【作者】 李银平；

【导师】 张振文；

【作者基本信息】 西北农林科技大学 ， 葡萄与葡萄酒学， 2012， 博士

【摘要】 葡萄籽是葡萄酒行业的废弃物,将其综合利用,既避免了环境污染、资源浪费,也提高了葡萄酒行业的经济效益。葡萄籽多酚提取物具有高效的保健功能。对于葡萄籽多酚的提取,传统的溶剂法提取时间长、效率低,超声波和超临界萃取技术设备要求高,难以大规模生产；而微波法提取效率高,且节省时间和溶剂,适合于工业化生产。微波辅助提取葡萄籽多酚的研究在国内外的报道不多,其中绝大多数以微波炉提供微波源,未曾采用正规的微波提取器并以合理的试验设计优化提取的最佳工艺。本研究以微波提取器,采用正交试验和中心点合成试验,优化微波辅助提取葡萄籽多酚的最佳工艺,为微波辅助提取葡萄籽多酚的工业化提供参考。对比了微波和超声波辅助提取葡萄籽多酚的效果和差异,并对葡萄籽多酚提取液的特性表征进行了研究。获得主要结果如下：1、获得了微波辅助提取葡萄籽多酚最佳工艺条件,建立了微波辅助提取葡萄籽多酚的数学模型。试验获得了总酚含量、单宁酸当量、没食子酸当量和咖啡酸当量最佳提取工艺和理论最大提取量,其中总酚的最佳提取工艺条件为：乙醇含量47.2%,液料比45.3：1,提取时间4.6min。以总酚最佳工艺提取葡萄籽粉,提取液的总酚含量为96.25mg GAE/gGS,与理论最大提取量96.79mg GAE/g GS基本相同。试验得到了葡萄籽提取物总酚含量、单宁酸当量、没食子酸当量和咖啡酸当量的二次回归方程式及其响应曲面,其中总酚含量的二次回归方程式为：y=2.013X1+1.688X2+6.906X3-0.020X12-0.758X32(P=0.005),其中X1、X2和X3分别代表乙醇含量、料液比和提取时间,y代表总酚含量。2、相同提取工艺下,微波比超声波辅助提取葡萄籽多酚的效果更好。试验对比了微波辅助提取葡萄籽多酚(MAlE)、短时超声波辅助提取葡萄籽多酚(UAE-1)以及长时超声波辅助提取葡萄籽多酚(UAE-2)的效果和差异。其中MAE和UAE-1提取条件相同。UAE-1提取液总酚的含量显著的低于UAE-2和MAE提取液。UAE-2提取液的提取率、280nmGAE含量和260nmTAE含量最高,MAE次之,UAE-1最低。具有相同提取条件的微波(MAE)比超声波(UAE-1)辅助提取葡萄籽多酚的效果更好。3、获得了葡萄籽提取液的多酚成分含量、提取液颜色和抗氧化能力等特性表征。(1) MAE、UAE-1和UAE-2提取液中,转色期葡萄籽的黄烷-3-醇和酚酸类含量之和(即单体酚之和)均大于采收期；转色期霞多丽的单体酚之和最多；转色期长相思的表儿茶素没食子酸酯含量最高。UAE-2提取液只检测出5种成分,未检测出苯甲酸。(2)采收期要比转色期葡萄籽提取液颜色更红、更黄、颜色更深。红色品种比白色品种的葡萄籽提取液颜色更红、更深。提取液的澄清透亮程度从MAE、UAE-1到UAE-2逐渐减小,红色和黄色从MAE、UAE-1到UAE-2逐渐增加,颜色从MAE、UAE-1到UAE-2逐渐加深。MAE、UAE-1和UAE-2提取液之间的澄清透亮程度差异、红色和黄色差异以及总颜色差异均达到极显著水平。(3)8个样品之间的抗氧化能力差异极显著。MAE和UAE-2提取液的抗氧化能力几乎相同,都比UAE-1提取液强。抗氧化能力最高的品种是霞多丽,最低的是西拉。(4) MAE、UAE-1和UAE-2提取液的总酚含量、单体酚之和、儿茶素含量、表儿茶素含量、表没食子儿茶素含量、表儿茶素没食子酸酯含量以及没食子酸含量,与提取液抗氧化能力(包括FRAP法和DPPH-法测定的抗氧化能力)均为线性正相关。更多还原

