过氧化物酶(POD)对协定糖化麦汁品质的影响

麦芽中的过氧化物酶(POD)具有活性高、热稳定强的特点,这为糖化阶段酶促氧化酚类物质的反应创造了条件.本文研究了大麦麦芽中POD活性对协定糖化麦汁品质的影响.结果表明:POD对麦汁的显著影响受限于H2O2的可得性,当H2O2的浓度为2 mmol.L-1时即可对麦汁酚类物质含量、抗氧化力、过滤速度和外观特性产生显著的不利影响.而在O2存在的情况下,高活性的POD同样可以氧化酚类物质,但对麦汁过滤速度和外观品质的影响不及H2O2显著.在实际糖化过程中由于底物H2O2和O2受限,使得POD酶促氧化多酚的反应未能充分表现.     

全酶法大麦糖浆的制备工艺

全酶法制备大麦糖浆的最佳工艺为：高温α－淀粉酶加量８ｕ／ｇ大麦,液化时间１０ｍｉｎ;糖化温度６０℃,ｐＨ６０,糖化时间８ｈ,β－淀粉酶加量１００ｕ／ｇ大麦。由此工艺制备的大麦糖浆的ＤＥ值为７２％,极限发酵度为７４％。     

啤酒生产中麦汁发酵过程的实验室模拟Ⅱ麦汁(主)发酵过程的热跟踪监测

利用ＤＤＣ－Ⅱ型补偿式数字精密量热系统和专门设计的ＣＣＵ－Ⅰ型量热单元，对啤酒生产中在控温下麦汁发酵过程进行了实验模拟，获得了过程的热谱图，并对葡萄糖液进行了相同的发酵过程的热监控。对比和分析了二者的热谱图，从量热的角度验证了文献中关于酵母对糖发酵的作用历程的认识。另外，对影响发酵的主要因素进行了试验研究，并在选定的通气速率条件下进行了相同的发酵试验，为改进啤酒生产工艺，提高啤酒质量和产量提供了实验依据     

Hyperforin is a novel type of 5-lipoxygenase inhibitor with high efficacy in vivo

We previously showed that, in vitro, hyperforin from St. John’s wort (Hypericum perforatum) inhibits 5-lipoxygenase (5-LO), the key enzyme in leukotriene biosynthesis. Here, we demonstrate that hyperforin possesses a novel and unique molecular pharmacological profile as a 5-LO inhibitor with remarkable efficacy in vivo. Hyperforin (4 mg/kg, i.p.) significantly suppressed leukotriene B₄ formation in pleural exudates of carrageenan-treated rats associated with potent anti-inflammatory effectiveness. Inhibition of 5-LO by hyperforin, but not by the iron-ligand type 5-LO inhibitor BWA4C or the nonredox-type inhibitor ZM230487, was abolished in the presence of phosphatidylcholine and strongly reduced by mutation (W13A-W75A-W102A) of the 5-LO C2-like domain. Moreover, hyperforin impaired the interaction of 5-LO with coactosin-like protein and abrogated 5-LO nuclear membrane translocation in ionomycin-stimulated neutrophils, processes that are typically mediated via the regulatory 5-LO C2-like domain. Together, hyperforin is a novel type of 5-LO inhibitor apparently acting by interference with the C2-like domain, with high effectiveness in vivo.