Subcritical Water Extraction And Separation Of Effective Polyphenols From Grape Seeds

Grape seeds are considered as the primary waste of grape juice,vintage and wine producing industries,therefore,grape seeds can be collected easily for further processing.Resveratrol and Procyanidine are two kinds of main polyphenol compounds in grape seeds,and they have effective medical fiunctions and massive potential for further research.However,due to the different physical properties,the traditional method can only be extracted these separately with the high cost,and the efficiency is low.In this study,without organic solvent under the conditions of the use of subcriticai water polarity continuous controllable principle,to achieve insoluble in water Resveratrol and soluble in water,two anthocyanins two polyphenols at the same time extraction process Economic green,turning waste into treasure.The contents of Resveratrol and Procyanidine are tested by high effieieney liquid chromatography(HPLC)and ultraviolet spectrophotometer respectively.The optimal extraction processing parameters are conducted by response surface methodology.Then the ratios of extraction are calculated and compared with conventional extraction methods,the research purifies Procyanidine by macroporous resins.Finally,the Resveratrol and Procyanidine are purified by preparative chromatograph and their structures are identified.The result of research are listed follows:(1)This research conducts a series of single-factor experiments to determine the influence of different processing parameters on extraction rate of Resveratrol,the optimal single factors are listed respectively:extraction pressure is 1.0Mpa,extraction temperature is 150?,extraction time is 25min and liquid-solid ratio is 15.Based on those single-factor experiments,the research optimize the processing condition by response surface methodology.The optimal extraction condition of Resveratrol:Extraction pressure is 1.02Mpa,extraction temperature is 152.32?,extraction time is 24.89min and liquid-solid ratio is 15.Under that condition above,the optimal extraction rate of Resveratrol reaches 6.90ug/g.The order of those processing parameters' impact on extraction is temperature>extraction time>extraction pressure>liquid-solid ratio.The standard deviation of extraction rate is less than 3%in the spike recovery experiment.(2)This research also conducts a series of single-factor experiments to determine the influence of different processing parameters on extraction rate of Procyanidine,the optimal single factors are listed respectively:extraction pressure is 0.5Mpa,extraction temperature is 170?,extraction time is 20min and liquid-solid ratio is 15.The optimal extraction condition is conducted by orthogonal experiments,the optimal extraction condition of Resveratrol:Extraction pressure is 0.5Mpa,extraction temperature is 170?,extraction time is 22min and liquid-solid ratio is 15.Under that condition above,the optimal extraction rate of Procyanidine reaches 82.19mg/g.AB-8 macroporous resin has better performance of absorption and desorption for Procyanidine other than S-8,D101 macroporous resin.The concentration of Proyanidine raises 3.2 times after purification.(3)The optimal extraction condition of combined extraction:extraction pressure is 0.5Mpa,extraction temperature is 152?,extraction time is 22min and liquid-solid ratio is 15.Under this condition,the extraction rate of Resveratrol and Procyanidine can be 6.78?g/g,81.38mg/g,respectively.In verification experiment,the actual extraction rates reaches 98.26%and 99.01%of the theoretical extraction rates respectively.Evidently,subcritieal water extraction have unparalleled advantages,such as less time spending,higher efficiency,free-solvent,compared with reflux extraction,microwave extraction and ultrasonic extraction.