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。     

芋艿分离蛋白的制备及工艺条件优化

利用响应面法对芋艿分离蛋白的制备工艺进行优化.在单因素试验基础上,以芋艿分离蛋白得率和纯度为响应值,进行四因素三水平Box-Behnken响应面优化设计.通过各个因素的显著性和交互作用分析,得到芋艿分离蛋白制备的最佳工艺条件为:浸提体系pH值为10.00,温度40℃,料液比1∶6,酸沉pH值为4.90,此工艺条件下制备的芋艿分离蛋白得率为1.33±0.020%,纯度为84.67±0.011%.     

响应面优化香蕉茎纤维-丙烯酰胺高吸水树脂的制备工艺

以香蕉茎纤维和丙烯酰胺为原料,过硫酸钾和亚硫酸钠为引发剂,制备了香蕉茎纤维-丙烯酰胺高吸水树脂.在单因素实验的基础上,以树脂吸水率为响应值,选取酰纤比、反应温度、引发剂用量和交联剂用量为自变量,利用Box-Behnken设计和响应面法对各自变量及其交互作用对树脂吸水率的影响进行了研究,得到了二次多项式回归方程模型.香蕉茎纤维-丙烯酰胺高吸水树脂的最佳制备工艺条件为:酰纤比9.9 g/g、反应温度48℃、引发剂用量1.9%和交联剂用量0.18%.在此条件下,测得所制备的吸水树脂吸水率为461.22 g/g,与预测值相对误差为0.68%,说明响应面优化香蕉茎纤维-丙烯酰胺高吸水树脂的制备工艺具有较高的准确性与可靠性,该方法可用于香蕉茎纤维-丙烯酰胺高吸水树脂制备工艺的优化.     

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。     

响应面法优化纤维素酶提取猫爪草多糖的工艺研究

利用响应面法优化纤维素酶提取猫爪草多糖的工艺,在单因素试验基础上,以猫爪草多糖得率为考察指标,釆用三因素三水平响应面法对酶用量、p H、酶解温度三个因素进行优化.最优工艺为:酶用量0.57%、p H4.9、酶解温度49.3℃、酶解时间120 min、料液比1:20,猫爪草多糖实际得率为5.86%.     

鲭鱼酶解工艺双响应面法优化及抗氧化活性研究

采用双响应面法优化超声波辅助酶解鲭鱼蛋白，制备鲭鱼多肽，探究其抗氧化活性.以酶解液对DPPH自由基和ABTS自由基的清除率为指标，获得最适蛋白酶并双响应面优化酶解工艺条件，探究其抗氧化活性.结果表明：木瓜蛋白酶为最佳水解酶，最优酶解工艺为pH 6.0、超声时间40 min、温度53℃、料液比1∶3(g/mL)、酶添加量3 000 U/g、酶解时间2 h，所得的酶解液DPPH自由基清除率为91.21%,ABTS自由基清除率为84.12%；鲭鱼多肽具有较好的抗氧化活性，ABTS自由基和DPPH自由基半抑制率IC₅₀分别为32.75μg/mL、1.20 mg/mL.该研究结果可为鲭鱼抗氧化肽的大量制备提供工艺参考，为鲭鱼抗氧化多肽在食品工业中的应用研发提供了理论基础.     

正交试验优化鱼鳔抗氧化肽的提取工艺

目的：优化鱼鳔抗氧化肽的提取工艺.方法：以ABTS清除率作为评价指标，以加酶量、pH、酶解温度和酶解时间为考察因素，选取单因素试验和正交设计，优化鱼鳔抗氧化肽的提取工艺.结果：碱性蛋白酶为最佳蛋白酶，最佳酶解条件pH9、加酶量10 000 U/g、酶解时间5 h、提取温度60℃.结论：优化了鱼鳔抗氧化肽的提取工艺，为后续的鱼鳔相关产品开发奠定了理论基础.     

响应面法优化桔梗发酵工艺初探

以桔梗为原料,基于单因素试验考察酵母接种量、料液比、发酵时间、发酵温度和pH对桔梗微生物发酵工艺的影响,利用响应面法构建了发酵时间、发酵温度、pH三因素三水平的回归模型,并以总黄酮含量和酒精度作为响应值.结果表明：回归模型具有较高的显著性,确定了微生物法发酵桔梗最优条件为：发酵时间9 d、发酵温度28℃和pH为5,在此条件之下,终产物中的总黄酮含量和酒精度分别为0.732 mg/mL和2.16%vol.响应面法优化得到的工艺条件合理可靠,是有利于桔梗发酵工艺的可行方法.     

龙须菜抗氧化肽的制备及其体外抗氧化活性

为优化碱性蛋白酶酶解龙须菜蛋白制备抗氧化肽的工艺条件,以二苯基苦基苯肼(DPPH)自由基的清除率为指标,单因素试验考察了酶解温度、酶解时间、酶底比([E]/[S])和pH值对制备抗氧化肽工艺的影响,并在此基础上应用正交实验进行优化.结果表明,碱性蛋白酶酶解龙须菜蛋白制备抗氧化肽的最佳工艺条件为:酶解温度65℃、酶解时间150min、[E]/[S]9 000U/g、pH 8.0,在此条件下制备的龙须菜抗氧化肽对DPPH自由基的清除率为77.44%±0.12%.体外抗氧化活性研究表明,抗氧化肽具有一定清除DPPH自由基、羟自由基、超氧自由基的能力,也有一定的还原力,但均弱于同浓度下的抗坏血酸.     

超声波制备低含油稳定原油乳化液的正交实验

为了利用超声波制备出稳定的低含油原油乳化液,选取乳化剂用量、超声功率、超声作用时间、乳化剂亲水亲油平衡(HLB)值4个影响因素,进行单因素实验和正交实验,筛选超声波制备低含油稳定原油乳化液的最佳条件。根据乳化剂用量单因素实验结果,确定最佳乳化剂用量为0.5%。通过超声功率、超声作用时间和HLB值3个因素的正交实验,进一步优化了制备稳定原油乳化液的条件。实验结果表明,对乳化效果影响大小的因素依次为超声作用时间、超声功率和乳化剂的HLB值;最佳乳化条件为超声功率400 W、超声作用时间10 min、HLB值6、乳化剂用量0.5%,在此最佳条件下可制备出含油率为1%~9%的稳定原油乳化液。     

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?     

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…     

库克斯顿城堡

城堡, 是欧洲典型的建筑之一, 每个城堡都有一个美丽的传说或是一段历史。从本期开始, 我们将推出“城堡之旅”, 带各位读者去浏览、观赏欧洲各地的城堡, 开始一段文化与历史的旅途!     

胡主席在印度,我却在中国

Today, Sunday morning, I sit thinking and typing at my computer. My thoughts are in my homeland, India and my body is in China. The body is here and mind there for a good reason. Mr. Hu is president and I am resident and both are in each other's countries (what a difference the absence of one small letter makes!). Mr. Hu will return in a few days and I will stay on longer.