Application of Taguchi orthogonal array design to optimize microencapsulation of zinc by spray-drying

Abstract

Zinc is an essential trace element for the body to maintain normal health and perform important functions. As zinc is not stored in the body, it needs to be replenished through our daily diet. Microencapsulation technique can be used to encapsulate the functional ingredient such as zinc by masking its metallic taste and enhancing its bioavailability. Among the microencapsulation techniques, spray-drying is the most economical and scalable method. Zinc was microencapsulated by spray-drying using maltodextrin, HI-CAP^® 100 and WPI along with gum Arabic as wall materials. The spray-drying conditions were optimized using Taguchi L₁₈ orthogonal array design using encapsulation efficiency and bulk density as response factors. The influence of wall materials, wall material to zinc ratio and inlet air temperature was evaluated. Microcapsules prepared with HI-CAP^® 100 in the ratio of 20:1 at 185°C showed maximum encapsulation efficiency, whereas microcapsules with HI-CAP^® 100 in the ratio of 10:1 at 185°C had maximum bulk density. The microencapsulated zinc powder had bulk density of 437.40-541.20 kg/m³ and encapsulation efficiency of 76.86-92.65%. Validation experiments confirmed that Taguchi orthogonal array design was successful in optimizing microencapsulation of zinc.  Microencapsulated zinc can be fortified in various delivery systems such as milk and milk products.