酶辅助法提取大青叶中总黄酮及抗氧化性研究

本论文采用酶辅助法提取大青叶中的总黄酮,先用纤维素酶酶解,再用乙醇回流提取大青叶中总黄酮。分别固定乙醇提取液的浓度为70%,料液比为1∶20g∕mL,回流时间为2h。初步探究了纤维素酶浓度、酶解pH、酶解温度、酶解时间四个单因素对大青叶中黄酮提取率的影响。设计正交实验确定酶辅助法提取大青叶中总黄酮的较佳条件为:纤维素酶浓度为4U/mL、酶解pH=4.5、酶解温度为40℃、酶解时间1.5h,总黄酮提取率高达2.85%。另外还研究了大青叶总黄酮提取液对羟自由基的清除活性,与BHT的抗氧化剂活性作对照实验,结果表明大青叶中的总黄酮对羟自由基有较强的清除活性。     

响应面优化酶法提取蓝莓果渣多酚工艺研究

目的:用纤维素酶提取蓝莓果渣多酚,以多酚得率为指标优化提取工艺。方法:选取纤维素酶添加量、酶解pH、料液比、酶解时间、酶解温度等5种因素分别利用单因素试验和响应面分析法,研究蓝莓果渣多酚最佳提取工艺。结果:当纤维素酶用量为6.8 mg/g,提取初始pH为4.8,料液比为1∶20,提取时间为6 h,温度为50℃时,蓝莓果渣中多酚的得率最高,达到8.130 6 mg/g。结论:纤维素酶水解法提取蓝莓果渣多酚,通过调整酶添加量、酶解pH、料液比、酶解温度、酶解时间可以显著增加蓝莓果渣多酚得率。     

纤维素酶法辅助提取火棘果多糖的工艺研究

以火棘果为材料,采用纤维素酶辅助提取火棘果中多糖类物质,以多糖提取率为指标,通过对料液比、酶浓度、酶解温度、酶解时间、乙醇体积分数、缓冲液pH等条件对多糖类物质提取效果的影响研究,经正交试验对各因素影响下的提取工艺进行了优化,确定火棘果中多糖提取的最优工艺为:料液比(g:mL)1:15、纤维素酶浓度0.6%、酶解温度50℃、酶解时间120 min、乙醇体积分数为80%、缓冲液pH为4.0,火棘果多糖的提取率为5.35%。     

襄麦冬总黄酮酶法提取的工艺优化

以襄麦冬为原料,通过正交试验,采用酶法提取探讨提取条件对襄麦冬块根中总黄酮类化合物提取的影响.结果表明襄麦冬总黄酮提取最佳的工艺条件为:酶添加量40mg,酶解时间3h,酶解温度50℃,介质pH值为5.0,总黄酮化合物的提取率平均值为0.495 mg/g.     

正交设计法优化纤维素酶提取滁菊黄酮类成分工艺研究

目的:采用正交设计法优化纤维素酶提取滁菊中黄酮类成分。方法:以木犀草素、香叶木素、芹菜素的含量为指标,高效液相色谱仪测定其含量,正交试验设计法优选纤维素酶提取滁菊中黄酮类成分工艺。结果:最佳提取工艺为温度45℃,pH 5.0,酶解1.5 h,酶用量0.6%,在此条件下,木犀草素、香叶木素、芹菜素的含量分别为1.49%、1.64%、1.69%。结论:在最佳酶解条件下,纤维素酶能显著地提高滁菊黄酮类成分的提取率。     

酶解-水蒸气蒸馏法提取桔皮精油的工艺研究

采取酶解法辅助水蒸汽蒸馏法提取桔皮中精油,探索了纤维素酶用量、酶解处理时间、酶解温度、蒸馏时间等工艺条件对桔皮中精油提取率的影响。通过正交实验,酶解一水蒸汽蒸馏法提取桔皮中精油的最佳条件为：酶用量是2000U／g,酶解温度是55℃,酶解时间是140min,蒸馏时间是2h。采用此工艺条件,桔皮中精油的提取率是3．14％。     

酶解法辅助提取花椒油树脂的工艺优化

试验以纤维素酶法辅助优化提取花椒油树脂。通过利用单因素和正交试验分析,结果表明,酶解温度为影响提取效果的显著因子,优化后提取条件为酶用量2.0mg/100mL,酶解时间1.5h,酶解温度45℃,在该工艺条件下提取一次花椒油树脂的平均提取率为30.2%。验证试验表明,经酶解提取法提取花椒油树脂与未经酶解处理的乙醇浸提法相比,结果增长25.8%。     

纤维素酶水解蓝莓果渣工艺条件的研究

采用纤维素酶对蓝莓果渣进行糖化水解,以增加料液中还原糖和花青素的含量,进而提高原料的利用率。试验研究了酶添加量、酶解初始pH、酶解温度及时间4个因素对水解效果的影响,先后采用单因素试验和正交设计试验对水解工艺条件进行优化,并经验证得出最佳工艺条件为:纤维素酶添加量40FPU/g果渣、初始pH4.8、酶解温度50℃、酶解时间持续24h,此条件下蓝莓果渣酶解液中的还原糖含量达14.21 g/L,花青素浓度为0.35g/L。     

酶法降解玉米芯以制备燃料乙醇的研究

目的：研究酶法降解玉米芯的最佳工艺和酵母菌发酵的最佳工艺.方法：采用纤维素酶对玉米芯进行酶解,采用酵母菌对酶解液进行发酵.结果：酶解条件：纤维素酶0.6mL,pH值为5～6,温度40℃,Tween-80添加量为1%,微量元素的添加量为0.5%,酶解48h后还原糖浓度达到最大值;发酵条件：活化后酵母菌的接种量40mL,发酵温度30℃,发酵36h后,乙醇产量的最高.结论：在较佳的酶解和较佳的发酵条件下,可显著提高酶解率和发酵率.     

酶法提取杜仲多糖的工艺研究

目的:确定杜仲中多糖的酶法提取工艺.方法:用正交试验的方法分别研究果胶酶、中性蛋白酶和纤维素酶对杜仲多糖提取率的影响.结果:果胶酶增加多糖提取率效果最为显著,其最佳提取条件是:酶加量0.10mg/L,酶处理温度50℃,酶处理时间3h.其次是中性蛋白酶,纤维素酶的效果最差.结论:果胶酶可明显增加杜仲多糖的提取率.     

卡思卡特城堡

It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,     

不同的吃喝玩乐

一、吃和喝吃苹果 eat an apple, 吃药 take medicine,吃糖 have some sweets,吃饭 have one's meals,吃馆子 dine out,吃惊 be surprised/     

漏洞百出的教育

Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help?     

Western and Eastern culture differences in commercial field

The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity.     

只要努力,不要后悔

There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love.     

浅谈移民问题

Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject.     

Sister Carrie, an Adherent of Desires

Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities.     

Improvement of one-cycle controller by use of proportional integral differential controller

1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec…     

风的曲线

Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose.