正交优化制备双醛淀粉的研究

本文以玉米淀粉为原料,高碘酸钠为氧化剂,采用正交优化法对制备双醛淀粉的工艺条件进行了研究.最佳工艺条件为:反应温度35℃,反应时间3.5h,高碘酸钠浓度0.5mol/L,pH值4.0,高碘酸钠与淀粉的摩尔比1.1:1.     

双醛淀粉制备工艺的优化研究

采用高碘酸盐氧化玉米淀粉的方法制备双醛淀粉,探讨了pH值、高碘酸钠与淀粉摩尔比、高碘酸钠浓度、反应温度、反应时间及投料方式对双醛淀粉中醛基含量的影响,得出双醛淀粉制备工艺的优化条件。结果显示,在pH值为1.2～1.5、高碘酸钠与淀粉的摩尔比为1.1∶1、高碘酸钠浓度为0.5mol/L、反应温度在33～40℃之间、反应时间3h条件下,并采用将淀粉加入到高碘酸钠溶液中的投料方式,可得到高醛基含量的双醛淀粉。     

大米双醛淀粉制备工艺的研究

双醛淀粉应用领域广泛,本文以大米淀粉为原料,用高碘酸钠作为氧化剂来制备大米双醛淀粉,从单因素实验到正交实验探索到大米淀粉双醛化的优化工艺条件:反应温度35℃、反应时间4h、反应pH=3.5、NaIO4水溶液浓度为0.3mol/L、高碘酸钠和原大米淀粉的摩尔比为1.1∶1;此条件下可以制备得到双醛化程度接近100%的大米淀粉。     

正交优化制备双醛淀粉的研究

本文以玉米淀粉为原料，高碘酸钠为氧化剂，采用正交优化法对制备双醛淀粉的工艺条件进行了研究。最佳工艺条件为：反应温度35℃，反应时间3．5h，高碘酸钠浓度0．5mol／L，pH值4．0，高碘酸钠与淀粉的摩尔比1．1：1。     

双醛淀粉湿强剂的合成

研究了以木薯淀粉为原料、以高碘酸钠为氧化剂合成双醛淀粉的工艺条件，通过对不同氧化度双醛淀粉的红外光谱和结晶研究，对制备DAS的反应进程进行了探讨，结果表明，根据需要可制得不同氧化程度的双醛淀粉，与原淀粉相比其物理和化学性质都发生了很大的变化。     

反应条件对双醛山药淀粉醛基含量的影响

以山药淀粉为原料,高碘酸盐为氧化剂制备双醛山药淀粉,考察了反应温度、反应时间、pH值、淀粉浆液质量分数,高碘酸钠与淀粉葡萄糖单元的摩尔比对醛基含量的影响。实验结果表明,制备醛基含量大于90%的双醛淀粉的适宜工艺条件为:反应温度40℃,反应时间4 h,pH值为4.0,淀粉浆液质量分数为20%,高碘酸钠与淀粉葡萄糖单元摩尔比为1.1:1,在此条件下醛基含量高达97.5%。     

双醛淀粉湿强剂的合成

本文研究了以木薯淀粉为原料，以高碘酸钠为氧化剂合成双醛淀粉（Dialdehyde starch,简称DAS）的工艺条件。通过对不同氧化程度双醛淀粉的红外光谱和结晶度研究，对制备DAS的反应进程进行了探讨。结果表明，根据需要可制和不同氧化程度的DAS，双醛淀粉与原淀粉相比其物理和化学性质都发生了很大的变化。     

木薯淀粉制备纸张湿强剂的研究

本文利用广西丰富的木薯淀粉为原料,以价格相对比较便宜的高碘酸钠为氧化剂,探索最优化的双醛淀粉合成条件,并对合成的双醛淀粉进行表征分析.     

