Yoon Y, Choe E
Department of Food and Nutrition, Inha University, Incheon 402-751, Korea.
J Food Sci. 2007 Aug;72(6):C317-23. doi: 10.1111/j.1750-3841.2007.00426.x.
Oxidation of corn oil during frying of soy-flour-added dough was studied. Flour dough containing soy flour at 0%, 10%, 20%, and 30% was fried in corn oil at 180 degrees C for 2.5 min, and a total of 60 fryings were performed every 30 min. The oxidation of oil was determined by contents of free fatty acids (FFA), conjugated dienoic acids (CDA), polar compounds, and p-anisidine values (PAV). Tocopherols and phospholipids (PLs) in the oil were determined by HPLC. Tocopherols were present in corn oil at 1000 ppm before frying and increased after the first frying of dough containing soy flour due to tocopherol transfer from soy-flour-added dough to the oil during frying. However, as the oil repeated frying, tocopherol contents decreased and its degradation rate was higher in the oil that fried soy-flour-added dough than in the oil that fried the dough without soy flour. PL was not detected in corn oil before and after frying. As the oil repeated frying, FFA, CDA, and polar compounds contents, and PAV of frying oil increased due to the oil oxidation. The values were higher in the oil which fried soy-flour-added dough than in the oil fried the dough without soy flour, indicating the acceleration of oil oxidation by soy flour added to dough. Increase in the oil oxidation by soy flour added to the dough was highly correlated with fast decomposition of tocopherol in the oil.
研究了在添加大豆粉的面团油炸过程中玉米油的氧化情况。将分别含有0%、10%、20%和30%大豆粉的面粉面团在180摄氏度的玉米油中油炸2.5分钟，每30分钟共进行60次油炸。通过游离脂肪酸（FFA）、共轭二烯酸（CDA）、极性化合物和对茴香胺值（PAV）的含量来测定油的氧化情况。通过高效液相色谱法测定油中的生育酚和磷脂（PLs）。油炸前玉米油中生育酚的含量为1000 ppm，在首次油炸添加大豆粉的面团后，由于油炸过程中生育酚从添加大豆粉的面团转移到油中，生育酚含量增加。然而，随着油的反复油炸，生育酚含量下降，并且在油炸添加大豆粉面团的油中其降解速率高于油炸无大豆粉面团的油。油炸前后玉米油中均未检测到PL。随着油的反复油炸，由于油的氧化，油炸油中的FFA、CDA和极性化合物含量以及PAV增加。在油炸添加大豆粉面团的油中这些值高于油炸无大豆粉面团的油，这表明添加到面团中的大豆粉加速了油的氧化。添加到面团中的大豆粉导致油氧化增加与油中生育酚的快速分解高度相关。
