【作者】 张杰；

【导师】 袁其朋； 王文雅；

【作者基本信息】 北京化工大学 ， 化学工程与技术， 2019， 硕士

【摘要】 原花青素(PC)有很好的抗氧化、抗肿瘤等药理活性,来源之一是葡萄籽,但葡萄籽中存在50%以上的不可提取的原花青素(聚合度相对较高),可提取原花青素中65%以上的是高聚原花青素(PPC)。碱法被证明能成功解聚A-型PC,蒸汽爆破法(SE)被证明能成功增加黄酮产量、解聚木质素和断裂糖苷键等,因此本研究的工作重点是探究SE和碱法预处理对低聚原花青素(OPC)释放及PPC解聚的影响。本研究主要的采用扫描电镜观察微观结构,香草醛法、福林酚法评估PC总量及总酚含量,苄硫醇-RP-HPLC评估PC的聚合组成单元和平均聚合度(mDP),又采用NP-HPLC表征PC组分的组成。为评估解聚效果,采用DPPH、FRAP和ABTS三个体外抗氧化活性实验。下述为蒸汽爆破和碱法预处理葡萄籽的重要研究内容:1、探究SE预处理对PC提取及解聚的影响。SE会破坏葡萄籽坚硬致密的纤维结构且会产生较多孔洞,但疏松和表面积增大的结构并没有促进PC的提取,但爆破组的mDP明显降低,三个体外抗氧化实验证明活性明显增强,单体及表儿茶素没食子酸酯(ECG)的峰面积增长比(PAGR)增加明显,并成功推测了 PPC的解聚机理。2、探究碱法预处理对PC提取和解聚的影响。不同碱预处理温度(40、60、80℃),碱处理时间(15、30、60 min),碱浓度(0、1、2、4、6 mol/L)的处理下,综合比较PC的mDP、OPC组分、OPC含量以及体外抗氧化活性,筛选出了最优的处理条件。最后根据OPC组分及OPC含量的变化推断了碱处理对葡萄籽PC的释放和解聚的作用规律。本研究针对PC提取和解聚问题提出了 SE和碱法两种解决方案,结果证明:SE法是一种高效、清洁的解聚方法,但针对OPC的增产,仅有单体和ECG组分增加明显,其他组分呈下降趋势;碱水解则是一种有效解聚和OPC增产的方法,但中和反应产生的盐,将会成为工业化生产的瓶颈,本研究采用的乙酸乙酯萃取的方法虽然有效,也会造成了产物的损失。综上,SE和碱法两种方案虽然已经取得阶段性成果,但实现工业生产还需进行更多探究。更多还原

【Abstract】 Procyanidin(PC)has good pharmacological activities such as anti-oxidation and anti-tumor.One of the sources is grape seeds,but there are more than 50%non-extractable procyanidins(the degree of polymerization is relatively high)in grape seeds.And more than 65%of the extractable procyanidins are polymeric procyanidins(PPC).The alkali method has been proven to successfully depolymerize A-type proanthocyanidins.The steam explosion(SE)method has been proven to successfully increase flavonoid yield,depolymerize lignin and cleavage glycosidic bonds.Therefore,the focus of this research is to study the effect of SE and alkaline pretreatment on releaseing oligomeric procyanidins(OPC)and depolymerizeing polymeric procyanidins.In this study,the microstructures were observed by scanning electron microscopy.The total procyanidins and total phenol content were evaluated by vanillin method and Folin-Ciocalteu method.The polymerization unit and the mean degree of polymerization of PC were evaluated by thiolytic degradation-RP-HPLC.And the composition of the PC fractions were characterized by NP-HPLC and each peak was distinguished in the light of the peak time of the standards.In order to evaluate the depolymerization effect,three in vitro antioxidant activity experiments of DPPH,FRAP and ABTS were used for evaluation.The following are important research contents of steam explosion and alkali method:1.To investigate the effect of SE pretreatment on the extraction and depolymerization of procyanidins.SE destroyed the hard and dense fiber structure of grape seeds and produce more porous holes,but the loose structures and surface area increase did not promote the extraction of procyanidins.Compared with the control group,the mDP of the exploded groups were significantly reduced,the antioxidant activities in vitro were significantly enhanced,and the peak area growth ratio(PAGR)of monomers and epicatechin-3-O-gallate(ECG)were significantly increased.From the above results,we tried to postulate the depolymerization mechanism of procyanidins.2.To investigate the effect of alkaline pretreatment on the extraction and depolymerization of procyanidins.Study different alkali pretreatment temperatures(40,60,80℃),time(15,30,60 min),alkali concentration(0,1,2,4,6 mol/L),and determine the effects of mDP,OPC component,OPC content and in vitro antioxidant activity.The results showed that compared with the control group 0 mol/L NaOH,treated at 60℃ for 15 min,10 mol/L NaOH,60℃ treatment for 15 min is the best treatment conditions.Finally,the effects of alkali treatment on the release and depolymerization of grape seeds procyanidins were inferred based on the changes of OPC components and OPC content.In summary,this study provides a new way of thinking for the production of OPC.In this study,two solutions of SE and alkali method were proposed for the extraction and depolymerization of procyanidins.The experimental results of two schemes proved that SE method is an efficient and clean depolymerization method,but for the increase of OPC,only the monomers and ECG components increased significantly,and other components showed a downward trend.The alkali method is a method for efficient depolymerization and OPC yield increase,but the salt produced by the neutralization reaction will become the bottleneck of industrial production.Although the ethyl acetate extraction method used in this study is effective,it also causes part of the product loss.In summary,although the SE and alkali method have achieved phased results,more research is needed to achieve industrial production.更多还原