Fluidized bed drying of dairy gel granules supported by in-line monitoring of the water content

Abstract

New flexibility in cheese processing is gained with this work, by producing a storable intermediate via drying of dairy gel granules. The granules tend to agglomerate without agitation and oil-out or transition from gel to sol at high temperatures. A fast drying is necessary to ensure quality, shelf life, and rehydration. Due to its high heat transfer and homogenous mixing fluidized bed drying was selected. However, the large and dense granules are a highly challenging product for fluidized bed drying. Consequently, two different in-line measurement techniques were installed and calibrated for monitoring the water content of the samples. A design of experiments with varying temperatures and volume flows was performed and different granule properties were optimized as responses. A capacitive and a near-infrared sensor were successfully calibrated to the water content for in-line monitoring as a first step to a smart and dynamic drying process.