Encapsulation of soybean extract using spray drying

Abstract

Soybean (Glycine max L. Merrill) is recognized as a health food due to its many health-promoting bioactive compounds. Phenolic compounds are the main bioactive compounds in soybean because their antioxidant properties. Soybean extract is recommended as an ingredient of many pharmaceutical products. However, the rather poor solubility of soybean extracts and their proneness to degradation/oxidation during storage may reduce the nutritional value of the extracts. A convenient way to improve the solubility and extend the shelf-life of an extract is encapsulation. Among various encapsulation techniques, spray drying is the most widely and typically used technique. The objective of this work is to study the effects of encapsulation via spray drying on various properties of encapsulated soybean extract. The studied spray drying parameters are inlet drying temperature (130-170°C) as well as the type of encapsulating material (maltodextrin, gum arabic and β-cyclodextrin). The ratio between soybean extract and encapsulating material is 30:70. The properties to be analyzed are moisture content, total phenolic compounds content, encapsulation yield, encapsulation efficiency, hygroscopicity, particle size distribution and microstructure of encapsulated particles. The results showed that both type of wall material and inlet temperature significantly influenced the properties of soybean extract encapsulated powder. Gum arabic as the wall material and an inlet temperature of 170^oC, were the suitable conditions for encapsulation, produced the best encapsulated powder properties.