【作者】 李晔；

【导师】 崔同；

【作者基本信息】 河北农业大学 ， 农产品加工及贮藏工程， 2010， 硕士

【摘要】 原花色素(proanthocyanidins简称PC)是一种以黄烷醇为主要结构单元,以不同连接方式聚合而成的复杂的多酚类植物次生代谢产物,水果是膳食PC的最主要来源。研究表明,PC具有很强的抗氧化、消除自由基、抗高血压、抗肿瘤等一系列重要生理作用,其生理作用及消化吸收率与它的平均聚合度密切相关。目前水果中PC含量分析方法有分光光度法和HPLC法,前者系统误差较大,而后者不能给出总含量和平均聚合度的信息。近年一些酸解-衍生化高效液相色谱法已经用于一些水果样品中PC的含量和平均聚合度的分析,但是这些结果都存在着分析品种单一,标准品不全等缺点。针对这些不足,本项研究对新方法进行了较系统的开发、评价和大量实际样品分析试验。对PC的酸解-苄硫醇衍生反应条件进行了研究,考察了苄硫醇试剂浓度、酸的配比和浓度、反应时间、反应温度等条件对衍生反应的影响。最后确定在PC溶液浓度不超过0.4%的水平下,反应液中苄硫醇的浓度为1%;冰乙酸:1 M盐酸= 5:1(v/v),反应温度为90℃,反应时间为60 min。此条件可以保证PC聚合体能够被彻底降解生成相应的黄烷醇及其苄硫醇衍生物。以工业品葡萄籽提取物为原料,通过酸解-苄硫醇衍生反应、正相HPLC、反相HPLC等步骤制备纯化了表儿茶素-苄硫醚(EC-S)和没食子酸表儿茶素酯-苄硫醚(ECG-S)两种衍生物。正相色谱分离条件为:色谱柱SinoChrom SiO2 (250 mm×20 mm i.d, 10μm),流动相:乙酸乙酯:石油醚(60:40,v/v),流速:10 mL/min,检测波长:280 nm。反相色谱分离条件为:色谱柱SinoChrom ODS-BP (250 mm×20 mm i.d, 10μm),流动相:70%(v/v)的甲醇(0.05%甲酸),流速10 mL/min,检测波长:280 nm。采用LC-MS法、1H和13C高分辨率二维NMR图谱方法对其进行了结构和纯度分析,结果表明,制备的两种成分确实为目标化合物。建立了水果中PC含量和平均聚合度的HPLC分析方法,其色谱条件为:Hypersil BDS C18分析柱(250 mm×4.6 mm i.d., 5μm);流动相A:500μL/L的甲酸水溶液;B:甲醇:乙腈= 1:2,含500μL/L的甲酸。梯度程序(min/B%)为:0/13,8/13,16/40,24/50,27/100,34/100,37/13,45/13。紫外检测器的检测波长为:280 nm;流速为:0.8 mL/min;柱温:35℃;进样量:5μL;峰面积外标法定量。分别统计没食子酸(GA)、儿茶素(CT)、表儿茶素(EC)、没食子酸表儿茶素酯(ECG)、EC-S、ECG-S的峰面积,通过标准曲线求出各种单体的含量和PC总含量,再由黄烷醇单体与衍生物的总浓度/黄烷醇单体浓度,即(CCT+CEC+CECG+ CEC-S +CECG-S)/(CCT+CEC+CECG),计算出样品中的PC平均聚合度。对山楂、葡萄等实际样品进行测定,各成分间有良好的分离,重复定量分析的相对标准偏差在0.4%～4.2%之间,最低检出限为:0.4 ng～4 ng之间,线性范围在0.8 ng～4000 ng之间,回归方程的相关系数达到0.9992～0.9999,45分钟内可以完成一次样品分析。采用开发的新方法对葡萄、苹果、山楂及其加工制品中的PC含量和平均聚合度进行了分析,结果表明,红星、金矮生、乔娜金、王林和富士5个品种的苹果中PC总含量范围为:0.14 mg/g～0.26 mg/g,平均聚合度为2.0～2.78;坂田、京亚、田康、计选、前锋、巨峰、漠王, 7个鲜食葡萄品种的籽中原花色素总含量范围为5.2 mg/g～26 mg/g,平均聚合度在2以下;对曾芳德、赤霞珠、梅辰、轭西拉、黑品乐、琼瑶浆、长相思、米勒、宝石、白思南、雷司令、美荣12种酿酒葡萄品种的葡萄籽中的PC进行了分析,PC总含量为8.4 mg/g～32 mg/g,平均聚合度为1.8～4.0;对一种葡萄籽提取物工业产品进行了分析,PC总含量为370 mg/g,平均聚合度为6.08;6种市售保健品中,PC总含量为6 mg/g～51 mg/g,平均聚合度在2.70～4.30之间。山楂鲜果中原花色素总含量为4.8 mg/g,平均聚合度为1.9;汇源山楂果汁、华旗山楂果汁中PC含量分别为0.065 mg/L和0.11 mg/L;而山楂糕、山楂羹、山楂片、果丹皮4种山楂加工制品中,PC含量为1 mg/g～2.4 mg/g,6种产品PC平均聚合度在1.77～2.23之间。本项研究还对干制和贮存过程中山楂PC的稳定性进行了研究。结果表明:真空冷冻干燥、80℃热风干燥和自然干燥三种干制条件干燥条件中,真空冷冻干燥后PC成分的损失最小,其总量的保存率为88%;热风干燥和自然干燥后PC成分的保存率分别为76%和25%。鲜果的冷藏试验结果表明,在0℃条件下经过110 d的贮存,山楂鲜果中的原花色素总含量相当于贮存初期含量的80%,好果率、色泽均符合正常标准。同山楂果的干制结果进行比较可以看出,鲜果低温冷藏PC成分损失率较低,适用于山楂原料的短期贮存,干制方法可用于长期贮存。本实验建立的用于分析水果中PC的酸解苄硫醇衍生HPLC法,以制备的EC-S、ECG-S衍生物等为标准对照品,具有操作简单准确快速等优点,不仅可以测出PC成分的总含量,而且还可以提供PC聚合程度的重要信息,可用于苹果、葡萄、山楂及其提取物、相关工业品以及保健食品的分析和质量评价。从实际样品分析结果可以看出,不同品种之间无论从PC含量还是平均聚合度都有较大的差异。山楂果实中PC含量较高,甚至接近葡萄籽提取物保健品中的含量,而其平均聚合度却明显低于所分析的保健品,因此是一种良好的水果PC资源。更多还原

【Abstract】 Proanthocyanidins （PC） is a complex polyphenolic plant secondary metabolite, which is polymerized in different ways taking flavanols as the main structural unit. Fruits are the main source of dietary PC. The results show that, PC has a series of important physiological effects, such as strong antioxidant, eliminating free radicals, anti-hypertensive, and anti-tumor. Its physiological effects and absorption rate are closely related to the average degree of polymerization. Currently, the analytical methods of PC content in fruits are spectrophotometry and HPLC method. The spectrophotometry method has a larger system errors and the HPLC method fails in providing the total content and the average degree of polymerization. In recent years, a number of thiolysis-high performance liquid chromatography methods have been used for the analysis of PC content and average degree of polymerization of some fruit samples. However, the results of those methods