Effect of carvacrol on the oxidative stability of palm oil during frying

Abstract

SUMMARY:Fats and oils deteriorate physically and chemically at frying temperatures due to several reasons. The objective of this study was to assess the effect of carvacrol on the oxidative stability of palm oil during a repeated frying process. Potatoes were serially fried in carvacrol-added palm oil, BHT-added palm oil and a control oil (without any antioxidants). After each tenth frying cycle, several chemical analyses were carried out on collected samples to evaluate deterioration in the oils. The free fatty acid, para-anisidine, iodine, and total polar component values of the fresh oil were 0.080, 2.85, 57.1 and 7.5, respectively. These values changed to 0. 165, 11.80, 46.7, 11.0, respectively for the control oil; 0.151, 11.28, 49.2 and 10.5 for 0.140, 7.19, 51.7, 10.0 for carvacrol-added oil after 40 frying cycles. The results revealed that the use of carvacrol could significantly improve the oxidative stability of palm oil when compared to the control samples. This effect was also comparable to BHT. Using carvacrol in frying oil slowed down the rate of the formation of conjugated dienes and trienes compared to the oil with BHT and the control. The frying process significantly changed the viscosity of the oil samples. KEYWORDS:Carvacrol; Frying; Natural antioxidant; Oxidative stability; Palm oil RESUMEN: Efecto del carvacrol en la estabilidad oxidativa del aceite de palma durante la fritura. Las grasas y aceites se deterioran física y químicamente a las temperaturas de fritura debido a diferentes razones. El objetivo de este estudio fue evaluar el efecto del carvacrol en la estabilidad oxidativa del aceite de palma durante el proceso de fritura repetida. Se sometió a fritura repetida patatas en el aceite de palma con carvacrol agregado, en aceite de palma con BHT agregado y en aceite control (sin antioxidante). Después de cada décimo ciclo de fritura, se realizaron diferentes análisis sobre las muestras recogidas para evaluar el deterioro de los aceites. Ácidos grasos libre, para-anisidina, índice de yodo y componentes polares totales del aceite fresco fueron: 0,080, 2,85, 57,1 y 7,5, respectivamente. Estos valores cambian a 0.165, 11.80, 46.7 y 11.0, respectivamente, para el aceite de control; 0.151, 11.28, 49.2 y 10.5 para el aceite con BHT añadido; 0.140, 7.19, 51.7 y 10.0 para el aceite con carvacrol añadido después de 40 frituras. Los resultados revelaron que el uso de carvacrol puede mejorar significativamente la estabilidad oxidativa del aceite de palma en comparación con las muestras control. Este efecto también era comparable a la del BHT. El uso de carvacrol en el aceite de fritura ralentizó la velocidad de formación de dienos y trienos conjugados en comparación con el aceite con BHT y el de control. Los procesos de fritura producen grandes cambios en la viscosidad de las muestras de aceite.

Effect of <em>Thymus vulgaris</em> and <em>Bunium persicum</em> essential oils on the oxidative stability of virgin olive oil

“…For instance, a report claims that Carumcopticum EO (0.075%) is more effective than BHA and BHT (0.02%) in retarding the oxidation of sunflower oil (Hashemi et al, 2014). Furthermore, Inanc and Maskan (2014) reported that carvacrol can significantly improve the oxidative stability of palm oil in comparison with the control sample. Also, the antioxidant activity of carvacrol is known to be similar to that of BHT.…”