大蒜多糖提取工艺优化及体外抗氧化活性研究

通过正交实验,对水提法提取大蒜多糖工艺进行了优化研究,并采用清除DPPH·(1,-二苯基苦基苯肼)自由基模型和抗油脂氧化模型评价了大蒜多糖的抗氧化能力.实验结果表明,各因素对多糖提取率的影响程度由大到小依次为:提取温度>料水比>提取时间.最佳提取工艺条件为:提取温度为80℃,料水比为1:30,提取时间为180min.大蒜多糖具有一定的清除DPPH·作用,其IC50为0.13g/mL,大蒜多糖时菜子油的抗氧化能力较Vc要强,能够有效抑制菜籽油的氧化.     

酶解-超声辅助联用提取塔尔米多糖

以生塔尔米粉为原料,分别采用超声辅助法、酶解-超声辅助联用提取塔尔米多糖,考查了酶解工艺对塔尔米多糖提取效果的影响,同时采用总抗氧化能力、DPPH·自由基和ABTS~+·自由基清除能力评价了塔尔米多糖的抗氧化活性。以提取率和纯度为考察指标,通过单因素实验和U_(10)(10~6)均匀设计实验优化超声辅助法工艺参数,采用L_9(3~4)正交实验优化酶解工艺。结果表明,酶解-超声辅助联用提取塔尔米多糖的最优工艺为:液料比20:1,酶解pH6.5,酶解温度50℃,酶解时间30 min,超声温度40℃,超声时间20 min,超声功率160W,塔尔米多糖提取率为5.24%,纯度64.32%。酶解处理显著提高了塔尔米多糖的提取效果,塔尔米多糖有一定的抗氧化能力,且呈量效关系。     

酶解法提取罗汉果多糖的工艺研究

目的确定以纤维素酶法提取罗汉果中多糖的最佳工艺条件。方法以多糖提取率为指标,首先以单因素试验分别考察了酶活力、酶解温度、酶解时间以及酶解p H对罗汉果中多糖提取率的影响,在此基础上,通过四因素三水平正交试验探讨了各因素对酶解法提取罗汉果多糖的影响程度及各因素的最佳水平。结果各因素的影响由大到小依次为:酶解温度酶活力酶解时间酶解p H,确定了纤维素酶法提取罗汉果中多糖的最佳工艺条件为:酶解温度50℃,酶活力500 U/g,p H为6.0,酶解时间55 min。在此条件下进行5次平行试验,多糖提取率为6.82%,相对标准偏差为2.2%。将本工艺与传统热水浸提法进行比较,结果表明本法比传统的热水浸提法提取罗汉果多糖的提取率提高了10%~22%。结论本工艺操作简单、提取率高,是提取罗汉果中多糖的一个有效途径,为综合利用罗汉果中多糖提供依据。     

大蒜多糖对几种自由基的影响

为探寻大蒜多糖清除自由基的能力,测定大蒜多糖对DPPH、超氧阴离子自由基和羟自由基三种自由基的影响.结果显示:大蒜多糖对于DPPH无清除作用,但对超氧阴离子自由基在浓度为1-10mg/mL时,清除率为24.04%～85.13%;对羟自由基在浓度为1～10 mg/mL时,清除率为46.11%～66.46%.     

酶法提取香菇多糖工艺研究

本实验将木瓜蛋白酶和纤维素酶应用于香菇多糖的提取，研究了酶法提取的工艺条件。结果显示，木瓜蛋白酶的最佳酶解条件是：酶浓度0.5%，酶解温度50℃，pH6～7，酶解反应1h；纤维素酶的最佳酶解条件是：酶浓度0.25%，酶解温度40℃，pH4.5～5.0，酶解反应1h。采用酶水解后，香菇多糖的提取率显著提高。     

正交试验优化大蒜素的提取工艺

对大蒜素的提取工艺进行了优化研究。通过正交试验确定了最佳提取的工艺条件是:酶解温度30℃,酶解时间80min,料液比(大蒜∶95%乙醇)1g∶4mL,离心前pH2.8,酶解pH6.0,大蒜素的提取率0.48%。试验方差结果表明:料液比是提取的主要影响因素。     

超声辅助双水相法提取大蒜素的工艺研究

为了探索大蒜素的提取纯化工艺,采用超声波处理和双水相体系相结合的方法提取大蒜中的大蒜素。选用新鲜大蒜为实验原料,以大蒜素的提取率为实验指标,考查聚乙二醇质量分数、硫酸铵质量分数、p H和超声时间等因素对大蒜素提取率的影响。然后采用响应曲面分析法,对聚乙二醇质量分数、p H和超声时间进行三因素三水平的优化实验,并建立了相应的回归模型。结果表明,聚乙二醇质量分数、p H和超声时间对大蒜素提取率影响显著,显著性顺序为:p H>聚乙二醇质量分数>超声时间;最佳提取工艺条件为:聚乙二醇质量分数19.4%,p H3.0,超声时间55min。在此条件下,大蒜素提取率的预测值为88.91%,实验值为88.89%±0.0112%,实验值与预测值基本相符。     

酶法辅助提取巴戟天多糖的工艺研究

应用单因素和正交试验探讨酶用量、酶解温度、时间和酶作用pH对巴戟天多糖提取率的影响.结果表明,纤维素酶能够显著提高巴戟天多糖的提取率,适宜提取工艺条件为温度55 ℃、pH 5.0、酶用量0.5%、提取时间2 h,此条件下多糖提取率为8.56%,为热水浸提法多糖提取率的1.91倍.     