【Abstract】 Grape seed is the waste of wine industry. Making good use of grape seed, will not only avoid environment pollution, but also increase the benefit of wine industry. Grape seed extract has efficient function for health keeping. As for the extraction of grape seed polyphenols, traditional solvent extraction needs long time and the extraction efficiency is low. Because of the high demand of equipments, UAE and supercritical CO2extraction are not often used in the industry. MAE efficiency is high and extraction time is short, which makes it suitable for the application in industry. There are only few studies concerned the MAE of grape seed polyphenols, and most of them ultilized the microwave oven to supply the microwave. But no one has utilized a formal microwave extractor and a proper experiment design to optimize the best condition of MAE of grape seed polyphenols. This study utilized microwave extractor and Central Composite Rotatable Design to optimize the best extraction condition of MAE of grape seed polyphenols, compared the effect of MAE and UAE of grape seed polyphenols, and studied the characteristic of grape seed extracts of MAE and UAE. Main concolusions are as follows:1、Best extraction condition has been optimized, and response surface plots of MAE of grape seed polyphenols have been modeled.Best extraction condition and optimized maximum level of TP content,280nmGAE,260nmTAE,320nmCAE have been achieved. Best extraction condition for TP is ethanol/water47.2%, liquid-solid radio45.3:1and time4.6min. TP content of the extract which was extracted with the best extraction condition is96.25mg GAE/g GS, which is about the same with optimized maximum content96.79mg GAE/g GS.2nd-Order polynomial equations and response surface plots of TP content,280nmGAE,260nm AE,320nmCAE and yield have been gained.2nd-Order polynomial equation for TP content is:y=2.013Xi+1.688X2+6.906X3-0.020Xi2-0.758X32(P=0.005)。2、With the same extraction condition, the effect of MAE of grape seed polyphenols is much better than UAE.This study has compared the effect of MAE of grape seed polyphenols、short time UAE of grape seed polyphenols (UAE-1) and long time UAE of grape seed polyphenols (UAE-2). MAE and UAE-1have the same extraction condition. TP content of UAE-1extract is much less than that of MAE and UAE-2extract. Yields,280nmGAE content and260nmTAE content in UAE-2extract are the highest, while in MAE extract is less, and in UAE-1extract is the least. With the same extraction codintion, effect of MAE is much better than UAE-1.3、Content of polyphenol monomers in grape seed extracts, color and antioxidant ability of extracts have been obtained.(1) Total monomer content in veraison grape seed extracts is higher than that in harvest. Total monomer content in Cha-ver extract is the highest. Epicatechin gallate content in Sau-ver extract is the highest. There is no benzoic acid in UAE-2extracts.(2) Extracts of veraison is much clearer than that of harvest. Extracts of harvest is redder, darker and got more yellow color than that of harvest. Extracts of red varieties is redder and darker than that of white varieties. Clarification levels gradually reduce from MAE, UAE-1to UAE-2extracts. Red and yellow color and total color levels gradually increase from MAE, UAE-1to UAE-2extracts. Difference of clarification, red and yellow color and total color between MAE, UAE-1and UAE-2extracts is highly significant.(3) Difference of antioxidant ability between8samples is highly significant. The antioxidant ability of MAE and UAE-2extracts is about the same, and both are bigger than that of UAE-1. Antioxidant ability of Chardonnay extracts is the highest, while Shiraz is the lowest.(4) The liner relationship between antioxidant ability (including the antioxidant capacity measured by FRAP and DPPH-methods) and TP content, total monomer content, catechin content, epicatechin content, epigallocatechin content, epicatechin gallate, gallic acid are all positive correlation.更多还原