Influencing Factors And Simultaneous Inhibition Of Acrylamide And 5-Hydroxymethylfurfural Formation In French Fries

The formation and inhibition of hazardous substances during heating food have received great attention in the food safety field.Acrylamide（AA）and5-hydroxymethylfurfural（5-HMF）,as common hazardous substances,are simultaneously formed in fried foods.Therefore,in this paper,a simultaneous determination method for the determination of AA and 5-HMF in foods was established.Then the effects of frying technology,raw material composition and acidity regulator on the formation of AA and 5-HMF in French fries were investigated.On this basis,further investigation was to explore the effect of hydrocolloids and ultrasound（US）treatment on the simultaneous inhibition of AA and 5-HMF in French fries.The main research contents and results are summarized as follows:1.A rapid and simple liquid chromatography-tandem mass spectrometry（LC-MS/MS）method was developed and validated for simultaneous determination of AA and 5-HMF in foods.Several clean-up methods based on Qu ECh ERS protocol were investigated and compared:（a）Dispersive solid-phase extraction（d-SPE）with Enhanced Matrix Removal-Lipid（EMR-Lipid）;（b）d-SPE with PSA;（c）without clean-up step;（d）clean-up with n-hexane.The results show that the EMR-Lipid was the best d-SPE sorbent for the pretreatment of Qu ECh ERS,with the highest recoveries and smallest matrix effect of AA and 5-HMF determination.Validation experiments were carried out for the method of using EMR-Lipid as a d-SPE sorbent.Excellent linearity（R²>0.999）was achieved and the limits of detection（LODs）of AA and 5-HMF were 2.5μg/kg and 12.5μg/kg,respectively.The recoveries of AA and 5-HMF levels obtained were in the range of 87.3-103.3%and 83.2-104.3%,with precision（RSDs）of 1.2-6.8%and 1.4-7.4%（n=3）,respectively.2.The effects of different frying temperature（160°C,170°C and 180°C）and frying time（1 min,3 min,5 min and 7 min）on the formation of AA,5-HMF andα-dicarbonyl compounds in French fries were investigated.The results showed that the contents of AA,5-HMF andα-dicarbonyl compounds in French fries significantly increased with the increase of frying time and temperature.Under the influence of time and temperature,there was a significant positive correlation between AA and5-HMF formation.The formation of AA and 5-HMF was significant positive correlation withα-dicarbonyl compounds,a*and oil absorption,while significantly negative correlation with L*,b*and water content.Moreover,the best sensory quality of French fries was obtained when frying 5 min at 170°C.3.The effects of the composition of potatoes on the formation of AA,5-HMF andα-dicarbonyl compounds in French fries were investigated.The results showed that the contents of sugar,asparagine,amino acid,protein and water vary greatly in different potato samples.The contents of AA and 5-HMF in 26 kinds of French fries ranged from 163.9 to 4968.5μg/kg and from 77.6 to 2500.1μg/kg,respectively.The contents of 3-DG,GO and MGO in 26 kinds of French fries were in the range of20.3-47605.1μg/kg,303.6～1841.2μg/kg,and 554.4-5202.2μg/kg,respectively.There are also great differences in the contents of AA and 5-HMF in French fries prepared by potatoes from the same origin and variety.The formation of AA,5-HMF andα-dicarbonyl compounds in French fries was significantly positively correlated with glucose and fructose but correlated not with asparagine,amino acids and protein.Moreover,5-HMF and 3-DG were also positively correlated with sucrose.The potatoes with lower contents of glucose and fructose would contribute to reducing the formation of AA and 5-HMF,and the potatoes with lower contents of sucrose would also help to reduce the content of 5-HMF in French fries.The results of PCA analysis showed that the potatoes with high glucose,fructose and water contents would lead to high contents of AA,5-HMF,3-DG,MGO and GO in French fries.4.The influence of acidity regulators on the formation of AA and 5-HMF in French fries and the underlying mechanism was evaluated.The results suggested that acid regulators（citric acid,acetic acid and sodium pyrophosphate）could inhibit AA formation,while they increased 5-HMF levels,especially for citric acid.Na₂HPO₄ and Na HCO₃ could inhibit 5-HMF formation in French fries but increased AA content.The AA level decreased and the 5-HMF level increased with decreasing p H of potato strips.Interestingly,increasing concentration of acid radical ions resulted in AA increase and 5-HMF decrease,which was opposite to the acidification effect of citric acid and acetic acid.Under the effect of acidity regulators,AA was significantly negatively correlated with 5-HMF and 3-DG and positively correlated with GO and MGO,while 5-HMF was positively correlated with 3-DG,but correlated not with GO and MGO.Moreover,acid regulators might impact AA formation by impacting the generation of MGO and GO and impact 5-HMF formation by impacting the generation of 3-DG.5.The effect of five hydrocolloids on the inhibition of AA and 5-HMF in French fries was investigated.It was found that sodium alginate（SA）had the best simultaneous inhibition effect on AA and 5-HMF in French fries,with inhibition rates of 35.3%and 26.2%,respectively.On this basis,further investigation was conducted for the effects of SA-ultrasound and SA-blanching pretreatment on the formation of AA and 5-HMF in French fries.With the pretreatments of SA-ultrasound and SA-blanching,the inhibition rates of AA were 50.6%and 56.7%and the inhibition rates of 5-HMF were 36.5%and 40.9%,respectively.Compared with the single SA pretreatment,the two combined pretreatments significantly improved the simultaneous inhibition effect of AA and 5-HMF in French fries.SA-ultrasonic pretreatment not only had a good simultaneous inhibition effect on AA and5-HMF but also maintained the color and sensory quality of French fries,which was the best choice for simultaneous inhibition of AA and 5-HMF formation in French fries.Moreover,the tendencies ofα-dicarbonyl compounds reduction were consistent with those of AA and 5-HMF.Therefore,the AA and 5-HMF might be inhibited according to reduce the formation of their intermediate productsα-dicarbonyl compounds in French fries.