微胶囊法提高益生菌抗逆性的研究

以嗜酸乳杆菌为研究对象,以明胶和阿拉伯胶为璧材,采用复凝聚法进行微胶囊化,并对其进行耐酸性、肠溶性和贮藏稳定性试验;以包埋率为考察指标,采用响应面分析法对菌胶质量比、搅拌速度和乳化时间进行分析和优化。结果表明:制备嗜酸乳杆菌微胶囊的最佳工艺条件为菌胶质量比1∶7,乳化搅拌速度611 r/min,反应时间15 min,p H 4.0;制得的微胶囊包埋率为93.5%,与模型预测值相对误差仅为0.46%;嗜酸乳杆菌微胶囊在人工胃液中仍有75%的存活率,在人工肠液中30 min内即可崩解完成。在-4℃和30℃下贮藏30 d后,存活率分别为82%和80%。     

海藻酸钠-乳清蛋白复合益生菌微胶囊的构建及性能评价

将两歧双歧杆菌包埋在海藻酸钠和乳清蛋白中制成微胶囊,探索影响制备益生菌微胶囊的因素,通过正交实验确定最佳的工艺参数及条件,并对益生菌微胶囊的耐酸、肠溶性等特性展开研究。制备微胶囊的最佳工艺参数:海藻酸钠浓度为3%,乳清蛋白浓度为10%,氯化钙浓度为2%,搅拌速度800r/min。此条件下包埋率达到(78.0±2.0)%。经人工胃液处理后菌体存活率≥70%,在模拟肠液中60min后能够完全释放出来,可显著提高两歧双歧杆菌在模拟消化液处理后或在4℃储藏期内的存活率。本研究为益生菌微胶囊的进一步开发利用奠定基础。     

海藻酸钠二次包衣对益生菌微胶囊包埋效果的影响研究

为了考察海藻酸钠二次包衣对两歧双歧杆菌F-35包埋效果的影响,本研究分别制备得到了海藻酸钠微胶囊(AL-M)、蛋白质微胶囊(WP-M)和海藻酸钠二次包衣的微胶囊(AL-CM),并从三个方面(壁材降解速度、益生菌释放速度和益生菌存活情况)对这三种微胶囊在连续模拟胃肠液环境下的降解进行了比较。结果表明,海藻酸钠二次包衣能够显著降低胃蛋白酶对乳清蛋白的降解作用。相比于AL-M和WP-M,AL-CM会延缓两歧双歧杆菌F-35在模拟肠液中的释放速率,并且在连续的模拟胃肠道中经过二次包以后的微胶囊中对两歧双歧杆菌F-35保护效果最好,两歧双歧杆菌F-35最终的存活率高达51.0%。     

高吸附铅乳酸菌的微胶囊化及特性

乳酸菌作为人体重要的微生物之一,在肠道内发挥益生作用,然而,其不良的环境耐受能力,使其生长、定植受到影响。研究乳酸菌的微胶囊化对提高其环境耐受性具有重要的意义。本研究选取具有高耐受和吸附铅能力的戊糖片球菌10-a-1为研究对象,采用内源乳化法制备海藻酸钠微胶囊,并优化其工艺。通过单因素试验和正交试验确定最优工艺参数,在此基础上利用壳聚糖进行二次包埋,比较两种微胶囊的特性。结果表明:在海藻酸钠质量分数3%,水油质量比30∶120,酸钙质量比3∶1,转速600 r/min,钙胶质量比1.5∶9条件下的海藻酸钠微胶囊的包埋率最高,可达86.3%。海藻酸钠-壳聚糖微胶囊的包埋率为65.6%。对比两种微胶囊的特性,海藻酸钠微胶囊比海藻酸钠-壳聚糖微胶囊释放快;海藻酸钠-壳聚糖微胶囊耐胃肠液的效果好,存活率高;两种微胶囊均可增强模拟胃肠液处理中菌吸附铅的能力,且海藻酸钠-壳聚糖微胶囊对铅的吸附效果更好。在4°C和20°C条件下分别贮藏28 d,海藻酸钠-壳聚糖微胶囊中菌的存活率最高。微胶囊化技术可显著提高戊糖片球菌10-a-1对不良环境的耐受能力,并减小模拟胃肠液处理对戊糖片球菌10-a-1吸附铅能力的影响。     

副干酪乳杆菌海藻酸钠微胶囊包埋工艺

研究副干酪乳杆菌海藻酸钠微胶囊的包埋效果,副干酪乳杆菌在冻干、贮藏及模拟胃胀道环境中的存活情况,并优化包埋工艺参数。结果表明,大豆蛋白分离物(SPI)是适宜的内层壁材,低聚异麦芽糖对副干酪乳杆菌的冷冻保护效果最佳。当SPI用量为3%,低聚异麦芽糖添加量5%,海藻酸钠浓度2%、氯化钙浓度为0.2 mo L/L,副干酪乳杆菌的包埋率可达93.31%,冷冻干燥后微胶囊4℃储存28 d的副干酪乳杆菌存活率达58.97%,微胶囊副干酪乳杆菌在模拟胃液中3 h存活率达67.52%,模拟肠液中45 min基本得到释放。由于挤压法制备的副干酪乳杆菌微胶囊较高的存活率,操作简便、经济,因此有较为广阔的工业化前景。     

