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Acceleration of the thermoxidation of oil by heme iron
Author(s) -
Artz William E.,
Osidacz Patricia C.,
Coscione Aline R.
Publication year - 2005
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/s11746-005-1112-3
Subject(s) - chemistry , heme , degradation (telecommunications) , organic chemistry , enzyme , telecommunications , computer science
Transition metals, including iron, occur naturally at significant concentrations in meat. Iron can be extracted from the food into the oil and potentially decrease the stability of the oil during frying by accelerating thermoxidation. The objective was to examine the thermoxidative stability of partially hydrogenated soybean oil after addition of heme iron. Heme iron (2.7 ppm) was added to the oil, and then oil samples were heated continuously at 160, 180, or 200°C for 72 h. Oil samples were removed for analysis every 12 h. The acid values, color, food oil sensor readings, and TAG polymer content of the heated oil samples were compared with oil samples containing no added iron that were held at the same temperatures. Generally, each oxidative index increased with (i) an increase in temperature, (ii) an increase in heating time, and/or (iii) the addition of iron. Generally, the extent of oxidation was greater for samples heated at 200°C than for oil samples heated at 160 or 180°C. The oil samples heated at 200°C reached the target polymer content of 20% after 27 h of heating. If heme iron accumulates in the oil, it will increase the rate of oxidation and thermal degradation and reduce the frying life of the oil.