Study On Efficiency Removal Of Heterocyclic Aromatic Amines From Sesame Oil

Heterocyclic aromatic amines are mainly found in heat-processed foods containing proteins,which have strong carcinogenic and mutagenic properties and pose a significant food safety risk.Currently,there is a lack of research on the risk of heterocyclic aromatic amines in edible vegetable oils,especially in the high-temperature frying process of edible oils with strong aroma(e.g.,sesame oil).Sesame oil,as a traditional frying oil in China,has become an indispensable seasoning oil in daily life because of its rich aroma,but the food safety problem of heterocyclic aromatic amines in sesame oil needs urgent attention and solution.Therefore,it is of great theoretical and practical importance to study the efficient removal of heterocyclic aromatic amines from sesame oil to reduce the food safety risk of fried fats and oils.In this paper,a liquid-liquid microextraction based on deep eutectic solvent combined with high performance liquid chromatography(HPLC)was developed for the detection of Heterocyclic aromatic amines in sesame oil,and then the effect of different types of extractants and extraction methods on the removal of Heterocyclic aromatic amines from sesame oil and the optimal extraction conditions were studied with leached sesame seed oil and sesame fragrance oil respectively,and the mechanism of heterocyclic amine removal was explored in order to effectively remove Heterocyclic aromatic amines from sesame oil while ensuring the flavor of sesame oil.Firstly,the types and contents of heterocyclic aromatic amines in commercially available sesame oil were analyzed,and the results showed that the commercially available sesame oil contained two non-polar heterocyclic aromatic amines,Harman and Norharman.Then,a simple and green liquid-liquid microextraction combined with HPLC method based on water based-deep eutectic solvent(DES)was developed for detectβ-carboline heterocyclic aromatic amines(Harman and Norharman)in sesame oil.DES composed of choline chloride and water(molar ratio 1:3)was selected as the extractant,and vortex-assisted extraction was used.The optimal extraction conditions were 0.1 g of oil,750μL of DES,1.0 m L of hexane and 5 min of extraction time.Under these conditions,the extraction yields of both Harman and Norharman were greater than 99%.The analytical method characterization test showed that Harman had good linearity in the concentration range of 10～1000 ng/m L(R~2=0.9995),the limit of detection(LOD)was 0.30 ng/m L,the recoveries were in the range of 97.14～102.44%,and the inter-day and intra-day precision were less than 3%;Norharman had good linearity in the concentration range of 10～1000ng/m L(R2=0.9995).R~2=0.9995)with good linearity in the concentration range of 0.98ng/m L for LOD and recoveries in the range of 95.19～102.03%with inter-day and intra-day precision less than 2%.The method was successfully applied to the determination of Harman and Norharman in different edible oil samples(sesame oil,concentrated rapeseed oil,peanut oil,sunflower oil),and the results were close to those obtained using cationic solid phase extraction column extraction-liquid mass detection,indicating that the method is suitable for the determination of Harman and Norharman in sesame oil and other common edible oils.Secondly,the changes of heterocyclic aromatic amines content in the sesame oil refining process(degumming,deacidification,decolorization and deodorization)were analyzed and the key process steps for heterocyclic aromatic amine removal were identified,using leached sesame oil as raw material.The results showed that the heterocyclic aromatic amines contained in the leached sesame oil were Harman and Norharman,and the content ofβ-carboline heterocyclic aromatic amines decreased significantly during the refining process,in which the content of Harman decreased from 300.95μg/kg to 0.52μg/kg,and the content of Norharman decreased from 251.39μg/kg to 0.35μg/kg,and the total content decreased from 502.34μg/kg to 0.87μg/kg.The decolorization process was a key step in the removal ofβ-carboline heterocyclic aromatic amines,and the type and amount of adsorbent affected the removal effect of hterocyclic aromatic amines in the decolorization process.For Harman and Norharman,the removal effects were in the following order:activated carbon>activated white clay>attapulgite>silica gel.In a certain range,the more adsorbent dosage,the better the removal effect.Finally,a 3%composite decolorizer(activated carbon:white clay=1:1)was selected to have the best effect on the removal of heterocyclic aromatic amines from sesame oil(heterocyclic aromatic amines were reduced to 0.80μg/kg).The acid value decreased from 1.72 mg/g to 0.28 mg/g and the peroxide value decreased from 0.037g/100g to 0.003 g/100g during the refining of sesame oil,which met the quality index of first grade refined sesame oil.Next,a green deep eutectic solvent(DES)was applied as an extractant for the removal ofβ-carboline heterocyclic aromatic amines from sesame oil(Harman and Norharman).The water based-deep eutectic solvent(WDES)consisting of choline chloride and water(molar ratio1:3)was chosen as the extractant,and stirring-assisted extraction was used.The optimum extraction conditions were extraction temperature of 40°C,stirring speed of 1300r/min,extraction time of 40 min and extractant dosage of 0.5 m L/g.Under these conditions,the removal rates of Harman and Norharman from the oil samples were 99.01%and 93.89%,respectively,and the total removal rate ofβ-carboline heterocyclic aromatic amines was96.45%.The mechanism of heterocyclic aromatic amine removal from oil samples by DES showed that the removal of Harman and Norharman from oil samples was achieved by aqueous DES mainly through hydrogen bonding interactions.The removal of heterocyclic aromatic amines from commercially available sesame flavor oils(pressed sesame oil and small mill sesame oil)by WDES(choline chloride/water)achieved a total heterocyclic aromatic amine removal rate of more than 90%without loss of the original flavor of the sesame oil.Finally,non-toxic quaternary ammonium salts were applied as extractants for the removal ofβ-carboline heterocyclic aromatic amines(Harman and Norharman)from sesame fragrance oil.Choline chloride was chosen as the extractant for solid-liquid extraction and removal by ultrasound-assisted extraction.The optimum extraction conditions were choline chloride dosage of 0.5 w/w,extraction temperature of 55℃,extraction time of 5 min and ultrasonic power of 390 w.Under these conditions,the maximum removal rates were 99.25%and 91.74%for Harman and Norharman,respectively,and the total removal rate ofβ-carboline heterocyclic aromatic amines was 95.50%.The mechanism study demonstrated the existence of hydrogen bonding interaction between choline chloride andβ-carboline heterocyclic aromatic amines,thus achieving the removal of heterocyclic aromatic amines.Choline chloride was also used to remove heterocyclic aromatic amines from commercially available sesame flavor oils(pressed sesame flavor oils and small-mill sesame flavor oils),with the removal rates of more than 90%for Harman and more than 80%for Norharman,without causing any loss of the original flavor of sesame flavor oils.