Inhibition of lipase from rice (Oryza sativa) by diethyl-p-nitrophenyl phosphate

The inhibition of rice bran lipase (RBL) by diethyl-p-nitrophenyl phosphate was studied with reference to kinetics, nature of inhibition and also elucidate the effect of the inhibitor on the structure—function of the enzyme. Enzyme activity measurements shows that the inhibitor is more effective at 0.050 mM concentration of diethyl-p-nitrophenyl phosphate and the activity is 50% at this level of inhibitor concentration. The affinity of substrate for the enzyme was observed by the increase in the velocity of the reaction with increase in the substrate concentrations and double reciprocal plot indicates that the inhibition followed a competitive in nature and inhibition constant K _i is found to be 0.016 mM at pH 7.0. The decrease in apparent thermal denaturation temperature to 4 °C compared to control indicates the destabilization of enzyme in the presence of inhibitor. Fluorescence spectral measurements suggests that pronounced quenching of fluorescence intensity of RBL occurs at higher concentrations of diethyl-p-nitrophenyl phosphate and ‘K _a’ value was found to be 2.4 × 10⁴ M⁻¹ with free energy change ΔG^o—26 kJ/mol at 30 °C suggesting strong binding between the enzyme and the inhibitor with microenvironmental changes occur at the active site or in the neighbourhood of active site. The far UV-CD data suggest that there is no significant changes in the conformation of the enzyme as a result of binding of diethyl-p-nitrophenyl phosphate. These results indicate that diethyl-p-nitrophenyl phosphate is a inhibitor of RBL and binds to the enzyme in brining about inhibition without any structural alterations.     

单烷基磷酸酯体系洁面乳基础配方的研究

目的改善以单烷基磷酸酯（MAP）为主表面活性剂的洁面乳体系的铺展性和流变性。方法研究不同的碱中和量、辅助表面活性剂、聚合物增稠剂等因素对产品黏度等性能的影响。结果MAP体系中和后pH6．2～6．6之间性能良好;辅助表面活性剂羟磺甜菜碱和咪唑啉椰油两性醋酸钠两者复配有很好的稳泡、增稠性能;聚合物中Greenthix ACS（丙烯酸酯共聚物）有较好的增稠和分散性能,并能赋予产品良好的剪切变稀性能,耐热再恢复至室温后产品流变性基本不变,具有耐热剪切变稀的良好性能。结论MAP洁面乳基础配方中表面活性剂选用羟磺甜菜碱和咪唑啉椰油两性醋酸钠,流变添加剂选用Greenthix ACS。     

化学沉淀稠油脱钙剂的研究

本文介绍了(NH4)2HPO4做为化学沉淀脱钙剂的室内研究,讨论了脱钙剂加入量、注水量、温度及混合强度对脱钙效果的影响。试验结果表明,在(NH4)2HPO4加入量为原油中Ca的摩尔数的6倍,注水量占原油量8%,反应温度100℃,乳化机搅拌8m in时,原油脱钙率可达90%,对普通碳钢无腐蚀作用。最后,提出循环沉降工艺是该技术的研究方向。     

离子色谱同时测定烘焙食品中两种形态磷酸盐

建立一种离子色谱电导抑制法同时测定食品中正磷酸盐和焦磷酸盐新的分析方法.样品经0.5％HCl溶液溶解,固相萃取柱去除有机杂质,Ag/H柱去除大量的Cl-后,以KOH作淋洗液梯度洗脱,电导抑制法检测.在优化的分离条件下2种添加剂的检出限分别为0.5mg/L和1.0mg/L,标准混合溶液连续6次进样,相对标准偏差为0.45％和0.69％,样品测定的平均回收率为96.5％、93.8％.该方法可快速、准确地分析烘焙食品中正磷酸盐和焦磷酸盐.     

草鱼盐溶蛋白保水性及流变性质的研究

研究了混合磷酸盐对盐溶蛋白的凝胶保水性影响及对其流变性进行测定,分析蛋白动态流变性质以及凝胶强度与保水性的相关性。结果表明:添加磷酸盐可提高盐溶蛋白的保水性;添加不同配比的混合磷酸盐对盐溶蛋白凝胶的保水性和凝胶强度影响显著;盐溶蛋白最终凝胶强度很大程度上受42.1～45.6℃或之前的凝胶强度的影响,盐溶蛋白的凝胶强度与凝胶的保水性不相关。     

磷酸根离子对固定化酵母细胞传质效果改善的研究

利用磷酸根离子对海藻酸钙凝胶有软化、破坏作用的原理,来处理用海藻酸钠-PVA混合载体包埋制得的固定化细胞颗粒,可有效降低凝胶结构的紧密程度,增强其通透性,获得较好的传质效果,通过扫描电镜对凝胶颗粒结构的袁征证实了实验效果。实验得出最好的磷酸根离子处理方式为：用0．8mol／L KH2PO4浸泡固定化细胞颗粒24h后再进行发酵生产。最后用多批次发酵实验验证了用磷酸根离子处理后的固定化酵母细胞的产酒、机械性能的稳定性。     

磷酸盐在肉制品中应用研究现状及发展趋势

本文主要论述了磷酸盐的分类,性质,在肉制品中的作用以及在肉制品生产中的注意事项和以后发展趋势,以便为肉制品加工起到指导作用。     

霄云矿井深部软岩巷道及硐室锚注支护研究与应用

锚注支护利用空心锚杆兼做注浆管,通过注浆将松散围岩胶结成整体,既提高了围岩自身的承载能力,又为锚杆提供了可靠的着力基础,从而有效地控制了深部软岩巷道及硐室的大变形,尤其对松软破碎岩体的支护极为有效。     

岩巷施工工艺的探索与研究

对岩巷锚喷施工工艺进行了探索与论证,详细阐明了"三掘三喷"工艺,解决了"二掘一喷"施工技术支护强度得不到保证、工程质量不易控制、掘进工作面迎头不安全、掘进单进不高等问题。     

瞬变电磁法在断层防治水中的应用

该文讨论了瞬变电磁法的原理,介绍了瞬变电磁法在阳城煤矿开拓大巷过季庄断层的应用设计施工,给出了季庄断层瞬变电磁法探测结果及结论,并根据结论采取了过断层的有效措施,通过巷道施工过程中的超前钻探及巷道实际揭露的断层的情况,验证了瞬变电磁法在断层防治水应用中可靠有效性。