共查询到20条相似文献，搜索用时 928 毫秒
1.
采用L9(34)正交试验法,探讨了海藻酸钠浓度、CaCl2浓度、壳聚糖含量和包埋菌量对固定化细胞产壳聚糖酶的影响.实验结果表明,海藻酸钠浓度是影响固定化细胞产壳聚糖酶的重要因素;最终确定的最佳组合为A1B3C3D3,即海藻酸钠浓度2%、CaCl2浓度4%、壳聚糖含量1.5%和包埋菌量6%. 相似文献
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采用在50 m L三角瓶中定量添加毒死蜱药液和固定化菌的方法研究了不同包埋条件对固定化蜡状芽孢杆菌(Bacillus cereus)降解毒死蜱的影响,最后将固定化条件进行了正交试验的优化。结果表明,游离化菌体的菌龄为20 h对初始浓度为50mg/L毒死蜱的降解率达最高。从降解曲线得出,海藻酸钠固定化菌降解毒死蜱的反应时间为24h时降解率达75.4%;菌体和海藻酸钠溶胶的包埋比为1∶20对毒死蜱的降解率达最高为76.8%;随着成型剂Ca Cl2浓度的增大,固定化菌对毒死蜱的降解率先上升后下降,Ca Cl2浓度为2%对毒死蜱的降解率达最大为82.6%,海藻酸钠溶胶浓度为3%对初始浓度为50 mg/L毒死蜱的降解率达最大为85.7%。通过正交试验得出,海藻酸钠浓度(A)、Ca Cl2浓度(B)和固定化时间(C)三者对固定化菌降解毒死蜱的影响都达到显著水平(P0.05),影响次序依次为CAB,最优水平分别为海藻酸钠浓度3.0%、Ca Cl2浓度1.5%和固定化时间32 h。因此,固定化蜡状芽孢杆菌对毒死蜱的降解率较高,在毒死蜱水体污染的降解去毒方面具有的应用价值较大。 相似文献
3.
紫苏子油软膏剂配方的筛选 总被引：4，自引：0，他引：4
[目的]筛选紫苏子油软膏剂的配方.[方法]选用液体石蜡,凡士林,羊毛脂,硬脂酸,单硬脂酸甘油酯、甘油、三乙醇胺,海藻酸钠,蒸馏水等乳剂型基质,通过乳化法以不同配方制备软膏剂,检测其涂抹分散性和涂抹肤感及其在耐寒、耐热试验中的稳定性.[结果]不含海藻酸钠的软膏稳定性差,涂抹分散性稍差,涂抹肤感油性稍弱;不含三乙醇胺的软膏稳定性很差;含有三乙醇胺和海藻酸钠的软膏稳定性和涂抹分散性好,涂抹肤感无油性,而且含10 g紫苏子油软膏稳定性及涂抹分散性比5 g、15 g好.[结论]以液体石蜡6 g、凡士林1 g、甘油5 g、羊毛脂5 g、硬脂酸12 g、单硬脂酸甘油酯3.5 g、紫苏子油10 g、三乙醇胺0.4 g、海藻酸钠0.5 g和蒸馏水51.6 g可作为制备紫苏子油软膏剂的配方. 相似文献
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《河南职业技术师范学院学报(职业教育版)》2021,(2)
以面包粉、白砂糖、酵母为原料,采用单硬脂酸甘油酯、大豆磷脂、海藻酸钠三种乳化剂复配研究其对面包品质的影响.通过单因素试验确定三种乳化剂的基本添加量,进一步通过正交试验确定三种乳化剂的最优复配方案.结果表明:海藻酸钠对面包品质的影响最大,大豆磷脂其次,单硬脂酸甘油酯最弱;添加质量分数为0.4%的单硬脂酸甘油酯、质量分数为0.5%的大豆磷脂、质量分数为0.1%的海藻酸钠,制作出的面包感官品质最好,面包表皮色泽鲜亮,质地柔软,形态完整,口感香甜细腻,保存时间长,不易老化. 相似文献
7.
