【作者】 苏钰琦；

【导师】 马惠玲；

【作者基本信息】 西北农林科技大学 ， 野生动植物保护与利用， 2008， 硕士

【摘要】 活性植物多糖是21世纪生命科学研究的重要领域之一。苹果渣中富含各种多糖化合物,其系统分析与活性测试却鲜有报导。本研究以陕西省眉县恒兴果汁厂生产浓缩果汁后的苹果渣为原料,分别采用各种提取方法的单级提取和各法结合的多级提取法从苹果渣中提取苹果多糖,比较了各种工艺的多糖得率与抗氧化活性,旨在通过苹果多糖的系统提取、分离,对各组分抗氧化活性的全面测定和分析,筛选出苹果高活性多糖及其优化提取工艺。研究结果如下:(1)水、碱、酸任何一种工艺都不可能对苹果多糖进行彻底提取,不同工艺下都可得到部分不同溶解性的多糖。水提→碱提→酸提的三级提取法对水溶、碱溶、酸溶性多糖分段提取,总得率为417.1±12.1g/kg DWB,远高于传统的单一果胶多糖(APS-AcEI)的得率97.9±5.8 g/kg DWB。(2)通过测定和全面比较各多糖半纯品对O2-·、·OH、DPPH·自由基的消除活性以及还原能力,筛选出苹果多糖抗氧化活性测定的最佳方法为还原力测定法。(3)不同提取方法得到的苹果多糖半纯品均有较好的抗氧化活性,水提、酸提法无论是单级提取还是多级提取所得多糖半纯品的活性均高于果胶提取法多糖(APS-AcEI),高活性苹果多糖提取的最佳工艺为高温下水提→酸提→碱提的三级提取法。(4)不同提取方法所得多糖半纯品的纯品组分都有一定的抗氧化活性,各组分均表现出不同的抗氧化活性,并具有水洗组分(弱极性)活性大于盐洗组分活性的总趋势,且分子量小的组分,抗氧化活性较大,分子量相近的其抗氧化活性无明显差异。以还原力为指标时,各组纯品多糖的抗氧化活性均与其分子量指数呈正线性相关,即与其分子量负相关。相同提取工艺下所得多糖半纯品与其纯品组分间的抗氧化活性不同;所有半纯品的活性均高于或接近其各纯品组分;未能脱色的碱提多糖(APS-AlTⅡ)例外,纯品组分(APS-AlTⅡ4 )的活性略高于其半纯品。更多还原

【Abstract】 Currently plant originated polysaccharide with biological activities is one of a great focus in life science. There are abundant and diverstile Malus Pumila polysaccharides in apple pomace, however, few systematic isolation and analysis have been done about them. Apple pomace produced from juice squeezing by Meixian plant, Shaanxi Hengxing Fruit Juice Company LTD. was employed to prepare polysaccharides with either one-step-extracting or step-on-extracting technology in this study. Yields and anti-oxidative activity were compared between each process and each product. Through systematic isolation and measurement Malus pumila polysaccharide(s) which is of high biological activity was screened and its preparing technology was optimized. All results are as flowing:(1) It is impossible with one-step-extracting methods likes water, alkali, acid, to extract the Malus Pumila polysaccharides thoroughly, and polysaccharides with different solubility were obtained with different methods. Total yield of polysaccharide from water-alkali-acid step-on-extracting method got to 417.1±12.1g/kg DWB,far more than that from the traditional acid-extracting process of pectin production, 97.9±5.8g/kg DWB.(2) Through the measurement and thorough comparison of the scavenging capacity to O2-·、·OH、DPPH·and the reducing capacity of each half pure Malus pumila polysaccharide, The index of reducing capacity was screened the best one to indicate the anti-oxidative activity of Malus pumila polysaccharide.(3) In terms of reducing ability, no matter one-step-extracting or step-on-extracting method., the half pure product of Malus pumila polysaccharides which were extracted by other methods, all showed higher anti-oxidative activity than pectin polysaccharide(APS-AcEI), among which the highest activity occurs with the water-acid-alkali step-on-extracting method(APS-AlTⅡ) and the two stage extraction method(water-acid)(APS-AcI’)。It concludes that the best extraction technique for Malus pumila polysaccharide is the water-acid-alkali step-on-extracting method at high temperature.(4) Different anti-oxidative activity exists in the pure composition within the half pure product of Malus pumila polysaccharide produced with different extraction methods. Each composition showed different anti-oxidative activity, most of the pure composition displays a trend that active of the water eluting composition (weak polarity) is stronger than that of the salt eluting compositions, and the less the molecular weight, the more stronger the anti-oxidative activity, thus almost the same activity obtained with the similar molecular weight product. Except for APS-AlTⅡextracted in the three stage extraction method(water→alkali→Acid), within which the activity of the salt eluting compositions(APS-AlTⅡ3、APS-AlTⅡ4)were more stronger than that of the water composition.The anti-oxidative activity is different between the half pure product and its pure compositions. Generally, half pure product possessed a more stronger anti-oxidative activity, except the alkali-extracted polysaccharide(APS-AlTⅡ), which activity of pure composition(APS-AlTⅡ4) was slightly stronger than that of half pure product.更多还原