高碘酸钠氧化木薯淀粉制备双醛淀粉工艺研究

以NaIO_4作氧化剂,氧化木薯淀粉制备双醛淀粉的适宜工艺条件为:淀粉乳含量10%,高碘酸钠与淀粉物质的量之比1.1:1,反应溶液pH值3,反应温度40℃,搅拌反应3h。在选定的试验条件下,制备的双醛淀粉产品中双醛含量93.5%,产率96.7%。制得的双醛淀粉经红外光谱表征,波长1 750cm~(-1)处出现明显吸收峰,波长2 750cm~(-1)处出现弱吸收峰,说明产物中醛基的存在。     

双醛蜡质玉米淀粉的制备与特性研究

以蜡质玉米淀粉为原料,高碘酸钠为氧化剂,通过单因素实验,得到双醛淀粉制备的最优工艺条件:高碘酸钠与淀粉物质的量之比1.1:1,反应pH3.0,温度30℃,反应时间2h,淀粉乳浓度8%,得到的双醛淀粉中醛基含量为87.36%。偏光显微镜图片显示,样品醛基含量越高,偏光十字越少;通过红外图谱的表征,发现在波长为1729cm-1处出现明显的吸收峰,说明反应产物中有醛基存在;布拉班德粘度曲线表明,双醛淀粉的起糊温度比原淀粉高,峰值粘度随氧化度的升高而降低;X-射线衍射图谱表明,强峰吸收随着醛基含量的升高而消失,说明淀粉的结晶结构被破坏。     

拟均相两段工艺氧化法制备双醛淀粉

以绿豆淀粉为原料,NaIO4为氧化剂的拟均相两段工艺制备双醛淀粉(dialdehyde starch,DAS),考察预处理阶段中温度、酶处理、超声活化和氧化阶段中反应温度、反应时间、pH值、投料比、NaIO4浓度、淀粉乳浓度、相转移催化剂对制备双醛淀粉的影响,前段的预处理采用超声活化处理,后段的氧化工艺考察相转移催化剂的影响,并用正交法对制备双醛淀粉的工艺进行优化。结果表明：在以醛基含量为考察指标,预处理时不宜用酶,处理温度50～60℃,经30℃、40W、40kHz超声活化淀粉乳30min能有效提高淀粉与NaIO4的氧化反应活性,制得高醛基含量的DAS。相转移催化剂对提高产品醛基含量有一定作用。经正交试验优化得到的最佳条件为：以十六烷基三甲基氯化铵为相转移催化剂、反应时间2h、反应温度40℃、n(NaIO4):n(淀粉)=1.0:1.0、NaIO4浓度0.5mol/L、淀粉乳质量分数10%、体系pH2,在此条件下,制得的DAS双醛含量为96.81%。经光谱和理化性能等指标的检测证实所得的DAS与文献报道的DAS相符合。     

Improved Calcium Sequestering Carbohydrate Based Agents

The improved tandem oxidation sequence of starch with the aim of developing, e.g. degradable co‐builders suitable for laundry formulations as an alternative to the currently used polyacrylates is described. The tandem oxidation of starch starts with sodium periodate treatment of granular starch followed by oxidation of the dialdehyde product with sodium chlorite to dicarboxy starch. It turns out that improving the periodate oxidation resulting in a more complete transformation of the glucose moiety into the dialdehyde product yields, after sodium chlorite oxidation, a dicarboxy starch with a calcium sequestering capacity of 3.3 mmol Ca²⁺ per gram of dicarboxy product. This is an improvement of about 25% compared with current literature data.     

Determination of the Carbonyl Groups in Oxidized Starches by Sodium Borohydride

A method of carbonyl groups determination in starches oxidized with nitrogen tetroxide or sodium has been modified. The carbonyl groups undergo the reduction with sodium meta periodate borohydride, added in known excess in alkaline medium. The unconsumed amount of hydride is then oxidized with sodium periodate in alkaline medium and unconsumed iodate determined iodometrically. A blank test is unavoidable. Standard deviation 0.106% and variation coefficient 6,960% were found from 10 determinations of carbonyl groups in a sample of starch treated with nitrogen tetroxide to low degree of oxidation. Similarly, standard deviation 0,802% and variation coefficient 3,290% of dialdehyde starch, oxidized to high degree of oxidation by sodium metaperiodate, were found.     

