EFFECT OF THYMUS DAENENSIS EXTRACT ON OXIDATION STABILITY AND FORMATION OF TRANS FATTY ACIDS IN FRIED PANJEREIE BREAD AND FRYING OIL

The effect of ethanolic Thymus daenensis extract (TE) incorporation, as a natural antioxidant, on oxidation stability as well as the formation of trans fatty acids in used frying oil in preparation of panjereie bread (Iranian traditional cookie) was investigated. The frying was done with a mixture of soybean and palm (1:1) edible oils contained (1, 2 and 3) % TE, in comparison to TBHQ (1 %), at180 degrees C for 1 hour. According to related results of acid value, peroxide value, conjugated diene value, anisidine value, and total polar compounds analysis; employing the TE or synthetic antioxidant could reduce the formation of oxidation compounds in frying oil in addition to fried panjereie bread. However, by elapsing of time, radical scavenging activity decreased for all samples, the lowest scavenging activity can be correlated to the samples containing 3 % TE. The slowest kinematic viscosity was observed in samples containing 3 % TE. However, the formation of trans fatty acids was increased by elapsing the frying time, the lowest amount of trans fatty acids was observed in prepared panjereie bread with oil containing 3 % TE. Moreover, TE of (1 and 2) % and TBHQ did not have significant difference (P<0.05). The TE can be used as a natural antioxidant to reduce the oxidation as well as formation of trans fatty acids in frying oils and fried products.