Visualization of Single and Aggregated Hulless Oat (Avena nuda L.) (13),(1 详细信息    查看全文

• 作者：Jia Wu ; Yun Zhang ; Lan Wang ; Bijun Xie ; Haibo Wang ; and Shaoping Deng
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2006
• 出版时间：February 8, 2006
• 年：2006
• 卷：54
• 期：3
• 页码：925 - 934
• 全文大小：814K
• 年卷期：v.54,no.3(February 8, 2006)
• ISSN：1520-5118

文摘

Surfactants were used to disperse oat -glucan. Atomic force microscopy (AFM) images of the resultingsamples revealed a distribution of extended chainlike molecules and allowed, for the first time, directvisualization of single oat -glucan molecules with cross-sectional heights of about 0.44 nm. Thenumber-average contour length (L_n) and root-mean-square end-to-end distance (<R_ee²>^1/2) measuredfrom the AFM images were 938 and 912 nm, respectively. The calculated persistence length (L_p)was 526 nm. The weight-average molecular weight (M_w) calculated from single -glucan moleculeswas 4.43 × 10⁵. Samples without surfactant showed a strong tendency to form aggregates. Thesample concentration, reserving time, and calcofluor as well as freezing could affect the formation ofaggregates. These aggregates were visualized by both AFM and confocal scanning laser microscopy.The shape of the aggregates changed from small dots with diameters of approximately 20-50 nm tomicrofibrils over 3 m long with the increasing of the concentration of oat -glucan from 10 to 100g/mL. The particle size distribution obtained by a laser particle size analyzer was 926 nm, whichconfirmed the size of oat -glucan molecules obtained from AFM images.Keywords: Oat; -glucan; atomic force microscope; confocal scanning laser microscopy; sodiumdodecyl sulfate; particle size