Modified Corn Starches with Improved Comprehensive Properties for Preparing Thermoplastics

A novel method of starch modification was developed to obtain thermoplastic starch plastics with improved comprehensive properties. Corn starch was oxidized under mild conditions using sodium periodate to prepare dialdehyde starch, which had an acceptable average molecular weight. The dialdehyde starch with 35.2% carbonyl content was reacted with different alcohols (methanol, ethanol, and glycol) to prepare a series of novel starch derivatives, whose structures were characterized by ¹H‐NMR and FT‐IR. The thermogravimetric analysis showed that these starch derivatives had an improved thermal stability compared with dialdehyde starch. Thermoplastic starch and its derivatives were prepared when water and glycerol were added as plasticizers. The modified thermoplastic starch and its derivatives had better mechanical properties than other modified starches, and lower humidity absorption than conventional thermoplastic starches. The highest tensile strength and elongation at break reached 17.5 MPa and 149%, respectively, and the highest humidity absorption was about 37%.     

纳米银/纳米二醛纤维素气凝胶的制备及表征

使用漂白硫酸盐针叶木浆为原料,以经高碘酸钠氧化后制备出的二醛纤维素为基材负载纳米银颗粒,后经高压均质法得到载银量为24.78%的纳米银/纳米二醛纤维素气凝胶。探讨高碘酸钠氧化反应时间对构成漂白硫酸盐针叶木浆的纤维素大分子以及针叶木纤维的影响。通过傅里叶变换红外光谱仪、X射线衍射仪、紫外可见分光光度计、扫描电子显微镜、透射电子显微镜和比表面积和孔径分析仪对样品进行表征。结果表明,随着氧化时间的增加,纤维素的醛基含量持续上升,当反应4 h时增至330 μmol/g,纤维的聚合度由1447大幅下降至525,同时零距抗张强度和长度也呈现下降趋势。制备出的载银气凝胶上负载的纳米银颗粒为球形,气凝胶的比表面积为35.40 m~2/g,平均孔径为19.62 nm。     

Chemical Process for Making Dialdehyde Starch

A practical, strictly chemical process has been developed for the periodic acid oxidation of starch to dialdehyde starch. In the procedure spent oxidant is converted by alkaline hypochlorite to insoluble sodium paraperiodate, which is recovered in high yield for recycling. The process is suitable for small-scale production of dialdehyde starches of various carbonyl contents.     

Transformations of Potato Starch During Oxidation with Hypochlorite

Five starch samples of different degree of oxidation were obtained with the help of sodium hypochlorite. Apart from that, commercial starch was divided into 3 fractions of differentiated size of grains and the fractions were also subjected to oxidation. The analysis of oxidized starch led to following results:

• large grains of starch undergo the oxidation process more easily than small grains, from oxidized starch hydrolysates glucuronic acid amounting to about 75% of carboxyl groups and gluconic acid to about 25% of carboxyl groups, can be separated;
• side reaction proceeding during oxidation process is hydrolytic degradation of starch molecules which is shown by the increase of reducing value and the decrease of viscosity of oxidized starch;
• in starch oxidized with hypochlorite absence of dialdehyde systems is characteristic in contrast to starch oxidized with periodate;
• in the process of oxidation with hypochlorite, starch molecules change their shape and spatial system, which is indicated by the changes of colour complexes with iodine, greater resistance to the action of amylolitic enzymes and greater capacity for forming flexible gels in the form of films.

     

Changes in the chemical and functional properties of protein fibers by reaction with carbonyl compounds. Part II. Reaction of arginine and amido groups. Quantitative determination of reacting carbonyl groups

The arginine content of Vicia faba protein/casein(1:1)-fibers is made to decrease up to 50 per cent by reaction with glyoxal and up to 15 per cent by dialdehyde starch. Formaldehyde and glutaric dialdehyde do not influence the arginine content. The content in amido groups is not affected by the reaction with glyoxal, dialdehyde starch, formaldehyde, and glutaric dialdehyde. The reaction of the fiber protein with the quoted aldehydes increases in the following order: glyoxal < formaldehyde < dialdehyde starch < glutaric dialdehyde and is dependent on the concentration of the specific aldehyde.     

氧化淀粉的理化性质和结构表征

淀粉是一种可再生资源，近年来淀粉在皮革上的应用和研究已经越来越受到重视。该实验通过双氧水和高碘酸钠两次氧化合成了一种同时含羧基和醛基的氧化淀粉，并且对该合成氧化淀粉进行了理化性质分析和结构表征，包括固含量、pH值、羧基、醛基和羰基含量的测定，利用红外和凝胶色谱进行了结构分析，有利于制革中的应用。