Evaluation of the lard oxidative stability added with rosemary extract and rosemary essential oil

Resumo

The production of undesirable compounds from oxidative processes in oils and fats is a problem when it comes to extending shelf life or deep-fat frying foods. In this work the use of rosemary extract and rosemary essential oil in the lard submitted to thermoxidation was evaluated and compared with the synthetic antioxidant TBHQ.The extract obtained from solvent extraction and the rosemary essential oil were submitted to free radical analysis DPPH^•and ABTS^•+, total phenolic compounds and total flavonoids. The lard was divided into four treatments: lard (control), lard + 100 mg kg^-1TBHQ (L + TBHQ), lard + 100 mg kg^-1rosemary extract (L + RE) and lard + 100 mg kg^-1rosemary essential oil (L + REO). The treatments were submitted to thermoxidation at 180°C, where samples were taken off at intervals of 0, 5, 10, 15 and 20 hours. The samples were analyzed for free fatty acid content, peroxide index and conjugated dienes. The extract showed better antioxidant potential when compared to the essential oil (15.20 and 18.51 mg mL^-1for EC₅₀; 917.87 and 321.71 ?mol ET mL^-1, respectively). The analysis for total phenolics compounds and total flavonoids showed no statistical difference (99.55 and 80.88 mg EAG L^-1; 29.79 and 31.42 ?g ER mL^-1, respectively). During the analysis of the thermoxidated lard, the rosemary essential oil showed results as favorable as those obtained by the antioxidant TBHQ, showing that the antioxidants from natural source can be a good alternative to synthetics ones.