Investigations Into The Inhibitory Mechanism Of Plant Polyphenol Against 5-(Hydroxymethyl)-2-Furaldehyde Formation During Thermal Starch Processing

5-?hydroxymethyl?-2-furaldehyde?HMF?is a kind of potential carcinogens,mainly produced in the starch-rich food products during the thermal treatment.Therefore,it is significant to study on the formation mechanism of HMF,find safe and effective inhibitory methods,reducing the HMF content during the food thermal treatment.In this topic study,we chose starch thermal treatment system to study the inhibitory effect and mechanism of quercetin or epicatechin on HMF formation.First of all,ultra-performance liquid chromatography coupled with high-resolution tandem mass spectrometry?UPLC-HRMS/MS?was employed to have quantitative analysis on HMF formation in pure wheat flour bread,wheat flour bread,pure wheat flour biscuit,and wheat flour biscuit.The results indicated that when wheat flour bread was baked with the added quercetin concentration of 1.90 mg/g in the dough at 160 ? for 30 min,the quercetin reduces the amount of HMF by 86.0%.When wheat flour biscuits are baked with 0.1% of epicatechin in the dough at 180 ? for 30 min,the epicatechin reduces the amount of HMF formed by 80.6%.Secondly,isotopomer analysis in the 1:1 ¹²C₆:¹³C₆ glucose+quercetin and 1:1 ¹²C₆:¹³C₆ glucose+epicatechin model systems indicated that the HMF or HMF precursors adducts of quercetin/epicatechin were detected,with the trapping of these compounds by quercetin/epicatechin to form corresponding adducts with HMF or its precursors in 1:1,1:2,1:3,and 1:4 ratios?where “1” refers to quercetin or epicatechin in all cases?.Isotopomer analysis in the 1:1 [D₁₂]-glucose + [3,3?,4?,5,7-?OD?₅]-quercetin indicated that intermolecular dehydration occurs between the hydroxyl hydrogen atoms of quercetin and the hydroxyl group of HMF and its precursors,thereby inhibiting HMF formation.Epicatechin has the similar structure with quercetin,the inhibitory mechanism can be analogized into epicatechin inhibitory mechanism on HMF formation.Finally,UPLC–HRMS/MS analysis further elucidated the structures of these adducts,and confirmed that the C–O bonds were formed between quercetin/epicatechin and HMF and HMF precorsors,thus further verified the proposed inhibitory mechanism.