Effect of gamma radiation on the lipid profiles of soybean, peanut and sesame seed oils

Abstract

RESUMENEfecto de la radiación gamma sobre el perfil lipídico de los aceites de semillas de soja, cacahuete y sésamo Semillas de soja, cacahuete y de sésamo se expusieron a diferentes dosis de radiación gamma (0,0, 0,5, 1,0, 2,0, 3,0, 5,0 y 7,5 kGy). Se determinaron los perfiles de ácidos grasos y el insaponificable de los aceites mediante cromatografía de gases y espectrometría de masas. Los resultados demostraron que las relaciones de ácidos insaturados a ácidos grasos totales saturados (TU/TS) e hidrocarburos totales a esteroles (TH/TSt) se alteró significativamente tras la irradiación. Estos cambios se observaron claramente en el aceite extraído de las semillas de sésamo irradiados, en comparación con los aceites de soja y cacahuetes irradiados. El mayor cambio en la composición de ácidos grasos fue la disminución de la cantidad de ácidos grasos insaturados (C18:1 y C18:2) en todos los casos. En contraste, los niveles de las fracciones de esteroles como colesterol, campesterol, estigmasterol y β-sitosterol de las semillas irradiadas fueron en general más bajo que el de las semillas sin irradiados. PALABRAS CLAVE: Ácidos grasos -Esteroles -Hidrocarburos -Irradiación Gamma -Semillas oleaginosas. SUMMARY Effect of gamma radiation on the lipid profiles of soybean, peanut and sesame seed oilsSeeds of soybean, peanut, and sesame were exposed to various doses of gamma irradiation (0.0, 0.5, 1.0, 2.0, 3.0, 5.0 and 7.5 kGy). Fatty acid and unsaponifiable profiles of the extracted oils were separated by gas chromatography mass spectroscopy. The results demonstrated that the ratios of unsaturated to saturated total fatty acids (TU/TS) and total hydrocarbons to sterols (TH/TSt) were significantly altered upon irradiation. These changes were clearly observed in the oil extracted from irradiated sesame seeds compared with the oils from irradiated peanuts and soybean. The major change in fatty acid composition was the decrease in the quantity of unsaturated fatty acids (C18:1 and C18:2) in all cases. In contrast, the sterol fractions such as cholesterol, campesterol, stigmasterol and β-sitosterol levels of irradiated seeds were generally lower than that of the un-irradiated seeds.

Fatty Acid Contents of Gamma Irradiated Sesame (Sesamumindicum L.) Peanut (Arachishypogaea L.) and Sunflower (Helianthus annuus L.) Seeds

“…The present finding agrees with those obtained by Afify et al [7] on peanut seed treated with dose up to 7.5 kGy. Similar results were reported by Olotu et al [2] for fatty acid profile of African oil bean seeds treated with 10 kGy of gammairradiation.…”

“…The present findings agree with previous studies, where it was found that gamma-irradiation had some effects on the physical and chemical composition of soybeans [29]. In contrast to our results, the fatty acid linoleic C18:2 is considered to be the most affected one by gamma-radiation which was decreased by over 2% followed by oleic C18:1 when irradiated at 7.5 kGy [7]. Finally Al-Bachir, [11] indicated that, SFA and USFA of …”

“…Irradiation (7.5 kGy) caused a significant gradual decrease in the unsaturated fatty acid content increase as irradiation dose increased in sesame seeds [7,17]. In addition, UV-irradiation obviously destroyed the unsaturated fatty acids in peanut oil at various degrees, and their decreases were time dependent [22].…”

“…It is well known that free radicals are formed in food by ionizing irradiation, and the ratio of unsaturated to saturated total fatty acids (TU/TS) was significantly altered upon irradiation [7].…”

“…Gamma-irradiation has wide range of applications in food technology [7][8][9]. Irradiation causes molecular changes, among which the formation of free radicals is one of the most important for a high fat content foods that in turn can change the fatty acid composition and consequently the fat functional benefits [9][10][11][12][13].…”