凝固型红薯保健酸奶的研制

研究了凝固型红薯酸奶的发酵生产工艺,旨在开发新型的功能性风味发酵乳。单因素和正交试验结果表明,红薯浆的添加量为10%,蜂蜜用量7%,稳定剂用量0.15%,发酵剂用量0.10%,发酵温度43℃,发酵时间5h,后熟时间20h,获得酸奶产品品质最佳。红薯酸奶成品色泽乳白稍呈浅黄色,组织状态均匀,具有发酵乳香味和红薯风味,其感官指标、理化指标和微生物指标均达到了国家标准。     

凝固型紫红薯酸奶制备工艺的研究

以紫红薯、脱脂奶粉和白糖为原料,采用保加利亚乳杆菌和嗜热链球菌发酵研制凝固型紫红薯酸奶.通过单因素试验验和正交试验优化,确定了凝固型紫红薯酸奶的制备工艺.试验表明,最佳紫红薯酸奶发酵条件为紫红薯与水按2:8的质量比、8%白砂糖、接种量4%及发酵时间6h,可生产出富含花青素的凝固型紫红薯酸奶.     

燕麦膳食纤维酸奶的研制

以燕麦与鲜奶为主要原料,研究了燕麦膳食纤维酸奶最适配方与最佳工艺条件。以产品的感官质量和理化分析为指标,采用正交试验法与模糊综合评判法确定了最佳基本配方和最优工艺条件为:燕麦粉添加量3%,酸奶添加量20%,白砂糖添加量6%;发酵时间4.5 h,发酵温度42℃。研制的燕麦酸奶具有燕麦独特的香味,酸甜适度。     

红薯浆的酶解与发酵制备红薯全汁酸奶的研究

以红薯浆为原料,通过添加纤维素酶,α-淀粉酶对其进行水解得到红薯浆全汁。结合单因素和正交实验,确定了最佳酶解工艺,即纤维素酶添加量0.7%、酶解时间3.0h、加水量与薯液比5:1,pH6.5,在此酶解工艺条件下,出汁率可达42%。以红薯乳全汁为原料,接种乳酸菌对其进行发酵制备红薯乳全汁酸奶;以产品酸度、黏度和持水力等理化指标并结合感官评价指标为考察依据,通过正交实验确定了最佳发酵工艺为:红薯浆与脱脂乳比例5:5,菌种接种量5%、发酵温度37℃、蔗糖添加量4%。在此条件下所得红薯全汁酸奶理化和感官指标均为最佳。     

芒果饮用型酸奶的研制

以脱脂奶粉、芒果浆为原料,研制了一款芒果饮用型酸奶。以芒果浆添加量、菌种添加量、发酵时间、发酵温度为因素进行单因素试验,采取正交试验筛选出控制酸奶色泽、组织状态、香气、滋味等要素的最优组合。结果表明,芒果浆添加量15%,菌种添加量2.5%,发酵温度42℃,发酵时间6 h为最佳工艺条件,制得芒果酸奶的口感最好。在此条件下,芒果饮用型芒果酸奶凝固状态最好,质地均匀,口感细腻,酸甜可口,具有芒果独特香味和浓郁的乳香味,且理化指标和微生物指标均符合国家标准。     

玫瑰希腊式酸奶生产工艺研究

以玫瑰花浆、乳清蛋白和奶粉为原料,研究了玫瑰希腊式酸奶的工艺条件。通过单因素试验和正交试验,以感官评定为标准,研究玫瑰希腊式酸奶的最佳工艺条件。结果表明,在乳清蛋白添加量为0.9%,玫瑰花浆添加量为8%,菌种添加量为5%,发酵温度42℃,发酵时间为7 h,感官评分最高。玫瑰希腊式酸奶质地均匀,口感细腻,酸甜适中,具有独特玫瑰清香味和浓郁的乳香味,其理化指标和微生物指标均符合国家标准。     

燕麦纤维酸奶的工艺研究

以燕麦和奶粉为主要原料,研究了燕麦纤维酸奶的最适配方和工艺条件.最适配方为燕麦添加量4%,奶粉添加最12%,白砂糖添加量5%.最适工艺条件为发酵温度42℃,接种量8%,发酵时间5.5h.研制的燕麦酸奶具有燕麦的独特香味,酸甜适口.     

紫薯南瓜凝固型酸奶发酵工艺研究

以紫薯、南瓜、牛奶为主要原料,利用乳酸菌进行发酵,得到一种风味酸奶。通过L_(16)(3~5)正交试验优化发酵工艺条件,最佳发酵条件为:紫薯---南瓜浆与牛乳的比例为1:5(g/mL),蔗糖添加量为9%,菌种接种量为0.7%,发酵时间为5 h,发酵温度42℃。在该条件下制成酸奶质地均匀,口感细腻,酸甜可口,具有紫薯、南瓜的香味和浓郁的乳酸菌发酵酸奶香味,理化指标和微生物指标均符合国家标准。     

三氯蔗糖在酸奶生产中的应用研究

以三氯蔗糖代替蔗糖应用于酸奶生产。通过单因素试验和正交试验确定酸奶的最佳发酵工艺条件为:三氯蔗糖添加量0.03%、柠檬酸的添加量0.4%、发酵时间7h、发酵温度40℃,所得产品质地均匀,口感细腻,酸甜可口,具有浓郁的乳酸菌发酵的奶香味,理化指标和微生物指标均符合国家标准GB19302-2010《食品安全国家标准发酵乳》。     

红薯糯米酒制作工艺研究

以红薯、糯米为主要原料,采用正交实验研究糯米酒发酵工艺配方,结果表明,红薯糯米酒最佳工艺参数为红薯糯米比例为2∶3,料液比1∶2,糖化酶添加量0.5%,酵母添加量0.5%,30℃下发酵7 d。在此工艺下酿造的红薯糯米酒色泽微黄,酒香和红薯香味浓郁,口感细腻。     

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.