Formation And Inhibition Of 3-Chloro-1,2-Propanediol Fatty Acid Esters And Glycidyl Esters During Processing In Sunflower Oil

Sunflower oil is one of the edible oil varieties in China,which is enjoyed by consumers because of its rich nutritional value,good taste and unique flavor.Risk components such as3-Chloro-1,2-Propanediol fatty acid esters(3-MCPD esters)and glycidyl esters(GEs)may be produced in sunflower oil during the production process,while the formation rules of risk components and effective control measures have not been studied.This topic studies the effects of roasting,refining,deodorization conditions and the addition of antioxidants in the processing process of sunflower oil on 3-Chloro-1,2-Propanediol fatty acid esters,glycidyl ester and nutrients tocopherols,phytosterols and fatty acids.The main research contents and conclusions are as follows.(1)Sunflower oil was prepared by roasting and pressing and the sunflower seeds from Gansu(China),Inner Mongolia(China)and Bulgaria.The roasting temperature and time were 200,220°C and 15,20,30,and 40 min,respectively.The content of chlorine ion in sunflower seed raw material,3-Chloro-1,2-Propanediol fatty acid esters,tocopherol and the content of chlorine ion in sunflower oil,as well as glyceride composition,acid value,peroxide value and color(red value)were detected to analyze the effects of roasting conditions on the formation of 3-Chloro-1,2-Propanediol fatty acid esters and quality of sunflower oil were analyzed.The results showed that the content of3-Chloro-1,2-Propanediol fatty acid esters in sunflower oil increased with the increasing of roasting temperature and roasting time,and the content of 3-chloropropanol ester in sunflower oil from Inner Mongolia was the highest.Meanwhile,after roasting,the chloride ion content in sunflower seed from Inner Mongolia decreased the most.After roasting for different time at the same temperature,there were significant changes in the content of chloride ion and glycerides composition in the oil from pressed sunflower oil(p < 0.05).The content of tocopherol in sunflower oil was significantly affected by the roasting time.The total amount of tocopherol decreased with the increasing of roasting temperature.The acid value and color of sunflower oil increased with the increasing of roasting temperature and roasting time,while the peroxide value increased gradually with the increasing of roasting time and decreased with the increasing of roasting temperature.Considering the formation of3-Chloro-1,2-Propanediol fatty acid esters and quality indexes,the sunflower oil with higher quality could be obtained when roasting temperature was lower than 200°C and roasting time was less than 40 min.(2)The effects of refining processes on the physical and chemical indexes,oxidation indexes,chemical composition and thermally harmful components of3-Chloro-1,2-Propanediol fatty acid esters and glycidyl ester of sunflower oil were investigated.The results showed that,compared with crude sunflower oil,the physicochemical index acid value,peroxide value and color of the refined sunflower oil decreased,and the saponification value did not change significantly.There was no significant change in the oxidation index anisidine value(p-AV)and TBA,while the conjugated diene and conjugated triene values increased,and the oxidation induction time(OIT)was shortened,indicating that the oxidative stability of sunflower oil decreased during the refining process.The chemical composition such as fatty acid composition and glycerides composition did not change significantly during the refining process,while phytosterols and tocopherols were lost during the refining process,and the loss ratio were19.16% and 12.21%,respectively.Phospholipids as an important indicator to be removed in the refining process,the removal ratio reached 99.44%.A small amount of3-Chloro-1,2-Propanediol fatty acid esters and glycidyl ester were detected in crude sunflower oil,and the content increased sharply in the deodorization stage of the refining process.It can be seen that the deodorization temperature and time have a significant impact on the formation of 3-Chloro-1,2-Propanediol fatty acid esters and glycidyl ester.(3)Sunflower oil was deodorized at different temperatures(210,230,250 and 270°C)and different times(60,80,100 and 120 min).Trans fatty acids,3-Chloro-1,2-Propanediol fatty acid esters,glycidyl esters,tocopherols,phytosterols were analyzed to explore the effect of deodorization conditions on the safety and nutritional quality of sunflower oil.The results showed that the contents of trans fatty acids,3-Chloro-1,2-Propanediol fatty acid esters and glycidyl esters were positively correlated with deodorization temperature and deodorization time,and the contents gradually increased with the increasing of deodorization temperature and deodorization time.Under the extreme deodorization conditions(270°C,120 min),the contents of trans fatty acids,3-Chloro-1,2-Propanediol fatty acid esters and glycidyl esters reached the maximum value,which were 0.698%,11.18 mg/kg and 18.42mg/kg,respectively.Tocopherols and phytosterols suffered severe losses during the deodorization process,and their retention ratios decreased from 96.29% to 44.83% and92.29% to 66.5%,respectively.The saturated fatty acid content in the fatty acid composition increased,while the monounsaturated fatty acid and polyunsaturated fatty acid content decreased after deodorization.(4)Six kinds of antioxidants,BHA,BHT,rosemary extract,tea polyphenols,sesamol and TBHQ were added to undeodorized sunflower oil,and the supplemental levels of each antioxidant were set to 0.01%,0.02%,0.03%,0.04% and 0.05%,respectively.The contents of 3-Chloro-1,2-Propanediol fatty acid esters and glycidyl ester,oil quality(free fatty acid,peroxide value,anisidine value,conjugated diene,conjugated triene and tocopherol)and antioxidant capacity of sunflower oil during deodorization were analyzed.The results showed that the addition of BHA,BHT,rosemary extract,tea polyphenols,sesamol and TBHQ to sunflower oil could inhibit the formation of 3-Chloro-1,2-Propanediol fatty acid esters and glycidyl ester during the deodorization process,and the inhibitory efficacy was gradually increased with the increasing of antioxidant level.The inhibition ratios of these six antioxidants on 3-Chloro-1,2-Propanediol fatty acid esters were 12.14%～20.52%,10.12%～19.08%,26.88%～46.24%,14.16%～28.61%,12.72%～23.99%,36.99%～56.36%,the inhibition ratios of glycidyl esters were 6.58%～24.34%,2.63%～15.79%,16.45%～38.16%,9.87%～29.61%,13.16%～30.92%,18.42%～39.47%,respectively.At the same time,these six antioxidants also played a good role in enhancing the antioxidant capacity of oil and improving the quality of oil.