The Effect Of Heat Treatment On The Formation Of Benzo(a)pyrene In Edible Oil

Benzo(a)pyrene(BaP)is a kind of polycyclic aromatic hydrocarbons(PAHs)with strong carcinogenic effect.It not only has strong lipophilicity,but also is stable and difficult to degrade.The sources of BaP in oils include endogenous generation in addition to exogenous pollution,endogenous BaP can access to the digestive system to endanger human health directly.Therefore,it is urgent to understand the formation mechanism of BaP and inhibit its formation from the source at high temperature.At present,there were few reports on the formation of BaP in oil at high temperature,and there was no report on the inhibition of BaP.This study first structured research system of heat treatment of oil based on three nutrients,a simple lard was took for research object,different categories amino acids and carbohydrate were added to study their effect on the production of BaP,that could further confirm whether they could promote the formation of endogenous BaP,and then screened the samples which generated the largest amount of endogenous BaP to study the formation mechanism.Compounds of sample and blank group were mensurated by GC-MS during heating,and then explored the related substrates in synthesis theory of BaP,these compounds were added to lard to verify the possibility of promoting the formation of endogenous BaP,the generation mechanism of endogenous BaP was elucidate.Lastly,quercetin and ?-tocopherol were added to sample to explore whether they can inhibit the production of endogenous BaP,the sample was selectd to study inhibition mechanism which was the most effective one on inhibiting the produce of endogenous BaP,GC-MS was used to determine whether the compounds was significantly reduced which promote the produce of endogenous BaP,and then the mechanism of inhibiting the production of BaP by two kinds of active substances was clear.In addition,BaP-d12 was introduced to ensure accuracy and reliability of the experimental results.These results were obtained as follow:(1)The yield of BaP of blank lard was up to 2.11?g/kg after being heated for 10 hours under 200?.The production of BaP in oil increased significantly after adding 20 natural amino acids and 7 kinds of common carbohydrate.The overall trend of increase was:polar amino acids>nonpolar amino acids,basic amino acids>acidic amino acids,monosaccharides>two sugars and aldose>ketosugar.This showed that the r-groups of side chain of amino acid are polar or contain amino and imino groups,the carbohydrate which are simpler and contain aldehyde group were easier to promote the formation of BaP in the process of heating,because they could produce more aldehydes during heating.Most of BaP in oil was produced which was added amino acids,and minimum generation of BaP in oil was added tyrosine,The contents of BaP were 5.22 and 2.24?g/kg respectively.The oil added glucose and sucrose produced the highest and lowest amount of BaP,and they were 3.20 and 2.43?g/kg,respectively.The produced of BaP in oil which was being added amino acids and carbohydrate at once was more than adding respectively.At the same time,The highest amount of BaP was produced by adding glucose and arginine at once,while the addition of sucrose and lysine was the least,The contents of BaP were 6.60 and 3.31?g/kg,respectively.(2)Adding glucose and arginine sample was selected to explore the generation mechanism of BaP which produced the largest amount of BaP.The sample and blank group were detected 22 kinds of compounds by GC-MS,the content of linoleic acid were significantly decreased of the sample compared with blank group,hexanal,heptanal and nonanal,eleven aldehydes and twelve aldehyde were increased significantly,and the increasing trend agreement with the rising trend of BaP.Therefore,linoleic acid,glucose and arginine could promote the formation of 5 kinds of aldehydes,the 5 kinds of aldehydes were the important substrates of endogenous BaP production.When the oil was being added glucose and arginine could promote linoleic acid cracking and accelerate the rise rate of aldehydes.The production of BaP in oil was increased by adding different concentrations of hexanal,heptanal,nonanal,eleven aldehydes and twelve aldehydes,and they showed dose-dependent.When the additive amounts were 25 g/kg,the productions of BaP increased by 102.37%,145.02%,167.77%,127.49%and 85.78%,respectively.Therefore,aldehydes were important intermediate products for BaP.In addition,it can be inferred that the increasing trend of BaP with the content of aldehydes.(3)It could inhibit the generation of BaP when the oil was added a certain concentration of quercetin and a-tocopherol.When the addition of quercetin was 400 and 600 mg/kg,?-tocopherol was 400,600 and 800 mg/kg had significant inhibitory effect on generating BaP.The inhibition effect was the best when the oil was being added 200 mg/kg of quercetin and ?-tocopherol at once,and the production of BaP was reduced by 25.45%.The degradation rate of linoleic acid in oil was decreased after adding quercetin and ?-tocopherol by GC-MS,and the formation of hexanal,heptanal,nonanal,eleven aldehydes and twelve aldehydes were also reduced significantly.Therefore,quercetin and ?-tocopherol inhibited the generation of aldehydes,which lead to reduce or slow down the formation of BaP.