几种改良剂对板栗面包焙烤品质及老化指标的影响

采用单因素实验,研究了黄原胶、α-淀粉酶、单甘酯三种面包改良剂对板栗面包焙烤品质及老化指标的影响。实验结果表明：黄原胶的添加对板栗面包的感官品质及老化指标均产生了显著影响,当添加量为板栗粉及面包粉总重的1%时,板栗面包具有良好的焙烤品质,贮存7天后,其硬度比对照组下降了9%;不同添加量的单甘酯对板栗面包的老化均有延缓作用,但对面包的焙烤品质均产生负面影响;当α-淀粉酶添加量为0.01%或0.005%时,板栗面包的抗老化效果及焙烤性能均好于对照组,但当添加量较高时,面包焙烤品质骤然下降。     

响应面法优化板栗面包复合改良剂的研究

利用响应面分析法优化三种面包改良剂在板栗面包中的添加量.以板栗面包评分为评价指标,在考察单因素对板栗面包抗老化效果及面包评分影响的基础上,利用Box-Beheken响应面分析法确定三种改良剂的最佳组合.实验表明:在板栗面包制作过程中按板栗粉及面包粉总质量添加0％α-淀粉酶、1.1％黄原胶、0.3％单甘酯时,板栗面包具有良好的焙烤品质,且在贮存7d后,面包芯硬度比对照组下降46.4％,有效延缓了面包老化,延长了其货架期.     

复配型面包品质改良剂的实验研究

采用单因素试验和正交试验对延缓面包老化速度的一些添加剂进行了研究.试验表明,在面包制作中按面粉用量添加0.09%α-淀粉酶、1%脱脂大豆粉、2%黄原胶、0.3%单甘酯、0.1%丙二醇脂肪酸酯和0.1%三聚甘油单硬脂酸酯时,面包的老化得到了很大程度的控制,品质得到了保证.     

板栗粉对面包老化及品质影响的研究

通过探讨板栗粉对面包焙烤品质、面包贮存过程中的老化程度的影响,结果表明,适量添加板栗粉可以增加面包的体积和比容,改善面包芯的硬度,对提高面包的营养和感官品质有促进作用,同时可有效地延缓面包的老化,延长其货架期.板栗粉最佳添加量为7.5%,体积增加55.7%,比容增加68.1%,硬度减少20%,老化速度减慢.     

面包改良剂配方的研究

面包改良剂是生产优质面包必不可少的食品添加剂。本文通过探讨不同用量的活性小麦蛋白、真菌α-淀粉酶在面包烘焙品质以及面包储存过程中老化程度的影响,找出了活性小麦蛋白、真菌α-淀粉酶单独作为面包改良剂的最佳添加量。再以这两者及魔芋精粉为原料,用正交实验法设计面包改良剂的配方。实验结果表明,2%活性小麦蛋白、0.0005%真菌α-淀粉酶、0.4%魔芋精粉为面包改良剂的最佳组合。     

品质改良剂对复合杂粮面包粉流变学特性的影响

以营养优化后的复配杂粮面包粉为原料,选择谷朊粉、硬脂酰乳酸钠（sodium stearoyl lactylate,SSL）、黄原胶及瓜尔豆胶为品质改良剂,通过单因素试验研究4 种品质改良剂对杂粮面包粉流变学特性的影响,在此基础上通过响应面分析试验,以面团综合得分为响应值,得出复合改良剂的最佳配方为：1 000 g杂粮面包粉（杂粮粉占比34%）为基重,谷朊粉3.77%、SSL 0.35%、黄原胶1.08%、瓜尔豆胶0.35%。各因素对杂粮面包粉综合评分的影响大小为：黄原胶添加量＞谷朊粉添加量＞瓜尔豆胶添加量＞SSL添加量。添加复合改良剂后杂粮面包粉的稳定时间由4.7 min上升到14.2 min,形成时间由3.9 min上升到了13.3 min,粉质指数从56上升到192。复配杂粮面包粉流变学特性有很大程度改善,达到制作杂粮面包的粉质要求。     

改良剂延缓糯米淀粉制品老化特性的研究

为了探讨复配改良剂对糯米淀粉老化特性的影响,以低温储存后凝胶硬度的变化为评价指标,通过单因素实验,研究改良剂对糯米淀粉老化的抑制效果;采用响应面法确定复配改良剂的最佳添加量。结果表明,复配改良剂的最佳添加量为:黄原胶0.53%、单甘脂0.43%、β-淀粉酶0.18%。延缓糯米淀粉老化效果的改良剂顺序为β-淀粉酶黄原胶单甘脂。对糯米淀粉凝胶进行TPA、FT-IR和DSC分析,结果表明,添加复配改良剂的凝胶硬度、红外吸光度比值、热焓△H均显著低于空白样品。说明复配改良剂能有效控制水分迁移,抑制直链淀粉双螺旋结构形成和分子交联聚合,缩短直链淀粉及支链淀粉直线分支长度,降低支链淀粉晶种源浓度,阻碍其重结晶,有效延缓糯米淀粉凝胶的老化。     

豆腐渣在面包中的应用研究

豆腐渣是加工豆腐、豆浆等产品的副产物,富含膳食纤维、蛋白质等营养成分,将其添加到面包中能够改善面包的营养价值。研究了豆腐渣粉、谷朊粉、异抗坏血酸钠、葡萄糖氧化酶、α-淀粉酶、单硬脂酸甘油酯、黄原胶添加量对面包品质的影响,结果显示,豆腐渣粉替代面粉的量以10%为宜,添加8%的谷朊粉能够显著改善豆渣面包的品质,添加1～5mg/100g的葡萄糖氧化酶、0.6mg/100g的α-淀粉酶、0.6%的单硬脂酸甘油酯或0.4%的黄原胶对豆渣面包品质有一定的改良作用。豆腐渣面包的最佳配方为：面包粉90g、豆腐渣粉10g、谷朊粉8g、酵母1.5g、食盐1.0g、砂糖10g、单硬脂酸甘油酯0.6g。     

赖氨酸在面包制作中的应用研究

通过探讨赖氨酸对面粉粉质、面包焙烤品质以及面包贮存过程中老化程度的影响,研究了赖氨酸作为面包添加剂的可行性。结果表明,赖氨酸可改变面团的流变特性,适量添加可以增加面包体积和比容,改善面包芯的硬度和组织结构,对增加成品的蛋白质含量,提高面包营养和感官品质有促进作用,同时有效地延缓面包的老化,延长其货架期。本实验条件下,添加1.2%为最适添加量,体积增加7.7%,比容增加5.3%,含水量增加9.9%,蛋白质增加4.0%,硬度减小36.6%,老化速度放缓。     

胡麻胶在面包中的应用

本文研究了胡麻胶在面包中的应用及其与改良剂、保鲜剂、单甘酯的组合情况。通过测定面包的比容、抗老化性及对面包的品质进行综合评定,确定胡麻胶对面包质量的影响和最佳组合配比。经研究表明,适量的胡麻胶对增大面包比容、延长老化有明显的效果。当胡麻胶用量1％、改良剂0.8％、保鲜剂0.5％、单甘酯0.2％时制成的面包效果最好。     

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.