| Frying is a common method of food processing,which not only produces enticing flavor and good texture but also helps the nutrients in food to be better digested and absorbed by the body.However,high-temperature heating above 120℃will form some harmful chemicals such as acrylamide,furan,and benzopyrene in the food.Research at home and abroad has shown that acrylamide has neurotoxicity,reproductive toxicity,immunotoxicity and potential carcinogenicity.In order to reduce the harm of acrylamide in fried foods to human health,the study of formation dynamics and mitigation strategies of acrylamide in high-temperature fried foods is of great significance.Therefore,this thesis developed a rapid method for determination of acrylamide in fried foods,studied the dynamics of acrylamide formation in the Maillard model system,and further developed the factors affecting the formation of acrylamide in fried sweet potato sticks,proposing reduction and mitigation strategies.The main research contents are as follows:1.Based on the principle of the addition reaction of reduced glutathione and acrylamide,an electrochemical biosensor for rapid determination of acrylamide in food was established by using acetylene black,chitosan and Fe3O4 nanoparticles as composite modification materials,and immobilizing reduced glutathione on the surface of glassy carbon electrode.The electrochemical properties of reduced glutathione and the effect of the addition reaction between the reduced glutathione and acrylamide on oxidation peak current of the reduced glutathione were investigated.The modified electrode was characterized by cyclic voltammetry and electrochemical impedance spectroscopy and the experimental conditions were optimized,the results as follows:the amount of modified liquid was 5μL,the ratio of the modified liquid was 1:1,the electrolyte solution p H was3.5 and the GSH loading amount was 30μg.At these conditions,the addition rate of reduced glutathione to acrylamide increased linearly with the concentration of acrylamide from 1.0×10?8 mol/L to 10.0×10?8 mol/L（y=0.1842x+17.021）,the correlation coefficient R2 was as 0.9960,the detection limit was 3.0×10?10 mol/L（S/N=3）.The developed electrochemical biosensor exhibited good anti-interference,stability and reproducibility.In the actual sample detection,the recovery rate was between 91.00%and 96.40%.The results were verified by ultra-high-performance liquid chromatography-tandem mass spectrometry,indicating that the method was feasible to rapidly determine the acrylamide content in food.2.Based on the composition of sweet potatoes and the main pathway for acrylamide formation,an Asn/Glu food simulation system was established,the influence of reaction conditions on acrylamide formation was explored and the acrylamide formation dynamics model was established by data fitting.When the reaction temperatures were 120℃,140℃,160℃and 180℃,the relationship between the acrylamide formation in the Asn/Glu food simulation system and the reaction time was linear,following the zero-order dynamics equation.At a reaction temperature of 200℃,it conformed to the Logistpk dynamics equation.When the p H values of reaction system were 5.0,6.0,7.0,7.5,8.0,8.5 and 9.0,the relationship between the acrylamide formation and the p H of the Asn/Glu food simulation system conformed to the Logistpk dynamics equation.When the ratios of Asn to Glu were 3:1,2:1,1:1,1:2 and 1:3,the relationship between acrylamide formation and Asn/Glu ratio conformed to the Exreme dynamics equation.Through the comparison of actual and predicted values as well as calculation of model evaluation parameters,it was found that the model had a high degree of fit with the experimental data and could be used as a predictive model for acrylamide formation.3.Studied the process conditions and the effects of adding different substances on the generation of acrylamide in fried sweet potato strips and proposed mitigation strategies.The effects of frying time and temperature on the production of acrylamide in fried sweet potato strips was studied,and it was found that both an increase in frying temperature and prolongation of frying time promoted the generation of acrylamide and had a significant impact.The effects of sunflower oil,olive oil,soybean oil,peanut oil（rich in unsaturated fatty acids）and lard（rich in saturated fatty acids）on the generation of acrylamide were studied,and it was found that the least amount of acrylamide was produced in peanut oil,while the most was produced in lard during the frying process.The effects of different types and concentrations of amino acids on the generation of acrylamide in fried sweet potato strips were studied,and it was found that cysteine,glycine,lysine and phenylalanine all had inhibitory effects on acrylamide production and when the cysteine concentration was 0.30%,the inhibition effect on acrylamide was the best,the maximum inhibition rate was 57.93%.The effects of water-soluble vitamins B1,B3,B6,and C on the generation of acrylamide were studied,and it was found that vitamin B3 had the best inhibitory effect,followed by vitamin C.The effects of different concentrations of asparaginase on the generation of acrylamide were studied,and it was found that the most suitable concentration of asparaginase was 0.10%.The effects of different organic acids and their concentrations on the generation of acrylamide were also investigated,and it was found that when anhydrous citric acid,glacial acetic acid and L-lactic acid were the optimal concentrations,the minimum acrylamide formation was 176.82±7.11μg/kg,220.31±9.72μg/kg and 251.76±7.22μg/kg,respectively.The effects of different natural antioxidants on the generation of acrylamide in fried sweet potato strips were studied,and it was found that the inhibitory rate of acrylamide varied from highest to lowest in the following order:puerarin（66.75%）>quercetin（51.13%）>luteolin（45.50%）>genistein（39.21%）.By optimizing the frying process conditions and adding different substances,the amount of acrylamide produced was effectively reduced,thereby improving the safety of the food.4.The effect of ultrasonic pre-treatment on the generation of acrylamide in fried sweet potato strips was studied.In the experiment,ultrasonic pre-treatment was applied to sweet potato strips to increase the leaching rate of reducing sugar and asparagine,reduce the precursor substances of acrylamide and thereby obtain fried sweet potato strips with lower acrylamide content.Based on single-factor experiments,ultrasonic temperature,ultrasonic time and ultrasonic power were selected as factors for response surface analysis.The inhibition rate of acrylamide was used as the evaluation index to determine the optimal ultrasonic treatment conditions:ultrasonic temperature of 51.92℃,ultrasonic time of 28.15 min and ultrasonic power of 79.80 W.After comprehensive consideration of practical production,the optimal treatment conditions were adjusted to an ultrasonic temperature of 52℃,an ultrasonic time of 28 min and an ultrasonic power of 80 W.At this point,the generation of acrylamide was reduced by 69.19%.The close proximity of the actual values and predicted values indicated that the model was reliable. |
