POLYMERIZATION OF CALCIUM CASEINATES SOLUTIONS INDUCED BY GAMMA-IRRADIATION

Solutions of calcium caseinate (5%) combined with propylene glycol (PG ) or triethylene glycol(TEG) (0, 2.5% and 5%) and used for the develop ment of edible films and coatings, were irradiated at doses between 0 to 128 kGy. Solutions were chromatographed through toyopearl HW 55F re sin to observe the effect of irradiation on cross-link reactions. In u nirradiated calcium caseinate solutions, two peaks could be observed ( fractions 30 and 37) while samples irradiated at 64 kGy and 128 kGy sh owed one shifted peak at fraction 32 and 29 respectively. No effect of the plasticizers was observed. According to proteins standards of kno wed molecular weights, the molecular weight of calcium caseinate incre ased approximately 10 times when irradiated at 128 kGy and 5 times whe n irradiated at 64 kGy. The physico-chemical properties of bio-films p repared with the irradiated solutions, demonstrated that tensile stren gth at break increased with increase of irradiation dose. A maximum do se was obtained at 16 kGy.