Quality characteristics and microbiological safety evaluation of oils extracted from gamma irradiated almond (<i>Prunus dulcis</i> Mill.) seeds

Abstract

The physicochemical attributes and microbial decontamination of oils extracted from gamma-irradiated almond (Mission and Price varieties) seeds, to the absorbed doses of 2-10 kGy, have been evaluated. Gamma irradiation exerted no considerable effect on the proximate seed composition. The physicochemical properties such as density and refractive index of the oils, extracted from gammairradieted seeds, were almost unaffected; the iodine value decreased while saponification value, unsaponifiable matter and free fatty acids increased. The oxidative status and tocopherol content of almond oils were negatively affected while the fatty acid profile slightly changed due to irradiation stress. Interestingly, these effects on the oil quality attributes were more pronounced at higher irradiation doses (> 6 kGy). Besides, microbial contamination was completely eliminated in the oils irradiated to an absorbed dose of 6.0 kGy. It could be concluded from the present findings that irradiation has a considerably positive or negative effect on some attributes of the almond oil. Therefore, an appropriate magnitude of gamma irradiation should be exercised to treat almond seeds in order to retain maximum nutritive benefits.<br><br>Se ha evaluado las caracteristicas fisico-químicas y la descontaminación microbiana de aceites extraídos de semillas de almendras (variedades Misión y Price) gamma-irradiadas a dosis absorbidas de 2-10 kGy. La radiación gamma no ejerce ningún efecto considerable en la composición próximal de las semillas. Las características fisico-químicas tales como la densidad y el índice de refracción de los aceites, extraídos a partir de semillas gamma-irradiadas, permanecieron casi sin afectar; el índice de yodo disminuye mientras que el valor de saponificación, la materia insaponificable y los ácidos grasos libres aumentan. El estado oxidativo y el contenido de tocoferoles de los aceites de almendra se vieron afectados negativamente, mientras que el perfil de ácidos grasos se modifica ligeramente debido al estrés de la radiación. Curiosamente, los efectos sobre los atributos de calidad del aceite fueron más pronunciados a dosis de radiación más altas (> 6 kGy). Además, la contaminación microbiana se eliminó por completo en los aceites irradiados a una dosis absorbida de 6,0 kGy. Se puede concluir a partir de los presentes hallazgos que la radiación tiene un efecto positivo o negativo considerable en algunos atributos de la aceite de almendras. Por lo tanto, se debe aplicar una magnitud apropiada de radiación gamma para el tratamiento de semillas de almendra con el fin de retener los máximos beneficios nutritivos

The deployment of γ-irradiation for reducing polycyclic aromatic hydrocarbons and microbial load in wheat kernels

“…The decrease in total aerobic mesophilic and mold population as a result of irradiation was in agreement with other studies (Bhatti et al 2013). Similar results were also reported by Thomas et al (2008), who studied colony formation in black tea irradiated with up to 10 kGy absorbed dose.…”

“…The increasing free fatty acids in wheat kernels may be attributed to the degradation of large lipid molecules producing smaller molecules including free fatty acids. The increase in acidity due to irradiation might be due to slight and random hydrolysis of triglycerol molecules to free fatty acids and diacylglycerols (Al-Bachir 2004;Bhatti et al 2013).…”

Effect of gamma radiation on storability and functional properties of sorghum grains (Sorghum bicolor L.)

“…Thus, several physical alternative methods have been suggested for postharvest pest control. Among these alternative methods, low doses of gamma radiation method has advantages in inhibiting the microbial growth in food (Iqbal, ; Bhatti, Iqbal, Anwar, Shanid, & Shahid, ; Mbarki, Sadok, & Barkallah, ), remove the toxicity from textile effluents (Iqbal & Nisar, ), enhancing the germination and seedling growth of seeds (Hussain et al., ), and enhanced its shelf life (Brewer, ). Furthermore, gamma radiation up to 6 kGy maintained the oil characteristics of almond (Bhatti et al., ).…”

Effects of gamma irradiation treatments and storage durations on fatty acid composition of natural hazelnut kernels

“…Irradiation treatments were applied to several nuts and most of them reported that irradiation treatments did not influence fatty acid composition (Lozoya, 2006;Sanchez-Bel et al, 2008;Bhatti et al, 2010;Antonio et al, 2012a;Di Stefano et al, 2014). On the other hand, irradiation stress may result in slight changes in fatty acid profile (Bhatti et al, 2013). There are some previous studies reporting decreasing mono and total unsaturated fatty acids and increasing total saturated fatty acids with increasing irradiation doses (Mexis and Kontominas, 2009b;Geçgel et al, 2011).…”