桑葚的提取及其自由基清除活性研究

在超声波辅助下,分别以无水乙醇、丙酮、蒸馏水为提取溶剂,对桑葚果实进行提取,浓缩后分别得无水乙醇提取物AE,丙酮提取物EE,蒸馏水提取物WE,通过测定提取物对DPPH·、ABTS~+·、·OH的清除作用评价桑葚的抗氧化活性。提取物AE、EE、WE对DPPH·的IC_(50)分别为0.173、0.18、0.19 mg/m L;对ABTS~+·的IC_(50)分别为0.044、0.052、0.06 mg/m L;对·OH的IC_(50)分别为0.67、0.83、1.02 mg/m L。提取物清除DPPH·、ABTS~+·、·OH的IC_(50)值均远远小于10 mg/m L,表明桑葚提取物具有良好的自由基清除活性。试验表明溶剂对提取物清除自由基的活性有一定影响。     

超声细胞破碎辅助提取江永香菇多糖工艺及其抗氧化活性研究

为优化江永香菇多糖提取工艺,采用超声波细胞破碎辅以热水浸提,通过单因素试验考察超声时间、超声功率、料液比、浸提时间、浸提温度5个因素对香菇多糖得率的影响,以香菇多糖得率为响应值,采用响应面设计优化工艺,同时对提取的香菇多糖进行抗氧化活性研究。结果表明,提取的最佳工艺条件为:超声时间6 min、浸提温度78℃、浸提时间51 min。在此条件下,江永香菇多糖的得率可达到29.71%。超声波细胞破碎法辅以热水浸提得到的江永香菇多糖体外清除DPPH自由基能力的IC_(50)值为0.35 mg/mL,清除ABTS+自由基能力的IC_(50)值为1.76 mg/mL,相同浓度下,其DPPH自由基清除能力和ABTS~+自由基清除能力均高于热水回流法提取得到的江永香菇多糖。     

山楂叶多酚的酶法提取及抗氧化活性研究

实验研究酶法提取山楂叶多酚的工艺条件,并对山楂叶多酚的体外抗氧化活性进行了探讨。结果表明,使用纤维素酶和果胶酶质量比为1:1的复合酶,其质量浓度为0.20 mg/mL时,在酶解pH4.5、酶解温度45℃下酶解120 min时多酚提取得率最大,为0.56%。体外抗氧化实验结果表明,山楂叶粗多酚具有较好的总还原能力,其清除DPPH自由基的IC_(50)值为1.02μg/mL,螯合Fe~(2+)的IC_(50)值为55.62μg/mL,清除羟自由基的IC_(50)值为11.23μg/mL,提示山楂叶多酚具有良好的抗氧化能力,有进一步开发利用的价值。     

樟头红青皮总酚超声波提取工艺及其抗氧化性分析

采用超声波辅助提取樟头红青皮总酚,通过单因素试验,结合响应面法,确定了樟头红青皮总酚的最适提取工艺,并通过4个抗氧化体系(DPPH,ABTS~+,·OH,还原能力)来评价其抗氧化活性。结果表明:樟头红青皮总酚的最适提取工艺条件为乙醇浓度56.2%、料液比1:52、超声时间22.5 min、超声功率108.3 W、提取2次,此条件下总酚得率为25.04 mg/g。樟头红青皮总酚对DPPH、ABTS~+、·OH自由基的清除能力和还原能力低于Vc,差异极显著(P0.01);樟头红青皮总酚对DPPH、ABTS~+自由基的清除能力很强,半抑制浓度分别为1.160 mg/mL和1.477 mg/mL;在一定浓度范围内,樟头红青皮总酚浓度越高,其对·OH自由基的清除能力和还原能力越强。     

响应曲面法优化黄参茎叶多酚的提取工艺及其抗氧化活性

研究黄参茎叶多酚的超声波辅助提取工艺及抗氧化活性,以响应曲面法优化黄参茎叶多酚的超声波辅助提取工艺,同时以分光光度法测定提取物的还原力,对羟基自由基(·OH)、DPPH自由基(DPPH·)的清除作用。结果表明:黄参茎叶多酚的最佳提取工艺条件为:乙醇体积分数75%、提取温度70℃、料液比(g/mL)1∶35、提取时间30 min,此时多酚得率为1.1448%;黄参茎叶多酚对羟基自由基、DPPH自由基具有良好的清除能力,同时还具有一定的还原能力,并且在0.1~0.6 mg/mL质量浓度范围内,黄参茎叶多酚对羟基自由基、DPPH自由基的清除率高于BHT,表明其具有良好的抗氧化作用,可作为天然抗氧化剂进一步开发和利用。     

