Due to the increasing production of food in the world with consequent increase of the production of waste, the importance of developing researches for its use is noticed. Thus, the interest in vegetable oils with bioactive compounds, such as the ones extracted from fruit seeds, is growing. Therefore, the present study aims to characterize the oils extracted from seeds of Hamlin, Natal, Pera-rio and Valencia orange varieties (Citrus sinensis), as to the levels of total carotenoids, total phenolic compounds, tocopherols and phytosterols, as well as to determine their antioxidant activity. The orange seed oils presented important content of total carotenoids (19.01 mg/kg), total phenolic compounds (4.43 g/kg), α-tocopherol (135.65 mg/kg) and phytosterols (1304.2 mg/kg). The antioxidant activity ranged from 56.0% (Natal) to 70.2% (Pera-rio). According to the results it is possible to conclude that the orange seed oils can be used as specialty oils in diet, since they contain considerable amounts of bioactive compounds and antioxidants.

This study aimed to characterize the seeds of oranges, varieties Hamlin, Natal, Pera-rio and Valencia, on the composition and physico-chemical properties of its oil through the determination of free fatty acids, peroxide value, refraction, iodine value, saponification value, unsaponifiable matter, oxidative stability and fatty acid profile. The results were submitted to analysis of variance and differences between the average results were tested at 5% probability by Tukey test. The orange seed oils showed high levels of lipids, about 40%, and showed a low degree of degradation, when analyzing the free fatty acids and peroxide value. It was found through the fatty acid profile and refraction and iodine indexes seed oil, Pera-rio orange was the most unsaturated. The seed oil, Valencia orange had a higher oxidative stability in Rancimat at 100℃.

PurposeThis research aims to evaluate the antioxidant potential of oregano extract (OE), as well as its isolated and synergistic effect when applied to soybean oil (SO) under thermal oxidation.Design/methodology/approachIn order to determine the antioxidant activity of oregano extract and its synergistic effect with tert‐butylhydroquinone (TBHQ), thermal oxidation was performed using the following treatments: SO, SO with 50 mg/kg of TBHQ, SO with 3,000 mg/kg of OE, and SO with 3,000 mg/kg of oregano extract and 50 mg/kg of TBHQ (mixture). The treatments underwent heating at 180°C for 20 hours, and analyses of oxidative stability, total polar compounds, tocopherols and fatty acids composition were performed. The results obtained were subjected to analysis of variance and Tukey test for averages at 5 percent, using the program ESTAT version 2.0.FindingsConsidering the results of antioxidant activity and total phenolic compounds, it was possible to verify that the ethanolic extract of oregano has presented antioxidant potential. Furthermore, considering the results obtained in the analyses of oxidative stability, polar compounds, tocopherols and fatty acids profile, it was possible to observe that the extract has prevented lipid oxidation when added to SO.Originality/valueThe study offers information on the use of natural antioxidants as an alternative to the use of synthetic antioxidants, which can be considered toxic.