During packaging process of food-powders, the level of residual oxygen is of great importance with regard to the shelf life of the packed product. To reduce the residual oxygen, embedded inside the powders, mechanical effort and a huge amount of shielding gas is required. The aim of the experiments presented in this work, is to examine the effects of different kinds of gas injection methods through the screw-conveyor using different injection positions. Five injection methods were used to compare the effects on different particle sizes as well as the impact of the injected gas volume on the residual oxygen level.