all have such flaws as little variety analyzed and standard product incomplete. According to these deficiencies, this study develops and evaluates a new method based on a large number of actual samples analysis.This study conducts research on the PC thiolysis reaction conditions, and investigated the effects of the Benzyl-thiol reagent concentration, ratio of acid concentration, reaction time and reaction temperature on the derivative reaction. It is finally determined that when the PC concentration level is less than 0.4%, the benzyl mercaptan concentration in the reaction solution is 1%; Acetic acid:1 M HCl = 5:1 （v/v）, with the reaction temperature is 90℃and the reaction time is 60 minutes. This condition can guarantee that the PC polymer can be completely degraded and generate the corresponding flavanols and the benzyl mercaptan derivatives.Taking the industrial Grape Seed Extract as the raw materials and through the following steps including thiolysis, normal-phase HPLC, and RP-HPLC, we purified such two derivatives as epicatechin-benzyl sulfide （EC-S） and gallic acid epicatechin-benzyl sulfide （ECG-S）. The Normal phase chromatography conditions are: column SinoChrom SiO2 （250 mm×20 mm i.d, 10μm）; mobile phase: Ethyl acetate: petroleum ether（60:40,v/v）; flow: 10 mL/min; detection: UV at 280 nm. The RP chromatographic conditions are: column SinoChrom ODS-BP （250 mm×20 mm id, 10μm）; mobile phase: 70% （v/v） methanol （0.05% formic acid）; flow: 10 mL/min; detection: UV at 280 nm. Using the LC-MS method and the ¹H and ¹³C high-resolution two-dimensional NMR profiles method to analyze and confirm their structure and purity. The results show that the two prepared components are indeed the target compounds.The HPLC analysis method was established to analyze the PC content and average degree of polymerization of the fruit. The chromatographic conditions are: column: Hypersil BDS C18（250 mm×4.6 mm i.d., 5μm）; mobile phase A:500μL/L aqueous Formic acid; mobile B: methanol: acetonitrile = 1:2 v/v ; 500μL / L of formic acid. The gradient procedure was: 0 min～8 min, 13% B （isocratic）; 8 min～16 min, 13%～40% B （linear gradient）; 16 min～24 min, 40%～50% B （linear gradient）; 24 min～27 min, 50%～100% B （linear gradient）; 27 min～34 min, 100% B （isocratic）, 34 min～37 min, 100%～13% B （linear gradient）; 37 min～45 min, 13% B （isocratic）. Detection UV: 280 nm; flow: 10 mL/min; temperature: 35℃; injection quantity: 10μL. The external standard calibration curves were used in quantification. Count respectively the peak area of gallic acid （GA）, catechin （CT）, epicatechin （EC）, （ECG）, EC-S, and ECG-S. Obtain the content of various monomer and the total content of PC through the Standard curve. And then, calculate the PC average degree of polymerization of the samples by using the total concentration/flavanols monomer concentration of the flavanols monomer and the derivatives, or （CCT+CEC+CECG+ CEC-S +CECG-S）/（CCT+CEC+CECG）. By this method, the actual samples of hawthorn, grape et al. were measured. The main components were separated and determined well. RSD of these components were 0.4%～4.2%. The detection limit was 0.4 ng～4 ng, The linearity range was 0.8 ng～4000 ng. The correlation coeffeicent （r） was 0.9992～0.9999. The analytic time of one sample was 45 min.Using the new method, analyze the PC content and average degree of polymerization of the grape, apple, hawthorn and its processing products. The results