Effects Of Phlorizin On Inhibition Of 5-HMF In Heated Food

In this paper,the method of detection of 5-hydroxymethylfurfural(5-HMF)in heattreated fried dough and milk were optimized.The concentrations of 5-HMF in fried dough and milk under different heat treatments were accurately determined.The changes of 5HMF content in fried dough and milk after adding phloridin were analyzed.Based on the research,it was expected to improve the determination method of 5-HMF in fried dough and heat-treated milk,and the feasibility of phlorizin in fried dough and heat-treated milk food will be further explored.The main research contents and results are as follows:(1)Optimization of 5-HMF ultrasonic extraction method in fried dough and verification of RP-HPLC determination method.The ultrasonic extraction methods were screened by three different pretreatment methods(degreased,deproteinized,degreasing and deproteinized)and different extraction solvent(water,methanol and ethyl acetate).The precision and recovery rate of the RP-HPLC determination method were verifi ed.At the same time,the ultrasonic conditions(A:material-to-liquid ratio,B:ultrasonic time and C:ultrasonic power)were optimized.The results showed that as the solvent was water,the 5-HMF detection peak separation effect was the most optimization when the sample was defatted and deproteinized.The precision of the equipment was good(RSD<2%),and the recovery rate was greater than 90%.The three conditions in the orthogonal test of ultrasonic extraction of 5-HMF had a significant effect on the measured value of 5-HMF(P<0.05),and the order of significance was A>B>C.The ideal conditions for extraction of 5-HMF were:the material-liquid ratio was 0.05:1(g/mL),the ultrasonic time was 10 min,the ultrasonic power was 225 W,and the best predicted 5-HMF content was 0.037mg/g while the verified content of 5-HMF was 0.036 mg/g.Conclusions:The pretreatment method of fried dough is optimized,and an efficient and accurate RP-HPLC method for 5-HMF in fried dough is obtained.(2)The effect of phlorizin on the 5-HMF in fried dough.The dough was fried by different temperatures(140,160,180 and 200?),different times(0.5,1,2 and 3 min)and different oil using number of times(1,2,3 and 4).The contend of 5-HMF was detected by RP-HPLC method,and the change of 5-HMF content of dough after adding phlorizin was analyzed.The results showed that the content of 5-HMF in the samples increased significantly with the increase of temperature(P<0.05).The content of 5-HMF in the samples with phlorizin decreased by 48.85%-58.01%.The content of 5-HMF in the sample increased significantly(P<0.05)with the extension of fiying time,the content of 5-HMF in the sample added with phlorizin decreased by 38.85%-59.78%.As the number of repeated heat-treatment increased,the content of 5-HMF in the sample significant increased(P<0.05).After adding phlorizin to the sample,the content of 5-HMF decreased by 43.43%-67.48%.Conclusions:the 5-HMF content in fried dough is positively correlated with temperature,time,and oil repeated heat-treatment times(P<0.05),and the addition of phlorizin can significantly reduce the production of 5-HMF during dough frying.(3)Optimization of the pretreatment method for the determination of 5-HMF in heattreated milk and the verification of the RP-HPLC determination method.Four different deproteinization methods of milk(trichloroacetic acid(TCA)method,glacial acetic acid method,acetonitrile method and Ministry of Agriculture standard method)were compared and screened.At the same time,the precision and recovery rate of the RPHPLC determination method were verified.The results showed that the 5-HMF concentration in the samples pretreated by the TCA method,acetonitrile method,glacial acetic acid method and the Ministry of Agriculture standard method were 1.36,0.71,0.67 and 0.57 ?g/mL,respectively.The shortest treatment time of TCA method was 20 min,and the minimum amount of reagent for TCA method was 1 mL when the peak separate on effect of TCA method was the most ideal.The recovery rate of 5-HMF by TAC method was between 84.71%and 101.39%,the limit of detection(LOD)and the limit of quantification(LOQ)were 0.0375 mg/L and 0.0659 mg/L,respectively.Conclusions:The TAC method is more environmentally friendly and easy to operate.The RP-HPLC method is accurate and stable,and it can be applied to determinated the content of 5-HMF in heat-treated milk.(4)The effect of phlorizin on the 5-HMF in milk.The milk was heat-treated by different temperatures(60,70,80,90,100,110 and 120?)and different heat-treated times(10,20,30,40,50 and 60 min),then the concentration of 5-HMF was deteminited by RP-HPLC method.Milk was high heat-treated after adding phlorizin,and its 5-HMF content was detected.The FAST index was calculated by fluorescence intensity,and the color,smell and taste of the high heat-treated milk containing phlorizin were measured by the color difference meter,electronic nose and electronic tongue.The results showed that the content of 5-HMF in milk increased significantly with the increase of temperature(P<0.05).The 5-HMF content reached the maximum at 90? for 40 min,and the content of 5-HMF showed not significantly change(P>0.05)when the heating time over 50 min.When the phlorizin concentration of milk was 50 mg/L,the level of 5-HMF,IAMP and FAST index were decreased while L*and ?E were increased,and there was no change on smell and taste.Conclusions:The content of 5-HMF in milk is positively correlated with time going and temperature increasing(P<0.05).The addition of phlorizin has inhibitory effect on the production of 5-HMF from Maillard reaction in heat-treated milk.The color of the milk is improved,and there are no significantly changes on the flavor of the milk.