Quality characteristics and microbiological safety evaluation of oils extracted from gamma irradiated almond (Prunus dulcis 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.