Effect of Treatment Process and Preservation Method on Shelf Life of Truffles: II. Non-Conventional Methods (Radiation)

摘要

Two varieties of local truffles namely (Zubide and Khlassi) were treated with acetic acid (pH = 3.6) and sodium oxalate (pH = 6.2) to eliminate the microbial flora from the surface. Seven doses of gamma radiation at the rate of 0,150,250, 500,1000,2500 and 3000 Gy were used to irradiate the truffles. In both the varieties, irradiated truffles, with or without prior treatment with acid and alkali and stored in refrigerator showed significantly longer shelf life than the control (un-irradiated samples)under the same conditions. However, pretreated samples stored in refrigerator showed comparatively longer shelf life than the control (un-treated samples). In general, the shelf life of truffles was longer under refrigeration as compared to storage at room temperature. Irradiated truffles stored at room temperature showed longer shelf life than the control only when pre-treated with acid and alkali. Without pre-treatment, shelf life of irradiated and un-irradiated truffles stored at room temperature (25 deg C) was similar except in truffles treated with 1000 and 2500 Gy which showed significantly longer shelf lives. Overall, the shelf life of truffles can be extend by the synergistic effects of pre-treatment with acid and alkali, mild radiation, and low storage temperature. Physical and chemical analysis showed that desert truffles are good source of food components.