Obtaining functional powder tea from Brazilian ginseng roots: Effects of freeze and spray drying processes on chemical and nutritional quality, morphological and redispersion properties

Abstract

In this work, the aqueous extract obtained from Brazilian ginseng (Pfaffia glomerata) roots (BGR), rich in beta-ecdysone and fructooligosaccharides (FOS), was powdered by spray drying and freeze drying techniques aiming to obtain a novel functional food product. The effects of these drying techniques on the chemical and nutritional quality, morphological and redispersion properties of the BGR powders were evaluated. The BGR powders obtained by both spray drying and freeze drying techniques maintained their beta-ecdysone and FOS contents after drying, demonstrating the stability of these functional compounds. It was found that the wettability of the powders obtained by different treatments was affected by the drying technique because freeze-dried particles reached the lower values (66 ± 5 s) while spray-dried particles showed a greater time for dispersion into water (150 ± 25 s). This behavior was mainly associated with differences between powder morphological properties since the freeze-dried particles presented a more porous structure, resulting in a greater water diffusivity into microstructure during the redispersion process. Drying process did not affect the storage stability of powders because the glass transition temperature (Tg) for both samples was approximately 160 °C at a relative humidity of 56%. Thus, both BGR powders presented adequate redispersion properties to constitute a new functional tea or even to be used as a functional ingredient in food products.