木素脱氢聚合物-葡萄糖复合体形成机理的研究

为阐明植物纤维细胞壁中木素与聚葡萄糖化学键的连接,本研究探讨了在(6-13C)葡萄糖和纤维二糖的存在下,松柏醇葡萄糖苷的过氧化物酶催化脱氢聚合过程中与碳水化合物之间化学键的形成。研究发现,木素脱氢聚合物(DHP)能与(6-13C)葡萄糖形成DHP-(6-13C)葡萄糖的聚合物,核磁共振碳谱(13C NMR)分析结果表明,葡萄糖C6位上的碳与木素结构单元以苯甲醚键连接。此外,研究还发现,木素前驱物与纤维二糖之间发生了共聚,得到了DHP-纤维二糖的复合体,13C NMR分析结果表明,纤维二糖与DHP之间可能存在苯甲醚键、苯甲酯键和α-缩醛键等化学键的连接。     

木素-木聚糖复合体化学结构的研究

在木聚糖存在的条件下,以木素前驱物-松柏醇葡萄糖甙作为起始物在多种酶(β-葡萄糖甙酶、葡萄糖氧化酶和辣根过氧化物酶)的协同作用下,生物合成出木素脱氢聚合物(DHP)与木聚糖的复合体(简称DHPXC)。对其进行酶降解处理除去游离的木聚糖,并对与木素有连接的木聚糖分子链进行切短,得到水不溶部分(简称DHPXC-IS)。利用高分辨率的固体和液体~(13)C-NMR对分离产物进行分析,结果表明,在木聚糖存在下,DHP生成过程中与木聚糖之间主要以苯甲醚键和酯键的形式连接。生成的木素主要以β-O-4、β-β、β-5和β-1为主,有一定量以α-O-4连接,含有少量的松柏醇/醛结构,另外还存在少量香草醛结构及α位带有亚甲基结构的苯丙烷结构和醚化5-5′结构。     

碳-13 同位素示踪结合13C-NMR分析稻杆木素结构

为了进一步了解单子叶植物的木紊,向生长中的水稻(Oryza sativa L.)茎秆节间的腔体分别注入在侧链α、β、γ位带13C标记的松柏醇葡萄糖甙,得到侧链带13C标记的稻秆木素.通过CP/MAS13C-NMR分析,发现外源性的松柏醇葡萄糖甙并不影响水稻中木素和碳水化合物的正常生物合成.液态13C-NMR检测结果证明稻秆原本木素的主要结构是β-O-4、β-1、β-β和β-5结构,还有少量的松柏醇和α-O4结构.另外,还证明了木素在α位与糖类等组分有共价键结合.     

未漂硫酸盐浆过氧化物酶催化交联的研究

低卡伯值末漂硫酸盐阔叶木浆与松柏醇葡萄糖苷在过氧化物酶体系存在下可发生聚合反应,生成脱氢聚合物(DHP)及DHP.碳水化合物复合体.用红外光谱和高分辨率CP/MAS 13C-NMR对DHP-碳水化合物复合体结构进行分析.结果表明,DHP-碳水化合物复合体中DHP结构单元之间主要通过β-0-4、β-β、β-5和卢-1方式连接,DHP结构单元还通过缩醛键、苯甲酯键和苯甲醚键与浆中碳水化合物相连;经过松柏醇葡萄糖苷处理后.纸张的干强度提高不大,但湿强度为空白样的2.1倍.     

~(13)C标记法用于硫酸盐法蒸煮浆中残余木素结构的研究

向生长中的银杏(Ginkgo biloba L.)植物体内投入在侧链α位被13C标记的木素前驱物松柏醇葡萄糖甙,得到13C标记的银杏木素,收集13C标记木素所在银杏木质部组织,模拟硫酸盐法蒸煮,对蒸煮得到的浆料进行酶降解处理得到13C标记浆中残余木素,用红外光谱和13C-NMR对其结构进行分析,发现浆料残余木素结构单元之间主要通过β-5方式连接,还有一定量以β-O-4的形式连接;此外,还含有大量的阿魏酸和松柏醇结构,含有少量的香草醛结构。     

