Microencapsulation of roselle (Hibiscus sabdariffa L.) anthocyanins: Effects of maltodextrin and trehalose matrix on selected physicochemical properties and antioxidant activities of spray-dried powder

Abstract

This research was conducted to improve the stability of roselle anthocyanins by spray-drying using a single matrix (maltodextrin) and a binary matrix (maltodextrin-trehalose = 1:1). Each matrix was added to the core material at three different ratios: 30:70, 40:60, and 50:50. The physicochemical characteristics and antioxidant activity of microencapsulated powders were compared. The process using a single matrix with a 50:50 maltodextrin-to-extract ratio (MD-3) was identified as optimal. Spray-drying yield of MD-3 was 73.6 %, significantly higher (P < 0.05) than the other formulas. Encapsulation efficiency of MD-3 was 50.28 % and the powders was light red with a non-sticky texture, 2.5 % moisture content, and its red color was stable at pH 2.6–5. Average particle size of MD-3 was 4.48 μm with homogeneous distribution (PDI = 0.41400), spherical and amorphous particles. In the DPPH scavenging method, MD-3 powders exhibited antioxidant activity with an IC50 of 3397.55 μg/mL. Although the addition of trehalose to maltodextrin in the binary matrix did not produce better physicochemical characteristics, it significantly (P < 0.05) improved encapsulation efficiency (66.65–76.53 %). Therefore, further exploration is necessary to determine the appropriate maltodextrin-to-trehalose ratio in microencapsulating roselle extract. These findings enable further industrial application of different matrices to encapsulate anthocyanin as well as other bioactive compounds.

Keywords

• Maltodextrin matrix
• Microencapsulation
• Natural colorant
• Roselle anthocyanins
• Spray-drying
• Trehalose matrix