Effect of Feed Material Properties on Microencapsulation by Spray Drying with a Three-Fluid Nozzle: Soybean Oil Encapsulated in Maltodextrin and Sugar Beet Pectin

Abstract

The relationship between the properties of wall material and spray-dried microcapsules was investigated. Soybean oil was encapsulated with various concentrations of maltodextrin (10 and 20% w/w) and sugar beet pectin (0.5, 1, 2, 3, and 4% w/w) solution via spray drying with a three-fluid nozzle (3FN). The rheological properties of the wall material solution were characterized using a controlled strain rheometer before spray drying and were found to fit the power-law model. The rheological properties of a wall material within the range of the samples tested had a limited impact on the morphology of the microcapsules. Most spray-dried samples had a wrinkled surface with some microcapsules having a spherical shape with a hollow core. As the consistency index of the wall material solution increased, the particle size distribution of microcapsules became wider. The surface oil content of the microcapsules was between 1.3 and 3.4%, generally increasing as the consistency index of the wall material solution increased. The encapsulation efficiency (EE) was between 74.7 and 91.2%. When compared with the sample produced with a two-fluid nozzle (2FN), 3FN microcapsules were larger and had higher effective EE and higher oil loading than 2FN microcapsules. This study revealed that oil could be encapsulated by wall materials, without the preparation of an emulsion, with a 3FN, which will save time and energy for the encapsulation process.