Exposure or release of ferulic acid from wheat aleurone: Impact on its antioxidant capacity

The relationship between the aleurone cell integrity and the exposure or release of bioavailable ferulic acid (FA) with the antioxidant capacity of aleurone in in vitro and under simulated gastric conditions was explored. The antioxidant capacity of aleurone was increased by around 2-fold when its median particle size was reduced to under 50 μm. The opening of aleurone cells increased the physical exposure of FA bound to the insoluble polysaccharides, which seemed to be responsible of the increased antioxidant capacity. Synergistic combination of xylanase and feruloyl esterase was found to be the most efficient enzymatic treatment releasing up to 86% of total FA in bioaccessible forms. This enzymatic treatment significantly enhanced the radical scavenging activity of aleurone by up to 4-fold, which overlapped the overall antioxidant potential estimated from the total content of FA in aleurone. The improvement in the antioxidant capacity of aleurone was also observed in the simulated gastric digestion by inhibition of lipid oxidation.     

固定化木聚糖酶的应用研究进展

木聚糖酶是半纤维素的主要生物催化剂,可将其主要成分木聚糖降解为木糖或低聚糖,木聚糖酶可广泛应用于食品、饲料、医药、能源等领域。固定化酶可以提高酶的使用效率,增加产物收率,降低生产成本,综述了木聚糖酶的性质,固定化酶的载体和方法,并对以后的发展趋势进行了探讨。     

木聚糖酶辅助漂白机理的研究进展

木聚糖酶能选择性地水解纸浆中的木聚糖,提高纸浆的可漂性,从而使漂白化学品更容易与木素作用。木聚糖酶助漂在一定程度上节约了漂白化学药品用量,减少了化学漂白过程对环境的污染。本文对木聚糖酶在纸浆漂白中漂白机理的研究现状进行了归纳和评述,并对木聚糖酶辅助漂白技术的发展进行了展望。     

木聚糖酶酶促磨浆对马尾松TMP湿部化学特性的影响

利用木聚糖酶对马尾松TMP进行预处理,然后进行磨浆,研究了酶促磨浆对纸浆某些湿部化学特性的影响。结果表明,木聚糖酶酶促磨浆,能够改善浆料的滤水性能,提高浆料的AKD施胶度和填料留着率。     

聚木糖酶对桉木KP预处理的影响

研究了聚木糖酶预处理的影响因素。添加表面活性剂可加强聚木糖酶的作用。聚木糖酶预处理可加强发包基团的去除，加强本素酚型结构与漂剂反应，提高次氯酸盐漂白浆白度，减少氯耗。     

Xylanase-mediated in situ production of arabinoxylan oligosaccharides with prebiotic potential in whole meal breads and breads enriched with arabinoxylan rich materials

Multiple studies have revealed the prebiotic activity of cereal derived arabinoxylan oligosaccharides (AXOS). This study investigated the in situ production of AXOS during bread making. In the first part, the AXOS producing capacity of different xylanases was compared in whole meal bread making. Three mesophilic xylanases originating from Bacillus subtilis, Aspergillus niger and Hypocrea jecorina, and one thermophilic xylanase from H. jecorina (HjXynA), were used in different dosages. At dosages that did not impair dough manageability, HjXynA solubilised and cleaved the arabinoxylan fraction to the largest extent, resulting in an AXOS content of 2.1% (dry basis) and an average degree of polymerisation (avDP) of 9. In the second part, the impact of HjXynA on the AXOS levels in dietary fibre enriched breads was studied. Rye or wheat bran fortified breads treated with HjXynA yielded good quality breads with AXOS levels above 2.0% with an avDP of 26 and 19, respectively.     

康氏木霉发酵液提取木聚糖酶的酶学性质研究

对康氏木霉（Trichoderma Koningii）发酵产木聚糖酶的酶学性质进行了研究。结果表明；该木聚糖酶的最适反应温度为65℃，酶反应最适pH为6．0；该酶在20～60℃范围内能保持87％以上的酶活，在pH3．0-9．0范围内能保持85％以上的酶活；金属离子K^＋、Ba^2＋、Pb^2＋、Fe^2＋、Fe^3＋、Al^3＋和12mmol／L的Cu^2＋对木聚糖酶的活性有抑制作用，而Ca^2＋，Zn^2＋和4mmol／L Cu^2＋等金属离子对该酶有激活作用。     

Simultaneous application of phytase and xylanase to broiler feeds based on wheat: in vitro measurements of phosphorus and pentose release from wheats and wheat-based feeds†

An in vitro procedure that simulated digestion in growing broilers was tested to predict phosphorus availability and arabinoxylan hydrolysis in samples of nine wheat varieties and in a wheat-based diet. Amounts of dialysable phosphorus freed from wheat samples correlated with activities of endogenous phytase (R = 0.913; p < 0.0001), whereas amounts of pentoses released were correlated with viscosities of the digested samples (R = 0.899; p < 0.0001). Differences in phosphorus release resulting from graded levels of microbial phytase added to feeds that were either autoclaved or not autoclaved revealed a decreasing role of endogenous phytase in dephosphorylation as levels of microbial phytase supplementation grew. Amounts of pentoses released from feeds containing two different xylanase preparations reflected literature data on different in vivo efficacies of those preparations. Simultaneous addition of phytase and xylanase affected phosphorus release in a manner that depended upon the form of xylanase preparation used (liquid or powder). There was a positive influence of acid protease on both phytate and arabinoxylan hydrolysis in feeds supplemented with phytase. Effects observed by the in vitro procedures corresponded to in vivo phenomena described in the literature. © 1999 Society of Chemical Industry     

一株侧耳木霉的鉴定及其产木聚糖酶研究

以分离自平菇栽培污染菌包的一株菌株ZJ-03为研究对象,采用形态学观察和分子生物学相结合的方法对其进行鉴定,并对其定性、产木聚糖酶活力和木聚糖酶生产低聚木糖进行了研究。结果发现,菌株ZJ-03的形态与侧耳木霉(Trichoderma pleuroticola)形态相似,系统进化树分析发现ZJ-03与T.pleuroticola ICMP:2080亲缘关系较近,聚为一类,将该菌株归属为侧耳木霉。菌株ZJ-03可产木聚糖酶,活性在3000 IU/g以上;木聚糖酶可产低聚木糖,占总糖含量72.0%。该结果可为进一步研究侧耳木霉产木聚糖酶用于生产低聚木糖的可行性奠定基础。