BACKGROUND: Oxidation of lipids results in changes that may affect the nutritional quality, wholesomeness, colour, flavour and texture of food. Canola oil is prone to oxidation because of high unsaturated fatty acids. Using synthetic antioxidant due to the possibility of toxic and carcinogenic effects is limited. Thus, it is important to research on replacing synthetic antioxidants by natural antioxidant. Objectives: The aim of this research was identification of the chemical compounds of Carum copticum essential oils (CEOs) and investigation of antioxidant and antiradical properties by using Diphenylpicrylhydrazyl (DPPH) method and β-carotene/linoleic acid system and assaying its antioxidant capacity in canola oil. Methods: Carum copticum essential oil was analyzed by GC/MS. Anti-radical activity of (CEOs) was investigated by using various methods and then antioxidant  was tested by measuring the peroxide value and thiobarbituric acid of canola oil samples containing different concentrations of C. copticum essential oil and synthetic antioxidant(BHT). Results: Results showed that thymol (36.4%), γ-terpinene (21.73%) and ρ-cymene (31.3%) were the major compositions of essential oil. IC50 value of (CEOs) was 21± 0.2  µg/ml. In both systems, the sequence of the power of antioxidant activity was BHT then C. copticum essential oil. In addition, by increasing the concentrations, their antioxidant activities were increased. Statistical results revealed C. Copticum essential oil at concentration of 400 ppm (P>0.05). Conclusions: Carum copticum essential oil is a potent antioxidant for stabilization of canola oil and can be used as a natural antioxidant. It seems that after complementary test it can be used as natural antioxidant in foodstuff, especially in edible oils.

Foram utilizadas poedeiras, da linhagem Babcock, alimentadas com dietas contendo 20% de semente de linhaça, 6% óleo de canola ou combinação entre eles (10% de semente e 3% de óleo), suplementadas com 0, 100 e 200 UI de vitamina E por quilo de ração. Analisaram-se os teores de gorduras saturadas, insaturadas e poliinsaturadas da gema, a incorporação de alfa-tocoferol, assim como o desempenho produtivo e a qualidade da casca dos ovos. Poedeiras alimentadas com dieta contendo 20% de semente de linhaça mostraram significativa piora na conversão alimentar, redução no peso do ovo, na produção de ovos, na espessura e peso da casca do ovo. A inclusão de semente de linhaça na dieta aumentou a incorporação de ácidos graxos poliinsaturados e diminuiu a de ácidos graxos monosaturados na gema do ovo. A concentração de alfa-tocoferol na gema foi diretamente proporcional aos seus teores na ração (R²=0,9613). Os grupos alimentados com 6% de óleo de canola obtiveram maiores concentrações de alfa-tocoferol na gema que os demais. | To investigate the effect of dietary sources of polyunsaturated fatty acids - canola oil (6%), flaxseed (20%) or the combination of both (3% canola oil and 10% flaxseed), and vitamin E supplementation (0,100 e 200 IU/kg of diet) upon the fatty acids and alpha-tocopherol deposition into the eggs, 288 Babcock laying hens were used for a 11 week experimental period. Hens fed 20% flaxseed diet showed a significant reduction of egg weight, feed efficiency, egg production, eggshell thickness and eggshell weight. The inclusion of flaxseed in the diet increased the polyunsaturated fatty acids, depressed monounsaturated fatty acids incorporated into the egg yolk, and increased the ratio P/S (polyunsaturated:saturated fatty acids). Yolk alpha-tocopherol concentration was proportional to its content in the diet (R²=0.9613). Birds fed diets with 6% of canola oil had greater alpha-tocopherol deposition into the eggs.