磷脂酶A2水解菜籽油脚的研究

油脚中含有丰富的磷脂,磷脂的酶改性产物溶血磷脂有极广的应用。以菜籽油脚为底物,以实验室自制的磷脂酶A2为水解酶,采用水相反应方式,通过单因素实验和多因素正交实验,分别对底物用量、Ca2 添加量、反应温度、起始pH等因素进行了系统的研究。结果表明,菜籽油脚酶解的最佳条件为:底物浓度20%,钙离子浓度0.3%,温度50℃,起始pH8.0。在最佳条件下,FFA生成量可达到172.3μmol/g。     

大豆粉末磷脂酶解改性及其性能研究

利用磷脂酶A,对大豆粉末磷脂进行水解,通过实验确定了大豆粉末磷脂酶解的最佳反应条件为：反应时间9h,反应温度50℃,起始pH5．1。在此条件下脂肪酸生成量达到0．802mmol／g。并对酶解后的粉末磷脂性能进行了测定,结果表明酶解后的粉末磷脂乳化稳定性和润湿能力都得到了明显改善,酶解后的粉末磷脂HLB值可以达到9左右。     

磷脂酶A1水解大豆浓缩磷脂研究

该研究采用磷脂酶A1水解大豆浓缩磷脂,通过单因素实验确定各因素合适范围,利用响应面实验方法,得到磷脂酶A1水解大豆磷脂最佳工艺条件为:反应温度51℃、反应时间6h、加酶量3．6％、 pH值5．0、底物浓度0．25 g／mL;利用气相色谱仪分析水解前后磷脂脂肪酸组成,硬脂酸完全水解,棕榈酸含量从20．2％减至5．1％。     

磷脂酶A1催化大豆粉末磷脂水解工艺研究

利用磷脂酶A1对大豆粉末磷脂进行水解,研究了反应温度、加酶(PLA1)量、反应时间、加水量及搅拌速度对磷脂酶A1水解大豆粉末磷脂的影响.通过单因素试验确定的最佳反应条件为:反应温度60℃,加酶量8%,反应时间8 h,加水量5 mL,搅拌速度500 r/min.在此条件下产物酸价可以达到101.4mgKOH/g.     

磷脂酶A_2水解大豆浓缩磷脂的研究(I) 富水相的水解及反应速度的测定

研究了磷脂酶A2 在水相 (富水 )中水解大豆浓缩磷脂 ,经过正交试验得到最佳工艺条件 :底物浓度 10 %,反应温度 5 5℃ ,pH值 8.5 ,Ca2 +浓度 0 .2mol/L。反应的水解率在 75 %～ 85 %。并研究了水解时间和水解速度的关系。     

固定化磷脂酶A1水解卵磷脂的研究

对固定化磷脂酶A1水解卵磷脂的条件进行优化，经正交试验确定最佳的酶解条件，即酶解温度为50℃，反应溶液pH为8．0，2％溶血磷脂4mL酶解时间10h，且酶解溶液中加入溶血磷脂对磷脂的水解影响最显著。     

微乳体系中磷脂酶A1水解磷脂酰胆碱的研究

在微乳体系中研究了新型磷脂酶A1(Lecitase Ultra)水解磷脂酰胆碱生成溶血磷脂酰胆碱的反应。磷脂酰胆碱既是反应底物,又是表面活性剂。分别讨论了底物浓度、酶浓度、水分含量对反应的影响,并采用响应面法分析了这3个主要因素的交互作用,确定反应的最佳工艺条件为:底物浓度0.0218 g/mL、酶浓度1.744 mg/mL、W0(水与表面活性剂的摩尔比值)为27.267、pH 5.0和温度50℃。经HPLC分析,反应转化率达到95.2%。     

磷脂酶A_2水解大豆浓缩磷脂的研究(II)贫水相的水解及产品性能的测定

研究了磷脂酶A2 在水相 (贫水 )中水解大豆浓缩磷脂 ,经过正交试验得到最佳工艺条件 :浓缩磷脂和水比例 5∶2 ;加酶量 173.2IU/g浓缩磷脂 ;反应温度 6 5℃ ,钙离子浓度 0 .1mol/L。研究了溶血磷脂产品乳化性能 ,结果表明其HLB值大于 8,能很好的乳化O/W型体系。     

大豆粉末磷脂的酶解工艺及产物性能研究

研究了放线菌型磷脂酶A2在水相中酶解大豆粉末磷脂的工艺条件,确定了最佳工艺组合为底物浓度10%,Ca2 浓度10mmol,温度40℃,初始pH值7.5,水解时间19h,磷脂转化率达43.3%;同时从宏观和微观两角度对酶解磷脂的乳化性能进行了研究,结果表明:酶解磷脂的乳化稳定性约为粉末磷脂的3倍,相同乳化能力下用量可减少50%,达到氧化平衡时的过氧化值为粉末磷脂的41.0%。     

大豆溶血磷脂的制备及其对面包品质的影响

利用液态磷脂酶A1,在水相中催化水解大豆粉末磷脂制备溶血磷脂,得出最佳反应条件为:磷脂与溶剂比为15%、加酶量6%、pH=5.0、反应温度50℃、反应时问8h,此条件下反应得磷脂酸值为79.46mg KOH/g.并研究了溶血磷脂对面包焙烤品质的影响,发现溶血磷脂的用量在0.60%～1.0%范围内能有效增大面包体积;硬度值测定结果表明,溶血磷脂对延缓面包老化有显著效果.     

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.     

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     

INFOPRINT 2014 was Successfully Held in Dongguan

Sponsored by Printing and Printing Equipment Industries Association of China （PEIAC） and organized by Print China magazine, the Seventeenth Beijing International Printing Information Conference （INFOPRINT 2014） was successfully held on 11th Dec. 2014 at Dongguan Exhibition International Hotel.