大米淀粉膜的制备及其性能

大米淀粉颗粒粒径较小且均匀,在水中有较好的分散性,具有良好的成膜性并且可以在自然中降解,在食品包装、医用敷料及化妆品行业中有着广泛的应用。以大米淀粉为原料,NaOH为糊化剂,甘油为增塑剂,柠檬酸为交联剂和pH调节剂,采用流延法制备了淀粉膜。通过对淀粉颗粒的形貌观察及糊化温度、淀粉溶液的表观粘度及pH值测定、淀粉膜的力学性能、透光率及承载甘草酸二钾释放性能等的测定,研究了大米淀粉的糊化条件,柠檬酸、淀粉和甘油质量分数对淀粉膜性质的影响以及承载物质的释放情况。结果表明,大米淀粉呈光滑的多边形颗粒,直径为5~8 μm,在偏光显微镜下呈现马耳他十字结构,糊化温度范围为82.5~100.8 ℃。柠檬酸在淀粉成膜过程中会与淀粉分子相互作用,同时能够调节溶液的pH值以适应人体皮肤。淀粉质量分数越高,淀粉膜断裂伸长率越低,拉伸强度越高;甘油质量分数越高,淀粉膜断裂伸长率越高,拉伸强度越低。在甘油质量分数为3.0%时淀粉膜透光率最佳,结晶度最低。制备的淀粉膜能够承载且能高效释放抗炎物质甘草酸二钾,在护肤领域具有广泛的应用前景。     

以淀粉溶液为催化剂一锅三组分法合成四氢苯并[b]吡喃和3,4-二氢吡喃并[c]苯并吡喃衍生物(英文)

Tetrahydrobenzo[b]pyran and 3,4-dihydropyrano[c]chromene derivatives were synthesized via a one-pot three-component condensation of aromatic aldehydes with malononitrile and dimedone or 4-hydroxycoumarin in excellent yields in the presence of starch solution as a highly efficient homogenous catalyst.The use of a nontoxic and biodegradable catalyst,simple work-up procedure,and short reaction time are advantages of this method.     

Increasing the sensitivity of the spectrophotometric determinations of the oxygen content in YBCO superconducting samples using the I3-starch compound

The conditions for formation of the I₃⁻-starch compound and measuring its absorbance have been found, and a spectrophotometric method has been developed for the determination of the oxygen content in YBa₂Cu₃O_y superconducting bulk samples. The method involves the following stages: a decomposition of the sample in an acid medium in the presence of iodide ions under inert atmosphere; formation of a complex between Cu(II) and glycine; binding the I₃⁻-complex with a starch and the absorbance measurement of the colored I₃⁻-starch compound. The coefficient of the active oxygen is calculated by the ratio of the absorbances of two solutions and the method does not require both calibration and precise measuring sample mass. The accuracy of the results is confirmed applying the comparative spectrophotometric method that uses the yellow I₃⁻-complex. The precision of the results evaluated by the relative standard deviation is 2%. The developed method is sensitive and allows a sample mass about 2 mg to be used. The analysis is rapid and requires a simple and inexpensive apparatus. Thus the new method would be useful for an express analytical control of the oxygen content of YBCO-superconducting materials produced for the electronics.     

Optical characterization of CdS semiconductor nanoparticles capped with starch

Starch capped cadmium sulfide (CdS) nanoparticles were synthesized by aqueous solution precipitation. Starch added during the synthesis of nanoparticles resulted in cadmium-rich nanoparticles forming a stable complex with starch. The size of the CdS quantum dots was measured using high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD). The average diameter (d) of nanoparticles spanned the range 4.8 ± 0.4 to 5.7 ± 0.2 nm when the pH of the solution was varied within the range 10-14. The main Raman phonon of CdS, the longitudinal optical mode located around 300 cm⁻¹, softens as diameter decreases, in accordance with theoretical predictions. In addition, the largest Raman response of starch, near 478 cm⁻¹, related with the important skeletal vibration modes of the starch pyranose ring, dominates the spectra of the CdS capped nanoparticles and also softens as the size decreases. This fact indicates a strain variation on CdS as a function of d which increases as the pH increases.     

