Physicochemical-Microbiological Studies on Irradiated Date Fruits with Studying Migration Monomers of Packages Materials

Abstract

Different food packaging materials (LDPE, HDPE colorless , PET and LDPE blue) were packaged with dates, and irradiated with γ-rays at 0.0, 1.0, 3.0 and 5.0 kGy. Physical, chemical analysis of Polyethylene low density LDPEblue layer and colorless-were used. Besides studying the changes of stored dates quality, which extend to nine months under room temperature (23-25°C, 70-75% RH%) and freezing (-3°C), no significant effects were observed in LDPE, as in the permeability of oxygen, carbon dioxide transmission rate and water vapor, or migration tests up to 20.0 kGy; whereas the differences were significant in the mechanical characters. Detection of free radicals using Electron Spin Resonance (ESR) proved presence of free radicals at high dose (20.0 kGy), then disappeared after three weeks. GC-MS analysis of polymers showed produce 18 compounds after irradiation processes, which are volatile or non-volatile compounds at the applied doses. The major constituent was din -butylphthalate, which was affected by irradiation. Its concentration was 98.33 % (control), and then decreased to 95.91%, 72.57% by 5.0 and 20.0 kGy, respectively. One of the Radiolytic Products (RPs) are more toxic as bis(2-ethylhexyl)phthalate (0.59%), as mentioned by WHO. Irradiation did not cause significant changes in date's quality, except the color; only more darkening in color during long storage was observed at room temperature, light color resulted at frozen storage. γ-rays eliminated insects completely and decreased the microbiological contamination in irradiated samples.