醇法制取玉米胚芽蛋白的工艺

研究了利用脱脂玉米胚芽粉采用醇法制备玉米胚芽蛋白的生产工艺.通过设计单因素试验和响应面分析试验,根据乙醇体积分数、液料比、浸提时间3个因素对蛋白提取率的影响,优化了玉米胚芽蛋白的制备工艺.经单因素试验得出利用玉米胚芽粉制备玉米胚芽蛋白的最佳提取条件为:乙醇体积分数为65％,液料比为10∶1 (mL∶g),温度为45℃,提取时间为1h.响应面优化的结果表明:影响玉米胚芽蛋白提取率的主要因素依次是:料液比、时间、乙醇体积分数;在乙醇体积分数为63.67％,液料比为10.25∶1(mL∶g),温度为45℃,提取时间为1.06h时,玉米胚芽蛋白的蛋白提取率达到最大.在最佳条件下蛋白质提取率可达81.87％,蛋白质质量分数达55.73％.     

玉米胚芽粕制备蛋白膜工艺优化及抗氧化研究

目的:利用玉米胚芽粕中的醇溶蛋白制备玉米醇溶蛋白膜,减少塑料膜对环境的污染。方法:以玉米胚芽粕为原料,通过碱溶酸沉从玉米胚芽粕中提取得到玉米醇溶蛋白,加入一定量的乙醇溶液再利用超声波辅助法加入适量的增塑剂和还原剂,在一定的水浴温度下水浴30 min,待膜液室温后,膜液流延成玉米醇溶蛋白膜。探究丙三醇添加量、超声时间、乙醇体积分数以及水浴温度4个因素对玉米醇溶蛋白膜的水溶性、水蒸气透过率、CO₂透过率的影响,得出最佳制备工艺,并通过将成膜液涂布在梨切片表面进行抗氧化保鲜试验,同时做涂膜空白对照,观察相同时间内梨切片表面的褐变程度。结果:通过正交试验,得到最优制膜工艺为丙三醇添加量0.3 g/g醇溶蛋白、超声时间5 min、乙醇体积分数80%、水浴温度70 ℃。在此条件下,玉米醇溶蛋白膜水溶性为19.75%、水蒸气透过率为6.13 g·mm/(m²·d·kPa)、CO₂透过率为0.21 g/(m²·h),玉米胚芽粕制备蛋白膜液能够使梨切片的褐变速度明显降低。结论:玉米胚芽粕制备蛋白膜可行,膜液能够在果蔬保鲜上起到很好的抗氧化效果。     

棉籽浓缩蛋白制备及其物理改性工艺研究

以低温脱溶棉籽粕为原料,选用乙醇洗涤法制备棉籽浓缩蛋白。考察了乙醇体积分数,醇洗温度,醇洗时间,醇洗次数,料液比对棉籽浓缩蛋白产品蛋白质含量的影响。得到的最佳工艺条件为:乙醇体积分数70%,醇洗温度50℃,醇洗3次(每次20 min),料液比1∶7;在最佳工艺条件下,制得棉籽浓缩蛋白产品蛋白质含量为68.25%(N×6.25,干基),游离棉酚含量下降到0.035 4%。为提高产品的溶解性,对醇洗棉籽浓缩蛋白进行物理改性研究,探讨了热水温度,捣碎均质时间,蛋白质溶液p H,超声波处理时间对产品溶解性的影响。得到的最佳工艺条件为:热水温度95℃,捣碎均质时间10 min,蛋白质溶液p H 9,超声波处理时间15 min;在最佳工艺条件下,制得的改性棉籽浓缩蛋白产品NSI由12.30%上升到26.59%,且高于原料棉籽粕的24.46%。     

苦杏仁醇洗浓缩蛋白制取及脱苷条件研究

以脱皮苦杏仁冷榨饼为原料,采用醇洗工艺制取浓缩蛋白同时脱除苦杏仁苷。通过单因素实验和正交实验得到的最佳工艺条件为:乙醇体积分数75%,提取温度50℃,液料比11∶1,提取时间50 min,提取次数5次。在最佳工艺条件下制取苦杏仁醇洗浓缩蛋白的蛋白质含量为73.61%,苦杏仁苷含量为5.53 mg/kg,苦杏仁苷近乎被完全脱除(脱除率为99.995%)。所得产品颜色洁白、风味清淡略有坚果香味,蛋白质NSI值64.61%,是一种优质的食用蛋白产品。乙醇萃取液即苦杏仁糖蜜中苦杏仁苷含量为3.94%,是提取苦杏仁苷的良好原料。     

吸附法脱除玉米油中玉米赤霉烯酮的研究

以玉米油中玉米赤霉烯酮(ZEN)脱除率为主要考察指标,以玉米油脱色效果为次要考察指标,研究吸附剂种类和吸附剂用量对玉米油中ZEN脱除效果和脱色效果的影响。结果表明:WY1活性炭对玉米油中ZEN的脱除效果优于其他吸附剂。当吸附剂用量为油重1%时,活性白土、凹凸棒石、WY1活性炭、WY2活性炭、普通活性炭及NORIT活性炭对玉米毛油中ZEN的脱除率分别为5.57%、10.73%、38.50%、11.10%、14.45%和17.35%,ZEN含量由8 026.67μg/kg分别降至7 579.28、7 165.38、4 936.46、7 135.34、6 867.12、6 634.27μg/kg。WY1活性炭用量2%时,ZEN脱除率达到48.25%,ZEN含量降至4 153.77μg/kg,明显高于欧盟要求400μg/kg的限量。因此,对于ZEN含量很高的玉米毛油,必须结合优化的碱炼脱酸及水蒸气蒸馏脱臭的精炼过程才能对ZEN进行系统和高效的脱除,但解决问题的根本是要严格控制待精炼玉米毛油的ZEN含量,即减少和控制玉米胚中ZEN含量,提高玉米胚质量。     