超声波-酶解法和超声波法提取裙带菜多糖的比较研究

比较研究超声波-酶解法和超声波法提取裙带菜多糖,并采用Fenton体系研究裙带菜中多糖对羟自由基清除活性作用。选取浸提时间、酶用量、固液比及温度4因素采用L16(45)和L9(34)两个方案分别对超声-酶解提取裙带菜多糖和超声波法提取进行正交试验。得到最佳的提取条件为：超声-酶解提取的裙带菜多糖得率与抗羟自由基优化组合为超声-酶解时间15min、纤维素酶用量2.8×104U/g(酶与藻粉比值)、温度70℃、固液比1:80为最佳条件,在此条件下,裙带菜多糖提取率为(4.522±0.028)%,3.60g/L的裙带菜多糖对羟自由基清除率为(51.70±0.47)%。超声-酶解结合方法提取试验条件对裙带菜多糖提取率影响显著(P＜0.01)。试验条件对提取得到的裙带菜多糖羟自由基清除率结果影响不显著(P＞0.05)。超声-酶解法的裙带菜多糖提取效果和及其羟自由基清除率能力明显优于超声波法,其结果具有显著性差异(P＜0.01)。超声波-酶解结合方法提取裙带菜多糖,提取效率高,多糖清除自由基效果好。     

响应面法优化复合酶提取芦荟多糖工艺及其抗氧化活性分析

研究复合酶提取芦荟多糖的工艺,并测定其抗氧化性。在单因素试验的基础上,利用响应面法对复合酶提取芦荟多糖的条件进行了优化,通过测定芦荟多糖的总抗氧化能力、DPPH自由基和羟自由基清除能力研究其抗氧化性。结果显示,当料液比1∶30（g/mL）、果胶酶与纤维素酶配比1∶3、pH 4.5时,优化最佳提取条件为加酶量0.3%、酶解温度48 ℃、酶解时间40 min,此条件下芦荟多糖的提取率为5.65%,和超声波辅助法相比提取率提高了4.2%。芦荟多糖具有较好的抗氧化性,随着质量浓度的增加,其总抗氧化能力、DPPH自由基和羟自由基清除能力逐渐增强,在25 mg/mL时其DPPH自由基和羟自由基清除率分别达到75%和90%。复合酶法是一种新的、有效的芦荟多糖提取方法;芦荟多糖具有较好的抗氧化性。     

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.     

Review of techniques to manufacture micro-hydrogel particles for the food industry and their applications

Microgels are ‘soft’ microscopic cross-linked polymeric particles that are being increasingly exploited in a variety of industries for rheology control, encapsulation and targeted delivery. They are valued because of the ability to tune their functionality to address specific applications in oil recovery, coatings, drug delivery, cosmetics, personal care and foods. Food microgels are typically biopolymer hydrogels in the form of microspheres, nanospheres (also called nanogels), spheroids and fibres. The utilisation of engineered microgels in foods has so far been limited, despite their great potential to address several needs in the food industry, including: satiety control, encapsulation of phytonutrients and prebiotics, texture control for healthier food formulations (e.g. reduced fat products), and targeting delivery to specific areas in the digestive tract. We review the scientific and patent literature on the utilisation and manufacturing methods for producing microgels with an emphasis on micro-hydrogels for food applications.     

12—A CRITIQUE OF SOME HYPOTHESES RELATING TO THE HETEROGENEITY OF THE HIGH-SULPHUR PROTEINS OF WOOL

Joubert and Burns prepared a large number of fractions from the high-sulphur proteins of wool and estimated their molecular weights and amino-acid compositions. Their data have been re-examined in order to look for statistically significant interrelations between amino acids and between the proportion of various amino acids and molecular weight. Statistical analysis of the data is also used to examine the credibility of some hypotheses concerning the mechanism of keratin biosynthesis and to provide further evidence for the existence of families of proteins within the high-sulphur fractions of wool.     

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 Latest Data about Development of Chinese Printing Industry in 2013

In the 2014 China（Shanghai）International Printing Week,Director Wang Yanbin released the latest data about development of Chinese printing industry in 2013.According to statistics,in 2013,the total output value of Chinese printing industry exceeded 1trillion Yuan for the first time,reaching 1.03985 trillion Yuan.There were 105,000 printing enterprises in China,employees were 3.415 million.The total asset was 1.06247 trillion Yuan;     

The State Council Issued "Directory of Government Approved Investment Projects(2013 Edition)"

正On December 2nd,2013,the State Council issued the notification of"Directory of Government Approved Investment Projects(2013 Edition)"(hereafter referred to as"notification").It is pointed out in the"notification"that in order to further deepen reforms in investment systems and administrative examination and approval systems,simplify administrative procedures and delegate powers to lower levels,earnestly     

Top Ten News of China's Paper Industry 2013

On December 24th, 2013, the meeting on the selection of top 10 news of China＇s paper industry 2013 sponsored by 〈China Paper Newsletters〉 was held in Beijing. The yearly selection of the top l0 news, which began in 2000, has become a brand activity widely recognized in the industry thanks to the support from the authorities at all levels and public participation.     

National Development and Reform Commission Issued Announcement for Selection of Major Preliminary Research Projects for the "13~(th) Five-Year Plan"

In Apri Commi major p Plan＂ （h 2014, the National Development and Reform ssion issued an announcement for selection of reliminary research projects for the ＂13th Five-Year ereafter referred to as ＂The Announcement＂）     

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 latest scientific     

China textile machinery: taking off in progress

正Among the 1600 exhibitors who take apart in the ITMA ASIA+CITME2014 2/3 are Chinese manufactures.If the numerous figures failed to attract your attention,the increase of quality should draw your focus.To adopt the demand of developing textile machine market,domestic textile machinery enterprises now follow the slogan of"technology drives development"to enhance product competitiveness.Our domestic sellers will showcase product ranging from spinning,weaving,dyeing and printing,