响应面法优化微波辅助酶解制备抗性淀粉工艺研究

采用微波辅助酶解制备玉米抗性淀粉,以玉米抗性淀粉收率为指标,在单因素试验基础上,进行BoxBehnken试验设计,对耐高温α-淀粉酶添加量和酶解时间、普鲁兰酶添加量和酶解时间4个因素进行响应面优化试验分析。结果表明4个因素的影响主次关系为普鲁兰酶酶解时间耐高温α-淀粉酶酶解时间耐高温α-淀粉酶添加量普鲁兰酶添加量。响应面优化试验确定微波辅助酶解制备玉米抗性淀粉的最优工艺参数:耐高温α-淀粉酶添加量3 U/g干淀粉、酶解时间30 min,普鲁兰酶添加量8 U/g干淀粉、酶解时间4.5 h。     

酶法联合压热-冷却循环处理制备抗性淀粉

本研究以玉米淀粉为原料,通过酶法联合压热-冷却循环处理制备抗性淀粉,测定酶解过程中淀粉的水解度(DE值)、脱支度和直链淀粉含量、样品抗性淀粉含量及其热稳定性,采用差示扫描量热仪(DSC)、扫描电子显微镜(SEM)分别测定抗性淀粉的热力学特性和颗粒形貌。结果表明,耐高温α-淀粉酶酶解能显著提高淀粉的水解度,耐高温α-淀粉酶联合压热-冷却循环制备的抗性淀粉含量为10.51%~12.16%;淀粉脱支度、抗性淀粉含量、直链淀粉含量随着普鲁兰酶酶解前压热-冷却循环处理次数增加而显著下降,抗性淀粉的热稳定性却得到提高;先普鲁兰酶酶解后压热-冷却循环处理3次得到的抗性淀粉含量最高,达到17.94%;抗性淀粉的糊化峰值温度为119.5℃~121.1℃,糊化焓随抗性淀粉含量的增大而增大,颗粒形状为不规则的碎石型。     

压热-酶法制备泽泻抗性淀粉的工艺

以泽泻淀粉为原料,研究压热-酶法处理对抗性淀粉形成的影响.结果表明:淀粉经高温高压糊化后,先后使用耐高温α-淀粉酶和普鲁兰酶进行淀粉降解脱支处理,生成更多的直链淀粉,促进淀粉分子重新结晶,提高抗性淀粉含量.试验表明,30%淀粉乳在120℃高温糊化50min,耐高温α-淀粉酶添加量为每克干淀粉6U,反应时间为30min,普鲁兰酶添加量为每克干淀粉4 PUN,55℃反应时间12 h,4℃冷藏36 h时抗性淀粉得率较高.正交试验表明普鲁兰酶反应时间影响最显著.     

酶法制备马铃薯抗性淀粉的工艺研究

以马铃薯淀粉为原料,经糊化后,先后使用耐高温a-淀粉酶和普鲁兰酶进行酶脱支处理,以生成更多的直链淀粉,利于分子重新结晶,提高抗性淀粉含量.试验表明,在耐高温a-淀粉酶添加量为4 NU/g干淀粉,反应时间为30min,普鲁兰酶添加量为4NPUN/g干淀粉,反应时间6 h,反应温度55℃时,抗性淀粉含量最高,可达到12.6%.最大影响因素为：普鲁兰酶反应时间.     

淀粉平均聚合度对抗性淀粉得率影响的研究

在对普鲁兰酶最佳酶解条件优化的基础上,采用普鲁兰酶与耐高温淀粉酶协同制备RS(resistantstarch),改变淀粉的聚合度,分析玉米淀粉聚合度与抗性淀粉得率的关系。结果表明:提高原料淀粉中直链淀粉含量并将其聚合度控制在一定程度,可有效的提高RS得率,同时,DSC(differentialscanningcalorimeter)和X-衍射图谱表明,抗性淀粉与原玉米淀粉在结构上有着显著差异。     

酶作用条件对抗性淀粉形成的影响

本文研究了耐高温α-淀粉酶和普鲁兰酶对小麦抗性淀粉形成的影响。研究结果表明：酶作用的适宜条件是α-淀粉酶2U/g干淀粉、酶解时间20min、酶解温度85℃,普鲁兰酶4U/g干淀粉、酶解温度55℃、酶解时间4.5h,测得淀粉分子平均聚合度为77,抗性淀粉得率为16.0%,其中耐高温α-淀粉酶加量对抗性淀粉的得率影响最大。     

响应面法优化微波辅助酶解制备木薯抗性淀粉的工艺研究

本研究采取微波糊化辅助,普鲁兰酶酶解方法制备木薯抗性淀粉(resistant starch,RS)。以木薯RS得率为衡量指标,开展单因素试验和Box-Behnken响应面试验。验证优化试验结果证实:当木薯淀粉乳浓度值为14.5%,脱支时间为2.0 h,普鲁兰酶添加量为125.5 U/g时,可获得最大木薯RS得率值(38.31%),实测值与回归方程理论值相对偏差<1%。试验表明,采用Box-Behnken响应面法获得的优化加工工艺精确性高。根据红外谱图官能基团变化,证明制备木薯RS过程中发生了化学变化。木薯淀粉和木薯RS理化指标测定结果显示:木薯RS与木薯淀粉相比,其持水性增强,膨胀度降低,溶解度升高,直链淀粉含量增大,而冻融稳定性方面,木薯淀粉反而比木薯RS好。     

油莎豆复合酶法抗性淀粉的制备及纯化工艺

以油莎豆淀粉为原料,通过高温α-淀粉酶水解,普鲁兰酶脱支,对淀粉进行连续处理,研究复合酶法油莎豆抗性淀粉的制备及纯化工艺条件,单因素及正交实验结果表明,油莎豆淀粉双酶法制备抗性淀粉酶解的最佳工艺条件是:高温α-淀粉酶添加量2μ/g、酶解温度95℃、酶解时间15 min。普鲁兰酶添加量15μ/g、酶解温度50℃、酶解时间20 h。此条件下制备的油莎豆抗性淀粉得率为39.48%,抗性淀粉含量为57.72%。     

酶法处理和超声波作用对抗酶解淀粉形成的影响

本文以木薯淀粉为原料,研究了α-淀粉酶、普鲁兰酶和超声波作用对抗酶解淀粉形成的影响。结果表明,酶作用对抗酶解淀粉形成的最佳条件为:淀粉浓度为5%,耐热α-淀粉酶量为10mL(酶活力为3U/mL),普鲁兰酶量为30mL(酶活力为22.5NPUN/mL),冷却升温次数为2次。得到的产品中抗酶解淀粉含量可达到14.52%。超声波频率为25kHz,作用时间为120s时,产品中抗酶解淀粉含量最高,为19.19%。     

酶解法制备荞麦抗性淀粉的工艺优化

为确定荞麦粉制备抗性淀粉的工艺条件,采用普鲁兰酶酶解脱支法,并通过单因素和正交试验研究了影响抗性淀粉得率的因素。结果表明：影响抗性淀粉得率的因素主次顺序依次为荞麦粉浓度、普鲁兰酶用量、酶解时间和酶解温度。酶解法制备荞麦抗性淀粉的适宜工艺条件为荞麦粉浓度5 g/（100 mL）、普鲁兰酶用量7.2 PUN/g、酶解温度45℃、酶解时间8 h,在此条件下测得的抗性淀粉含量为15.82%。与原粉相比,普鲁兰酶酶解脱支与湿热法相结合制备荞麦抗性淀粉使其抗性淀粉含量显著提高。     

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.