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 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 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 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.
Nature has always been, and still is, a source of foods and ingredients that are beneficial to human health. Nowadays, plant extracts are increasingly becoming important additives in the food industry due to their antimicrobial and antioxidant activities that delay the development of off-flavors and improve the shelf life and color stability of food products. Due to their natural origin, they are excellent candidates to replace synthetic compounds, which are generally considered to have toxicological and carcinogenic effects. The efficient extraction of these compounds from their natural sources, along with the determination of their activity in the commercialized products, have been great challenges for researchers and food chain contributors to develop products with positive effects on human health. The objective of this Special Issue is to highlight the existing evidence regarding the various potential benefits of the consumption of plant extracts and plant extract-based products, with emphasis on in vivo works and epidemiological studies, the application of plant extracts to improve shelf-life, the nutritional and health-related properties of foods, and the extraction techniques that can be used to obtain bioactive compounds from plant extracts.
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