Pyrodextrin powder production from sorghum beer residue: optimisation of spray drying parameters for improved conservation properties

Abstract

Pyrodextrins are polysaccharides with the potential to be used as food additives,standing out for their nutritional interest associated with their behaviour as solubledietary fiber. Being isolated from a gluten-free cereal, it is possible to add them toproducts suitable for individuals with coeliac disease. In the present study, the impactof the spray drying process of sorghum pyrodextrins obtained by pyroconversion ofbeer mashing residues, is investigated. The operating conditions for laboratory-scaledrying are optimised to produce a stable powdered material for storage. The responsesurface methodology was used for different drying air inlet temperatures (150-250 °C),feed flow rates (20-80%) and drying airflow rates (20-80%). To characterize the spraydriedsorghum pyrodextrins, their water activity, moisture content, color, particle sizedistribution and glass transition temperature were analyzed. It was verified that theoperational variables evaluated had an impact on the characteristic parameters ofsorghum pyrodextrin powders. The optimal drying conditions determined a drying airtemperature of 181,9 °C, feed flow rate at 23% and drying airflow rate at 78%, allowingpowders with stability suitable for conservation to be obtained. The utilization of asubstantial waste from another process enhances efficiency and contributes tosustainability.