果胶前驱体6-~(13)C标记示踪法研究果胶与木质素的连接方式

为了从碳水化合物的角度研究果胶-木素复合体之间的结构,本文采用13C同位素示踪标记法,通过对植物体中的果胶前驱物α-D-葡萄糖醛酸6位碳上进行13C同位素标记,得到植物体内合成的带13C6标记的果胶-木素复合体,并用果胶酶对果胶-木素复合体进行酶解,利用红外、高分辨率固体13C-NMR以及液体13C-NMR技术分析带13C标记的稻秆粉末、LCC以及酶解后LCC,发现果胶通过6位上的C原子与木质素苯丙烷结构以酯键的形式连接,且样品中木素结构单元之间主要以β-O-4、β-1、β-5和松柏醇结构的方式连接。     

未漂硫酸盐针叶木浆漆酶催化交联的研究(Ⅰ)——松柏醇葡萄糖苷与未漂浆的反应机理

采用红外光谱和高分辨率CP/MAS 13C-NMR研究了松柏醇葡萄糖苷与未漂硫酸盐针叶木浆在漆酶体系作用下的聚合反应机理.结果表明:在漆酶体系作用下,松柏醇葡萄糖苷能够与未漂硫酸盐浆发生聚合反应,生成脱氢聚合物(Dehydrogenation Polymer, DHP)及DHP-碳水化合物复合体.DHP结构单元之间主要通过β-O-4、β-β和β-5方式相连接; DHP与碳水化合物之间是通过苯甲酯键和苯甲醚键相连.这些结果也表明,纤维之间除了氢键连接外,还可以通过DHP及DHP-碳水化合物复合体型式连接起来,从而提高纸张的湿强度.     

~(13)C同位素标记法研究硫酸盐木素结构

向生长中的银杏(Ginkgo biloba L.)植物体内投入在侧链α位被13C标记的木素前驱物松柏醇葡萄糖苷,得到13C标记的银杏木素,分别收集13C标记的木素所在的银杏木质部组织,模拟硫酸盐法蒸煮,对蒸煮得到的黑液进行酸化,得到13C标记的硫酸盐木素。用红外光谱和13C-NMR对其结构进行分析,发现硫酸盐木素中含有少量的碳水化合物,并以苯甲醚键的形式与木素连接。木素结构单元之间主要通过β-β、β-O-4、β-1的形式连接,苯丙烷结构单元的侧链含有一定量的双键结构,此外,还含有一定量的香兰素、松柏醇结构,少量的松柏醛、苯基香豆满结构。     

木素酶降解蔗渣浆残余木素机理的研究

采用核磁共振氢谱(^1H-NMR)和碳谱(^13C-NMR)的分析手段，研究白腐菌Phanerochaete Chrysasporium固体发酵分泌的木素酶降解蔗渣浆中残余木素的机理。^1H-NMR分析表明，经过木素酶预处理残余木素部分苯环结构发生了开环反应，产生C—C双键结构．酚羟基含量降低，含酚羟基的木素优先降解，残余木素中的醇羟基含量升高；^13C-NMR分析结果表明木素分子的Cα-Cβ连接键、部分侧链、β-O-4结构和甲氧基发生氧化断裂导致木素大分子降解。     

松柏醇葡萄糖苷用于提高纸张物理强度的研究

本文研究了在过氧化物酶的体系下利用木素前驱物松柏醇葡萄糖苷与果胶和葡苷聚糖的复合体来提高纸张的强度.生成的复合体由于有木素,在酶的作用下与纤维上的碳水化合物及残余木素聚合,从而将果胶与葡苷聚糖联接到纤维上,使得果胶-葡苷聚糖-DHP复合体与纤维接枝、缠绕和互穿,从而提高纸张的强度.经过处理后的纸张有明显的干强度提高,湿强度有很大的提高,湿抗张指数从2.13 N·m/g提高到4.53 N·m/g,提高了112.7%.从处理后的浆的红外谱图及核磁谱图的分析表明松柏醇葡萄糖苷在纤维表面生成了DHP-碳水化合物复合体,DHP结构单元之间主要通过β-O-4、β-β和β-5方式相连接;DHP与碳水化合物之间主要是通过苯甲酯键和苯甲醚键相连的.     

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,