MICROBIOLOGICAL, SENSORIAL AND CHEMICAL QUALITY OF GAMMA IRRADIATED PISTACHIO NUT (PISTACIA VERA L.)

The present study investigated the effect of gamma irradiation and storage period on quality retention of raw pistachio nut. Var. Halebi. Kernel of the pistachio nuts were exposed to 1, 2 and 3 kGy of gamma irradiation. Irradiated and unirradiated nuts were kept at room temperature for 12 months. Used doses of irradiation significantly reduced the total bacterial plate counts (TBPCs) and total fungal counts up to undetectable level (less than 10 CFU g(-1)). Irradiation doses of 1, 2 and 3 kGy of gamma irradiation seem to be suitable for post-harvest sanitation and decontamination treatment, without significant changes in the sensorial properties (texture, odor, color and taste), chemical quality (free fatty acids and pH value) or in contents of moisture, proteins, sugars, lipid, and ash, with respect to the control samples. The highest used dose (3kGy) slightly decreased the fatty acid content and pH value, and treatment with higher doses (2 and 3 kGy) significantly increased the total volatile nitrogen TVN.