Equal portions of a Maillard-type browning mixture (0.2 M glucose+0.2 M glycine), heated at 100℃ for 12 hr, were extracted with the same amounts of eight solvents, respectively. The extracts were then dissolved in equal amounts of an edible soybean oil, and the resulting substrates and a portion of the soybean oil (Control) Were stored in an incubator kept at 45.0±1.0℃ for three weeks. Peroxide values and TBA values of
Control and the substrates were determined regularly during the storage period.
The POVs of Control and the substrates containing acetone, benzene, chloroform, ethanol, diethyl ether, methanol, methylene chloride, and petroleum ether extracts after 12 days of storage were respectively 60.0±3.6, 31.9±0.9, 37.6±2.2, 48.1±1.1, 11.9±1.3, 4.85±0.4, 11.5±1.0, 45.3±0.3, and 43.3±4.2 m. mole/kg oil. Tlie TBA values after 16 days of storage were respectively 0.28±0.02, 0.20±0.01, 0.21±0.01, 0.26±0.03, 0.16±0.02, 0.28±0.02, 0.17±0.01, 0.33±0.05, and 0.31±0.02.
The induction periods (arbitrarily taken as the time in hours for a substrate to reach a peroxide value of 30 m. mole/kg oil) of Control and the substrates were respectively 193, 280, 252, 220, 478, 229, 455, 217, and 214 hr.
The antioxidant activity of each extract estimated on the basis of the length of the induction periods was, in decreasing order, as follows; ethanol$gt;methanol$gt;acetone$gt;benzene$gt;diethyl ether$gt;chloroform, pertroleum ether, methylene chloride.
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