微波加热对米糠稳定性影响的实验研究

本文对微波加热稳定米糠的工艺参数，微波处理时间、料层厚度、米糠原始水分、储藏时间对米糠稳定性的影响进行了试验。结果表明，微波处理时间150—200s、料层厚度30—70mm、初始水分为15．8％—21％的米糠，经微波处理后强化贮藏，6周内游离脂肪酸(FFA)的增长率在12％以下。     

微波加热不同水分米糠对其储藏和功能性质的影响

本文研究微波加热原始水分和充分水化米糠对其游离脂肪酸含量，蛋白质溶解性和乳化活性的影响。结果表明，米糠水分含量对微波稳定化效果影响很大。微波加热原始水分米糠能够部分抑制脂肪水解酶活性，对可溶性蛋白质含量和蛋白质乳化活性影响很小，可用于米糠短期储藏。经微波稳定化处理的充分水化米糠于35℃储藏4周，其游离脂肪酸值几乎未变，但米糠功能性质破坏较大。     

水分调节对原料米糠微波稳定化的增效作用

食品物料中大都有水分存在,而水分子作为极性分子在微波场中有着极强的响应,本研究从优化微波稳定米糠工艺的角度出发,以米糠脂肪酶残余活力和酸价为主要指标值,着重考察米糠水分含量对微波稳定米糠效果的影响。研究发现,提高米糠水分含量对微波有明显的增效作用,通过单因素和正交试验得出微波稳定米糠影响因素大小依次为:米糠含水率>微波功率>微波处理时间;微波稳定优化水平组合为米糠含水率23%、微波功率800 W、微波处理时间105 s,该优化条件下米糠脂肪酶残余活力为20.24%,显示出高抑酶率且对米糠无热损伤。同时,以原始米糠为对照,将按上述最优条件处理的米糠和仅以功率800 W、时间105 s处理的米糠进行储存对比实验,定期测定米糠酸价以验证协同水分调节的最优微波稳定方案的稳定效果,实验证明,水分调节和微波协同作用处理后的米糠储存时间最长,分别为原始米糠储存时间的3.4倍和仅微波处理米糠的1.5倍,证实基于水分调节的微波处理对米糠稳定有显著效果。     

微波处理对米糠稳定性及脂肪酸组成的影响

采用微波加热技术对米糠进行稳定化处理。考察米糠水分含量、微波处理时间和微波功率对米糠中过氧化物酶残余相对活力的影响和储藏30 d后酸值变化情况,采用正交试验优化微波工艺参数,得到最佳工艺参数。结果表明：当料层厚度为1 cm时,米糠最佳微波处理工艺参数为：水分含量28%、微波时间90 s、微波功率600 W,微波处理后米糠中的过氧化物酶残余相对活力为1.9%,小于最大允许值5%,并在37 ℃的恒温培养箱中储藏30 d后,脂肪酸值为17.5 mg KOH/g,远小于空白组中212.0 mg KOH/g的脂肪酸值。同时,对微波稳定化处理前后的米糠进行气相色谱-质谱法分析,结果表明微波稳定化处理对米糠油中主要脂肪酸的组成影响较小。微波处理后可明显提高米糠稳定性,有利于米糠油的提取。     

米糠稳定化方法的实验研究

分别利用干热、湿热、微波加热等处理方式,探讨了稳定米糠的有效方法。以过氧化物酶残余活力为标准进行比较,将3种稳定化米糠置于37℃储藏30d,比较其游离脂肪酸的变化。研究结果表明:相对于干热和湿热稳定方法,微波加热米糠是一种较为有效的处理方法。     

富硒米糠和普通米糠的微波稳定化技术研究

本研究以新鲜富硒米糠和普通米糠为研究对象,以过氧化物酶残余活力为指标,研究了微波处理对米糠过氧化物酶活力的影响,采用三因素三水平正交实验优化了工艺参数。结果表明,富硒米糠和普通米糠的较佳处理工艺参数均为:加热功率1000W,处理时间90s,料层厚度20mm,处理后的富硒米糠和普通米糠的过氧化物酶残余活力分别为4.8%和4.2%,水分含量分别为5.5%和6.2%;微波处理后的富硒米糠和普通米糠在室温贮存期间游离脂肪酸(FFA)值上升不到15%,而对照组的FFA值高达92%;处理后的富硒米糠和普通米糠冷藏期间FFA值上升不到11%,而对照组的FFA值高达70%,说明冷藏并不能有效抑制脂酶的活性,并进一步表明微波处理对米糠稳定化效果非常显著。     

重庆糯小米米糠的稳定化及脱脂工艺优化

采用微波加热技术对重庆糯小米米糠进行稳定化处理,经正交试验优化微波工艺参数,考察米糠水分含量、处理时间和微波功率对小米米糠贮藏6 周酸值变化情况。结果表明,当料层厚度为1 cm时,小米米糠稳定化最佳工艺参数为：水分含量27%、微波功率600 W、处理时间90 s。此条件下,样品37 ℃贮藏6 周后,脂肪酸值为21.40 mg KOH/g,远小于空白组的171.00 mg KOH/g。通过响应面优化工艺设计获得超声波辅助重庆糯小米米糠脱脂的最佳工艺,研究脱脂温度、脱脂时间、料液比对小米米糠脱脂率的影响,得出小米米糠脱脂工艺的最佳组合为：脱脂温度59 ℃、脱脂时间17 min、料液比1∶2.5（g/mL）、超声功率60 W。在此条件下进行小米米糠的脱脂,其脱脂率为90.89%,有较好的脱脂效果。     

米糠稳定化方法的研究现状

米糠稳定化处理的意义在于使米糠品质稳定，提高储藏性。稳定化处理的方法有化学稳定法和物理稳定法，物理稳定又分低温储藏、辐射处理、热处理、微波和挤压膨化，微波稳定法由于自身独特的优点使其应用前景十分广阔。     

微波和红外处理对油茶仁油组成和稳定性影响规律

通过微波和红外两种方式加热油茶籽,研究了油茶仁的水分、含油率以及压榨油茶仁油的水分、氧化稳定时间、分子质量组成、液质成分等的变化规律.研究结果表明,微波和红外加热均可有效去除油茶仁和油茶仁油中的水分,相比油茶仁随加热强度增大水分降低的规律,油茶仁油中水分在加热后期有略微上升.不同功率微波处理油茶籽后,油茶仁油的氧化稳定...     

稳定化处理对米糠蛋白提取效果的影响

分别利用干热、湿热、微波加热等方式对米糠进行稳定化处理,探讨了三种稳定方法对米糠蛋白质的提取及特性产生的影响。研究结果表明：三种方法均会在一定程度上影响米糠中的蛋白质提取,且干热稳定方式对米糠蛋白的提取损失程度尤为严重。稳定化处理后,所提取蛋白中的各组分含量发生了变化,且米糠蛋白的等电点由pH4附近偏移至pH6左右。     

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