| Phthalatic acid esters(PAEs) are a group of widely existed compounds that can be appeared in the production of edible vegetable oil, and owing to their lipophilic property, the final oil products are easily contaminated by these kinds of chemical contaminations. PAEs are endocrine disruptors that may damage human reproductive system, liver and nervous system, thus issues of the existence of PAEs in edible oils are received highly concern and close attention from all over the world. The purpose of this study was to investigate the content of PAEs in various oilseeds, meals and cakes, refined oils in every process as well as processing agents, so that to study the PAEs change rules in different procedures of oil production and demonstrated that adsorbent was the most contributing source in the oil refining process. Meanwhile, the effects of plastic impurities on PAEs pollution and the influences of regular refining means on highly contaminated oils were investigated. Finally, the effects of integrated refining process on the removal of PAEs were studied and to help further provide technique support to the safe production of edible vegetable oil.Through determined PAEs contents in peanut skin and embryo from two samples and soybean skin and embryo from two samples,the distribution of PAEs in oilseeds was investigated. The results showed that there is nonuniform distribution of PAEs in oilseeds, which PAEs contents in soybean embryo was higher in soybean skin;the contents of PAEs in soybean embryo and skin, samples from Yangguang oil plant, were 17004.6 μg/kg, 460.2 μg/kg, for samples from Jiayue oil plant, the content of DBP were 256.1 μg/kg, 156.9 μg/kg; PAEs contents in peanut skin were higher than that in peanut embryo, and wizened seeds were heavily polluted than the plump ones. The contents of PAEs in two samples of peanut skin were 6096.3 μg/kg, 9194.9 μg/kg, for peanut embryo were 696.0 μg/kg, 736.0 μg/kg, respectively. DEHP levels in skin and embryo of plump peanuts were 5.44 mg/kg and 0.51 mg/kg, respectively. The counterparts of that in wizened peanuts were 8.35 mg/kg and 0.53 mg/kg, respectively.The rapeseed, maize germ, cakes meals were determined, results showed that PAEs contents in meals were higher than that in cakes. The PAEs contents in Rapeseed meal was 704.1 μg/kg,higher than 430.0 μg/kg in rapeseed;that contents in maize germ meal was 80.44 mg/kg,also higher than 57.69 mg/kg in maize germ,respectively。The contents of PAEs in every process and processing agents were determined,and then, this study investigated the effects of different refining process as well as processing agents. The results showed that decoloration had the most harmful effect on oil PAEs contents and can make it raise,whereas deodorization had a remarkable removal efficacy on PAEs. Degumming and alkali refining had a certain removal effects on oil PAEs. For this reason, PAEs contents in processing agents were investigated and found that they are significant source of PAEs contamination. DEHP amounts in four clays were ranged from 2.166~9.634 mg/kg, DBP and DEHP amounts in sodium hydroxide were 12.535 mg/kg and 3.13 mg/kg. DEHP content in phosphoric acid was 8.243 mg/kg.The effects of content of plastic impurities on PAEs in crude oils obtained from oilseeds by solvent extraction and pressure were studied. The results showed that crude oils extracted by organic solvent were highly contaminated;the contents of PAEs in crude oils extracted from pure peanut,rapeseed and maize germ were 1.886 mg/kg、0.401 mg/kg、1.335 mg/kg,respectively;for contained 0.5% of plastic woven bag impurities(PP)were 2.212 mg/kg、0.413 mg/kg、23.776 mg/kg;and for contained 0.5% of plastic bag impurities(PE)were 2.271 mg/kg、2.613 mg/kg、31.170 mg/kg. They also showed that plastic bag was worse than plastic woven bag. In pressured crude oils, except for the effect of plastic impurities, the types of oilseeds also had a influence on PAEs concentration. For example, PAEs contents in pressured peanut and rapeseed were increased, whereas that in maize germ was decreased.The effects of adsorption and deodorization process on highly contaminated oils were investigated and the optimum conditions were selected. The results showed that under the best condition of H-2 activated carbon, adsorption time of 35 min and adsorption temperature of 110 0C, the content of DMP, DEP, DBP, BBP and DEHP in corn germ crude oils decreased form 8.459 mg/kg, 8.522 mg/kg, 8.866 mg/kg, 7.390 mg/kg, 9.9528 mg/kg to 3.224 mg/kg, 4.332 mg/kg, 7.424 mg/kg, 5.708 mg/kg, 8.011 mg/kg, and rates were 61.17%, 49.14%, 16.30%, 22.67%, 19.52%, respectively; the counterparts in pressured rapeseed oils decreased from 7.031 mg/kg, 10.134 mg/kg, 5.683 mg/kg, 7.916 mg/kg, 12.4398 mg/kg to 3.958 mg/kg, 6.977 mg/kg, 5.042 mg/kg, 6.854 mg/kg, 11.450 mg/kg, and rates were 43.72%, 31.15%, 11.28%, 13.41%, 11.28%, respectively. Under the best experimental conditions(the temperature was 260 0C, the time was 140 min), the concentrations of DBP and DEHP in corn germ crude oils decreased from 8.866 mg/kg, 9.953 mg/kg to 0.350 mg/kg, 4.146 mg/kg; the counterparts in pressured rapeseed oils decreased from 5.683 mg/kg, 12.440 mg/kg to 0.511 mg/kg, 4.294 mg/kg. Only apply adsorption or deodorization process can’t decrease contents of PAEs to the limits of the national standard about food and food additives.The effects of integrated refining process on highly contaminated oils and normally contaminated oils were further investigated The results shows that, for extremely contaminated oils,the removal rates of DBP was more than 74%,DEHP was more than53%,however,they were unable to reach the national limits;the concentrations of DBP in normally contaminated corn germ crude oils and normally contaminated pressured rapeseed oils were 0.106 mg/kg, 0.271 mg/kg, and the removal rates were 94.23%,85.13%, respectively. The counterparts,the concentrations of DEHP were 0.582 mg/kg, 1.185 mg/kg, the removal rates of DEHP were 71.23%,49.755, which had reached the national limits about food and food additives, DBP≤0.3mg/kg,DEHP≤1.5mg/kg. |
PDF Full Text Request