酯化修饰对二氢杨梅素性能的影响

用月桂酰氯对二氢杨梅素进行不同程度的酯化修饰,探讨不同程度的酯化修饰对二氢杨梅素溶解性和抗氧化性能的影响。结果表明：与二氢杨梅素相比,二氢杨梅素酯化物在油中的溶解度提高20～300 倍,并且随着酯化程度加大,二氢杨梅素酯化物在油中溶解度增加。二氢杨梅素酯化物在极性溶剂中清除DPPH 自由基和H2O2 的能力比二氢杨梅素低,酯化物的抗氧化活性随着酯化程度的增加呈下降趋势;在铁离子- 抗坏血酸诱导的卵磷脂过氧化反应体系中,二氢杨梅素酯化物的抗氧化活性明显优于二氢杨梅素,且不受酯化程度的影响,表明二氢杨梅素及其酯化物在卵磷酯脂质体中的抗氧化活性受溶解性和羟基数目双重影响。     

用ESR检测二氢杨梅素对自由基的清除作用的研究

为研究二氢杨梅素对不同活性氧自由基的清除作用,采用ESR和自旋捕集技术测定二氢杨梅素对·OH、·O2-和DPPH自由基的清除效果。结果表明,二氢杨梅素对活性氧自由基有较好的清除作用,并呈现出一定的量效关系;二氢杨梅素对活性氧自由基有较好的清除作用,并呈现出一定的量效关系;二氢杨梅素清除和抑制·O2-、·OH-和DPPH自由基的IC50分别为7.4μg/mL、297.8μg/mL和12.4μg/mL,表明二氢杨梅素对不同自由基的清除能力有显著差异,对超氧自由基具有更强的清除作用。     

二氢杨梅素在猪油体系中的抗氧化作用研究

二氢杨梅素是一种开发前景广阔的新型食品用天然抗氧化剂。旨在研究二氢杨梅素及其增效剂对其在猪油体系中的抗氧化活性的影响,通过测定丙二醛吸光值和过氧化物值来评价抗氧化效果,确定纯度为95%的二氢杨梅素在猪油体系中的最优添加量为0.04%;当添加量为0.02%时,L-抗坏血酸、柠檬酸和EDTA可有效地提高二氢杨梅素的抗氧化性能。     

脂溶性二氢杨梅素的制备及其抗氧化性研究

为改善二氢杨梅素的脂溶性,采用化学修饰法制备了二氢杨梅素癸酸酯。考察该产品的溶解性及不同酯化物对猪油的抗氧化活性。结果表明：通过癸酰氯修饰的二氢杨梅素在油溶性基质中具有良好的分散稳定性,当酯化度为3时,其对猪油的抗氧化能力最强,在相同质量分数时二氢杨梅素癸酸酯的抗氧化活性优于二氢杨梅素和BHT,0.05%二氢杨梅素癸酸酯的抗氧化性能与TBHQ接近。     

牛蒡提取物体外抗氧化性的研究

研究了牛蒡提取液清除超氧自由基02^-·、羟基自由基·OH、过氧化自由基R00·的效果。结果表明：牛蒡提取液对超氧阴离子（O^2-·）和羟自由基（·OH）均具有较强的清除能力，对油脂也具有明显的抗氧化能力，并且随着提取液浓度的增加，这些能力有增强的趋势。     

天然抗氧化剂对鳡鱼内脏油的抗氧化研究

以过氧化值为指标,以空白样和添加TBHQ样为对照,采用Schaal烘箱法研究了茶多酚、迷迭香酸、二氢杨梅素与VE4种天然抗氧化剂对鳡鱼内脏油的抗氧化效果。结果表明,当添加量均为0.02%时,其对鳡鱼内脏油抗氧化效果强弱为:TBHQ二氢杨梅素茶多酚迷迭香酸VE;茶多酚、迷迭香酸和二氢杨梅素最适添加量分别为0.04%、0.06%和0.04%;VC对茶多酚和二氢杨梅素均具有一定的增效作用;复配天然抗氧化剂的最佳组合为0.02%二氢杨梅素+0.02%茶多酚,并以0.02%的VC为增效剂;复配天然抗氧化剂对鳡鱼内脏油的抗氧化效果明显好于单一天然抗氧化剂的,且接近于TBHQ的。     

