【作者】 曾辉；

【导师】 钱和；

【作者基本信息】 江南大学 ， 食品科学， 2006， 硕士

【摘要】 本文以魔芋葡甘露聚糖(KGM)为研究对象,以提高生物活性为目标,研究了具有较高分子量的魔芋葡甘露糖醋酸酯(AKGM)的制备工艺、超声波降解KGM和AKGM的工艺,以及类Acemannan物质AKGM的乙酰化度和分子量与生物活性之间的关系,并筛选得到了具有最佳生物活性的产物。AKGM的制备工艺研究中,以改进的碱性羟胺比色法测定乙酰基含量,以乙酰化度和代表分子量大小的特性粘度为指标,研究并确定了较优的实验室制备工艺条件为:乙酸酐和魔芋葡甘露聚糖的质量比=15,反应温度60～80℃,反应时间0.5～1.5h,催化剂无水乙酸钠用量0.4～0.8g,得到魔芋葡甘聚糖乙酰化度回归方程。此乙酰化方法获得的产物乙酰化度范围在0.3～1.1之间,具有较高的分子量。超声波降解KGM工艺的研究表明超声波功率决定产物分子量的降解底限;降解时间决定产物分子量分布分散度;超声波功率和多糖浓度决定降解速度。研究证实了超声波降解KGM可以产生分子量分布较为均一的产物,且在实验功率(<70*9W)下对侧链、乙酰基无降解,建立了以水为溶剂条件下KGM的Mark-Hoodwink方程为[η]=4.5×10-2Mw0.7。分别设计制备三种水平的乙酰化度和分子量,并采用体外培养的方法研究AKGM的乙酰化度和分子量对免疫活性和成纤维细胞增殖活性的影响。试验证明了AKGM的乙酰化度和分子量与免疫活性和成纤维细胞增殖活性存在不同的构效关系。乙酰化度对促增殖作用活性排序为: 0.48>0.76>0.22 ,分子量(Da)对促增殖作用活性排序为:55,000>150,000>300,000;乙酰化度对免疫活性排序为:0.76>0.48>0.22,分子量(Da)对免疫活性排序为:300,000>150,000>55,000。实验还采用极差分析和两因素分析方法,对比了乙酰化度和分子量对活性增强影响的大小,并对乙酰化度和分子量的交互作用进行了评价。分析结果表明成纤维细胞增殖活性影响因素排序为乙酰化度>分子量,乙酰化度和分子量的交互作用对促增殖活性的影响高度显著(P<.0001)。在细胞免疫方面,激发巨噬细胞吞噬功能的能力排序为分子量>乙酰化度,交互作用对吞噬功能影响的显著性一般(P<0.05);促进淋巴细胞转化增殖能力排序为乙酰化度>分子量,交互作用对促进淋巴细胞转化增殖方面的影响高度显著(P<.0001)。研究中筛选得到AKGM-II-3具有最优的促进成纤维细胞增殖活性,而AKGM-III-1则具有最优的提高免疫活性的能力。更多还原

【Abstract】 This paper is mainly focused on the modification of konjac glucomannan polysaccharide (KGM) and the improvement of its bioactivity. In this paper, the preparation of water-soluble high molecular weight acetylated KGM (AKGM) with high acetylating degree and degradation of KGM by ultrasonic were studied. Through biological technique, the relationship between bioactivity and degree of acetylating substitution and the relationship between bioactivity and molecular weight were also studied.In the AKGM preparation section, improved spectrophotometric method was used to inspect acetylating content, with both the acetylating degree and molecular weight used as the criteria, and the optimal laboratory preparation Parameters were determined: mass ratio of Acetic anhydride to KGM 15, reaction temperature 60-80℃, reaction time 0.5-1.5h, Sodium Acetate 0.4-0.8g. Based on the above results a significant regression equation about acetylating degree was obtained. In this way, AKGM have high molecular and its acetylating degree can be controlled within 0.3-1.1.In the ultrasonic degradation section, effects of single factor (such as power of ultrasonic, ultrasonic processing time, concentration of KGM and so on) on ultrasonic production were studied. Results showed that: under different ultrasonic power degradation productions had different molecular weight limits; Bandwidth of molecular weight distribution depended on degradation time; and the degradation speed depended on ultrasonic power and KGM concentration. It was also confirmed that the broken location of KGM main chain by ultrasonic degradation was non-random, and side chain was not destroyed. According to the data of HPGFC and [η], Mark-Honwind equation was established, [η]=4.5×10-2Mw0.7.Based on biology technique, cell proliferation activity and immune-activity of AKGMs with different molecular weight and acetylating degree were studied. These two factors have significant effects on bioactivity, but they were different. The orders of significance of different factors to bioactivities were investigated. The result were as follows: acetylating degree to cell proliferation activity: 0.48>0.76>0.22; acetylating degree to immunocompetence: 0.76>0.48>0.22; molecular weight to cell proliferation activity 55,000>150,000>300,000; and molecular weight to immunocompetence 300,000>150,000>55,000. Orthogonal tests analysis showed that acetylating degree had more important roles in cell proliferation activity and proliferation of lymphocytes, and molecular weight had more important roles in phagocytosis of peritoneal macrophage. Further study of the interaction between molecular weight and acetylating degree showed that the interaction was significant in cell proliferation activity and proliferation of lymphocytes, but not in phagocytosis of peritoneal macrophage.更多还原