Powder Properties and System Behavior during Spray Drying of Bauhinia forficata Link Extract

Abstract

This article presents a study of the effects of the spray-drying conditions on product properties and dryer performance during manufacture of dried extracts of Bauhinia forficata. The product properties (loss on drying of the dried extract, flavonoids degradation ratio, product size distribution, bulk and loose densities, powder morphology) and the equipment performance were determined as a function of the input parameters (dryer inlet temperature, ratio between the feed flow rate of the extract to the dryer evaporation capacity, and feed flow rate of the drying gas). Regression equations correlating powder characteristics and dryer behavior to input process parameters were obtained. The results demonstrate significant impact of the processing conditions on product properties and dryer performance. The loss on drying is a key property, since low values are demanded for the acceptance of the dried extract. In general, due to strict product specifications, the drying conditions that give an end product with the required quality are not associated with the optimal drying performance.

Keywords:

• Bauhinia forficata
• Dried extract
• Drying
• Herbal medicinal product
• Spray drying

ACKNOWLEDGEMENT

The authors thank the São Paulo State Research Support Foundation (FAPESP), for the fellowship to the first author and for financial support (Proc. 03/08317-1 and 01/10140-7).