Change And Control Of Parent And Oxygenated PAHs During Processing And Storage In Three Vegetable Oils

Polycyclic aromatic hydrocarbons(PAHs)and oxygenated PAHs(OPAHs)are harmful organic compounds,because of the high lipophilic property they are commonly and abundantly occur in oils and fried foods.In this study,we assessed the levels of these compounds in vegetable oils during refining and storage.The effect of synthetic and natural antioxidants on the levels of 16 PAHs and 5 OPAHs in fried peanuts and youtiao were also measured.The effects of refining and storage on sixteen PAHs and five OPAHs concentrations in soybean and rapeseed oils were studied.Concentrations of PAHs and OPAHs were determined by gas chromatography-mass spectrometry.The levels of PAHs and OPAHs in soybean oil decreased from 48.72 and 20.04 ?g/kg to 19.71 and 2.04 ?g/kg,respectively,after refining.In rapeseed oil they decreased from 38.02 and 6.56 ?g/kg to17.25 and 2.03 ?g/kg,respectively.The most significant reduction in PAHs was attributed to neutralization(up to 54.79% of the total reduction),while the most significant reduction in OPAHs was attributed to bleaching(up to 84.83% of the total reduction).However,the concentrations of PAHs and OPAHs in both crude and refined oils increased along with the storage time.Different storage temperature and refining degree posed different influence on variation tendency.Oils stored under room temperature after refining showed the largest growth rate of both PAHs(151.51% in soybean oil)and OPAHs(429.03% in rapeseed oil)concentrations.The sum of OPAH concentrations was positively correlated with the peroxide value of oils.The effects of tert-butylhydroquinone(TBHQ)and peanut skins on the concentrations of PAHs and OPAHs in fried peanuts were investigated.Addition of TBHQ to the frying oil reduced the total PAH and total OPAH concentrations by up to 71.75% and 74.80%,respectively.After frying,average PAH and OPAH levels were respectively 22.63% and 79.22% lower in peanuts with skins versus those without skins.The concentration of benzo[a]anthracene(BaA)was significantly correlated with that of benzo[a]anthracene-7,12-dine(BaAQ)in the fried peanuts.To further evaluate the effect of antioxidant on PAHs and OPAHs in fried food,youtiao,TBHQ and three other natural antioxidants were selected,including rosemary extract,tea polyphenols and antioxidant of bamboo leaves.TBHQ and AOB with high levels(more than 120 ppm)in frying oils have significant inhibitory effect on PAHs and OPAHs in youtiao.Up to 39.26% of PAHs and 85.08% of OPAHs contents can be reduced during frying.