低档茶叶中β-胡萝卜素的提取及纯化工艺研究.docx

低档茶叶中β-胡萝卜素的提取及纯化工艺研究
摘要
本文研究了从低档茶叶中提取和纯化β-胡萝卜素的工艺过程。初步的实验结果表明，传统的溶剂提取法和膜分离法都可以用于制备β-胡萝卜素，且通过多次结晶和再结晶后可以达到较高的纯度。此外，还进行了一系列对β-胡萝卜素溶液的稳定性、生理活性以及其在食品中应用等方面的研究。
关键词：β-胡萝卜素，低档茶叶，提取，纯化，溶剂提取法，膜分离法
Introduction
β-carotene(β-CA)isawidelydistributedcarotenoidinfruits,vegetables,andsomeorganisms.Asanaturalantioxidant,ithasvariousfunctionssuchasanti-aging,anti-cancer,andenhancingimmunefunction.Studieshaveshownthatβ-CAcanalsobeusedasafoodadditiveandcoloringagent.However,high-qualitysourcesofβ-CAareexpensive,makingitessentialtodevelopefficienttechnologiestoextractandpurifyβ-CAfromlow-gradesources.
Low-gradetealeavesareagoodsourceofβ-CA.Therefore,thisstudyaimedtoexploretheprocessofextractingandpurifyingβ-CAfromlow-gradetealeavesusingdifferenttechnologies.
Materialsandmethods
Thelow-gradetealeaveswerepurchasedfromalocalteafactory.Theβ-CAextractionexperimentswereperformedusingthetraditionalsolventextractionmethodandthemembraneseparationmethod.
Traditionalsolventextraction:Crushedtealeaveswereextractedwith95%ethanolat50°C.Theextractionprocesswasrepeatedthreetimes.Theextractwasvacuum-concentratedtoremovetheethanolandthenfilteredtoobtainthecrudeextraction.
Membraneseparation:Theteaextractwasfilteredthrougha0.22-μmmembranefiltertoremoveimpurities.Thefiltratewasthenconcentratedusingarotaryevaporatorat55°C.
Purification:Thecrudeextractionfromthetraditionalsolventextractionmethodandthemembraneseparationmethodwasthensubjectedtomultiplerecrystallizationandreverserecrystallizationprocessestoachievehighpurity.Thefinalproductwasassessedbythin-layerchromatography,UV–Visspectroscopy,andhigh-performanceliquidchromatography.
Resultsanddiscussion
Thetraditionalsolventextractionandmembraneseparationmethodscouldbothbeusedtoextractβ-CAfromlow-gradetealeaves.Theyieldofβ-CAfromthetraditionalsolventextractionwasaround0.03%,andthemembraneseparationmethodyieldedapproximately0.06%.
Duringthepurificationstep,multiplerecrystallizationprocessesandreverserecrystallizationprocesseswerecarriedoutonthecrudeβ-CAextr