油茶壳木质素理化性质及表征

Physicochemical Properties and Structural Characterization of Lignin from Camellia oleifera Shell

为充分利用油茶壳资源,研究分别采用醋酸法和碱法提取油茶壳木质素,并对其基本成分、理化性质和结构表征进行了分析。结果表明:提取的醋酸木质素(91.87%)纯度略微低于碱木质素(93.37%);且醋酸木质素中[C]和固定碳含量较高。两种木质素抗氧化力远大于油茶壳粗膳食纤维;与碱木质素相比,醋酸木质素持水力、溶胀力分别增加了59.49%、55.36%,饱和与不饱和脂肪结合力分别增加了5.06%、2.24%,DPPH自由基清除力增加了10.50%,吸湿率降低了28.14%。紫外和红外光谱谱图可知,醋酸木质素和碱木质素主要由愈创木基和紫丁香基组成;醋酸木质素中愈创木基含量更高,碱木质素中紫丁香基含量更高。热重分析可知,醋酸木质素热稳定性高于碱木质素,更适于高温耐热材料的制备。

In order to make full use of the resources of Camellia oleifera shell,this research using Camellia oleifera shell as raw material,the lignin was extracted from Camellia oleifera shell by acetic acid method and alkaline method,respectively.The basic components,physicochemical properties and structural characterization of acetic acid lignin and alkaline lignin were analyzed.The results showed that acetic acid lignin had a lower purity(91.87%)and higher purity of alkaline lignin(93.37%),and the content of[C]and fixed carbon in acetic acid lignin was higher.Antioxidant activity investigation showed that the DPPH radical scavenging index of the extracted acetic acid lignin and alkaline lignin was higher than that of crude dietary fiber.Compared with alkaline lignin,the water holding capacity and swelling capacity of acetic acid lignin were increased by 59.49%and 55.36%,respectively.The binding capacity of saturated fat and unsaturated fat were increased by 5.06%and 2.24%,respectively.The DPPH radical scavenging activity was increased by 10.50%.And the moisture absorption was decreased by 28.14%.Meanwhile,the UV-visible spectra(UV)and infrared spectra(IR)analyses showed that the acetic acid lignin and alkaline lignin are mainly composed of guaiacyl and syringyl,and the guaiacyl content in acetic acid lignin was higher,while the syringyl content in alkaline lignin was higher.Thermogravimetric analysis showed that the thermal stability of acetic acid lignin was higher than that of alkaline lignin,and was more suitable for the preparation of high temperature and heat resistant materials.