紫薯酸奶发酵工艺研究

以紫薯和脱脂乳粉为主要原料,制得一种新型的发酵紫薯酸奶。选用嗜热链球菌和保加利亚乳杆菌,以3:2的比例组成混合发酵剂进行乳酸发酵,以感官评价等为考察指标,通过正交试验确定紫薯酸奶发酵工艺条件。结果表明,紫薯酸奶发酵最佳工艺参数为:白砂糖添加量7%、发酵温度41℃、发酵时间6h、紫薯添加量6%。在此条件下发酵,得到色泽均匀、组织状态良好、口感细腻、具有保健功能的凝固型紫薯酸奶。     

紫薯醋酿造工艺研究

以紫薯为原料,进行酶解处理,再利用液态深层发酵的方法生产紫薯醋,研究了紫薯醋酿造的最佳发酵工艺,结果显示,在温度30℃下,酒精发酵最佳条件为:初始pH5、初始糖度14%、酵母添加量0.2 g/（100 ml）;醋酸发酵最佳条件为:初始酒精度为6%、菌种添加量18%、装瓶量50%,对以薯类等淀粉基原料进行醋的工业化生产具有一定指导意义。     

紫薯枸杞酸奶发酵工艺研究

研究了紫薯枸杞酸奶的生产工艺。以牛奶、紫薯和枸杞为原料,经过正交试验法优化发酵工艺参数。结果表明,果浆与牛奶比例5:5、接种量5%、加糖量6%、发酵温度42℃、发酵时间6h,即可获得品质优良的紫薯枸杞酸奶。     

植物乳杆菌发酵紫薯饮料的研制

以紫薯为原料,利用植物乳杆菌为发酵剂,对紫薯乳酸发酵饮料的加工工艺进行研究。结果表明:紫薯用5倍水打浆,加入6U/100m L薯浆α-淀粉酶于60℃条件下酶解20min,再添加55U/100m L薯浆的糖化酶在p H4.5条件下糖化90min,可得理想的淀粉水解效果。通过正交实验,确定产品的最佳发酵工艺条件为接种量4%,发酵温度37℃,发酵时间14h;实验最佳配方为蔗糖8%,柠檬酸0.1%,黄原胶0.02%,CMC-Na 0.02%,PGA 0.02%。     

紫薯酸奶的研制

以鲜牛奶,新鲜紫薯为主要原料,添加嗜热链球菌和保加利亚乳杆菌,研究搅拌型紫薯酸奶的加工工艺条件。通过单因素试验和正交试验确定制作紫薯酸奶的最佳工艺参数。结果表明,紫薯与鲜牛奶的比例为1∶4,接种量为4%,发酵温度37℃,发酵时间为12 h,白砂糖添加量为9%。此条件下制作的酸奶呈淡紫色,质地均匀一致,具有紫薯和浓郁的乳酸菌发酵酸奶的香味,酸甜可口,口感细腻,柔和。     

紫薯莜麦酒酿造工艺优化

以紫薯、莜麦为原料,在单因素试验的基础上采用三步响应面法优化紫薯莜麦酒的酿造工艺。得到紫薯莜麦酒发酵工艺条件为:发酵时间6 d,发酵温度18℃,SO_2添加量96 mg/L。在该发酵条件下酿造而成的紫薯莜麦酒酒精度11.00%vol,花色苷和β-葡聚糖含量分别为21.23和36.85 mg/L,显著高于对照组。     

紫薯凝固型酸奶的加工工艺研究

该研究以紫薯为原料,通过双酶解法处理紫薯浆,得到紫薯汁,在鲜牛乳中加入紫薯汁和白砂糖进行调配,经过酸奶发酵剂发酵得到具有紫薯风味的新型酸奶。结果表明:紫薯凝固型酸奶的最佳发酵工艺条件的参数为:发酵温度为41℃,紫薯汁添加量为30%,发酵剂为0.15 g/100 mL,白砂糖为8 g,所得的酸奶品质最好。     

紫薯酸奶的研制

以紫薯制作酸奶,对紫薯酸奶配方和发酵工艺进行了研究,经正交实验确定紫薯酸奶的最佳配方为:6%的紫薯浆、7%的白砂糖、0.1%CMC和0.1%海藻酸钠的复合稳定剂,最佳发酵工艺为:接种量4%、发酵温度41℃、发酵时间5h。不仅丰富了酸奶的品种,且提高酸奶的营养价值。     

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。     

紫薯黄冠梨复合果酒酿制工艺研究

以紫薯、黄冠梨为主要原料,经淀粉酶液化,果胶酶和糖化酶糖化,添加白砂糖,经酵母菌发酵,制得紫薯梨复合果酒,采用单因素实验和正交试验优化制备工艺。结果表明,淀粉酶对紫薯液化过程的最佳条件为酶添加量0.12%,酶解pH值6.0,酶解温度50℃,酶解时间30 min,此时出汁率为68.00%。果胶酶、糖化酶对混合果汁酶解过程的最佳条件为酶添加量0.10%,酶解pH值4.0,酶解温度50℃,酶解时间90 min,此时混合果汁的出汁率为70.65%,最优配方及发酵工艺条件为:物料比1∶5,紫薯∶梨为1∶1,酵母添加量4%,白砂糖添加量15%,28℃发酵5天,制得紫薯梨复合果酒,测得复合果酒的酒精度为12.8%。     

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.     

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.     

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.     

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.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the