采用量子化学计算法探讨二氢杨梅素抗氧化机制

二氢杨梅素为活性黄酮类物质，具有良好的抗氧化活性。本研究采用Gaussian系列程序计算二氢杨梅素各羟基组成原子的前沿轨道系数、分子总能量以及二氢杨梅素供氢后的分子结构能量，采用“从头计算”法，选取6-31G＊基组。计算结果认为二氢杨梅素分子供氢后结构的稳定性是决定二氢杨梅素物质抗氧化能力的主要因素，确定二氢杨梅素分子B环上3’位、4’位、5’位酚羟基结构是抗氧化活性中心。     

藤茶二氢杨梅素茶氨酸复合物的制备及抗氧化活性研究

二氢杨梅素在天然藤茶中含量高达25.6%,具有多种生理功能,受到广泛关注。但二氢杨梅素常温水溶性差,生物利用度较低,限制了其应用范围,为了提高二氢杨梅素的水溶性,对二氢杨梅素进行分子修饰,制备了二氢杨梅素-茶氨酸复合物,利用紫外光谱、红外光谱、质谱和核磁共振氢谱对复合物进行了结构表征,测定了复合物的理化性质,并考察了复合物的抗氧化活性。通过结构分析,二氢杨梅素分子中C3-OH、C5-OH、C7-OH、C3′-OH、C5′-OH与茶氨酸的活泼氢通过氢键结合形成复合物;复合物清除·OH自由基的能力均强于二氢杨梅素和Vc,清除O2-·自由基和DPPH自由基的能力和二氢杨梅素相当,比Vc强。二氢杨梅素和茶氨酸的复合,不仅提高其水溶性,在抗氧化活性方面也起到了强化的作用。     

低分子量壳聚糖对镉染毒引起的氧自由基变化的影响

采用浸浴法研究了镉（Cd^2＋）胁迫下,添加不同浓度低分子量壳聚糖（LMWC）对长江华溪蟹（Sinopotamon yangtsekiense）超氧阴离子（O2^-·）、羟自由基（·OH）和过氧化氢（H2O2）三种氧自由基的影响,并初步探讨了LMWC的作用机制。实验设置5个LMWC与Cd^2＋联合作用组（5、10、20、40和80mg/L）、1个Cd^2＋对照组（58mg/L）和1个空白对照组,分别在96h后测定鳃、肝胰腺和心脏的抗O2^-·能力、抑制·OH能力和H2O2含量。结果显示,Cd^2＋可以诱导蟹体产生大量的氧自由基,并导致机体的抗氧化能力降低,LMWC的加入可以有效抑制Cd^2＋引起的氧化损伤,其抑制作用随LMWC浓度的增大逐渐增强。LMWC浓度达到40mg/L和80mg/L时抑制作用显著。LMWC对镉染毒引起蟹体内过量氧自由基有一定的清除作用。     

桑叶酸性蛋白多糖(APFM)抗氧化作用的实验研究

目的：研究桑叶酸性蛋白多糖（APFM）的抗氧化作用。方法：在化学模拟实验中，测定APFM对羟自由基（·OH）和超氧阴离子自由基（O2^-·）的清除作用，并测定APFM对·OH诱导的小鼠脏器中MDA形成和积累的影响，以及对小鼠肝线粒体肿胀的抑制作用。在小鼠模型实验中，观察和分析APFM对四氧嘧啶所致糖尿病模型小鼠脏器中MDA含量和SOD活性等生理指标的影响。结果表明APFM可以有效清除化学模拟体系中形成的·OH和O2^-·，抑制小鼠脏器在该体系和糖尿病模型中MDA的形成和积累，明显减轻·OH诱导的小鼠肝线粒体的肿胀和模型小鼠脏器中SOD活性的降低，并都存在明显的量效关系。结论：可以认为APFM具有良好的体外和体内的抗氧化作用，是一种有效的自由基淬灭剂。     

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,     

Anti-mutagenic compounds from corn

In previous studies with aflatoxin-contaminated corn an uncharacteristic response for AFB₁ in the Salmonella/microsomal mutagenicity assay (Ames test) was observed and the presence of anti-aflatoxin factors in the corn was suggested. In the current study, corn was extracted and fractionated using thin layer chromatography (TLC) using different developing solvent systems and the Ames test was used to monitor for anti-mutagenic activity in the corn fractions. Both Salmonella tester strains TA98 and TA100 with metabolic activation (S9) were used. Several corn fractions, at different stages in the isolation and purification process, showed anti-mutagenic dose-responses when exposed to pure AFB₁. Corn extracts were non-toxic to the tester strains and TLC fractions that showed the best anti-mutagenic dose-responses were selected for further partial characterization analyses.