FOOD SCIENCE ›› 2019, Vol. 40 ›› Issue (11): 42-48.doi: 10.7506/spkx1002-6630-20180504-042

• Basic Research • Previous Articles     Next Articles

Effects of Deep-Fat Frying Methods and Foodstuffs on Contents of 3-Monochloropropane-1,2-diol Esters and Glycidyl Esters in Frying Peanut Oil

LIU Yulan1, LIU Hailan1, HUANG Huina1, MA Yuxiang1, AN Jun2, WANG Manyi3   

  1. 1. School of Food Science and Technology, Henan University of Technology, Zhengzhou 450001, China; 2. COFCO Fortune Food Sales & Distribution Co. Ltd., Beijing 100020, China; 3. COFCO Nutrition & Health Research Institute Co. Ltd., Beijing 102209, China
  • Online:2019-06-15 Published:2019-06-28

Abstract: Different foodstuffs (deep-fried dough sticks, French fries, chicken wings, tofu and blank control) were subjected to different deep-fat frying methods: 32 h continuous frying and intermittent frying for a total of 15 h. Sampling was carried out during these processes for determination of the contents of polar components (PC), 3-monochloropropane-1,2-diol esters (3-MCPDE) and glycidyl esters (GEs) in the frying peanut oil. The purpose of this study was to investigate the effect of different frying methods and foodstuffs on the contents of 3-MCPDE and GE esters in the frying oil. The results showed that the content of 3-MCPDE in peanut oil when used for consecutive deep-fat frying of deep-fried dough sticks, French fries, chicken wings, tofu and blank control increased from an initial value of 0.84 to the maximum value of 2.08, 2.96, 17.45, 7.12 and 8.02 mg/kg after 12, 4, 12, 16 and 8 h, respectively, followed by a decrease afterwards, and the content of GEs increased from an initial level of 2.43 to 20.80, 7.20, 5.00, 2.10 and 66.34 mg/kg at the end of the 32 h frying period, respectively. When PC reached the national standard limit of 27%, the sum of 3-MCPDE and GEs in different frying oils followed the decreasing order of blank control (66.51 mg/kg) > deep-fried dough sticks (21.48 mg/kg) > tofu (12.93 mg/kg) > French fries (8.51 mg/kg) > chicken wings (6.60 mg/kg). The contents of 3-MCPDE in frying oils from French fries, chicken wings, tofu, deep-fried dough sticks and blank control increased to 9.96, 2.17, 4.60, 11.02 and 5.41 mg/kg over the first 3 h of intermittent frying, and were 3.51, 1.58, 12.88, 11.81 and 3.72 mg/kg, respectively at the end. The content of GEs increased from 2.43 to 46.47, 9.06, 9.00, 40.36 and 47.05 mg/kg over the 15 h intermittent frying period, respectively. After 15 h of intermittent frying, none of the five frying oils had a PC content exceeding the national standard limit, and the sum of 3-MCPDE and GEs was in the descending order of chicken wings (52.17 mg/kg) > blank control (50.87 mg/kg) > deep-fried dough sticks (49.98 mg/kg) > tofu (21.88 mg/kg) > French fries (10.64 mg/kg). The increase in the sum of 3-MCPDE, GEs and PC over the 32 h consecutive frying period was ranked in the decreasing order of blank control > deep-fried dough sticks > French fries > chicken wings > tofu, while that over the 15 h intermittent frying period in the decreasing order of chicken wings > deep-fried dough sticks > blank control > tofu > French fries. For each food stuff, the increase in the sum of 3-MCPDE, GEs and PC in the 16 h continuous frying oil was lower than that in the 15 h intermittent frying oil. In summary, the health risk of 3-MCPDE and GEs formed during deep-fat frying should be taken seriously.

Key words: frying methods, foodstuffs to be fried, 3-monochloropropane-1,2-diol esters, glycidyl esters, polar components

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