酥梨柚子复合果醋发酵工艺的研究

以新鲜酥梨、柚子为原材料,经过酒精发酵和醋酸发酵酿造酥梨柚子复合果醋。通过L9(33)正交试验确定酒精发酵最佳工艺条件:酥梨汁∶柚子汁为2∶1(V/V),初始糖度18%,酵母接种量0.25%;醋酸发酵最佳工艺条件:发酵温度34℃,醋酸菌接种量0.2g/L,发酵时间10d。在此条件下,可得酸度为4.39g/dL、感官评分为91.6分、颜色呈棕黄色、澄清透亮、酸甜爽口的优质酥梨柚子复合果醋。     

响应面优化益生菌发酵复合果蔬汁的加工工艺

以甘蔗、番茄及胡萝卜为原料,嗜酸乳杆菌(La)、嗜热链球菌(St)、植物乳杆菌(Lp)为发酵菌种,利用响应面分析法优化益生菌发酵复合果蔬汁加工工艺。经过单因素实验得出:发酵复合果蔬汁最佳原料比为甘蔗汁:番茄汁:胡萝卜汁=5:1:2(V/V/V);最优菌种混合比为嗜酸乳杆菌(La):嗜热链球菌(St):植物乳杆菌(Lp)=3:2:1(V/V/V);最适初始pH在6.4;优化发酵温度为39～40℃、接种量为2.5%;响应面分优化实验得出最佳发酵工艺为:发酵温度37.91℃,初始pH 6.72,接种量2.88%;考虑实际操作,对各参数稍作调整:发酵温度为38℃,初始pH为6.7,接种量为3%。且此款发酵果蔬汁的感官指标、理化指标及微生物指标等各项质量指标均符合T/CBFIA 08003-2017中国生物发酵产业协会团体标准。     

红茶菌主要功能菌株发酵糖茶水条件的研究

葡糖酸醋酸杆菌(Gluconacetobacter sp.A4)作为红茶菌中的主要功能菌株具有很强的产D-葡萄糖二酸1,4内酯(DSL)能力.本实验探讨了温度、pH、叶酸、木糖醇和发酵时间对A4生长及代谢产DSL的影响,得出最佳培养工艺:培养液组成为红茶0.5%(W/V)、葡萄糖5%(W/V)和木糖醇3%(W/V),接种量10%(V/V):在发酵过程中维持pH为4.0、发酵温度30℃,静止培养8d.发酵结束后,葡萄糖利用率达82%,DSL产量为4.69mg/ml.     

香蕉与山楂复合果醋酿造工艺的研究

以香蕉、山楂为主要原料,对香蕉山楂复合果醋酿造工艺进行优化,最终确定了香蕉山楂复合果醋酒精发酵工艺最佳条件:香蕉汁∶山楂汁(V/V)为2∶1,酵母接种量为3%,温度控制为30℃,发酵时间为4天。醋酸发酵工艺最佳条件:初始酒精度为8%,醋酸菌接种量为8%,发酵温度为32℃,发酵时间为8天。经过二次发酵得到的香蕉山楂复合果醋营养丰富,口感纯正,风味独特。     

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。     

黑加仑、蓝莓复合果醋饮料的研发

本试验采用二次发酵法,通过对黑加仑、蓝莓复合果醋的酒精发酵及醋酸发酵的优化,最终确定黑加仑、蓝莓复合果醋的酒精发酵最佳工艺为:黑加仑果汁与蓝莓果汁3:2复合,在初始糖度8°BX、初始pH3.8、28℃发酵6d、。醋酸发酵最佳条件为:发酵温度35℃,通风量为l:0.10～0.15(V/V/min),酒精含量6.0%,接种量8.0%,初始pH5.5。黑加仑、蓝莓复合果醋饮料配方:12%复合果醋、5.5%白砂糖、2%蜂蜜、0.1%食盐、0.06%复合香料,评分为92分。工艺调整后的放大生产产品质量仍稳定、达标。产品具有食醋清香和黑加仑、蓝莓果香,酸味柔和,风味独特。     

二次通用旋转组合设计优化杏皮渣醋酒精发酵阶段工艺

以杏皮渣为原料,采用果酒酵母和产酯酵母对杏皮渣汁进行酒精发酵。研究了果酒酵母和产酯酵母的用量对杏皮渣汁发酵产酯量和酒精产量的影响,同时研究了初始可溶性固形物含量、初始pH、接种量和发酵时间对酒精产量的影响。利用二次通用旋转组合设计优化酒精发酵工艺参数。结果表明:果酒酵母与产酯酵母的比例为2∶1(V/V)时,产酯量为0.104g/L,酒精度为6.25%(V/V)。当最佳可溶性固形物含量为18%,最佳初始pH值为3.8,最佳接种量为3%(V/V),最佳发酵时间为5天时,杏皮渣汁发酵的酒精度可达7.26%(V/V)。     

马铃薯酸奶加工工艺优化

为探讨马铃薯酸奶的加工技术,研究发酵剂接种量、发酵时间、培养温度等工艺参数对发酵效果的影响,并优化发酵工艺条件。结果表明,马铃薯酸奶最佳发酵工艺为:马铃薯浸提液与鲜牛奶体积比20∶70,蔗糖4%(m/V),发酵剂添加量8%(V/V),发酵时间6h。该条件下加工的产品质量最佳。     

木瓜西柚复合发酵果醋工艺研究

以木瓜和西柚为原料,采用安琪酵母、醋酸杆菌作为发酵菌种酿造复合果醋,对混合果汁配比、酒精发酵、醋酸发酵等工艺进行研究。结果表明:木瓜汁和西柚汁最佳混合体积比为3∶2,果胶酶添加量为200mg/L,40℃酶解处理4h,出汁率达到93%;酒精发酵最优工艺条件:初始糖度14%、酵母菌接种量10%(V/V)、发酵温度30℃、发酵时间4天;醋酸发酵最优工艺条件:初始酒精度7%、醋酸菌接种量8%(V/V)、发酵温度30℃、发酵时间5天;调兑后得到色香味纯正、理化指标达标的复合果醋饮料。     

马铃薯发酵乳饮料的研制

以马铃薯、牛奶为主要原料,利用乳酸菌发酵研制出马铃薯发酵乳饮料。通过单因素试验和正交试验对饮料的配方及稳定性进行探究,确定最佳的工艺参数与产品配方。以感官评分为评价指标,结果显示最佳工艺参数为:马铃薯浆与牛奶比例为6∶4(v/v),乳酸菌接种量4%(v/v),发酵温度41℃,发酵时间为20 h。以感官评分与沉淀率为评价指标,结果显示最佳产品配方为:蔗糖添加量8%(w/w),复合酸味剂(柠檬酸∶酒石酸=1∶2)添加量0.1%(w/w),复配稳定剂(琼脂∶果胶∶单甘酯=4∶1∶1)添加量为0.2%(w/w)。制得的马铃薯发酵乳饮料风味独特,口感细腻,酸甜可口。     

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.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

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.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

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.