Study On Enzymatic Conversion Of Phloridzin To Functional Yellow Pigment

Pigment is a common food additive in our daily life.Its security has been high concerned.Synthetic pigment continue to be exposed out of security problems,so that safe stable natural pigments are more and more get people's attention.This paper mainly through forming process by using simulation in vitro transformation of yellow pigment in apple juice to establish the optimum technical methods on enzymatic conversion of phloridzin to functional yellow pigment,develop the safe and stable crude functional apple yellow pigment,study on stability and in vitro antioxidant activity to make its features and applications clearly,make a preliminary study of the immobilized enzymatic conversion of the preparation of functional yellow pigment.A determination method of the enzymatic reaction products was established in this paper.Chromatographic separation was performed by Waters ACQUITY UPLC BEH C18column?2.1×100mm,?1.7?m?using the mobile phase isocratic elution of methanol-phosphoric acid?40:60?with a flow rate of 0.3m L·min^-1 at 30? and the UV detective wavelength was287 nm.The enzymatic reaction products was separated rapidly within 5min.And get the enzymatic reaction product chromatogram.The calibration curve of phloridzin was linear in the range of 0.10 1.0mg/m L with R2=0.9993.The minimum detection limit is 0.0279 mg/L,quantitative limit is 0.1863 mg/L,and the precision is good.The recovery and RSD were98.69% and 1.39% respectively.This method is accurate and reliable for determination of the enzymatic reaction products.Using phlorizin as the raw material,with polyphenol oxidas to enzymatic conversion and preparation of functional yellow pigment.Get the reaction optimum temperature is 35?,the optimum p H is 6.5.Reaction process studies have shown that conversion of phlorizin in the reaction time of 90 min to reach the maximum conversion rate substantially.The reaction kinetics of the enzyme showed that under the experimental conditions,the saturation concentration of the substrate is 1mg / m L,kinetic equation:v=?0.0397S?/?3.3113+S?Enzymatic reaction liquid was extracted with ethyl acetate 4-5 times to make the phlorizin removed completely.The yield was 42.69%.After yellow pigment sample was dissolved in methanol to remove buffer salts,the yield was 86.85%.There are some differences between phlorizin and enzymatic reaction products as a yellow pigment of antioxidant activity.The yelllow pigment after desalting on DPPH radical scavenging ability was significantly stronger than phlorizin and yellow pigment sample before desalting,but weaker than ascorbic acid.It also stronger than phlorizin and yellow pigment sample before desalting about the reducing power of Fe3+.The results obtained by these two methods is consistent.Yellow pigment is a water soluble pigment with strong polarity.It relatively stable at acidic and neutral conditions.High temperature and sunshine for a long time is of certain influence to the stability of yellow pigment.But it can keep stable at 100? for 3h;Pigment has high stability with sodium,potassium and magnesium ions.The rest of the metal ion and sucrose,hydrogen peroxide show the stability of yellow pigment solution in low concentration.By using sodium alginate embedding method to fixed the polyphenol oxidase and get the I-PPO.Enzyme activity was reduced by 51.6% with phlorizin conversion rate reduced by 24.35% after four reactions.More solid structure of the immobilized enzyme need to be seeking for in order to increase the number of reactions and slow down the rate of loss of enzyme activity.