。红曲霉发酵后其发酵液对α-葡萄糖苷酶和α-淀粉酶的抑制活性最强,依次为26.3%和22.6%,相对发酵空白分别提高了78.9%和86.8%。     

不同菌种发酵乳品质与抗氧化能力研究

研究了由不同菌种制作的酸奶发酵乳在冷藏期21 d内品质、抗氧化活性的变化,研制具有高抗氧化活性的发酵乳。通过对比传统发酵乳与两种益生菌发酵乳贮藏期的p H值、滴定酸度、黏度、持水力、ABTS自由基清除率、DPPH自由基清除率和总还原能力等指标,研究益生菌对发酵乳品质和抗氧化活性的影响。结果表明,益生菌发酵乳在维持酸奶品质、延长市场货架期方面优于传统发酵乳,在冷藏期21 d内三种菌种发酵乳DPPH自由基清除能力和还原能力均有明显的增加(P0.05),动物双歧杆菌BB-12发酵乳A700nm最高达0.481±0.06。在冷藏期1~7 d益生菌发酵乳ABTS自由基清除能力明显高于传统发酵乳。     

猴头菇多糖对胃肠道益生菌生长的影响

胃肠道益生菌群具有促进食物消化和营养吸收、改善肠道微生态平衡,增强机体免疫力等作用。为明确猴头菇多糖对胃肠道益生菌生长的影响,本研究通过在培养基中添加0.3%、0.5%、0.7%的猴头菇多糖,用平板菌落计数法检测保加利亚乳杆菌(Lactobacillus bulgaricus)、青春双歧杆菌(Bifidobacterium adolescentis)、嗜热链球菌(Streptococcus thermophilus)3种胃肠道益生菌的生长情况。接着通过体外模拟人胃和肠道环境试验,分析猴头菇多糖对这3种菌在胃肠道模拟环境中的生长影响。结果显示:与未添加猴头菇多糖的培养基相比,随着猴头菇多糖含量的增加,均能够显著促进保加利亚乳杆菌和青春双歧杆菌的生长(P<0.05),0.7%的猴头菇多糖添加量增殖效果最为明显;而随着猴头菇多糖含量逐渐增加,嗜热链球菌的生长量增速放缓,0.5%的猴头菇添加量即达到促进的最大值。7%的猴头菇多糖添加量能够显著增强保加利亚乳杆菌对胃液和肠液的耐受性(P<0.05),增强青春双歧杆菌对肠液的耐受性,显著增强嗜热链球菌对肠液的耐受性(P<0.05)。因此0.3%~0.5%的猴头菇多糖添加量可促进胃肠道益生菌的生长;7%的猴头菇多糖添加量可提高益生菌对胃肠道消化液的耐受力。     

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.