《滁州学院学报》2021,(5):3-7
为延长草莓的贮藏期,探讨可食用涂膜对草莓生理生化及品质的影响,本实验以海藻酸钠(0.01g/mL)作为主剂,与不同浓度茶多酚(0、0.5%、1.0%、1.5%)进行复配制成复合保鲜剂分别处理草莓样品,置于4℃保存,贮藏期间对草莓果实进行感官评定、抗坏血酸含量、可滴定酸含量、可溶性固形物含量和丙二醛含量的测定。结果表明,与单独的海藻酸钠涂层相比,茶多酚-海藻酸钠复合涂层对草莓的保鲜效果更好,且当海藻酸钠浓度为0.01g/mL,茶多酚浓度为1.0%时效果较好,在储藏第5天时仍能保持较好的感官品质,且可滴定酸、可溶性固形物和VC的损失最少,同时能有效抑制采后贮藏期间丙二醛含量的上升,为草莓的储藏保鲜提供参考。 相似文献
8.
为了改善海藻酸钠固定化酶微球的扩散性与酶活稳定性,以纳米二氧化钛修饰海藻酸为固定化酶载体,Ca2+,Ce3+,Ni2+,Cu2+和Fe3+为杂化凝胶的阳离子交联剂,木瓜蛋白酶为模型酶,制备固定化酶微球.通过UV-Vis光谱检测酶活,考察了5种交联剂对固定化酶的动力学和稳定性的影响,结果表明:当Cu2+为交联剂时,固定化酶具有最高的亲和性、最低的米氏常数(Km=11.0 mg/m L)和最高的稳定性.研究了TiO 2与木瓜蛋白酶的质量比对固定化酶稳定性以及酶蛋白泄漏的影响,结果显示纳米二氧化钛与木瓜蛋白酶的质量比为10∶1时,制备的固定化酶微球性能最好,因为二氧化钛能有效阻止固定化酶的泄漏.通过离子胶凝制备Cu/海藻酸/TiO 2杂化凝胶可获得较好的扩散能力和酶活稳定性. 相似文献
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《武汉职业技术学院学报》2015,(5):101-103
β-胡萝卜素是脂溶性色素,采用乳化工艺制成的O/W型乳状液可用于饮料等食品中。本文以能够反映乳状液自身稳定性的Ke值为主要指标,采用单因素实验和正交实验研究了乳化工艺对β-胡萝卜素乳状液的性状和稳定性的影响。 相似文献
10.
以海藻酸钠为壁材,桉叶油为芯材,Ca Cl2为固化剂,采用锐孔-凝固浴法制备桉叶油微胶囊.用L9(33)正交实验优化了制备工艺,得到了桉叶油微胶囊制备的最佳工艺条件为:海藻酸钠质量分数2.5%、芯壁比5:1、Ca Cl2质量分数3.5%.在最佳工艺条件下制备的桉叶油微胶囊的包埋率可达69.54%,且重现性好.对制备的桉叶油微胶囊的缓释性及抗菌性进行了研究,结果表明:桉叶油微胶囊的缓释性良好;桉叶油微胶囊对于黄曲霉、黑曲霉、白色念珠菌有明显的抑菌效果,相比之下,桉叶油微胶囊对于黄曲霉、黑曲霉的抑菌效果更佳. 相似文献
11.
Yun-jian Zhang Qiang Li Yu-xiu Zhang Dan Wang Jian-min Xing 《Journal of Zhejiang University. Science. B》2012,13(2):103-110
Succinic acid is considered as an important platform chemical. Succinic acid fermentation with Actinobacillus succinogenes strain BE-1 was optimized by central composite design (CCD) using a response surface methodology (RSM). The optimized production
of succinic acid was predicted and the interactive effects between glucose, yeast extract, and magnesium carbonate were investigated.
