米醋生产用米酒发酵工艺优化

以大米为试验原料,葡萄糖值（DE值）和酒精度为考察指标,研究大米酒精发酵工艺对米醋生产过程的影响。通过正交试验确定大米液化的最佳工艺条件为料水比1∶2.5（g∶mL）,液化酶0.3%,氯化钙0.1%,液化温度97 ℃,液化时间90 min;糖化的最佳工艺条件为糖化酶0.2%,糖化温度65 ℃,糖化时间为60 min;酒精发酵的最佳工艺条件为酵母接种量0.25%,发酵温度33 ℃,发酵时间12 d。在此最佳条件下,最终发酵前醪液的还原糖含量和DE值分别达到19.8 g/100 mL和75.8%,发酵后酒精度达到12.0%vol,出酒率为37.67%。     

玉米粉液化及糖化工艺条件优化

以玉米粉为原料,葡萄糖当量（DE）值作为评价指标,研究料液比、时间、酶添加量、温度、pH值对玉米粉液化及糖化效果的影响,采用单因素及正交试验对液化、糖化工艺参数进行优化。结果表明,将玉米粉加水配制成料液比1∶4（g∶mL）的浆料,调pH 6.2,最佳液化工艺条件为α-淀粉酶添加量8 U/g、液化温度80 ℃、液化时间60 min、液化液调pH 4.3;最佳糖化条件为糖化酶添加量250 U/g、糖化温度60 ℃、糖化时间12 h。在此最佳条件下,葡萄糖当量值达到93.1%。     

酿造苦荞酱油用糖浆的液化和糖化工艺优化

以苦荞碎米为原料对酶法制备苦荞酱油糖浆盐水的液化及糖化工艺进行研究。通过单因素和正交试验,以液化液中还原糖含量和透光率,糖化液中还原糖和总黄酮含量为指标,探讨不同因素对苦荞碎米液化和糖化过程的影响。苦荞碎米的最佳液化条件为:α-淀粉酶添加量50 U/g,料水比1∶9.0(g∶m L),液化温度90℃,液化时间10 min,p H6.5~7.0;最佳糖化工艺条件为:糖化酶添加量250 U/g,糖化温度60℃,糖化时间5 h,p H4。在此工艺条件下,糖化液中还原糖含量为13.70%,总黄酮含量为6.95 mg/g。     

液化法酿造燕麦黄酒工艺条件优化

以炒制后粉碎的裸燕麦为原料,葡萄糖当量值、还原糖含量与固形物含量作为综合评价指标,通过单因素试验与正交试验对液化法酿造燕麦黄酒的工艺条件进行优化。研究结果表明,最佳液化工艺条件为耐高温α-淀粉酶添加量5 U/g、液化温度95℃、液化时间40 min;最佳糖化条件为糖化酶添加量100U/g、糖化温度65℃、糖化时间180 min;最佳主发酵工艺条件为料液比1∶3.5、发酵温度30℃、酵母添加量为0.25%、发酵时间5 d。在此条件下,16℃稳定25 d后得到燕麦黄酒,口味醇和爽口,品质指标符合国家标准的各项要求。本研究及结果可为燕麦黄酒工业化生产提供理论依据。     

发酵型野木瓜果酒加工工艺研究

以天然特产资源野木瓜为原料,研究发酵型野木瓜果酒的加工工艺。确定大米糖化工艺最佳参数:大米料水比为1∶1(w/v),α-淀粉酶用量2.0%,液化时间1h,液化温度65℃;糖化酶用量2.5%,糖化时间5h,糖化温度55℃。在此基础上,通过单因素试验以及正交试验进一步确定了酒精发酵的最佳工艺条件为发酵温度28℃,大米浆∶野木瓜果汁比例为1∶1.75(w/w),酵母接种量为4%。在此最佳条件下进行酒精发酵,发酵6d,所得果酒酒精度达14.0%vol,感官指标、理化指标及微生物指标均符合产品质量标准。     

