Hajji Sawssen, Younes Islem, Ghorbel-Bellaaj Olfa, Hajji Rachid, Rinaudo Marguerite, Nasri Moncef, Jellouli Kemel
Laboratory of Enzyme Engineering and Microbiology, National School of Engineering of Sfax, University of Sfax, B.P. 1173, 3038 Sfax, Tunisia.
Laboratory of Enzyme Engineering and Microbiology, National School of Engineering of Sfax, University of Sfax, B.P. 1173, 3038 Sfax, Tunisia.
Int J Biol Macromol. 2014 Apr;65:298-306. doi: 10.1016/j.ijbiomac.2014.01.045. Epub 2014 Jan 24.
Three marine sources of chitin from Tunisia were investigated. Structural differences between α-chitin from shrimp (Penaeus kerathurus) waste, crab (Carcinus mediterraneus) shells, and β-chitin from cuttlefish (Sepia officinalis) bones were studied by the (13)C NMR, FTIR, and XRD diffractograms. The (13)C NMR analysis showed a splitting of the C3 and C5 carbon signals for α-chitin, while that of β-chitin was merged into a single resonance. The bands contour of deconvoluted and curve-fit FTIR spectra showed a more detailed structure of α-chitin in the region of O-H, N-H and CO stretching regions. IR and (13)C NMR were used to determine the chitin degree of acetylation (DA). XRD analysis indicated that α-chitins were more crystalline polymorph than β-chitin. Shrimp chitin was obtained with a good yield (20% on raw material dry weight) and no residual protein and salts. Chitosans, with a DA lower than 20% and relatively low molecular masses were prepared from the wet chitins in the same experimental conditions. They were perfectly soluble in acidic medium. Nevertheless, chitin and chitosan characteristics were depending upon the chitin source.
对突尼斯的三种海洋几丁质来源进行了研究。通过碳-13核磁共振（¹³C NMR）、傅里叶变换红外光谱（FTIR）和X射线衍射图谱（XRD）研究了虾（Penaeus kerathurus）废弃物中的α-几丁质、蟹（Carcinus mediterraneus）壳中的α-几丁质与乌贼（Sepia officinalis）骨中的β-几丁质之间的结构差异。¹³C NMR分析表明，α-几丁质的C3和C5碳信号出现分裂，而β-几丁质的这些信号合并为一个单一共振峰。去卷积和曲线拟合FTIR光谱的谱带轮廓显示，在O-H、N-H和CO伸缩区域，α-几丁质具有更详细的结构。利用红外光谱（IR）和¹³C NMR测定了几丁质的乙酰化度（DA）。XRD分析表明，α-几丁质比β-几丁质具有更多的结晶多晶型。虾几丁质的产率较高（占原料干重的20%），且无残留蛋白质和盐分。在相同实验条件下，由湿几丁质制备了乙酰化度低于20%且相对低分子量的壳聚糖。它们在酸性介质中完全可溶。然而，几丁质和壳聚糖的特性取决于几丁质的来源。
