预处理玉米秸秆发酵生产燃料酒精的研究

本文利用正交试验对玉米秸秆发酵生产燃料酒精的条件进行了摇瓶试验。试验发现,采用管囊酵母SQY-001与 酿酒酵母SQY-002混合菌种发酵生产酒精的最适条件为发酵温度36℃,发酵周期为72h,转速为80～100r/min,纤维素酶用量为 40IU/g底物,管囊酵母与酿酒酵母的接种比例为2:1,并在此条件下得到酒精产率为0.148g/g。     

甜高粱汁发酵酒精培养基的优化研究

该文优化了甜高粱汁发酵生产酒精的培养基。通过正交试验的方法对发酵过程的氮源及营养盐进行优化。结果显示,甜高粱发酵生产酒精的最优条件为:硫酸铵为6.0g/L、氯化钙为10.0g/L、硫酸镁为10.0g/L、磷酸二氢钾为0.3g/L。在此培养基条件下对发酵温度进行了优化,试验结果显示,发酵温度32℃的发酵效果最好,在此条件下,发酵成熟醪酒分可达12.94%vol。     

预处理玉米秸秆发酵生产燃料酒精的研究

本文利用正交试验对玉米秸秆发酵生产燃料酒精的条件进行了摇瓶试验。试验发现，采用管囊酵母SQY－001与酿酒酵母SQY－002混合菌种发酵生产酒精的最适条件为发酵温度36℃，发酵周期为72h，转速为80－100r/min，纤维素酶用量为40IU／g底物，管囊酵母与酿酒酵母的接种比例为2：1，并在此条件下得到酒精产率为0．148g/g。     

菠萝皮渣生产酒精关键工艺研究

对影响菠萝皮渣发酵生产酒精的工艺过程及其关键工艺参数进行了研究。通过单因素试验初步确定了菠萝皮渣酒精发酵的工艺条件,然后通过正交试验进一步优化了工艺参数和工艺过程。结果表明:发酵温度33℃、酵母用量5 g/100g、发酵时间3 d为菠萝皮渣酒精发酵生产酒精的最优工艺条件。     

纤维废弃物发酵生产酒精的工艺研究

以纤维废弃物为原料,采用纤维素酶降解糖化发酵生产酒精.结果表明:甘蔗渣经1.0%稀硫酸121℃保温2 h预处理后,采用40 U/g纤维素酶,50℃,pH=5.0,酶解120 min,得糖率为36.8%.由正交试验分析可知,用酿酒酵母发酵生产酒精的最佳条件为:发酵时间72 h,发酵温度为28℃,酵母接种量1.00%,在此条件下,酒精产率为15.31 g/g;4个因素对酒精产率的影响,其重要性顺序依次为发酵时间>发酵温度>酵母接种量>纤维素酶用量.     

利用生产大豆浓缩蛋白副产物发酵酒精的研究

该文利用大豆糖蜜发酵制备酒精,研究了发酵时间、发酵温度、糖蜜浓度、接种量、pH对发酵酒精的影响,并通过正交试验对糖蜜发酵生产酒精工艺条件进行优化,确定其最佳发酵条件为:糖蜜浓度55g/L,发酵温度32℃,发酵时间72h,接种量9％,pH5.0.在最佳条件下,大豆糖蜜发酵酒精得到的酒精度为7.3％vol.     

橡实淀粉生料发酵生产燃料酒精工艺研究

对以橡实淀粉为原料生料发酵生产燃料酒精的工艺条件进行了研究。结果表明:采用超声波助提法可有效脱除单宁,提高橡实淀粉的燃料酒精转化率。单因素试验和正交试验得出的橡实淀粉生料发酵最佳工艺参数为料水比16∶10,α-淀粉酶50 U/g,糖化酶190 U/g,发酵温度25℃,发酵时间7 d。     

以豆渣为基料灵芝菌丝体液体发酵饮料的研制

研究以豆渣为基料灵芝菌丝体液态培养及酒精发酵的条件,并将其应用在果汁复合饮料的研究中,以生产新型功能性保健发酵饮料。通过对PDA液态培养基和豆渣液态培养基的对比试验,确定出豆渣培养基更适合灵芝菌丝体的生长,优化的培养基配方为豆渣90g/L、葡萄糖20g/L、MgSO4 1.5g/L、KH2PO4 1.0g/L。在灵芝菌丝体酒精发酵试验中,通过正交试验确定最佳酒精发酵条件：酵母接种量0.2%、发酵温度30℃、发酵时间5d。在灵芝发酵饮料的调配试验中,通过正交试验确定饮料的配方,通过感官评定得到色泽、风味和组织形态最佳的产品。     

残次山楂果脯酒精发酵工艺的研究

选用果脯厂生产山楂果脯的残次脯作为原料,对其进行果胶酶酶解和酒精发酵工艺参数研究,在单因素试验的基础上,以L(934)正交试验确定果胶酶酶解的最佳工艺条件为果胶酶添加量为8mL/kg,酶解时间为1.5h,酶解温度为55℃,酶解完成后还原糖含量提高了39.55g/L可达到167.28g/L,酒精发酵的最佳工艺条件为接种量为7%,发酵时间为7d,发酵温度为30℃,发酵完成后酒精度可达到8.9%vol,残糖量为4.3g/L。     

全液态发酵红曲米醋工艺的研究

以大米为原料,利用液态深层发酵制醋设备生产液态红曲米醋。工艺上采用了大米粉碎浓醪调浆、α-淀粉酶高温液化、红曲糖化、液态纯种酒精发酵及液态纯种醋酸发酵技术。在单因素试验的基础上,分别采用正交试验L_9(3~4)和正交试验L_9(3~3),确定了红曲米酒最佳工艺条件:料水比1∶2.0,红曲添加量12%,酒精发酵温度28℃,发酵时间9天;醋酸发酵的最佳工艺条件:初始发酵酸度4.5g/dL,初始发酵酒精度4.0%(V/V),发酵温度32℃。在上述工艺条件下,生产的红曲米醋呈红棕色,有光泽,具有红曲米醋特有的香气,体态澄清,发酵总酸8.0~8.5g/dL,氨基酸态氮达到0.388g/L,不挥发酸达到0.589g/L。     

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.