3种含笑属植物种子含油量和脂肪酸分析

测定了含笑属中平伐含笑、球花含笑和乐昌含笑3种植物种子的含油量,并用气相色谱对其油脂进行了脂肪酸组成和相对含量分析。结果表明:3种含笑属植物种子的含油量介于39%～44%之间,乐昌含笑的含油量最高,为44%;3种含笑属植物种子油的主要成分为棕榈酸、硬脂酸、油酸和亚油酸,油酸和亚油酸的含量相对较高,油酸相对含量介于22.05%～33.73%之间,亚油酸相对含量介于36.18%～50.43%之间,总不饱和脂肪酸相对含量介于70.74%～74.20%之间。通过综合分析,该属的这3种植物都可以作为新的油料植物资源。     

蒲公英与葵花籽仁提取绿原酸的协同抗氧化作用

以ABTS自由基清除能力为考察指标,研究不同反应温度和反应pH对蒲公英和葵花籽仁绿原酸抗氧化活性的影响,以抗氧化活性的IC₅₀为复配依据,评价蒲公英和葵花籽仁绿原酸复合物的协同抗氧化作用。结果表明:反应体系pH 6、45℃条件下,蒲公英和葵花籽仁绿原酸对ABTS自由基清除率达到最高,分别为91.78%和90.51%。蒲公英和葵花籽仁绿原酸复配品可提高对ABTS自由基清除效率,具有协同抗氧化作用。     

水代法提取葵花籽油及乳状液的破除

利用激光共聚焦电镜对葵花籽原料中的油体和蛋白质的分布状态进行了表征。再以脱酚葵花籽仁为原料,结合激光共聚焦显微镜分析,探讨了不同的粉碎粒度对葵花籽提油率的影响。结果表明,当平均粒径小于30μm时,葵花籽的游离油率最高。水代法的最高提油率为87.12%。然而,水代法提取葵花籽油过程中会产生大量高含油量的乳状液难以破除。因此比较了不同的破乳处理方法,包括乙醇辅助、热处理、高速剪切、冷冻解冻及不同种类酶处理等方法的破乳效果,结果表明,冷冻解冻法破乳效果最优,破乳率为94.01%。乙醇辅助破乳法次之,破乳率为92.02%,使得最终葵花籽总提油率达到95.63%。将水代法制取的葵花籽油与市售压榨的葵花籽油进行比较,结果表明,水代法所提油脂具有较好的品质,达到了冷榨一级油标准。优化的葵花籽油提取工艺合理、可行。     

水酶法提取葵花籽仁油工艺的优化及对油脂品质的影响

目的 优化水酶法提取葵花籽仁油工艺, 探究水酶法对油脂品质的影响。方法 以葵花籽仁为原料, 研究预处理条件(粉碎程度、预处理温度、时间、pH)和酶反应条件(反应温度、时间pH、酶制剂种类)对葵花籽仁油提油率的影响, 并比较水酶法制油工艺与压榨工艺、浸出工艺对葵花籽仁油品质的影响。结果 水酶法提取葵花籽油最优预处理条件为95 ℃、pH 4.8、60 min; 最佳酶反应条件为55 ℃、pH 4.8、采用复合纤维素酶和蛋白酶(各1 mL)、反应3 h; 水酶法提油率可达90.17%。水酶法所制葵花籽仁油的过氧化值优于浸出法, 但酸价高于压榨法所制毛油, R值明显高于压榨法和浸出法所制毛油; 维生素E含量明显低于压榨法和浸出法所制毛油; 3种方式所制毛油的脂肪酸组成上无显著性差异。结论 经过工艺优化, 水酶法提取葵花籽仁油的最高提取率约90.17%, 接近其提油率的上限。     

商品酶Cellulase A “Amano”3处理提升葵花籽蛋白色泽和功能性质

为消除绿原酸对葵花籽蛋白在食品应用中的限制作用,以脱壳葵仁为原料,微酸浸提预先脱除葵仁中部分绿原酸,水媒法提取葵花籽油和蛋白质的同时,添加含绿原酸水解酶活力(3.31 U/g)的商品酶水解残余绿原酸,冷冻干燥得完全脱除绿原酸的葵花籽蛋白质。结果显示,微酸浸提可脱除约76%的绿原酸,酶处理后总脱除率达99.6%。经脱酚和酶处理的葵花籽蛋白色泽明显改善,亮度值L~*和红值a~*由47.1、-7.4提高至70.3、3.3,持水持油性、乳化稳定性显著提高,溶解性由59.0%提升至87.0%。电泳分析,葵花籽蛋白分子质量集中于10~50 kDa,酶处理后分子质量为34.1 kDa的蛋白条带有一定降解。含绿原酸水解酶活力的商品酶可以完全水解葵仁中残留绿原酸,结合水媒法提油技术制备得到的葵花籽蛋白质具良好的色泽和功能特性,为提取优质葵花籽蛋白质提供了新方法。     

