International Journal of Agricultural Policy and Research Vol.1 (4), pp. 093-102, June 2013
© 2013 Journal Issues
Article ID JPR20, 10 pages
Original Research Paper
Legume phytases: Characteristics and changes in activity during germination
A.S.*Abdel-Gawad1 B.R.Ramadan1 and R.E.A.Oraby2
1Department of Food Science and Technology Faculty of Agriculture Assiut University. Assiut ,Egypt.
2Department of Food Science and Technology Faculty of Agriculture Sohag University. Sohag, Egypt.
Corresponding Author E-mail: firstname.lastname@example.org
Accepted 16 May, 2013
The activity of phytases from raw, soaked, and germinated Faba bean, lentil, kidney bean and pea were assayed followed by characterization of partial purified phytases from these legumes. The optimal pH value was 5.0 for lentil and pea and 5.2 for Faba bean and kidney bean. The optimal temperature of Faba bean, lentil and kidney bean was 50°C, while of pea it was 45°C. Both optimal pH and temperature of phytases of different legume seeds did not affected by soaking or germination processes. The maximal activity of phytase was found to be at 2.0 mM sodium phytate concentration from Faba bean, lentil and pea, and at 1.5 mM from kidney bean. The calculated Michael’s constant (Km) were 0.14, 0.18, 0.07 and 0.71 mM, and their corresponding Vmax values were 1.7, 1.7, 1.6 and 1.04 µM Pi of Faba bean, lentil, kidney bean and pea; respectively. The enzyme activity was decreased with extending the incubation time more than 1 hr for Faba bean, lentil and kidney bean, and more than 2 hrs for pea phytase. Calcium ions addition at concentration of 10-2 M caused increases in the phytase activity of kidney bean by 12 and pea 13%. The phytase activity of all studied legumes was diminished by addition of Fe-3, Fe-2 and Zn++ ions; however, these metal ions had variable effects on decreasing activity which was found to be depending on the added metal ion concentration. Faba bean and pea showed high increases in their phytase activity by 10.3 and 8.5- folds after 144-hrs germination, whereas lentil and kidney bean by 7.5 and 7.7-folds after 120-hrs germination, after that the enzyme activity decreased with prolonging time of germination.
Key words: phytase, activity, legume, seeds, soaking, germination,characterization