FUNCTIONAL-PROPERTIES OF PROTEASE MODIFIED WHEAT FLOURS

The effect of enzymatic modification of wheat flour proteins on their functional properties was evaluated as a function of the degree of hyd rolysis (DH). Soluble protein increased from 7.1 to 53% for 0% to 36.7 % DH flour, and viscosity and yield values decreased concomitantly. Em ulsion capacity slightly decreased up to 14% DH and then increased. Ba ummann water and oil absorption capacities and farinograph water absor ption had similar trends; they showed a maximum increase at 3.8% DH wh ere Baumann and farinograph absorption values increased by 30%. Limite d degree of hydrolysis (3.8-14.1% DH) was sufficient to improve qualit y parameters of cakes such as volume, moisture and crumb colour Added protease resulted in pronounced reduction in molecular mass distributi on of wheat proteins, especially glutenins. The increase in water solu ble protein as hydrolysis proceeded was related to proteins of molecul ar mass less than 25 kDa. The reduction in viscosity and foam stabilit y was related to the extent of hydrolysis of high molecular mass glute nin protein. The increased Baumann and farinograph water absorption by limited hydrolysis up to 3.8-5.4% DH may be related to increased numb er of polar sites and flexibility of protein network, without extensiv e degradation of glutenins.