Application of FT-Raman Spectroscopy and Chemometric Analysis for Determination of Adulteration in Milk Powder

In this work, FT-Raman spectroscopy is explored as a rapid technique for the assessment of the milk powder quality. Based on information provided by Raman spectra of samples adulterated with starch and whey, a quantitative method is developed to identify the fraud, using Partial Least Squares regression (PLS). In regression models using PLS the results are satisfactory, and such models can be used to identify and quantify samples presenting whey and starch in milk powder at concentrations of 2.32% and 1.64% (w/w), respectively. In the whey determination, the obtained values in the PLS model of the new samples are compared with those obtained by the spectrophotometric method of acid ninhydrin. This result shows that there is no significant difference with the 95% level of confidence between the values provided by the PLS regression method and the acid ninhydrin. The present work shows Raman spectroscopy as an analytical tool which can be used in quality control of milk powder, even in fraud processes, and the calculated figures of merit such as sensitivity, accuracy, limit of detection and limit of quantification clearly demonstrate this potential use. Although the multivariate models developed are not strictly quantitative, especially for low concentrations, they can be used as screening methods for routine analysis, as showed by this work.     

Superabsorbent nanocomposite and its properties

Starch-g-poly (AM-AMPS)/illite superabsorbent nanocomposite was synthesized by grafting copolymerization reaction of starch, acrylamide(AM) and 2-acrylamido-2- methyl propane sulfonic acid (APMS) in the presence of illite micropowder in deionized aqueous solution. The influence factors on water absorbency of the superabsorbent nanocoposite was optimized by single factor experiment. The synthesized superabsorbent nanocomposite exhibited the maximum water absorbency of 1320?g H₂O/g in deionized water and 142?g H₂O/g in 0.9?wt% sodium chloride (NaCl) solution. FTIR spectra confirmed that the grafting copolymerization between -OH groups on starch and monomers generated during the reaction. XRD analysis confirmed that crystal interlayer of illite was pulled open to 3.61?nm. TEM showed that illite slice layer randomly dispersed in the matrix of superabsorbent nanocomposite. The superabsorbent nanocomposite had a better thermal stability the corresponding superabsorbent material without illite by TGA and DSC analysis. The superabsorbent nanocomposite with excellent water absorbency and water retention could be especially useful in industry, agricultural, horticultural applications.     

Microcalorimetric study of the enzymatic hydrolysis of starch: An α-amylase catalyzed reaction

Microcalorimetric studies of enzyme activities have been made on the hydrolysis of starch catalyzed by α-amylase. The best conditions for the hydrolysis of starch in the presence of α-amylase have been pointed out and the α-amylase activity was determined by isothermal batch microcalorimetry. The heat changes involved during the hydrolytic reaction can be related to the starch concentrations in a linear way and the heights of the calorimetric curves can be directly related to the amylase activities. Calibration curves were obtained. The new method for starch assay and α-amylase activity determination is direct, simple, accurate and it needs no pretreatment of the sample or auxiliary reactions. The α-amylase catalytic activity has also been investigated by microcalorimetry in the presence of some metal ions.     

应用单宁与淀粉为交联剂改性聚氨酯

通过植物原料单宁与淀粉对聚氨酯的改性可提高聚氨酯的机械性能和热性能 ,单宁成分的导入还能有效提高聚氨酯交联点密度、组分相容性和体系的形态结构均匀性 .当单宁的含量占投入的植物原料的6 0wt%时 ,单宁和淀粉聚氨酯网络互相贯穿表现出良好的相容性 ,其拉伸强度、杨氏模量分别提高到 5 1 9MPa和 30 8 4MPa ,积分程序分解温度达到 375℃ .同时单宁成分有望在一定范围内调节聚氨酯的降解速度 .     

Ce~（4＋）－Ce~（3＋）循环体系引发淀粉与丙烯酰胺接枝共聚合反应动力学研究

Ｃｅ~（４＋）－Ｃｅ~（３＋）循环体系引发淀粉与丙烯酰胺接枝共聚合反应动力学研究张连生，王玉芹，杨巍（黑龙江大学化学系，哈尔滨，１５００８０）（黑龙江商学院商管系，哈尔滨，１５００７６）关键词Ｃｅ~（４＋）－Ｃｅ~（３＋）循环引发、Ｃｅ~（４＋）复合引发?..     

淀粉和生物降解大分子间的半互穿聚合物网络的耐水性研究

以淀粉和可生物降解的PCL或PHBV等疏水性脂肪族聚酯为原料, 制备了淀粉基的Semi-IPN材料. 加入PCL或PHBV等疏水性大分子的使淀粉基Semi-IPN材料的耐水性能相对于原淀粉有很大的改善, 通过热处理和溶剂化作用能使Semi-IPN的耐水性进一步提高.