超临界CO2萃取牡丹籽粕多酚工艺 及其抗氧化性评价

为充分利用牡丹籽粕中的多酚资源,采用响应面法优化超临界CO_2萃取牡丹籽粕多酚工艺,以多酚提取量为响应值,得到了乙醇(夹带剂)体积分数、萃取温度和萃取压力的最优条件;通过测定牡丹籽粕多酚对DPPH和ABTS自由基的清除能力,对其抗氧化活性进行评价。结果表明,超临界CO_2萃取最佳工艺条件为乙醇体积分数83%、萃取温度52℃、萃取压力32 MPa,此条件下牡丹籽粕多酚提取量可达18.58 mg/g;牡丹籽粕多酚和VC对DPPH·清除率的IC_(50)分别为128.22μg/mL和147.72μg/mL,对ABTS~+·清除率的IC_(50)分别为109.18μg/mL和142.66μg/mL,牡丹籽粕多酚对DPPH·和ABTS~+·的清除能力均显著强于VC。     

腰果叶多酚超声波辅助提取工艺及其抗氧化能力测定

以腰果叶为原料,采用超声波辅助手段对腰果叶多酚进行提取。在单因素试验基础上,通过响应面法优化腰果叶多酚提取工艺条件。1.0 g腰果叶粉末,所得到最优提取工艺条件为:丙酮体积分数60%、提取温度60℃、提取时间90 min,实测得率为10.29%,接近预测值10.33%。通过腰果叶多酚提取物对DPPH自由基清除能力,ABTS+自由基清除能力,铁离子还原能力,得出腰果叶多酚提取物具有抗氧化能力,相同浓度下腰果叶多酚提取物抗氧化性高于天然抗氧化剂VC。     

提取方式对玉米须总多酚抗氧化活性的影响研究

以玉米须为原料,利用酶法、微波、超声波和微波辅助超声波四种方式提取玉米须中的多酚,并研究了不同提取方式得到多酚的抗氧化活性。通过测定多酚的体外还原能力以及DPPH自由基、超氧自由基、羟基自由基和ABTS自由基的清除能力,考察四种提取方式得到多酚的抗氧化活性并进行比较。结果表明,微波辅助超声波提取得到的多酚含量最高,为1.975 mg/g;四种提取方式得到的多酚对DPPH自由基、超氧自由基、羟基自由基和ABTS自由基均具有较强的清除作用,且相关性显著,其中酶法提取多酚的清除能力均强于其余三种提取方式的清除能力,抗氧化活性由强到弱依次为酶法提取微波辅助超声波提取微波提取超声波提取。     

树莓酵素与蓝莓酵素有机酸分析及其体外抗氧化性能

研究树莓酵素和蓝莓酵素中有机酸种类与含量及其体外抗氧化性能。采用高效液相色谱法,准确地测定其有机酸含量及种类,并以还原力、DPPH自由基清除能力、超氧自由基清除能力、羟基自由基清除能力和ABTS~+自由基清除能力为抗氧化性指标,多体系地考察其体外抗氧化性能。结果表明,树莓酵素和蓝莓酵素均以酒石酸、乙酸和柠檬酸为主,同时因发酵代谢积累了少量丙酮酸、莽草酸和富马酸,而在蓝莓酵素中未检测到没食子酸。树莓酵素和蓝莓酵素的DPPH自由基清除能力、还原力、超氧自由基清除能力、羟基自由基清除能力和ABTS~+自由基清除能力均表现出浓度依赖性。在实验剂量内,树莓酵素和蓝莓酵素DPPH自由基清除能力的IC_(50)分别为2.00 mg V_C当量/m L和8.70 mg V_C当量/m L,还原力的IC_(50)分别为4.53 mg V_C当量/m L和7.62 mg V_C当量/m L,超氧自由基清除能力的IC_(50)分别为0.53 mg V_C当量/m L和2.05 mg V_C当量/m L,羟基自由基清除能力的IC_(50)分别为8.92 mg V_C当量/m L和9.14 mg V_C当量/m L,ABTS~+自由基清除能力的IC_(50)分别为3.59 mg V_C当量/m L和6.81 mg V_C当量/m L。树莓酵素有机酸种类多于蓝莓酵素,且树莓酵素的抗氧化性能优于蓝莓酵素。     

超声波辅助提取菠萝皮渣多糖及其抗氧化活性研究

采用超声波技术辅助提取菠萝皮渣多糖,利用正交设计实验优化其提取工艺,并利用体外实验研究该多糖对羟自由基(·OH)、DPPH自由基(DPPH·)的清除能力及其还原能力,以评价其抗氧化活性。研究结果表明,超声波辅助提取最佳工艺参数为:料液比1∶50(m/v),时间40 min,温度60℃,功率为570 W,该条件下多糖的得率为2.38%;在本实验浓度范围(1.50~3.50 mg/m L)内,菠萝皮渣多糖对·OH的清除率随其浓度的增加而增加,但清除能力均低于同浓度VC,清除DPPH·自由基的IC_(50)为2.47 mg/m L,对Fe~(3+)的还原能力随多糖浓度的增加而增加。可见,超声波辅助提取工艺效果较好,能缩短提取时间,提高菠萝皮渣多糖的得率;体外抗氧化实验表明菠萝皮渣多糖具有一定的抗氧化活性。从菠萝皮渣中提取活性多糖,可以变废为宝,实现菠萝资源的高值化利用。     

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.