应用酶制剂进行木薯发酵乙醇的工艺优化研究

本研究以木薯为主要原料，添加α-淀粉酶、糖化酶和果胶酶进行液化、糖化，加酵母进行发酵实验。通过单因素试验和正交试验，优化液化工艺，结果显示：在料液比1∶2.5，液化温度105℃，液化时间60 min的条件下，发酵酒精浓度为12.58%vol。残还原糖3.3 g/L；进一步研究添加不同用量果胶酶对糖化和发酵酒精的影响，添加75 U/g果胶酶，得到酒精浓度为14.40%vol，可以有效的提高发酵酒精得率。     

葛根酒的开发

以葛根作为酿酒原料,对葛根酒研制中的酶解液化、糖化、酒精发酵等工艺过程进行了研究。确定了酶解液化时料液比为1∶1.5,纤维素酶添加量为10 u/g,酶解1.5h,α-淀粉酶添加量为0.7%,液化4 h;糖化过程中糖化酶添加量为3%,糖化3 h,得到还原糖含量较高的糖化醪;再通过正交试验得到酒精发酵的工艺方案:糖化醪初始糖度为18%,2∶1的混合酵母接种量为5%,发酵温度25℃,发酵时间48 h。该方法能在较短的时间内酿制出具有葛根风味的低度发酵酒,该酒葛根味浓郁、色泽清亮、口感醇厚。     

苦荞酒液态发酵工艺条件的优化

以重庆酉阳生产的苦荞为原料,应用液态发酵技术,通过单因素和正交试验对苦荞酒的酿造工艺条件进行优化,从而确定苦荞酒的最佳工艺参数。结果表明：苦荞酒最佳液化工艺条件为α-淀粉酶添加量0.15%、pH 6.5、温度60 ℃、液化时间2.5 h;最佳糖化工艺条件为糖化酶添加量1.5%、pH 5.0、温度60 ℃、糖化时间3 h;最佳发酵工艺条件为酵母菌添加量0.1%、发酵温度28 ℃、pH 4.5。在此条件下发酵72 h即可得到酒度为9°左右的苦荞酒。     

大豆薏米复合饮料的研制

以大豆和薏米为主要原料,将大豆浸泡、打浆、煮沸制得豆浆,薏米进行浸泡、烘烤、糊化、液化、糖化制得薏米糖化液,将两者按一定比例混合后加入稳定剂,制得一种新型大豆薏米复合饮料。通过单因素分析和正交试验确定最佳实验方案。结果表明,大豆的最佳浸泡条件为豆水比1∶3,温度25℃,时间6h;薏米的最佳烘烤条件为温度160℃,时间60min;薏米的最佳液化条件为料水比1∶10,温度90℃,时间60min,加酶量为每克淀粉12u;薏米的最佳糖化条件为温度65℃,加酶量为500g干粉0.75g,时间60min;饮料配比的最佳条件为,薏米糖化液与大豆浆最佳混合比例为3∶1;饮料中稳定剂添加量为0.2‰黄原胶、0.15‰果胶和0.6‰单硬脂酸甘油酯,复配时得到的饮料口感与状态最佳。产品的可溶性固形物含量为10.6%,总糖含量为8%。     

芭蕉芋原料清液酒精发酵工艺初步研究

以芭蕉芋粉为原料,考察了芭蕉芋原料清液酒精生产工艺,对料水比、液化、糖化、温度、接种量等条件进行初步研究.结果表明,芭蕉芋酒精清液生产最佳工艺为:料水比1∶3.0,拌料水温是60℃,拌料时间为30 min,液化酶用量为6 U/g,液化时间为50 min,糖化酶用量150 U/g,糖化时间30 min,发酵pH 4.2,发酵温度30℃,接种量0.17%(v/v),在此发酵工艺条件下,芭蕉芋发酵醪液的酒精含量达8.8%vol,淀粉利用率为72.14%,原料出酒率达到20.2%.     

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.     

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.     

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.     

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.