ENZYME CHANGES IN ROUGH RICE DURING PARBOILING

The enzymes amylase, protease, phosphatase and beta-glucosidase in rou gh rice (paddy) were activated during the soaking step of parboiling. The extent of activation of these enzymes varied with the soaking dura tion and the parboiling methods adopted. Highest activities were obser ved in the cold soaking method followed by the double steaming and hou sehold methods. beta-Glucosidase activity was eliminated in the preste aming stage of the double steaming process. Hot soaking inactivated al l these enzymes. The steam in the parboiling process inactivated the e nzymes partly while the pressure parboiling process inactivated them t otally. Studies with purified enzymes also revealed the activation of enzymes during soaking. Enzyme activity contributes to the loss of sol ids during soaking and also to the characteristic odor of parboiled ri ce.