As a result, a model for predicting the concentration of succinic acid production was developed. The accuracy of the model
was confirmed by the analysis of variance (ANOVA), and the validity was further proved by verification experiments showing
that percentage errors between actual and predicted values varied from 3.02% to 6.38%. In addition, it was observed that the
interactive effect between yeast extract and magnesium carbonate was statistically significant. In conclusion, RSM is an effective
and useful method for optimizing the medium components and investigating the interactive effects, and can provide valuable
information for succinic acid scale-up fermentation using A. succinogenes strain BE-1. 相似文献
12.
丹参具有抗氧化、抗凝血、抗肿瘤等作用,含有多种有效成分,目前国内外对丹参单体的研究已较为深入,利用先进的现代生物学技术对单体药物的作用机制及作用靶点进行研究的报道也较为多见。丹参有效成分主要分为脂溶性的丹参酮类和水溶性的丹酚酸类,该文将对丹参脂溶性有效单体丹参酮ⅡA和水溶性有效单体丹酚酸A的近期药理作用研究进展进行综述。 相似文献
13.
ATMEL AVR单片机SPI接口的应用研究 总被引：3，自引：0，他引：3
李振军 《湖南广播电视大学学报》2003,(4):90-91
SPI(SerialPeripheralInterface)串行外围设备接口是一种 3线同步串行全双工通信接口。本文从SPI接口本质、ATmega8515的SPI接口、ATmega8515接口应用等几个方面介绍了ATMELAVR单片机SPI接口。 相似文献
14.
用干灰化法将三乙酰氧基硼氢化钠中的有机硼转化为硼酸盐,在适宜的pH条件下,将硼酸盐转化为硼酸,用甘露醇强化硼酸的酸性,酸碱滴定法确定硼酸的含量,计算出三乙酰氧基硼氢化钠的含量.此方法的精密度、准确度良好.标准偏差为0.39%,相对标准偏差为0.39%,回收率为100%. 相似文献
15.
Response surface methodology （RSM） was used to optimize the fermentation medium for enhancing pyruvic acid production by Torulopsis glabrata TP19. In the first step of optimization, with Plackett-Burman design, ammonium sulfate, glucose and nicotinic acid were found to be the important factors affecting pyruvic acid production significantly. In the second step, a 23 full factorial central composite design and RSM were applied to determine the optimal concentration of each significant variable. A second-order polynomial was determined by the multiple regression analysis of the experimental data. The optimum values for the critical components were obtained as follows： ammonium sulfate 0.7498 （10.75 g/L）, glucose 0.9383 （109.38 g/L） and nicotinic acid 0.3633 （7.86 mg/L） with a predicted value of maximum pyruvic acid production of 42.2 g/L. Under the optimal conditions, the practical pyruvic acid production was 42.4 g/L. The determination coefficient （R^2） was 0.9483, which ensures adequate credibility of the model. By scaling up fermentation from flask to jar fermentor, we obtained promising results. 相似文献
16.
Xiao-xin Chen Xiao-bing Wu Wei-ming Chai Hui-ling Feng Yan Shi Han-tao Zhou Qing-xi Chen 《Journal of Zhejiang University. Science. B》2013,14(10):903-915
In this research, the conditions for extraction of phenolics from leaves of Ficus virens were optimized using response surface methodology (RSM). The extraction abilities of phenolics (EAP) and flavonoids (EAF), the 2,2-diphenyl-1-pierylhydrazyl (DPPH) free-radical scavenging potential, and the ferric reducing/antioxidant power (FRAP) were used as quality indicators. The results of single-factor experiments showed that temperature, ethanol concentration, extraction time, and the number of extraction cycles were the main influencing variables, and these provided key information for the central composite design. The results of RSM fitted well to a second degree polynomial model and more than 98% of the variability was explained. The ideal extraction conditions for EAP, EAF, DPPH free-radical scavenging potential, and FRAP were obtained. Considering the four quality indicators overall, the ideal extraction conditions were 58% ethanol at 57 °C for 37 min with three extraction cycles. At the ideal extraction conditions, the values of EAP, EAF, DPPH free-radical scavenging potential, and FRAP were 5.72%, 3.09%, 58.88 mg ascorbic acid equivalent (AAE)/g dry weight (DW), and 15.86 mg AAE/g DW, respectively. In addition, linear correlations were observed between EAP, EAF, and antioxidant potential. 相似文献
17.
