ACTIVITY OF HYDROLASE AND OXIDOREDUCTASE ENZYMES IN SOME FOODS TREATED WITH"( RAYS

Abstract

It was aimed throught the scope of the study to look forward about the effect of irradiation on the velocity of oxidoreductase and hydrolase enzymes in some food stuffs. The investigated enzymes namely polyphenolase and peroxidase representing the former group, while the pectin methyl esterase was chosen to represent the latter one. Food stuffs that being under test within the research at hand were: mango fruits, potato tubers, onion, garlic bulbs and pistachio nuts. These aforementioned samples were treated with specific irradiation doses and stored for different periods according to the following model: ** Mango fruits; were treated with 500, 1000, 1500, 2000, 2500 and 5000 Gy. Storage was performed for three weeks at 20 ± 2°C. ** Potato tubers, onion, and garlic samples; were irradiated with 160, 200, 250, 300, 1000 and 5000 Gy. Storage was achieved at 20 ± 2°C.for the following corresponding periods 20 weeks, 6 and 8 months. ** Pistachio nuts were treated with 250, 500 and 2000 Gy and stored for 6 months under similar storage condition. The velocity of the three enzymes; i.e. polyphenoloxidase, peroxidase and pectin methyl esterase were measured in each of the studied food stuffs within a different substrate and enzyme concentrations. Kinetic aspects of the same enzyme in terms ofKm, Vmax, slope of activity, angle of activity, pseudo value and catalytic affinity were considered for individual samples withdrawn during the aforementioned storage periods. Moreover, fatty and