焙炒工艺对葵花籽仁油风味及微观结构的影响

以葵花籽仁为原料制备葵花籽仁油。在单因素试验的基础上通过正交试验优化葵花籽仁油的焙炒工艺,并对其挥发性物质和微观结构进行分析。结果表明：最佳焙炒工艺为焙炒温度150℃、焙炒时间30 min、入榨水分含量3.5%,在此条件下制备的葵花籽仁油含有56种挥发性物质,其中吡嗪、醛类物质含量较高。微观结构分析表明,焙炒过程中细胞结构完整性被破坏,结晶度降低,蛋白质类和糖类物质含量增加。     

三相卧螺法生产小麦淀粉的颗粒形态、晶体特征和消化性能的研究

以三相卧螺法生产小麦淀粉的三种淀粉产品：A淀粉、B淀粉及副产物轻相液中的淀粉（简称轻相淀粉）为原料,对其颗粒形貌、结晶特征和消化性能进行了研究。结果表明,A淀粉平均粒径〉B淀粉平均粒径〉轻相淀粉平均粒径。三种淀粉颗粒的X衍射谱是典型的A型结构,其相对结晶度大小顺序为：B淀粉〉A淀粉〉轻相淀粉。A淀粉慢速消化淀粉（SDS）含量最高为50.14%,B淀粉抗性淀粉（RS）含量最高为32.14%,轻相淀粉快速消化淀粉（RDS）和抗性淀粉（RS）含量分别为54.39%、10.81%。结晶度与AAS呈显著正相关性（r=0.96,p〈0.05）,微晶含量与RDS呈显著负相关性（r=-0.97,p〈0.05）。     

CO2充气储藏对葵花籽营养品质的影响

为了保持葵花籽储藏中营养品质,采用CO_2充气包装,研究CO_2浓度分别为10%,50%,100%及自然空气对照组在储藏8个月的过程中葵花籽水分含量、蛋白质、脂肪、碘值变化的影响。结果表明,充气组储藏条件下,葵花籽水分含量变化为25%左右,有利于葵花籽储藏;纯CO_2组蛋白质总含量变化为0.9%,而10%CO_2、50%CO_2为16%左右;充气组葵花籽仁含油量变化基本维持在6.91%~7.38%;碘值变化维持在117.11~141.91g/100g。因此,采用纯CO_2储藏葵花籽的营养品质在整个储藏期几乎不变。     

葵花籽仁粕乙醇提取物抗氧化性的研究

以油葵、食葵的葵花籽仁除油后乙醇提取物为研究对象,在测定其提取物中总酚酸含量的基础上,用K3[Fe(CN)6]测定了它们的还原力;采用D-脱氧核糖-铁体系、超氧阴离子自由基体系、二苯代苦味酰基自由基(DPPH.)体系进行抗氧化活性的研究,并同Vc进行了比较。结果表明:油葵、食葵的葵花籽仁粕乙醇提取物均有显著的抗氧化性,呈剂量效应关系,其中葵花籽仁粕乙醇提取物的抗氧化活性与其总酚含量密切相关。当葵花籽仁粕多酚浓度为0.05 mg/mL时,对DPPH.的清除率都超过了95%;当多酚浓度为0.2 mg/mL时,对超氧阴离子自由基的清除率,油葵、食葵分别为57.83%4、5.24%;对.OH的清除率,油葵、食葵分别达到77.61%6、8%;在实验浓度范围内0.005 mg/mL～0.2 mg/mL,葵花籽粕乙醇提取物的抗氧化性高于VC。     

不同产地美藤果籽的物性比较

为了给美藤果的开发利用提供参考数据,采集了中国云南省普洱、西双版纳、红河,老挝4个产地的美藤果籽,对其感官特性、理化特性及营养特性进行分析比较。结果表明：美藤果籽为类椭圆形,色泽呈浅褐色至深褐色,具有美藤果特有的植物香气;4个产地的美藤果籽单粒厚度为6.8～11.28 mm,粒径为15.81～24.83 mm,单粒质量为0.82～1.53 g,壳仁比为0.52∶ 1～0.78∶ 1,水分含量为7.21%～7.90%;美藤果籽粗脂肪含量为44.98%～50.25%,粗蛋白质含量为27.65%～3028%,总糖含量为3.05%～3.21%,灰分含量为2.28%～2.63%;美藤果籽中维生素E含量为122～190 mg/100 g,钙含量为60.2～63.8 mg/100 g,磷含量为517～535 mg/100 g,钾含量为108～112 mg/100 g,必需氨基酸总量为10.07～10.68 g/100 g,氨基酸总量为31.55～32.82 g/100 g;4个产地的美藤果籽油中棕榈酸含量为3.82%～4.62%,硬脂酸含量为1.87%～3.87%,油酸含量为711%～11.09%,亚油酸含量为37.30%～38.58%,亚麻酸含量为40.78%～48.40%。总体来说,不同产地的美藤果籽感官特性、理化特性及营养特性差异较大,相比较而言,中国普洱产地的美藤果籽在物性指标方面表现更为突出,可作为美藤果油和美藤果蛋白原料的选择。     

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.