苹果醋饮料生产工艺的研究

以新鲜苹果汁为原料,通过正交试验研究了发酵温度、接种量、起始糖度、时间对酒精发酵的影响以及初始酒精度、接种量、装液量对醋酸发酵的影响。结果表明:酒精发酵的最佳条件为:发酵温度27℃、糖度20%、接种量8%。醋酸发酵过程中,以酒精转酸率和酒精转化率为考查指标时的最佳发酵条件为:初始酒精度15%(体积分数)、接种量20%、装液量65 mL/100 mL三角瓶、发酵温度30℃。     

液态发酵法酿造野木瓜果醋

以野木瓜为原料,采用液态发酵法酿造野木瓜果醋。对酵母菌进行选择,当安琪葡萄酒干酵母与马克思克鲁维酵母菌GIM2.119以1∶1(体积比)比例混合时,最适合野木瓜酒精发酵。研究发酵温度、初始糖度、酵母量对酒精发酵影响,采用均匀设计试验确定酒精发酵最佳工艺条件:温度为28℃,酵母量为8.5%,初始糖度为17.0%,在此最佳条件下进行酒精发酵,酒精度可达8.13%vol。探讨了温度、酒精度、醋酸菌接种量、转速对醋酸发酵的影响,响应面分析法结果表明醋酸发酵最佳工艺条件,酒精度为7.0%vol,接种量为8.0%,温度为32℃,转速为115 r/min,在此条件下,总酸含量为7.60 g/100 mL。野木瓜果醋成品感官、理化、微生物指标符合国标。     

香蕉菠萝复合果醋生产工艺的研究

以香蕉和菠萝为原料,进行液体发酵酿造香蕉菠萝复合果醋,研究了初始糖度、酵母菌接种量、发酵温度对酒精发酵的影响,以及初始酒精度、发酵温度和醋酸菌接种量对醋酸发酵的影响,并确定了酒精发酵和醋酸发酵的最佳工艺参数。酒精发酵的最佳条件为初始糖度18%,接种量0.2%,温度26℃;醋酸发酵的最佳条件为:初始酒精度7%(V/V),发酵温度35℃,接种量10%,发酵时间6天。酿制出来的香蕉菠萝复合果醋澄清透亮,醋味浓郁,具有香蕉和菠萝特有的清香味。     

番木瓜-菠萝复合发酵果醋工艺研究

以番木瓜、菠萝为原料生产复合发酵果醋,果醋加工工艺条件:番木瓜与菠萝混合果汁配比3∶2,果胶酶的添加量200mg/L,酒精发酵中初始糖度16°Bx,酵母接种量12%,发酵温度25℃。醋酸发酵的初始酒精度控制在10%,醋酸菌菌种接种量12%,发酵温度30℃。     

李子保健果醋饮料的工艺研究

探讨了以李子为原料的果醋生产工艺,通过单因素试验和正交试验确定了李子果醋的最佳工艺参数.酒精发酵的最佳工艺条件为发酵温度20℃,果汁的初始糖度16%,酵母菌接种量10%,发酵7d左右.醋酸发酵最佳工艺条件为发酵温度30%,醋酸菌接种量12%,初始酒精度8%,发酵8d.,酿制出的李子果醋香味独特,品位纯正.     

李子果醋饮料的工艺研究

探讨了以李子为原料的果醋生产工艺,通过单因素试验和正交试验确定了李子果醋的最佳工艺参数。酒精发酵的最佳工艺条件为发酵温度20℃、果汁的初始糖度16％、酵母菌接种量10％、发酵7d左右;醋酸发酵最佳工艺条件为发酵温度30℃、醋酸菌接种量12％、初始酒精度8％、发酵8d。该工艺酿制出的李子果醋香味独特,口味纯正。     

金桔果醋发酵工艺研究

以金桔为原料,采用液态发酵工艺,分别进行酒精发酵、醋酸液体摇瓶发酵制成金桔果醋.试验结果表明,酒精发酵阶段的最适宜工艺条件:初始糖度17％,活性干酵母接种量0.2％,发酵温度为32℃;醋酸发酵适宜条件:醋酸菌接种量10％,初始酒精度7％vol,醋酸菌的适宜发酵温度为32℃.在此最佳条件下,金桔果醋的醋酸含量达到4.7g/100mL以上.     

红树莓果醋生产工艺的研究

探讨了以红树莓为原料的果醋生产工艺。通过单因素试验和正交试验确定了红树莓果醋的最佳工艺参数。酒精发酵的最佳工艺条件为发酵温度20℃,果汁的初始糖度16％,酵母菌接种量10％,发酵7d左右。醋酸发酵最佳工艺条件为发酵温度30℃,醋酸菌接种量12％,初始酒精度8％,发酵8d。酿制出的红树莓果醋香味独特,品位纯正。     

番木瓜芒果复合发酵果醋工艺研究

番木瓜、芒果通过果胶酶取汁、酒精发酵、醋酸发酵等工艺生产果醋。果醋加工工艺条件为番木瓜与芒果混合果汁配比2∶1,果胶酶的添加量200mg/L,酒精发酵中初始糖度16°Bx,酵母接种量11%,发酵温度28℃。醋酸发酵的初始酒精度控制在8%vol,醋酸菌菌种接种量11%,发酵温度30℃。     

响应面法优化无花果-仙人掌果酒的发酵工艺

该试验以无花果、仙人掌果为原料制备果酒,并研究复合果酒的最优发酵工艺。通过单因素试验及响应面试验,探讨了酵母接种量、发酵温度、初始pH值、初始糖度、发酵时间对无花果-仙人掌果酒发酵产酒精量的影响。结果表明,最佳发酵条件为仙人掌果∶无花果=1∶2,酵母接种量0.04%,发酵温度25 ℃,初始pH值3.40,初始糖度20 °Bx,发酵时间7 d,在此优化条件下,制得无花果-仙人掌果酒的酒精度为11.01%vol,感官评分为97分,总花青素含量为50.68 mg/100 mL。果酒鲜艳紫红,酒体清澈,具有浓郁的果香和醇厚的口感。     

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.