Role of -Relaxation and Glass Transition in Understandings Stickiness of Milk Solids

Stickiness of powder particles is often responsible for their impaired flow characteristics. Stickiness resulted from glass transition showing a relationship with mechanical -relaxations, and stickiness occurred differently in dairy solids modified in their lactose and protein contents. Glass transition, -relaxation and stickiness properties of milk solids systems were related to their solids composition and water plasticization. Lactose showed high magnitudes of mechanical -relaxations, which were less pronounced at the lower lactose contents. There was a correlation with the magnitudes of mechanical properties above the glass transition and the steepness of the increase of torque values at sticky-point temperature (STP). The results indicated that mechanical -relaxations were significant to understanding flow characteristics and the stickiness behavior of food solids. Stickiness can be reduced by mixing proteins to dairy solids. The present study provided useful information for the control of particle flow and powder stickiness in dairy and food powder industries.