Studies On The Formation,Inhibition And In Vitro Digestion Of Different Bound States Of Heterocyclic Amines In Roast Beef Patties

Heterocyclic amines(HAs)are carcinogenic and mutagenic polycyclic aromatic compounds that are generated via glucose,creatine,and amino acids during the processing of muscle-rich materials at high temperatures.Because of the high protein content in meat products,HAs may exist in the protein-bound states.However,the current literatures on HAs were all based on the free states.Therefore,the roast beef patties were used as objects in this thesis,and the qualitative and quantitative method for 17 HAs by UPLC-MS/MS in combination with PCA was developed.In this thesis,the formation of HAs in different bound states(free and bound states)and the effects of spices(chili,Sichuan and black pepper)and their characteristic amide compounds(capsaicin,sanshoamide and piperine)on free and bound HAs were investigated.At the same time,the in vitro digestion model was further used to study the digestive regularities of HAs,which were expected to provide experimental basis for the biotoxicity evaluation of HAs.The effects of different roasting temperatures(150°C,175°C,200°C,225°C and 250°C)on the contents of HAs were studied.The results showed that the higher temperatures the more kinds of free HAs(up to 10)and the higher contents(up to 37.32 ± 1.26 ng/g).Although the fewer species of bound HAs(only 6)at low temperatures were generated,the higher contents(2579.91 ± 68.20 ng/g)were generated and significantly(p<0.05)higher than those of free HAs,and reached ?g level.MeA?C,A?C,and Phe-P-1 existed only in bound states;IQx existed only in free state;PhIP,DMIP,1,5,6-TMIP,Me IQ,MeIQx,4,8-DiMeIQx,Norharman and Harman existed in two states.The effects of chili,Sichuan and black pepper and their characteristic amides such as capsaicin,sanshoamide and piperine on the different states of HAs in the roast beef patties were also investigated.The results showed that the three spices had significant(p<0.05)inhibitory effects on free DMIP,PhIP,Me IQx and 4,8-DiMeIQx,and the inhibition rates were between 16% and 100%,and the inhibition rates of total free HAs were between 15% and 51%.For the bound HAs,except for the significant(p<0.05)promotion effects of chili pepper on IQ,IQ [4,5-b] and MeIQx,the other experimental groups had different degrees of inhibition,and the inhibition rates were between 8% and 100%,and the inhibition rates of total bound HAs were between 23% and 60%.The inhibitory effects of amide compounds on free DMIP,Ph IP,MeIQx,4,8-DiMeIQx,Harman,and bound MeIQ,4,8-DiMe IQx,Harman,Norharman,MeA?C,and A?C were basically consistent with the effects of spices on them,indicating that the inhibitory effects of spices on them may be related to the amide compounds.The in vitro digestion results showed that the contents of HAs increased significantly(p<0.05)with the increasing temperatures,with a maximum of 79.80 ± 3.02 ng/g.Although the total contents of ?-carbolines before digestion reached ?g level,the contents after digestion were only between 8.18 and 24.82 ng/g,indicating that only some of the bound ?-carbolines were released.Beef patties added with spices after in vitro digestion,the results showed that the three spices could significantly reduce the contents of MeIQ,Me IQx,7,8-DiMeIQx,MeA?C,A?C,Norharman,Harman and the total HAs compared with the control group,and the total content of HAs in the group of 0.5% chili pepper was the lowest,indicating that mild spicy could effectively reduce the bio-exposure level of HAs in roast beef patties.Beef patties added with amide compounds after in vitro digestion,the results showed that the the three amide compounds could significantly reduce the contents of the most of HAs(except for capsaicin on A?C and MeA?C)and the total HAs compared with the control group,and the reduction rates were obviously better than that of spices,further demonstrating that the inhibitory effects of spices on HAs were related to the amide compounds.Therefore,the addition of appropriate spices during the processing of meat products and the promotion of dissolution of amide compounds(such as cooking wine)could effectively inhibit the formation of HAs.