文冠果种仁冷榨饼制取醇洗浓缩蛋白的研究

以文冠果种仁冷榨饼为原料,利用醇洗工艺制取醇洗浓缩蛋白。通过单因素试验和正交试验得到的最佳工艺条件为:乙醇体积分数55%,醇洗时间60 min,醇洗温度50℃,液料比10∶1,醇洗次数2次。各因素对蛋白质含量的影响大小顺序依次是乙醇体积分数醇洗温度液料比醇洗时间。在最佳工艺条件下所得文冠果种仁醇洗浓缩蛋白的蛋白质含量为67.80%,氮溶解指数(NSI)为35.10%。文冠果种仁醇洗浓缩蛋白是一种优质的食用浓缩蛋白。     

玉米毛油中玉米赤霉烯酮脱除技术研究

以玉米赤霉烯酮含量高的玉米胚芽及玉米毛油为原料,以玉米赤霉烯酮含量及脱除率为实验验证指标,研究碱液处理玉米胚芽原料后ZEN的的脱除效果,利用物理吸附剂蒙脱石脱除玉米毛油中的玉米赤霉烯酮。实验结果表明:用pH9~10的碱液处理玉米油原料玉米胚芽时,玉米油中的赤霉烯酮能够从201.6μg/kg降到79.6μg/kg,采用蒙脱石吸附添加量在0.6%时,玉米油中的赤霉烯酮能够从213.4μg/kg降到47.5μg/kg并且对有效降低了玉米油的酸价,不影响玉米油的过氧化值和风味。两种工艺都能有效脱除赤霉烯酮,其中蒙脱石吸咐工艺相对简单,在工业化应用中前景广阔。     

玉米胚中醇溶蛋白的提取工艺

以玉米胚芽为原料,采用乙醇溶解萃取原理。通过单因素和正交试验,确定了乙醇萃取的最佳条件。结果表明:温度为55℃、时间为2.0h、pH8.0、乙醇浓度为80%、液固比为12∶1(mL/g)。本工艺中最高产量可达0.212g/25g;制取的醇溶蛋白中蛋白质含量可达92.56%。     

响应面法优化玉米醇溶蛋白提取工艺的研究

玉米黄粉为原料,冰醋酸为溶剂,以超声时间、冰醋酸体积分数、料液比为变量,醇溶蛋白收率和含量的综合因素为考察指标,通过单因素和响应面试验优化的最佳条件为料液比1∶10(g/m L)、冰醋酸体积分数80%、超声时间3 h。在此条件下的醇溶蛋白收率为55.3%、含量为69.4%、综合指标为60.94%,与模型的预测值基本相符。与传统的以乙醇为溶剂提取醇溶蛋白相比,在醇溶蛋白含量不降低的情况下,可提高醇溶蛋白收率。     

淡碱蒸胚对玉米胚及其毛油中真菌毒素的降解消除作用

利用湿热和碱性条件对真菌毒素的破坏作用,以不同质量分数淡碱(NaOH)溶液调节玉米胚达到适宜蒸胚水分质量分数(14%),用115℃过热蒸汽蒸胚30 min,对蒸胚前后玉米胚及所制取玉米毛油中黄曲霉毒素B_1(aflatoxin,AFB_1)、玉米赤霉烯酮(zearalenone,ZEN)和呕吐毒素(deoxynivalenol,DON)含量进行检测,研究淡碱蒸胚对玉米胚及其毛油中真菌毒素的降解消除效果及碱液质量分数对降解消除效果的影响。结果表明:碱液质量分数为5.29%时,淡碱蒸胚对玉米胚中ZEN和DON的降解消除效果最好,ZEN含量从697.41μg/kg降至246.25μg/kg(降解率64.69%),DON含量由2 417.07μg/kg降至802.83μg/kg(降解率66.78%),所制取玉米毛油中ZEN含量从266.44μg/kg减少至140.02μg/kg,DON含量从150.76μg/kg降低至108.47μg/kg;碱液质量分数为6.55%时,淡碱蒸胚对玉米胚中AFB_1的降解消除效果最好,AFB_1含量从7.91μg/kg降至0.77μg/kg(降解率90.30%),所制取玉米毛油中AFB_1含量从2.11μg/kg减少至0.51μg/kg。随碱液质量分数的增大,淡碱蒸胚所得玉米胚及其毛油的色泽有所加深,毛油酸价和过氧化值明显降低。采用淡碱蒸胚不仅能对玉米胚中真菌毒素进行有效降解,大幅降低玉米胚及其毛油中真菌毒素含量,同时也能降低玉米粕中真菌毒素含量,实现玉米油食用安全和玉米粕饲用安全的同步提升。     

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.     

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     

Chinese CTP Market

According to Printing and Printing Equipment Industries Association of China（PEIAC）＇s statistics to the plate manufucturer in China, in 2013, the actual offset plate production has reached 346 million square meters in China. Among them, the CTP production volume was 245 million square meters, up by 11% than that of last year; the total sales of the CTP plate was 239 million square meters, up by 13%.     

Preparatory Work of Print China 2015 is Going Smoothly

正Held at Guangdong Modern International Exhibition Center,Print China 2015 will cover 7exhibition halls,besides the original Hall No.3,4,5,6,7,the newly built F zone of Hall 3 will be used too.The total area will be140,000 square meters.Hall 3:Offset and large printing equipment,package printing equipment,post press