果浆酶和植物复合水解酶对香蕉果浆的酶解效果比较

研究了果浆酶Pectinex xxl和植物复合水解酶Viscozyme L的酶添加量、酶解温度、酶解时间对香蕉果汁得率、澄清度、粘度和浊度的影响,确定了Pectinex xxl和Viscozyme L酶解香蕉浆的最佳工艺。在此基础上通过对酶解后香蕉浆和香蕉汁的成分和特性分析,对两种酶的酶解效果进行了比较。结果表明,Viscozyme L降解香蕉浆中的果胶和纤维素的活力较强,酶解效果较佳。     

酶制剂在澄清香蕉汁加工中的应用

利用淀粉酶、果胶酶制剂处理香蕉果浆,结果表明:在55℃下,香蕉果浆中加入0.4％的淀粉酶酶解30min,可明显提高香蕉果汁的得汁率;在45℃下,香蕉果汁中加入0.015％的果胶酶酶解60min,可明显提高香蕉果汁的澄清度。     

澄清型香蕉汁加工工艺的研究

以完全黄熟的鲜香蕉为原料,采用正交实验,研究了澄清型香蕉汁的酶解工艺条件及滋味调配。结果表明:用果胶酶酶解香蕉汁有明显的澄清效果,酶解香蕉汁的优化工艺条件为果胶酶用量0.03%、酶解温度45℃、酶解时间2.0h;在打浆时加酸量为0.5%的条件下,酶解后的香蕉汁的最佳滋味配方为调糖度至15°Brix、抗坏血酸添加量0.02%、无需二次加酸。     

果浆酶和果胶酶对猕猴桃出汁率的影响

为制取猕猴桃汁,通过单因素和正交试验,以出汁率、VC保存率和果汁色泽香气变化为指标,用果浆酶和果胶酶对猕猴桃进行酶解处理,探索更适合的猕猴桃制汁工艺条件。结果表明：两种酶都能大幅提高猕猴桃的出汁率,果胶酶酶解条件较剧烈,虽出汁率较高,但对VC含量和果汁色泽香气影响较大;果浆酶酶解条件较温和,总体指标较好,最佳酶解条件为酶解温度30℃、果浆酶加酶量10000U/kg、酶解时间2h、出汁率0.853mL/g,VC保存率67%。果浆酶更适合猕猴桃果汁的制取。     

酶法加工黑莓混汁工艺的研究

冷冻黑莓经解冻、蒸汽热烫及破碎后,采用果胶酶处理果浆,显著提高了黑莓混汁的出汁率,并且提高了黑莓汁的悬浮稳定性。通过单因素和正交试验确定了果胶酶加工黑莓混汁的最佳工艺条件:酶解温度45℃,果胶酶添加量为0.007%,酶解时间90min。     

复合酶解制备甜橙全果浊汁工艺优化

以甜橙全果为原料制备甜橙全果浊汁,通过单因素试验和正交试验,以全果浊汁的出汁率和悬浮稳定性为指标,用果胶酶和蛋白酶进行酶解处理,得出酶解最优工艺条件为:果胶酶添加量0.01%,蛋白酶添加量0.2%,酶解时间40min,酶解温度40℃,该条件下果浆含量30%的全果果汁的出汁率为83.27%,660nm处的OD值为0.431。该复合酶解方法能显著提高甜橙全果果汁的出汁率并使果汁保持较好的悬浮稳定性,经酶解后,果浆含量20%和30%的全果果汁具有较好的感官品质。     

酶法生产澄清型香蕉汁的研究

采用正交实验研究了酶加入量、酶解时间、酶解温度对香蕉汁得率和澄清度的影响,结果表明果浆酶液化香蕉浆的最佳工艺条件是:酶量0.08%、酶解温度45℃、酶解时间120min,其中酶解温度是主要影响因素,生产的香蕉汁保留了香蕉鲜果的大部分营养成分。     

酶解对香蕉果酒发酵前后风味的影响

本研究针对香蕉浆粘度高不易取汁的特点,分别对香蕉浆进行酶解和直接加水处理,制备酶解香蕉汁和非酶解香蕉汁,比较不同处理的香蕉果酒发酵前后理化指标和挥发性成分的变化。结果表明,经果胶酶处理的香蕉汁（果酒）可溶性固形物（TSS）和总酸（TA）分别为24.91° Brix(8.40° Brix)和4.70 g/L(5.67 g/L)高于非酶解处理的香蕉汁（果酒）,pH则低于非酶解的香蕉汁（果酒）;酶解样品酒精度11.5%vol,高于非酶解样品。采用顶空固相微萃取-气相色谱-质谱联用技术（HS-SPME-GC-MS）分析样品中的挥发性成分,在四个样品中共检出87种挥发性物质,其中酯类43种,醇类13种,其他种类物质相对较少,结合香气活度值（OAV）和主成分分析（PCA）,共发现OAV>1的香气物质15种,正己醇、乙酸乙酯、乙酸异丁酯、乙酸丁酯、丁酸异戊酯、反式-2-己烯醛、己醛等10种物质是果汁中主要的挥发性成分,这些物质主要与甜香、香蕉香、覆盆子香、梨香、桃香、青草味相关,经果胶酶处理后的果汁中与青草味相关的己醛含量更少;苯乙醇、异戊酸乙酯、辛酸乙酯、癸酸乙酯、乙酸异戊酯等7种物质对果酒...     

桔梗汁的酶法制备工艺优化及其抗氧化活性评价

以桔梗为原料通过酶解法制备桔梗汁,以期提高桔梗的出汁率和品质.采用单因素试验和响应面设计优化分析得到了最佳酶解制备条件,并对其体外抗氧化能力进行评价分析.结果 表明,桔梗酶解法制汁的最佳工艺条件为果浆酶添加量0.29％、酶解时间103 min、酶解温度52℃,在此工艺条件下,桔梗汁出汁率67.21％,多酚含量692.5...     

酶糖结合法制备红枣澄清汁

以红枣为原料,采用果浆酶和壳聚糖结合法制备红枣澄清汁,利用分光光度法进行检测以确定最佳实验条件。结果表明:果浆酶的最佳酶解条件为酶用量0.03%,温度30℃,酶解时间3 h;壳聚糖的最佳澄清条件为壳聚糖用量2.0%、温度为45℃、澄清时间为45 min,可制得73.54%透光率的红枣澄清汁。     

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