Stability Testing of Spray- and Spouted Bed–Dried Extracts of Passiflora alata

The aim of this research was to perform a stability testing of spray- and spouted bed–dried extracts of Passiflora alata Dryander (Passion flower) under stress storage conditions. Spouted bed– and spray-dried extracts were characterized by determination of the average particle diameter (d P ), apparent moisture content (X P ), total flavonoid content (T F ), and vitexin content. Smaller and more irregular particles were generated by the spouted bed system due to a higher attrition rate (surface erosion) inside the dryer. The SB dryer resulted in an end product with higher concentration of flavonoids (≈10%) and lower moisture content (1.6%, dry basis) than the spray dryer, even with both dryers working at similar inlet drying air temperature and ratio between the extract feed flow rate to drying air flow rate (W s /W g ). Samples of the spouted bed– and spray-dried extracts were stored at two different temperatures (34 and 45°C) and two different relative humidities (52 and 63% RH for 34°C; 52 and 60% RH f...