Effect of a herbal extract powder
In the manufacture of herbal medicinal tablets, dried plant extracts are employed as the therapeutic ingredient. These powders, usually obtained by spray drying, are typically hygroscopic and possess poor flow and compactability for the manufacture of tablets by direct compression (DC). Besides, spray-drying operating conditions and liquid feed composition are reported to be dependent on the herbal medicine. Consequently, the production of dried extracts implies long new product development times. Therefore, the goal of this paper was to: (a) provide recommendations as initial production point of fruit powder suitable for DC by spray drying and (b) study the powder properties to identify those that are affected by the extract nature. Particularly, a unique set of operating conditions was found to be appropriate to produce powders of seven different medicinal plant extracts. In fact, all the spray-dried products showed adequate flowability, stability and compactability.
Powders properties, as particle size and morphology, moisture content, hygroscopicity, flowability and compact hardness were not a function of the type of herb. Conversely, the process yield and glass transition temperature, particle and bulk densities, powder composition, compact porosity, wetting and disintegration times were found to be dependent on the chemical nature of the herbs.
Graphical abstract
A single set of spray-drying operating conditions and a unique liquid feed formulation are proposed to process different aqueous medicinal extracts in order to obtain powders with adequate flowability, stability and compactability.
Fermented plant extract (FPE) is a kind of plant functional food fermented by various microorganisms to make a beverage or other physical forms. To provide technical support for the industrial production of gynostemma extract powder, the quality characteristics of fermented plant extract prepared by hot air-drying, spray drying, vacuum microwave drying, and freeze-drying are compared for an FPE product. The effects of maltodextrin, soluble starch, and β-cyclodextrin as a drying agent on drying effect were studied. Results show that spray-dried FPE powder has the highest bulk density, the smallest average particle size, while the vegetable powder produced by freeze-drying has the best color and flavor, the highest content of key components including total sugar, soluble protein, vitamin C, total polyphenol content, and highest antioxidant capacity.