铜络合电镀废水的石灰—次氯酸钠氧化处理工艺初探 总被引：1，自引：0，他引：1
王伟洲 《晋城职业技术学院学报》2010,3(6):47-49
采用次氯酸钠络合解离—碱性沉淀法对含柠檬酸络合铜离子废水进行处理,考察了pH、次氯酸钠用量、以及反应时间对该方法处理络合铜离子废水结果的影响。结果表明,在体系pH=13,次氯酸钠溶液用量达到4%,反应时间120min的条件下废水中的铜离子可下降到0.2mg.L-1左右,低于国家工业废水排放标准。 相似文献
18.
陈宝璠 《三明高等专科学校学报》2012,(6):66-71
以聚乙二醇单甲醚（MPEG－1200）与丙烯酸（从）为单体,通过酯化,合成聚乙二醇单甲醚丙烯酸酯大分子单体（MPEGAA）。再用MPEG从与丙烯酸（从）和2－丙烯酰胺－2－甲基丙烯磺酸钠（AMPS）共聚,即制得MPE—GAA－从－AMPS三元共聚聚羧酸类高效减水剂。用红外光谱（FT—IR）表征了该高效减水剂的分子结构。并重点研究了MPEG支链长度、MPEG从／从摩尔比和MPEG从／AMPS摩尔比等因素对水泥分散效果的影响．同时用SEM观察了水泥石的微观结构．进一步探讨该减水剂对水泥水化过程作用的微观机理。结果表明。该高效减水剂对水泥具有良好的分散性及分散保持性能,掺量（固掺量）为0．3％,mw/mc=0．29时,水泥净浆初始流动度为300mm。30min可达322mm,120min经时损失率只有5％。SEM分析表明,该高效减水剂对水泥水化晶体生长时形成的晶体结构更为密实有利。 相似文献
19.
Nutritional evaluation of caseins and whey proteins and their hydrolysates from Protamex 总被引：4，自引：0，他引：4
夏文水 《Journal of Zhejiang University. Science. B》2006,7(2):90-98
Whey protein concentrate （WPC 80） and sodium caseinate were hydrolyzed by Protamex to 5%, 10%, 15%, and 20% degree of hydrolysis （DH）. WPC 80, sodium caseinate and their hydrolysates were then analyzed, compared and evaluated for their nutritional qualities. Their chemical composition, protein solubility, amino acid composition, essential amino acid index （EAA index）, biological value （BV）, nutritional index （NI）, chemical score, enzymic protein efficiency ratio （E-PER） and in vitro protein digestibility （IVPD） were determined. The results indicated that the enzymatic hydrolysis of WPC 80 and sodium caseinate by Protamex improved the solubility and IVPD of their hydrolysates. WPC 80, sodium caseinate and their hydrolysates were high-quality proteins and had a surplus of essential amino acids compared with the FAO/WHO/UNU （1985） reference standard. The nutritive value of WPC 80 and its hydrolysates was superior to that of sodium caseinate and its hydrolysates as indicated by some nutritional parameters such as the amino acid composition, chemical score, EAA index and predicted BV. However, the E-PER was lower for the WPC hydrolysates as compared to unhydrolyzed WPC 80 but sodium caseinate and its hydrolysates did not differ significantly. The nutritional qualities of WPC 80, sodium caseinate and their hydrolysates were good and make them appropriate for food formulations or as nutritional supplements. 相似文献
20.
硫酸氢钠能够代替硫酸作为酯化催化剂，在一水硫酸氢钠存在下，由正丁酸和异丁醇合成了丁酸异丁酯。当正丁酸、异丁醇和硫酸氢钠的物质的量比为4：3：0．07，回流分水60分钟，酯收率达99．3％，研究了催化剂的重复使用性能。 相似文献