Study On Degradation Of Patulin In Juice By Glow Discharge Plasma

Glow discharge plasma（GDP）is a new type of electricity chemistry degradation technology that has the advantages of rapid,high efficiency and no secondary pollution,and can efficiently degrade harmful organic substances.Our previous research showed that GDP could effectively degrade patulin（PAT）in aqueous solution and apple juice.But the degradation of PAT in other juices by GDP,the effect of GDP on juice quality such as physicochemical properties,aroma components and sensory,and also the mechanism of degrades PAT by GDP are all had not been studied.Therefore,in this study,we used the grape juice,pear juice and hawthorn juice used as materials.The three juices containing PAT were treated with GDP at different voltage,time,initial concentration and catalyst conditions.Firstly,the degradation rate of PAT was taken as the index,the response surface was optimized for the optimal degradation process conditions.Secondly,under the above conditions,the effects of GDP on the physical and chemical indicators,aroma substances,sensory evaluation and cytotoxicity of three kinds of juices were analyzed and evaluated.Finally,the degradation liquid in the process of PAT degradation by GDP was determined.The degradation mechanism of pH,conductivity,H₂O₂ and·OH content was discussed.The results showed that as follows:（1）Elevated voltage and prolonged time can effectively improve the degradation rate of PAT in three kinds of juices by GDP;within a certain concentration range,the initial concentration of PAT has little effect on the degradation rate;When ferrous sulfate（FeSO₄）,Hydrogen peroxide（H₂O₂）and ascorbic acid（AA）are used as the catalyst,the degradation rate of PAT in the three juices could be effectively improved,and the degradation effect was best when H₂O₂ was used as the catalyst.（2）Response surface results showed that the order of influence of various factors on PAT degradation rate is voltage<initial concentration<time;the interaction between voltage and time has the most significant effect on degradation rate of PAT;the optimum process conditions for GDP degrades PAT in grape juice,pear juice and hawthorn juice are:voltage at560 V,time at 3 min,initial concentration of PAT at 5 mg/L.（3）The grape juice,pear juice and hawthorn juice had no significant effect on the pH,total acid,reducing sugar,viscosity,permeability and soluble solids when treated by GDP.The total phenol and total flavonoids content increased with time increasing,the turbidity of the three juices decreased with time increasing;the sensory evaluation of grape juice,pear juice and hawthorn juice did not have a significant effect within 20 min by GDP treatment;grape juice,pear and hawthorn juice after 5 min by GDP treatment significantly increased the activity of HUVE cells.Compared with grape juice and pear juice,the hawthorn juice after GDP treatment increased the viability of HUVE cells slowly.（4）According to the results of HS-SPME-GC/MS analysis,the main aroma substances in grape juice are esters and alcohol compounds.The main aroma substances in pear juice are ester compounds.The main aroma substances in hawthorn juice are alcohols.After 5 min of GDP treatment,the characteristic aroma and main aroma substances in grape juice,pear juice and hawthorn juice were increased,but the change was not significant.（5）When the solutions in which the concentration of PAT was 5 mg/L and 0 mg/L were treated by GDP.With the extension of time,the pH of the two degradation solutions were all decreased firstly and then increased;the conductivity of the two degradation solutions were all increased firstly and then decreased gradually;the concentration of H₂O₂ and·OH showed an upward trend along with the degradation time.After 3 min of GDP treatment,the pH change rate of the 5 mg/L PAT degradation solution was much higher than that of the no PAT degradation solution,and its·OH concentration was significantly lower than the·OH concentration without the PAT degradation solution;after 5 min of GDP treatment,the conductivity of the 5 mg/L PAT degradation solution was always greater than the conductivity of the no PAT degradation solution.In summary,in the process of efficiently degrading PAT in grape juice,pear juice and hawthorn juice,GDP could improve the clarity and antioxidant capacity of the three juices,could not change the basic nutrient composition,sensory evaluation and the aroma substance,could not produce toxic substances in the three juices;the main factor for degrading PAT in the GDP system is·OH.