Retention of aroma components in extractive drying of aqueous carbohydrate solutions

A new drying technique, extractive drying, has been studied experimentally. The retention of the components methanol, n‐propanol and n‐pentanol in extractive drying of a model liquid food was investigated. The model liquid food consisted of an aqueous solution of mixtures of dextrin and malto‐dextrin, to which the alcohols were added in low concentrations. As extraction liquid polyethylene glycol (PEG) 400 was used. The solution to be dried was dispersed in the PEG in the form of droplets. High losses of the alcohols were found when the feed droplets were distorted upon contact with the extraction liquid. This distortion does not occur when the viscosity of the feed solution is higher than approximately 150 cP. For such feed solutions, containing 40% water and on dry basis 25% dextrin and 75% malto‐dextrin, very high aroma retentions were found. The effects observed agree with the selective diffusion theory.