荔枝果酒酿造工艺研究

以荔枝为主要原料,研究采用控温发酵技术酿制荔枝果酒的工艺流程,通过对比试验确定最佳工艺参数为:果胶酶用量为80 mg/L,SO2添加量为50mg/L～100mg/L,发酵温度为22℃,含糖量调整为22%,酵母接种量为6%.     

三种不同生产工艺的荔枝酒品质对比

为了探索冷冻浓缩工艺对荔枝酒品质的影响,以荔枝汁为原料,通过直接发酵、发酵-冷冻浓缩、冷冻浓缩-发酵3种工艺分别生产发酵荔枝酒、发酵-浓缩荔枝酒、浓缩-发酵荔枝酒,并对比分析3种荔枝酒的基本组分、游离氨基酸含量、挥发性物质和感官评价。结果显示:发酵荔枝酒的酒精度为8.48%、总酸为4.80 g/L、单宁含量为0.53 g/L、游离氨基酸总量为40.38 mg/L、醇酯比为0.86,果香清淡,口感一般。发酵-浓缩荔枝酒和浓缩-发酵荔枝酒的酒精度为16.10%和16.47%、总酸为9.57 g/L和7.70 g/L、单宁含量为1.02 g/L和1.13 g/L、游离氨基酸总量为102.97 mg/L和493.17 mg/L,均显著高于发酵荔枝酒(p0.05),其中发酵-浓缩荔枝酒的醇酯比为0.50,酒香增加,但由于酸度及不良风味物质偏高,口感欠佳,而浓缩-发酵荔枝酒的醇酯比为0.26,果香浓郁,口感甜润饱满,酒体醇厚。荔枝汁先冷冻浓缩再发酵的工艺可以生产更高品质的荔枝酒。     

荔枝保健果醋酿造工艺研究

采用液态深层全发酵法研究了荔枝果醋的酿造工艺。通过正交实验确定了荔枝果醋酿造过程中酒精发酵最佳工艺参数:发酵温度为30℃,SO2添加量为40mg/L,发酵时间为6d,接种量为5%;醋酸发酵最佳工艺参数:搅拌转速为80r/min,发酵温度为33℃,发酵时间为7d,接种量为5%。优化工艺条件下进行10L规模中试发酵,所得产品质量较好。     

荔枝酒发酵工艺研究

分析发酵条件对荔枝果酒品质的影响,确定荔枝果酒的发酵工艺.结果表明,荔枝酒较优发酵茵种为VL2,最适接种量0.5%,起始发酵液pH为4.0,总糖含量20 g/100mL,发酵时问4d,所得成品果酒酒精度12.23(体积比),残糖0.87g/100mL,总酸含量5.94g/L,多酚含量435mg/L,产品色泽淡黄、口感醇和、荔香明显,典型性突出.     

菠萝果酒酿造工艺研究

以菠萝为主要原料,研究采用控温发酵技术酿制菠萝果酒的工艺流程,通过对比试验确定最佳工艺参数为:果胶酶用量为100 mg/L,SO2添加量为50～100mg/L,发酵温度为22℃,糖度调整为22%,酵母接种量为8%.     

不同发酵条件对荔枝酒中高级醇生成的影响

采用4因素3水平的正交试验,分析了影响荔枝酒中高级醇含量的酿造工艺.通过极差分析表明,正交试验4因素中发酵液的α-氨基氮含量对荔枝酒酿造过程中高级醇生成量影响最大,其次是接种量、发酵温度,影响最小的因子是发酵液的初始pH值.荔枝酒发酵中高级醇生成量较少的工艺条件为:α-氨基氮含量为190mg/L,接种量为150 mg/L,发酵温度为15℃,发酵液的初始pH值为3.5.     

香蕉果酒酿造工艺研究

以香蕉为主要原料,研究采用控温发酵技术酿制香蕉果酒的工艺流程,通过对比试验确定最佳工艺参数为:果胶酶用量100mg/L,SO2添加量50～100mg/L,发酵温度24℃,精度22%,酵母接种量6%.     

葡萄冰酒干酵母R2发酵冰荔枝酒工艺条件的优化

以冻藏荔枝经低温榨取或低温浓缩后的荔枝汁为原料,利用葡萄冰酒干酵母R2发酵酿制冰荔枝酒,研究了发酵温度、接种量、SO2添加量、起始糖和酸含量、硫酸铵添加量等因素对发酵的影响。通过正交试验确定了冰荔枝酒最佳的发酵条件为发酵温度10℃、SO2添加量100mg／L、起始糖度330g／L、硫酸铵添加量600mg／L、起始酸含量为7．7g／L、接种量为375mg／L。可生产酒精体积分数为10％-12％的冰荔枝酒,产品呈金黄色,清亮透明,果香浓郁,丰满醇厚,甜润爽口,具有较好的类似于葡萄冰酒的品质。     

菠萝果酒发酵工艺条件的优化

以菠萝汁为原料,对菠萝果酒的发酵工艺进行研究。通过正交试验得出菠萝果酒发酵的最佳工艺条件为:酵母接种量6%,糖含量240 g/L,SO2添加量80 mg/L,果胶酶用量120 mg/L,主发酵温度为22℃,发酵6 d,再经后酵和陈酿,得到果香浓郁、色泽金黄的优质菠萝果酒。     

桑葚酒发酵工艺的研究

以PDM酵母为发酵酵母,以高产乙醇为目的,通过单因素试验探讨发酵条件对桑葚酒发酵的影响,得到最佳工艺条件为:接种量6%~8%、果胶酶EX最佳添加量70mg/L、分两批添加果葡糖浆、最适发酵温度22℃~25℃、初始pH3.5(即不调整pH)、初始SO_2浓度60mg/L~80mg/L。以感官评分为标准,响应面试验对发酵条件进行优化得到最佳工艺参数为:发酵温度25℃、果胶酶用量80mg/L、酵母接种量7%,感官评价理论最大值为96.70,实际感官评价分数为93.5,与理论最大值相比准确率为96.69%。     

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.     

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.     

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.     

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.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.     

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.