showed that, the total PC content is 0.14 mg/g～0.26 mg/g in such five kinds of apples as Hongxing, Jinaixing, Qiaonajin, Wanglin and Fushi, and the average degree of polymerization is 2.0～2.78. The total content of the proanthocyanidins in the seed of such seven table grapes as Bantian, Jingya, Tiankang, Jixuan, Qianfeng, Jufeng, and Mowang is 5.2 mg/g～26 mg/g. The average degree of polymerization is below 2. Analyze the PC content of the seed of 12 kinds of wine grape such as Zengfangde, Chixianzhu, Meizhenge, Xila, Heipinle, Qiongyaojiang, Changxiangsi, Mile, Baoshi, Baisinan, Leisiling, and Meirong. The total content of PC is 8.4 mg/g～32 mg/g, the average degree of polymerization is 1.8～4.0. Analyze a kind of grape seed extract industrial product. The total PC content is 370 mg/g, and the average degree of polymerization is 6.08. In the six kinds of commercial health products, the total PC content is 6 mg/g～51 mg/g, and the average degree of polymerization is between the 2.70～4.30. The total content of proanthocyanidins in the hawthorn fruit is 4.8 mg/g, and the average degree of polymerization is of 1.9. The PC content of Huiyuan Hawthorn Juice and Huaqi Hawthorn Juice are respectively 0.065 and 0.11 mg/L. While in the four kinds of processed hawthorn products including the hawthorn cake, hawthorn soup, hawthorn slice, and sweetend roll, the PC content is 1 mg/g～2.4 mg/g, and the average degree of polymerization of the PC of the six kinds of products is between 1.77～2.23.This research also studied the stability of hawthorn PC during the drying and storage process. The results show that among the three drying conditions including vacuum freeze-drying, 80℃drying, and natural drying, the Vacuum freeze-drying has the minimum loss of PC components, and the retention rate of the whole amount is 88%; the retention rate of the PC components of hot air drying and natural drying are 76% and 25%. The results of the experiment on the frozen fruits show that after stored for 110 days in 0℃, the total amount of proanthocyanidins in the hawthorn fruits is 80% of that in the initial storage, the rate of good fruit is high, and the color and luster of the fruit meet the normal standard. Through the comparison with the result of dried and dehydrated hawthorn fruit, we can see that under refrigeration, the fruit has a lower loss rate of its PC components and is suitable for short-term storage of the hawthorn raw materials, while the dried method can be used for long-term storage.The thiolysis-HPLC method, developed in this study to analyze PC in the fruit, takes the prepared EC-S, ECG-S derivatives as the standard reference substance, and has the advantages of simple, accurate, and quick operation. It can not only measure the total content of the PC components, but also can provide important information of the degree of polymerization of PC. It can be used the analysis and quality evaluation of apples, grapes, hawthorn and its extracts, related industrial products, and health food. From the analysis results of the actual sample, we can see that there is a large variety in the PC content and the average degree of polymerization between different species. The hawthorn fruit has a higher PC content, even close to that in the the grape seed extract health products, while its average degree of polymerization is much lower than the analyzed health care products. Therefore, it is a good fruit PC resource.更多还原