Thermographic studies of cocurrent and mixed flow spray drying of heat sensitive bioactive compounds

Publication date: Available online 30 September 2019Source: Journal of Food EngineeringAuthor(s): J.M. Obón, J.P. Luna-Abad, B. Bermejo, J.A. Fernández-LópezAbstractProduction of powders of heat sensitive bioactive compounds in a bench scale spray drier was studied under cocurrent and mixed flow pattern conditions using two inlet air temperatures of 200 and 120 °C. Two natural colorants (riboflavin-5-phosphate and red beet) and an enzyme (alpha-amylase), were selected for experimentation. Thermographic studies showed interesting asymmetric profiles of temperatures outside and inside of the drying chamber, because turbulent air flow conditions and thermal trajectories of atomized drops during its drying process were dependent on flow patterns. Powders of natural colorants maintained its color strength, and alpha-amylase powders retain more than 82.9% of its enzyme activity even at the highest air temperature of 200 °C and using mixed flow. This work concludes that spray drying under cocurrent and mixed-flow patterns of heat labile bioactive compounds is feasible, influencing drying yields and the properties of powders obtained.
Source: Journal of Food Engineering - Category: Food Science Source Type: research