| Apple is the main fruit in the world and China is the first country in the production and export of apple and apple products.The reason that limitting the export of apple juice concentrate is patulin exceeded.Patulin was defined as a class III carcinogen by International Agency for Research on Cancer which mainly produced by the expansion of Penicillium secondary metabolites,with the effect of carcinogenic,teratogenic,neurotoxic and genotoxic.The rate of patulin contamination is high in apple juice,which not only seriously threatens the health of consumers but also results in huge economic losses to the processor.Consequently,the research in detoxification or reduction of patulin in apple juice becomes the focus in the world.In this thesis,an UV irradiation technology was used to eliminate the PAT in apple juice.In addition,UV detoxification technology was optimized by explore impact factors of the UV detoxification efficiency.Meanwhile,the quality and safety of apple juice were investigated and the cell toxicity testing was used to evaluate the edible safety of apple juice after detoxification.The detailed results are as follows:1)The main factors affecting the detoxification efficiency of PAT in apple juice are UV wavelength,the content of soluble solids,irradiation time,irradiation intensity,the initial concentration of patulin,material depth and whether stirring.The results are as follows: The results showed that the degradation of patulin was significant at 254 nm.Both of the decrease of soluble solid content and the increase of initial concentration of patulin could attribute to the degradation rate of patulin increased first and then decreased.The degradation rate of patulin increased significantly with the prolonging of irradiation time and the increase of irradiation intensity while the degradation rate was slightly increased by stirring.However,the degradation rate decreased with the increase of material depth.The degradation rate of patulin increased significantly with the prolonging of irradiation time and the increase of irradiation intensity while the degradation rate was slightly increased by stirring.However,the degradation rate decreased with the increase of material depth.The degradation rate was slightly increased by stirring.2)At the room temperature,the order of main influencing factors was irradiation intensity>irradiation time>initial concentration of patulin.The response surface methodologywere employed in this study to optimize the best condition of detoxification.The optimal results were as follows: the UV lamps(power 36W)wavelength 254 nm,irradiation intensity5.00 mW/cm2,and irradiation time 17.5 min.Under the optimal detoxification conditions,PAT in apple juice was decreased from 241.51±2.52 μg/L to 9.80±0.52 μg/L.The degradation rate of patulin is 95.93%.The residue of PAT in apple juice was far less than 50 μg/L,a limit level set by China.3)In this study,UV radiation had no significant effect on density,turbidity,pH,soluble solids content,total acidity and reducing sugar content(P>0.05),however,the transmittance and color value of apple juice was improved effectively.After 15 min of UV irradiation,the transmittance decreased from 95.4±0.4% to 96.2±0.5%(P<0.05),and the color value decreased from 36.7±0.7% to 42.4±0.2%(P<0.05).After UV irradiation,vitamin C content of apple juice decreased from 14.53±0.23 mg/100 m L to 13.00±0.14 mg/100 mL,reduced by13.46±1.52%.The loss rate is in the acceptable range.4)The safety of apple juice was evaluated after UV irradiation by HepG2 cell cytotoxicity test.After 15 min of UV irradiation,Compared with the positive control,there was no significant in The cell viability of HepG2 cell treated with apple juice containing PAT extract and the HepG2 cell viability. |
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