双歧杆菌混凝胶微囊制备及其胃肠释放特性研究

为克服双歧杆菌不耐酸、不耐氧的缺点,本试验建立制备双歧杆菌微胶囊的方法。以海藻酸钠和氯化钙形成海藻酸钙水凝胶,再与壳聚糖复合形成聚电解质膜,通过单因素及Box-Behnken响应面试验优化制备双歧杆菌混凝胶微囊工艺,使用扫描电镜观察胶囊结构,并采用模拟胃液及肠液的独立影响实验和模拟连续消化道实验考察胶囊中双歧杆菌的释放特性及存活率,探究其稳定性。结果表明:离心菌体与1.5%海藻酸钠均匀混合,注射到1.2%氯化钙溶液中,再与0.5%壳聚糖固定化35 min最佳。此条件下胶囊形状完整,扫描电镜图显示微胶囊结构致密、具有较好的包埋性,胃肠释放实验证明胶囊具有肠溶胃不溶和缓释的载体特性,胶囊中的双歧杆菌在肠液中的存活率平均值为72.3%,经模拟消化道处理后的存活率为49.8%。此结果为双歧杆菌微胶囊化提供参考。     

低聚木糖复配冻干保护剂的优化及其对双歧杆菌微胶囊性能的影响

为提高双歧杆菌在微胶囊制备过程中以及人体胃肠系统中的存活率,本文通过单因素和正交试验确定了低聚木糖复配冻干保护剂的最佳比例,同时考察了保护剂的加入对微胶囊性能的影响。结果表明,保护剂最佳配比为低聚木糖4.0%、甘油2.0%、谷氨酸钠1.0%,由此制备的双歧杆菌微胶囊包埋率和冻干存活率分别为81.5%±0.7%与88.1%±0.3%,与未添加组相比,其最终活菌负载率提高了约21.6%;添加复配保护剂的微胶囊表面更加平整致密,经模拟胃液处理2 h,双歧杆菌存活率为65.9%,相对于对照组提高了约15.3%;在人工肠液中,添加入保护剂的微胶囊的活菌释放量明显高于未添加保护剂组;在4 ℃和25 ℃贮存35 d后,添加复配保护剂的微胶囊活菌量分别为8.1 lg CFU/g和7.0 lg CFU/g,显著高于未添加保护剂的微胶囊(P<0.05)。因此,添加低聚木糖复配的冻干保护剂可以有效提高双歧杆菌微胶囊对不良环境的抗性。     

干酪乳杆菌/乳糖醇双层合生元微胶囊制备及其在橙汁中的应用

目的:利用酶促法制备干酪乳杆菌/乳糖醇合生元微胶囊,研究乳糖醇浓度对微胶囊特性的影响,并对制备的微胶囊开展应用研究。方法:以黏玉米来源谷氨酰胺转氨酶(TGZ)为催化剂,以酪蛋白和海藻酸钠为壁材,通过内源乳化法对合生元进行双层包埋。利用粒径和干酪乳杆菌在模拟胃肠液中的存活率为指标,确定乳糖醇的添加量,并对其进行形态学观察。最后将制备的微胶囊添加到橙汁饮料中,评价干酪乳杆菌在低温贮藏时的存活情况。结果:TGZ可以交联酪蛋白对干酪乳杆菌/乳糖醇合生元进行包埋。当乳糖醇添加量为1.0 g/100 mL时,双层包埋的微胶囊粒径最小,包埋率最大为61.73%。在模拟胃肠液实验中,添加1.0 g/100 mL的乳糖醇可以提高干酪乳杆菌的存活率。扫描电镜结果表明,干酪乳杆菌完全包裹在壁材中,表明微胶囊的抗穿透物理屏障对益生菌的保护作用。贮存试验发现,添加乳糖醇后橙汁中的活菌数比未添加乳糖醇的高0.56个对数值。结论:双层微胶囊对乳酸菌的存活有很好的保护作用,且乳糖醇的存在也可以提高益生菌的存活率,因此益生菌/乳糖醇合生元微胶囊在食品,尤其是功能性食品方面具有广阔的应用前景。     

两歧双歧杆菌微胶囊化及其性质研究

以明胶、果胶、海藻酸钠、氯化钙和壳聚糖为壁材,采用乳化法双层包埋制备双歧杆菌微胶囊。制备的微胶囊粒径在10～30μm。检测结果表明,微胶囊内活菌数可达到109 CFU/g以上,菌体包埋率可达到82.24%。经模拟胃酸、胆汁酸处理后活菌数仍在108 CFU/g以上,对酸有很高的耐受力;经人工肠液处理15min,微胶囊几乎全部崩解,肠溶释放率可达到95.81%。通过经典的加速实验证明微胶囊的活菌贮藏稳定性较好,室温下贮藏1年其活菌数仍可以保持在108CFU/g以上。     

内源乳化法制备干酪乳杆菌微胶囊

为提高益生菌干酪乳杆菌KLDS 1.0301对不利环境的抗性,采用内源乳化法,将菌株包埋在海藻酸钠和浓缩乳清蛋白中制成微胶囊制剂。通过响应面实验对微胶囊包埋工艺参数进行优化,并通过人工胃肠液对微胶囊的耐受性进行分析。结果表明,微胶囊的最佳制备工艺:海藻酸钠1.93%,海藻酸钠与浓缩乳清蛋白80的质量比1∶1,水油体积比1∶2.7,碳酸钙与海藻酸钠质量比1∶2.18,包埋率为93.51%。干酪乳杆菌微胶囊在模拟人工胃液中处理3 h后活菌数下降2个对数值,而未经包埋的干酪乳杆菌在相同条件下活菌数下降4个对数值。干酪乳杆菌微胶囊在人工肠液中处理60 min后,活菌数基本保持不变,表明了干酪乳杆菌微胶囊具有较好的肠溶性。将包埋的微胶囊与嗜热链球菌KLDS 3.0501和保加利亚亚种ATCC 11842在乳清粉底料中进行混合发酵,发现包埋的干酪乳杆菌在发酵期间同样能够良好产酸,并对产酸量几乎没有影响。     

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.