4TH International Congress on Technology - Engineering & SCIENCE - Kuala Lumpur - Malaysia (2017-08-05)

A Study Of Caking Behaviour Of Lactose Polymorphs Under Humid Conditions
This study deals with the caking behaviour of anhydrous lactose when stored controlled ambient conditions. It has been suggested that anhydrous lactose could undergo caking due to a phase transition to lactose monohydrate. Experiments were conducted on a home-made multi-cell caking device situated at controlled temperature and relative humidity as well as a separate controlled-humidity chamber. The effect of operating conditions (relative humidity, normal pressure, time and air flow rate) on the caking extent and the structural properties of resulting cakes were investigated. The results were interpreted based on intrinsic kinetics of phase transition established at different relative humidities. The physical properties of the cakes formed were investigated using a Shimadzu tensile testing machine. It was found that anhydrous lactose began to form hard cakes at ambient temperatures when exposed to air with a relative humidity in excess of 70%. This result was found in samples from both the caking device and the humidity chamber. At relative humidity values below this, the samples formed soft cakes which disintegrated when handled. Physiochemical analysis of the caked samples suggested that only a small amount of anhydrous lactose converted to lactose monohydrate which suggests that this is not the dominating caking mechanism.
Zahra Afrassiabian, Joseph Fussell, Khashayar SALEH