Studies On Extration, Isolation And Preservation Application Of Guava Polyphenols

Polyphenol is a general name of some polyhydroxy compounds. Which arewidely present in plant. Polyphenols has the effect of anti-oxdation, antibacterial andantiviral, it also can prevent cardiovascular diseases. It widely be used as antioxidantsand preservatives in food industry. Guava is widely present in Guangdong, Guangxi,Hainan and Yunnan, et al. Previous studies found that Guava is rich in polyphenols.So developing and using the polyphenol of Guava has considerable realisticsignificance. The technology of extraction and separation from Guava and theirpreservation was dicussed for providing a theoretical basis on comprehensiveutilization of Guava.In this paper, the main contents and results are as follows:1．The organic solvent extraion and Ultrasonic extraction wre studied. Choosingproper extraction solvent and using one-factor experiment and reponse surface todevelop extraction model of Polyphenols from Guava, consider all those fators,ethanol-water is used as extraction solvent, the best technology condition wereconcentration of ethanol58%, temperature95℃,time40min, ratio of solid to liquid1:30(g/mL) by the organic solvent extraion and ultrasonic power350W,concentration of ethanol40%, time30min, ratio of solid to liquid1:30by theultrasonic extraction. In their respective optimum technological conditions forvalidation test findings, extraction ratio of Ultrasonic extraction is higher, it is moreapplicable to the extraction of Guava polyphenol.2．NKA-9macroporous resin was determined as the best for separating Guavapolyphenol by comparation of the ability of static absorption and disadsorption of fivemacroporous resin. On that basis, by the statiac and dynamic tests, the optimumpurification condition was determined as followings: column sizes1.6×40cm,column volme40mL, the sample solution pH2.0, the concentration of samplesolution1.2mg/mL, the current velocity of the sample solution1mL/min, the volumnof the sample solution8BV, the eluenting reagent:50%ethanol, pH3.0, the elutevelocity1mL/min and the eluting reagent volumn3BV. In the above condition, theweight percent of polyphenol in the preliminary purification extract is46.5%, the recovery rate is83.0%.On this basis, the preliminary purification of polyphenol was separated andpurified further by Sephadex LH-20, Three main components P-1, P-2and P-3wereobtained. Then three components were identified by HPLC, the results show that eachcomponent was different, but not the single compound.3．The components which were purified by Sephadex LH-20were identifiedpreliminary by color reaction, Ultaviolet spectrum analysis and HPLC-ESI-MS. Theresults of color identification and Ultraviolet spectrum analysis show that P-1, P-2andP-3were polyphenols. According the result of HPLC-MS, galic acid, chlorogenic acid,ferulic acid, caffeic acid, phlorizin, protocatechuic acid and kaempferide werepreliminary identified.4．Litopenaeus vannamei was treated with0.4%,0.5%and0.6%polyphenolsand0.15%potassium sorbate, the preservation effect of polyphenols purified ofGuava was evaluated by sensory evaluation, total bacterial count, TVB-N value andpH value. The results show that sensory evalution, total bacterial count, TVB-N andpH index of shrimp mince treated by Guava polyphenols and potassium sorbate wereobviously below control group. All this illustrated the polyphenols of Guava andpotassium sorbate can inhibit bacteria growth in shrimp mince and extend the lengthfor preservation when refrigeration. Moreover, in effect, conpare both methods,potassium sorbate usage less, but the effect of preservation of polyphenols solutionespecially0.6%polyphenols solution was better than which treated than others,moreover it has higer safety, so it was a kind of feasible preservation method totreated shrimp mince with polyphenols solution.