Relationship between physicochemical and functional properties of amaranth (Amaranthus hypochondriacus) protein isolates

Protein isolates from six amaranth lines/cultivars (APIs) were evaluated to study their physicochemical (hunter colour, protein content and zeta potential), structural (thermal and conformational) and functional (emulsification, foaming, water and fat absorption) properties. APIs had protein content, whiteness index and gel temperature in range of 79.4–85.4%, 41.17–54.26 and 87.8–91.8 °C, respectively. The Fourier‐transform infrared spectra of APIs revealed α‐helix, β‐sheets and random coil conformations in the secondary structure. APIs with higher relative proportion of β‐sheets had higher Differential Scanning Calorimeter denaturation temperature and gel temperature. Minimum protein solubility (PS) was observed at pH 5.0, indicating isoelectric point (pI) of amaranth proteins. The PS, emulsifying activity index (EAI), emulsifying stability index (ESI), foaming capacity (FC) and foam stability (FS) of APIs at neutral pH were related to their zeta potential (ζ). The emulsifying and foaming properties were also determined at different pHs (between 2.0 and 9.0). The EAI‐pH profile of APIs confirmed close relationship between the emulsifying ability and PS.     

Physicochemical properties of nanopowdered eggshell

This study was carried out to investigate the physicochemical properties of nanopowdered eggshell (NPES). These characteristics were determined based on the particle size, particle morphology, zeta potential, moisture sorption behaviour, purity and crystallinity. Homogeneous, aggregated and spherical crystals of NPES particles were observed through scanning electron microscope and transmission electron microscope. The average particle sizes of NPES and powdered eggshell (PES) were 202.3 ± 28.9 nm and 113.89 ± 79.37 μm, respectively. Zeta potentials of NPES (?15.41 mV) suggested an incipient instability of the colloidal system. Moisture sorption analysis indicated a higher water adsorption capacity of NPES than that of PES. X‐ray diffractometer (XRD) analysis confirmed the presence of calcite in both NPES and PES. The chemical compositions of the NPES and PES particles were strongly associated with the presence of calcium carbonate, as determined by the Fourier transform infrared (FTIR) spectra. Therefore, eggshell nanopowder has a great potential to be utilised as a component for biomedical applications.     

基于Fourier与Hilbert变换的纱线信号谱分析研究

介绍了两种信号谱分析方法——基于Fourier变换思想的波谱分析及基于经验模态分解的Hilhert边际谱分析,并将其分别应用到纱线信号的时频分析中。基于经验模态分解的边际谱分析方法是一种完全不同于传统Fourier谱分析的新方法,文中介绍了Hilhert边际谱的求解过程,通过将Fourier谱图与Hilbert边际谱进行对比可知,Hilhert边际谱更适用于对纱线信号的非平稳过程处理。     

大豆分离蛋白与低浓度尿素相互作用红外光谱分析

对大豆分离蛋白(SPI)与低浓度尿素溶液相互作用红外光谱进行酰胺Ⅲ带研究。研究结果表明,溶解在不同浓度尿素溶液中大豆分离蛋白二级结构与大豆分离蛋白水溶液相比发生很大变化,在0.1mol·L~(-1)尿素溶液中大豆分离蛋白β-折叠含量最小,随着尿素浓度增加,β-折叠含量增加,无规卷曲含量在0.1mol·L~(-1)尿素溶液中达到最大,之后随尿素浓度增加而降低;α-螺旋和β-转角随着尿素浓度增加,其含量都呈现先增加后下降趋势,在1mol·L~(-1)尿素溶液中两者含量与大豆分离蛋白水溶液中含量相比变化不大。     

基于机器视觉的加工面缺陷检测方法

针对生产过程中对产品检测提出的新要求,介绍一种基于机器视觉的加工面缺陷检测方法。它利用小波变换对图像进行多尺度分析,然后对反映纹理特征的分量进行处理,达到增强非纹理性质的特征的目的,从而检测出掩埋于加工纹理背景中的细小裂纹和缺陷。此方法的研究与实现,可在线检测系统实施过程中有效提取掩埋于高强度纹理背景中的图像奇异特征,从而保证检测过程准确、高效地进行。     

Application of brown-rot basidiomycete Fomitopsis sp. IMER2 for biological treatment of black liquor

Acid-producing fungi can be used for the treatment of black liquor by biological acidification for the precipitation of alkali lignin. The effects of alkali lignin obtained from black liquor on the growth, acid-producing capacity and glucose consumption of a brown-rot fungus Fomitopsis sp. IMER2 were investigated and the changes in the functional group in the resulting alkali lignin were analyzed by Fourier transform infrared (FTIR) spectroscopy. Although the presence of alkali lignin inhibited fungal growth and acid production, it enhanced glucose consumption. This suggests that the physiological response of this fungus to stress induced by alkali lignin is unique. Furthermore, the analysis of the effects of the resulting alkali lignin on the growth rate showed that several functional groups were evidently improved for the use of available resources.     

Study of the retrogradation behaviour of rice cake using rapid visco analyser,Fourier transform infrared spectroscopy and X‐ray analysis

Retrogradation of gelatinised starch is the main phenomenon that influences the texture of MiGao (rice cake). The hardness of the MiGao increased during stored at 25 °C for 5 days. Rapid visco analyser (RVA), Fourier transform infrared (FT‐IR) spectroscopy and X‐ray were quantified to analysis the retrogradation behaviour of MiGao. The most significant change in the pasting curve was the increase in peak viscosity over time measured with an RVA. FT‐IR indicated changes in crystallinity of the MiGao crumb. The X‐ray diffraction patterns could be classified as typical of A‐type starch for the fresh MiGao. With aging, the B‐type structure increases, while the A‐type structure remains virtually unchanged. All the results suggested that the main mechanism underlying the changes in properties is suggested to be slow amylopectin crystallisation.     

小型手持式套准误差自动检测仪器的研制

针对市场上中小型单张纸胶印机没有配备自动套准检测装置,且在实际印刷中,套准线的检测主要是由操作工人利用放大镜进行估算,耗时耗力,不够准确等问题。研制了一种基于图像处理的单张纸胶印机套准误差自动检测仪器。该仪器通过单片机控制高精度CMOS摄像头对套准线进行拍照,采用Hough变换原理检测套准线的横向偏差、纵向偏差和对角线偏差。试验结果证明,该仪器测定的横向偏差检测精度为0.01mm,纵向偏差检测精度为0.01mm。     

Mellin 变换在处理光束漂移中的应用

从Mellin变换理论出发,推导了激光光束在湍流大气中斜程传输时的光束漂移公式,并在此基础上分析了准直激光光束漂移方差与靶标高度,光束半宽的关系.从结果可以看出,斜程传输在一定的距离内,靶标高度越高,光束的漂移方差越小;光束的初始半宽越大,光束的漂移方差越小.在斜程传输1km到10km距离下,随着靶标高度的逐渐增大,光束漂移方差的变化幅度越来越小,这时大气湍流的影响比水平传输时要小得多,上述理论结果与其他文献结果一致,从而也说明了Mellin变换理论在处理光束漂移方面的可行性.     

按时间抽取的FFT矩阵形式的研究

借助于奇、偶行（列）矩阵,前、后行（列）矩阵,奇偶行（列）分块矩阵及分块矩阵的准数乘运算等概念,分析了按时间抽取（DIT）的基-2 FFT算法分量形式的特点．将以自然数次序输出的按时间抽取（DIT）的基-2 FFT算法用较简单的矩阵形式来表示．